Aortic Coarctation

Practice Essentials

Aortic coarctation is a narrowing of the aorta most commonly found just distal to the origin of the left subclavian artery. The vascular malformation responsible for coarctation is a defect in the vessel media, giving rise to a prominent posterior infolding (the “posterior shelf”), which may extend around the entire circumference of the aorta.

Essential update: Risk factors associated with surgically repaired aortic coarctation

A review of 819 patients with isolated aortic coarctation who were treated surgically concluded that surgery should be performed early and patients followed for life because of the high risk of cardiovascular consequences.[1, 2] In this study, most patients received a simple or extended end-to-end anastomosis (n = 632); the remainder received patch angioplasty (n = 72), interposition grafts (n = 49), bypass grafts (n = 30), or subclavian flaps or other procedures (n = 35). Mean age at repair was 17.2 years; mean follow-up was 17.4 years.

Actuarial survival was 93.3% at 10 years, 86.4% at 20 years, and 73.5% at 30 years. Mean age at death was 34 years.[2] Older age at repair (>20 years) and preoperative hypertension were significantly associated with decreased survival. In all, 124 patients required a reoperation at some point, primarily for aortic valve replacement (n = 52) or another coarctation intervention (n = 53). Younger age at the time of repair and an end-to-end anastomosis were each independently associated with lower reintervention rates on the descending aorta (P

Compared with age- and gender-matched controls, patients who underwent surgery for aortic coarctation had significantly reduced long-term survival (P [2] Patients treated before the age of 5 years were at higher risk for reoperation, whereas those treated when they were older than 9 years had more residual hypertension.

Signs and symptoms

Symptoms of aortic coarctation may include the following:

Early life – Congestive heart failure, severe acidosis, or poor perfusion to the lower body.Beyond infancy – Usually none; however, hypertension, headache, nosebleed, leg cramps, muscle weakness, cold feet, or neurologic changes may be seen

The diagnosis of coarctation generally can be made on the basis of physical examination. Blood pressure differential and pulse delay are pathognomonic. The following physical findings may be noted:

Frequently normal physical appearance (except when coarctation compromises the origin of the left subclavian artery or in cases of XO Turner syndrome) Abnormal differences in upper- and lower-extremity arterial pulses and blood pressures; diminished and delayed pulses distal to obstruction Characteristic murmurs and sounds on auscultation (eg, continuous or late systolic murmur posteriorly over the thoracic spine, bilateral collateral arterial murmurs, aortic ejection sound, short midsystolic murmur, or early diastolic murmur of aortic regurgitation) Associated cardiac defects (eg, left-side obstructive or hypoplastic defects and ventricular septal defects, bicuspid aortic valve, aortic arch hypoplasia, and, rarely, various right-side cardiac obstructive lesions) Extracardiac vascular anomalies (eg, aberrant subclavian artery, berry aneurysms of the circle of Willis, development of large upper-to-lower collateral arteries, or hemangiomas) Extracardiac nonvascular anomalies (eg, head and neck, musculoskeletal, gastrointestinal, genitourinary, or respiratory)

See Presentation for more detail.

Diagnosis

No specific laboratory tests are necessary for coarctation of the aorta. Imaging studies that may be helpful include the following:

Chest radiography – Findings vary with the clinical presentation of the patientBarium esophagography – Classic “E sign,” representing compression from the dilated left subclavian artery and poststenotic dilatation of the descending aorta Echocardiography (2-dimensional echocardiography, pulsed-wave Doppler, and color flow mapping) – In older patients, surface echocardiography may not suffice, and magnetic resonance imaging (MRI), transesophageal echocardiography (TEE), or cardiac catheterization with angiogram may be necessary Fetal echocardiographyMRI – This test is sensitive but expensive, time-consuming, and not universally available; it is seldom used as a primary diagnostic tool

Other studies that may be useful are as follows:

Cardiac catheterizationElectrocardiography

See Workup for more detail.

Management

Medical treatment of neonates with severe aortic coarctation may include the following:

IntubationInfusion of prostaglandin E1 (PGE1) to open the ductus arteriosusCorrection of acidosisInotropic support to improve symptoms of congestive heart failure (CHF)

Medical treatment of less severe aortic coarctation beyond the neonatal period may include the following:

Administration of digoxin and diuretics for chronically increased afterload and signs of CHFPostponement of intervention (eg, surgery or balloon dilatation) until the patient is hemodynamically stable

At present, the following 3 specific indications exist for intervention:

Significant coarctation or recoarctation of the aorta with long-standing hypertension with or without symptomsHemodynamically significant aortic stenosisFemale patient contemplating pregnancy

The following surgical procedures have been performed to treat aortic coarctation:

Resection of the coarctation site and end-to-end anastomosis to repair coarctation (still the preferred surgical method)Patch aortoplastyLeft subclavian flap angioplastyBypass graft repair bridging the ascending and descending aorta

Catheter-based intervention is now the preferred therapy for recurrent coarctation when the anatomy permits and necessary skills are available. Its use in native or unoperated coarctation is less well established.

See Treatment and Medication for more detail.

NextBackground

Coarctation of the aorta is a narrowing of the aorta most commonly found just distal to the origin of the left subclavian artery. Most patients with coarctation have juxtaductal coarctation. Older terms, such as preductal (infantile-type) or postductal (adult-type), are often misleading.

ACC/AHA 2008 guidelines of coarctation of aorta in adults (adapted)

Recommendations for clinical evaluation and follow-up[3]

Class I recommendations are as follows:

Every patient with systemic arterial hypertension should have brachial and femoral pulses palpated simultaneously to assess timing and amplitude evaluation to search for the brachial-femoral delay of significant aortic coarctation. Supine bilateral arm (brachial artery) blood pressures and prone right or left supine (popliteal artery) blood pressures should be measured to search for differential pressure - level of evidence, C Initial imaging and hemodynamic evaluation by transthoracic echocardiogram, including suprasternal notch acoustic windows, is useful in suspected aortic coarctation - level of evidence, B Every patient with coarctation (repaired or not) should have at least one cardiovascular MRI or CT scan for complete evaluation of the thoracic aorta and intracranial vessels - level of evidence, B

Recommendations for interventional and surgical treatment

Class I recommendations are as follows:

Intervention for coarctation is recommended in the following circumstances: (1) Peak-to-peak coarctation gradient greater than equal to 20 mm Hg (level of evidence, C) and (2) Peak-to-peak coarctation gradient less than 20 mm Hg in the presence of anatomic imaging evidence of significant coarctation with radiological evidence of significant collateral flow (level of evidence, C) Choice of percutaneous catheter intervention versus surgical repair of native discrete coarctation should be determined by consultation with a team of adult congenital heart disease cardiologists, interventionalists, and surgeons at the adult congenital heart disease center - level of evidence, C Percutaneous catheter intervention is indicated for recurrent, discrete coarctation and a peak-to-peak gradient of 20 mm Hg - level of evidence, B Surgeons with training and expertise in congenital heart disease should perform operations for previously repaired coarctation and the following indications: (1) Long recoarctation segment (level of evidence, B) and (2) concomitant hypoplasia of the aortic arch (level of evidence, B)

Class IIb recommendation is as follows:

Stent placement for long-segment coarctation may be considered, but the usefulness is not well established and the long-term efficacy and safety are unknown - level of evidence, C

Recommendations for key issues for evaluation and follow-up

Class I recommendations are as follows:

Lifelong cardiology follow-up is recommended for all patients with aortic coarctation (repaired or not), including an evaluation by or consultation with a cardiologist with expertise in ACHD - level of evidence, C) Patients who have had surgical repair of coarctation at the aorta or percutaneous intervention for coarctation of the aorta should have at least yearly follow-up - level of evidence, C Even if the coarctation repair appears to be satisfactory, late postoperative thoracic aortic imaging should be performed to assess for aortic dilatation or aneurysm formation - level of evidence, B Patients should be observed closely for the appearance or reappearance of resting or exercise-induced systemic arterial hypertension, which should be treated aggressively after recoarctation is excluded - level of evidence, B Evaluation of the coarctation repair site by MRI/CT scan should be performed at intervals of 5 years or less, depending on the specific anatomic findings before and after repair - level of evidence, C

Class IIb recommendation is as follows:

Routine exercise testing may be performed at intervals determined by consultation with the regional ACHD center - level of evidence, C

For the full guidelines, see ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease.

PreviousNextPathophysiology

The vascular malformation responsible for coarctation is a defect in the vessel media, giving rise to a prominent posterior infolding (the "posterior shelf"), which may extend around the entire circumference of the aorta. The gross pathology of coarctation varies considerably. The lesion is often discrete but may be long, segmental, or tortuous in nature.

Histology

The coarctated aortic segment reveals an intimal and medial lesion consisting of thickened ridges that protrude posteriorly and laterally into the aortic lumen. The ductus (ie, patent embryonic remnant) or ligamentum arteriosus (closed and fibrosed) inserts at the same level anteromedially. Intimal proliferation and disruption of elastic tissue may occur distal to the coarctation. At this site, infective endarteritis, intimal dissections, or aneurysms may occur. Cystic medial necrosis occurs commonly in the aorta adjacent to the coarctation site and acts as a substrate for late aneurysm formation or aortic dissection in some patients.

Embryology

Coarctation is due to an abnormality in development of the embryologic left fourth and sixth aortic arches that can be explained by 2 theories, the ductus tissue theory and the hemodynamic theory.

In the ductus tissue theory, coarctation develops as the result of migration of ductus smooth muscle cells into the periductal aorta, with subsequent constriction and narrowing of the aortic lumen. Commonly, coarctation becomes clinically evident with closure of the ductus arteriosus. This theory does not explain all cases of coarctation. Clinically, coarctation may occur in the presence of a widely patent ductus arteriosus, and it may occur quite distant from the insertion of the ductus arteriosus, such as in the transverse arch or abdominal aorta.

In the hemodynamic theory, coarctation results from reduced volume of blood flow through the fetal aortic arch and isthmus. In a normal fetus, the aortic isthmus receives a relatively low volume of blood flow. Most of the flow to the descending aorta is derived from the right ventricle through the ductus arteriosus. The left ventricle supplies blood to the ascending aorta and brachiocephalic arteries, and a small portion goes to the aortic isthmus. The aortic isthmus diameter is 70-80% of the diameter of the neonatal ascending aorta.

Based on this theory, lesions that diminish the volume of left ventricular outflow in the fetus also decrease flow across the aortic isthmus and promote development of coarctation. This helps to explain the common lesions associated with coarctation, such as ventricular septal defect, bicuspid aortic valve, left ventricular outflow obstruction, and tubular hypoplasia of the transverse aortic arch. This theory does not explain isolated coarctation without associated intracardiac lesions.

PreviousNextFrequencyUnited States

This condition represents 5-10% of all congenital cardiac lesions. It represents 7% of critically ill infants with heart disease.

PreviousNextMortality/MorbidityPatients who are not treated for coarctation of the aorta may reach the age of 35 years; fewer than 20% survive to age 50 years. If coarctation is repaired before the age of 14 years, the 20-year survival rate is 91%. If coarctation is repaired after the age of 14 years, the 20-year survival rate is 79%. After repair of the aortic coarctation, 97-98% of patients are New York Heart Association (NYHA) class I. Impaired diastolic left ventricular function and persistent hypertrophy due to increased pressure gradient at the coarctation site during exercise may result in myocardial hypertrophy despite successful hemodynamic results. Overall, left ventricular systolic function is normal or hyperdynamic in these patients. Pregnancy: Most women reach childbearing age. If maternal coarctation is not repaired, the risk to fetus and mother is increased. The maternal mortality rate is approximately 3-8%. Even women who have had their coarctation repaired have an increased risk of aortic dissection and rupture of a cerebral aneurysm in the third trimester and peripartum period due to hemodynamic and hormonal changes. All pregnant women with a history of coarctation, either native or repaired, should be considered high risk. Significant stenosis—native, residual, or recurrent—is a contraindication to pregnancy. Race

Coarctation is 7 times more common in whites than Asian persons. It has a lower incidence among Native Americans than other population groups in Minnesota.

Sex

Male-to-female predominance is 1.3-2:1 in most series.

Age

Age at detection of coarctation of the aorta is dependent on severity of obstruction and coexistence of other lesions.

PreviousProceed to Clinical Presentation , Aortic Coarctation

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Emergent Management of Acute Aortic Dissection

Overview

Aortic dissection is the most common catastrophe of the aorta, 2-3 times more common than rupture of the abdominal aorta. When left untreated, about 33% of patients die within the first 24 hours, and 50% die within 48 hours. The 2-week mortality rate approaches 75% in patients with undiagnosed ascending aortic dissection.

The establishment of the International Registry of Acute Aortic Dissection in 1996, which gathers information from 24 centers in 11 countries, has helped in the development of an understanding of the complexity of aortic dissection.

Dissections of the thoracic aorta have been classified anatomically by 2 different methods. The more commonly used system is the Stanford classification, which is based on involvement of the ascending aorta and simplifies the DeBakey classification.

Go to Aortic Dissection for complete information on this topic.

Stanford classification

The Stanford classification divides dissections into 2 types, type A and type B. Type A involves the ascending aorta (DeBakey types I and II); type B does not (DeBakey type III).

This system helps to delineate treatment. Usually, type A dissections require surgery, while type B dissections may be managed medically under most conditions.

DeBakey classification

The DeBakey classification divides dissections into 3 types, as follows:

Type I involves the ascending aorta, aortic arch, and descending aortaType II is confined to the ascending aortaType III is confined to the descending aorta distal to the left subclavian artery

Type III dissections are further divided into IIIa and IIIb. Type IIIa refers to dissections that originate distal to the left subclavian artery but extend proximally and distally, mostly above the diaphragm.

Type IIIb refers to dissections that originate distal to the left subclavian artery, extend only distally, and may extend below the diaphragm.

Thoracic aortic dissections should be distinguished from aneurysms (ie, localized abnormal dilation of the aorta) and transections, which are caused most commonly by high-energy trauma.

NextPrehospital Care

Assure adequate breathing, maintain oxygenation, treat shock, and obtain useful historical information.

Establishing the diagnosis in the field is usually difficult or impossible, but certain salient features of aortic dissection may be observed. It is life threatening if not quickly recognized and treated.

Radio communication with the receiving hospital permits the medical control physician to direct care and select a capable destination hospital, while permitting the emergency department (ED) to mobilize appropriate resources.

In the rare event that the diagnosis can be made based on prehospital information, the physician directing prehospital care should request transport to a facility capable of operative treatment of an aortic dissection.

PreviousNextEmergency Department Care

The mortality rate of patients with aortic dissection is 1-2% per hour for the first 24-48 hours. Initial therapy should begin when the diagnosis is suspected. This includes 2 large-bore intravenous lines (IVs), oxygen, respiratory monitoring, and monitoring of cardiac rhythm, blood pressure, and urine output.

Clinically, the patient must be assessed frequently for hemodynamic compromise, mental status changes, neurologic or peripheral vascular changes, and development or progression of carotid, brachial, and femoral bruits.

Aggressive management of heart rate and blood pressure should be initiated.

Beta blockers should be given initially to reduce the rate of change of blood pressure (dP/dt) and the shear forces on the aortic wall.

The target heart rate should be 60-80 beats per minute.

The target systolic blood pressure should be 100-120 mm Hg.

End organ perfusion should be evaluated. Balancing the risks of dP/dt on the aortic wall versus the benefits of acceptable end organ perfusion may be a difficult clinical decision.

Retrograde cerebral perfusion may increase the protection of the central nervous system during the arrest period.

The mortality rate from aortic arch dissections is about 10-15%, with significant neurologic complications occurring in another 10% of patients. The mortality rate is influenced by the patient's clinical condition.

The American College of Radiology has established ACR Appropriateness Criteria for the diagnosis and treatment of suspected aortic dissection.[1]

Type A dissections

Urgent surgical intervention is required in type A dissections.

The area of the aorta with the intimal tear usually is resected and replaced with a Dacron graft.

The operative mortality rate is usually less than 10%, and serious complications are rare with ascending aortic dissections.

The development of more impermeable grafts, such as woven Dacron, collagen-impregnated Hemashield (Meadox Medicals, Oakland, NJ), aortic grafts, and gel-coated Carbo-Seal Ascending Aortic Prothesis (Sulzer CarboMedics, Austin, Tex), has greatly enhanced the surgical repair of thoracic aortic dissections.

With the introduction of profound hypothermic circulatory arrest and retrograde cerebral perfusion, the morbidity and mortality rates associated with this highly invasive surgery have decreased.

Dissections involving the arch are more complicated that those involving only the ascending aorta, because the innominate, carotid, and subclavian vessels branch from the arch. Deep hypothermic arrest usually is required. If the arrest time is less than 45 minutes, the incidence of central nervous system complications is less than 10%.

Aortic stent grafting is a challenging technique. It may prove feasible and has offered good results in a small series of patients. It may be a reasonable alternative in high-risk patients in the near future.

Type B dissections

The definitive treatment for type B dissections is less clear.

Uncomplicated distal dissections may be treated medically to control blood pressure. Distal dissections treated medically have a mortality rate that is the same as or lower than the mortality rate in patients who are treated surgically.

Surgery is reserved for distal dissections that are leaking, ruptured, or compromising blood flow to a vital organ.

Acute distal dissections in patients with Marfan syndrome usually are treated surgically.

Inability to control hypertension with medication is also an indication for surgery in patients with a distal thoracic aortic dissection.

Patients with a distal dissection are usually hypertensive, emphysematous, or older.

Long-term medical therapy involves a beta-adrenergic blocker combined with other antihypertensive medications. Avoid antihypertensives (eg, hydralazine, minoxidil) that produce a hyperdynamic response that would increase dP/dt (ie, alter the duration of P or T waves).

Survivors of surgical therapy also should receive beta-adrenergic blockers.

A series of patients with type B dissections demonstrated that aggressive use of distal perfusion, CSF drainage, and hypothermia with circulatory arrest improves early mortality and long-term survival rates.

Endovascular stenting remains an option for treatment of some type B dissections. Some studies recommend that patients with complicated acute type B dissections undergo endovascular stenting with the goal of covering the primary intimal tear.[2]

Definitive treatment

Definitive treatment involves segmental resection of the dissection, with interposition of a synthetic graft.

When thoracic dissections are associated with aortic valvular disease, replace the defective valve.

With combined reconstruction–valve replacement, the operative mortality rate is approximately 5%, with a late mortality rate of less than 10%.

Operative repair of the transverse aortic arch is technically difficult, with an operative mortality rate of 10% despite induction of hypothermic cardiocirculatory arrest.

Repair of the descending aorta is associated with a higher incidence of paraplegia than repair of other types of dissections because of interruption of segmental blood supply to the spinal cord.

The operative mortality rate is approximately 5%.

In a study by Mimoun et al of patients with Marfan syndrome who had acute aortic dissection, the patients were found to have a better event-free survival when there were no dissected portions of the aorta remaining after surgery.[3]

PreviousNextConsultations

Once a thoracic dissection is suspected, consult a thoracic surgeon. Because many patients with this disorder have concomitant medical illness, consult the patient's primary care provider to expedite preoperative preparation. Early consultation is encouraged when ordering further imaging studies if the patient requires rapid operative intervention.

Consult a radiologist prior to obtaining aortography.

PreviousNextInpatient Care

Patients with symptomatic dissection should undergo immediate repair, especially if it is leaking or expanding.

Symptomatic patients require admission to a center experienced in cardiopulmonary bypass and operative care.

Completely asymptomatic patients may have their repair performed electively but may require admission to expedite their evaluation or for preoperative stabilization of their condition.

Patients with chest pain should undergo serial echocardiograms (ECGs) and creatine kinase (CK) determinations if acute myocardial infarction (AMI) is indicated.

PreviousNextOutpatient Care

Follow-up examinations with radiologic studies are recommended at 3-month intervals for the first year and every 6 months for the next 2 years.

After this, follow up annually.

PreviousNextTransfer

Symptomatic patients require care at a facility equipped to perform cardiopulmonary bypass with aortic and/or valvular repair.

Contact the receiving physician as soon as possible to transfer patients before their condition deteriorates.

Early airway management is indicated in the presence of hemoptysis or stridor.

If coronary insufficiency is suspected, nitrates may be used, but therapy with thrombolytic agents and aspirin should be avoided.

Patients should be monitored and accompanied by personnel capable of resuscitation.

If a prolonged ground transport time is anticipated, consider air transport.

Previous, Emergent Management of Acute Aortic Dissection

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Thoracic Aortic Aneurysm

Background

Aneurysmal degeneration can occur anywhere in the human aorta. By definition, an aneurysm is a localized or diffuse dilation of an artery with a diameter at least 50% greater than the normal size of the artery.

A blood vessel has 3 layers: the intima (inner layer made of endothelial cells), media (contains muscular elastic fibers), and adventitia (outer connective tissue). Aneurysms are either true or false. The wall of a true aneurysm involves all 3 layers, and the aneurysm is contained inside the endothelium. The wall of a false or pseudoaneurysm only involves the outer layer and is contained by the adventitia. An aortic dissection is formed by an intimal tear and is contained by the media; hence, it has a true lumen and a false lumen.

Most aortic aneurysms (AA) occur in the abdominal aorta; these are termed abdominal aortic aneurysms (AAA). Although most abdominal aortic aneurysms are asymptomatic at the time of diagnosis, the most common complication remains life-threatening rupture with hemorrhage.

Aneurysmal degeneration that occurs in the thoracic aorta is termed a thoracic aneurysm (TA). Aneurysms that coexist in both segments of the aorta (thoracic and abdominal) are termed thoracoabdominal aneurysms (TAA). Thoracic aneurysms and thoracoabdominal aneurysms are also at risk for rupture. A recent population-based study suggests an increasing prevalence of thoracic aortic aneurysms. Thoracic aortic aneurysms are subdivided into 3 groups depending on location: ascending aortic, aortic arch, and descending thoracic aneurysms or thoracoabdominal aneurysms. Aneurysms that involve the ascending aorta may extend as proximally as the aortic annulus and as distally as the innominate artery, whereas descending thoracic aneurysms begin beyond the left subclavian artery. Arch aneurysms are as the name implies.

Dissection is another condition that may affect the thoracic aorta. An intimal tear causes separation of the walls of the aorta. A false passage for blood develops between the layers of the aorta. This false lumen may extend into branches of the aorta in the chest or abdomen, causing malperfusion, ischemia, or occlusion with resultant complications. The dissection can also progress proximally, to involve the aortic sinus, aortic valve, and coronary arteries. Dissection can lead to aneurysmal change and early or late rupture. A chronic dissection is one that is diagnosed more than 2 weeks after the onset of symptoms. Dissection should not be termed dissecting aneurysm because it can occur with or without aneurysmal enlargement of the aorta.

The shape of an aortic aneurysm is either saccular or fusiform. A fusiform (or true) aneurysm has a uniform shape with a symmetrical dilatation that involves the entire circumference of the aortic wall. A saccular aneurysm is a localized outpouching of the aortic wall, and it is the shape of a pseudoaneurysm.

Treatment of abdominal aortic aneurysms, thoracoabdominal aneurysms, and thoracic aneurysms involves surgical repair in good-risk patients with aneurysms that have reached a size sufficient to warrant repair. Surgical repair may involve endovascular stent grafting (in suitable candidates) or traditional open surgical repair.

NextHistory of the Procedure

The development of treatment modalities for thoracic aneurysms followed successful treatment of abdominal aortic aneurysms. Estes' 1950 report revealed that the 3-y survival rate for patients with untreated abdominal aortic aneurysms was only 50%, with two thirds of deaths resulting from aneurysmal rupture.[1] Since then, increased attempts were made to devise methods of durable repair.

Most of these initial successful repairs involved the use of preserved aortic allografts, thus triggering the establishment of numerous aortic allograft banks. Simultaneously, Gross and colleagues successfully used allografts to treat complex thoracic aortic coarctations, including those with aneurysmal involvement.[2]

In 1951, Lam and Aram reported the resection of a descending thoracic aneurysm with allograft replacement.[3] Ascending aortic replacement required the development of cardiopulmonary bypass and was first performed in 1956 by Cooley and DeBakey.[4] They successfully replaced the ascending aorta with an aortic allograft. Successful replacement of the aortic arch, with its inherent risk of cerebral ischemia, was understandably more challenging and was not reported until 1957 by DeBakey et al.[5]

Although the use of aortic allografts as aortic replacement was widely accepted in the early 1950s, the search for synthetic substitutes was well underway. Dacron was introduced by DeBakey. By 1955, Deterling and Bhonslay believed that Dacron was the best material for aortic substitution.[6] Numerous types of intricately woven hemostatic grafts have since been developed and are now used much more extensively than their allograft counterparts. Such Dacron grafts are used to replace ascending, arch, thoracic, and thoracoabdominal aortic segments.

However, some patients required replacement of the aortic root, as well. Subsequently, combined operations that replaced the ascending aneurysm in conjunction with replacement of the aortic valve and reimplantation of the coronary arteries were performed by Bentall and De Bono in 1968, using a mechanical valve with a Dacron conduit.[7] Ross, in 1962, and Barratt-Boyes, in 1964, successfully implanted the aortic homograft in the orthotopic position.[8, 9] In 1985, Sievers reported the use of stentless porcine aortic roots.[10]

More recently, less invasive therapy for descending thoracic aortic aneurysm have been developed. Dake et al reported the first endovascular thoracic aortic repair in 1994.[11] In March 2005, the US Food and Drug Administration (FDA) approved the first thoracic aortic stent graft, the GORE TAG graft (W.L. Gore and Associates; Flagstaff, AZ).[12] Since 2005, 2 other devices have gained FDA approval: the Talent Thoracic endograft (Medtronic; Santa Rosa, CA) and the Cook TX2 endograft (Cook; Bloomington, IN). Several successive next-generation reiterations of all of these devices have also gained approval.

Given the relative acceptance of the indications for thoracic endografts as an alternative to open procedures in the treatment of uncomplicated diseases of the descending thoracic aorta, experienced users of the devices now use them "off-label" in increasingly more complex indications, including use via "hybrid-procedures" in the ascending aorta and aortic arch. However, little long-term data are available at this time to support use in this fashion.

PreviousNextProblem

Aneurysms are usually defined as a localized dilation of an arterial segment greater that 50% its normal diameter. Most aortic aneurysms occur in the infrarenal segment (95%). The average size for an infrarenal aorta is 2 cm; therefore, abdominal aortic aneurysms are usually defined by diameters greater than 3 cm.

The normal size for the thoracic and thoracoabdominal aorta is larger than that of the infrarenal aorta, and aneurysmal degeneration in these areas is defined accordingly. The average diameter of the mid-descending thoracic aorta is 26-28 mm, compared with 20-23 mm at the level of the celiac axis.

PreviousNextEpidemiologyFrequency

Although findings from autopsy series vary widely, the prevalence of aortic aneurysms probably exceeds 3-4% in individuals older than 65 years.

Death from aneurysmal rupture is one of the 15 leading causes of death in most series. The estimated incidence of thoracic aortic aneurysms is 6 cases per 100,000 person-years. In addition, the overall prevalence of aortic aneurysms has increased significantly in the last 30 years. This is partly due to an increase in diagnosis based on the widespread use of imaging techniques. However, the prevalence of fatal and nonfatal rupture has also increased, suggesting a true increase in prevalence. Population-based studies suggest an incidence of acute aortic dissection of 3.5 per 100,000 persons; an incidence of thoracic aortic rupture of 3.5 per 100,000 persons; and an incidence of abdominal aortic rupture of 9 per 100,000 persons. An aging population probably plays a significant role.

PreviousNextEtiology

Aneurysmal degeneration occurs more commonly in the aging population. Aging results in changes in collagen and elastin, which lead to weakening of the aortic wall and aneurysmal dilation. According to the law of Laplace, luminal dilation results in increased wall tension and the vicious cycle of progressive dilation and greater wall stress. Pathologic sequelae of the aging aorta include elastic fiber fragmentation and cystic medial necrosis. Arteriosclerotic (degenerative) disease is the most common cause of thoracic aneurysms.

A previous aortic dissection with a persistent false channel may produce aneurysmal dilation; such aneurysms are the second most common type. False aneurysms are more common in the descending aorta and arise from the extravasation of blood into a tenuous pocket contained by the aortic adventitia. Because of increasing wall stress, false aneurysms tend to enlarge over time.

Authorities strongly agree that genetics play a role in the formation of aortic aneurysms. Of first-degree relatives of patients with aortic aneurysms, 15% have an aneurysm. This appears especially true in first-degree relatives of female patients with aortic aneurysms. Thus, inherited disorders of connective tissue appear to contribute to the formation of aortic aneurysms.

Marfan syndrome is a potentially lethal connective-tissue disease characterized by skeletal, heart valve, and ocular abnormalities. Individuals with this disease are at risk for aneurysmal degeneration, especially in the thoracic aorta. Marfan syndrome is an autosomal dominant genetic condition that results in abnormal fibrillin, a structural protein found in the human aorta. Patients with Marfan syndrome may develop annuloaortic ectasia of the sinuses of Valsalva, commonly associated with aortic valvular insufficiency and aneurysmal dilation of the ascending aorta.

Type IV Ehlers-Danlos syndrome results in a deficiency in the production of type III collagen, and individuals with this disease may develop aneurysms in any portion of the aorta. Imbalances in the synthesis and degradation of structural proteins of the aorta have also been discovered, which may be inherited or spontaneous mutations.

Atherosclerosis may play a role. Whether atherosclerosis contributes to the formation of an aneurysm or whether they occur concomitantly is not established. Other causes of aortic aneurysms are infection (ie, bacterial [mycotic or syphilitic]), arteritis (ie, giant cell, Takayasu, Kawasaki, Behçet), and trauma. Aortitis due to granulomatous disease is rare, but it can lead to the formation of aortic and, on occasion, pulmonary artery aneurysms. Aortitis caused by syphilis may cause destruction of the aortic media followed by aneurysmal dilation.

Traumatic dissection is a result of shearing from deceleration injury due to high speed motor vehicle accidents (MVA) or a fall from heights. The dissection occurs at a point of fixation, usually at the aortic isthmus (ie, at the ligamentum arteriosum, distal to the origin of the left subclavian artery), the ascending aorta, the aortic root, and the diaphragmatic hiatus.

The true etiology of aortic aneurysms is probably multifactorial, and the condition occurs in individuals with multiple risk factors. Risk factors include smoking, chronic obstructive pulmonary disease (COPD), hypertension, atherosclerosis, male gender, older age, high BMI, bicuspid or unicuspid aortic valves, genetic disorders, and family history. Aortic aneurysms are more common in men than in women and are more common in persons with COPD than in those without lung disease.

PreviousNextPathophysiology

The occurrence and expansion of an aneurysm in a given segment of the arterial tree probably involves local hemodynamic factors and factors intrinsic to the arterial segment itself.

The medial layer of the aorta is responsible for much of its tensile strength and elasticity. Multiple structural proteins comprise the normal medial layer of the human aorta. Of these, collagen and elastin are probably the most important. The elastin content of the ascending aorta is high and diminishes progressively in the descending thoracic and abdominal aorta. The infrarenal aorta has a relative paucity of elastin fibers in relation to collagen and compared with the thoracic aorta, possibly accounting for the increased frequency of aneurysms in this area. In addition, the activity and amount of specific enzymes is increased, which leads to the degradation of these structural proteins. Elastic fiber fragmentation and loss with degeneration of the media result in weakening of the aortic wall, loss of elasticity, and consequent dilation.

Hemodynamic factors probably play a role in the formation of aortic aneurysms. The human aorta is a relatively low-resistance circuit for circulating blood. The lower extremities have higher arterial resistance, and the repeated trauma of a reflected arterial wave on the distal aorta may injure a weakened aortic wall and contribute to aneurysmal degeneration. Systemic hypertension compounds the injury, accelerates the expansion of known aneurysms, and may contribute to their formation.

Hemodynamically, the coupling of aneurysmal dilation and increased wall stress is defined by the law of Laplace. Specifically, the law of Laplace states that the (arterial) wall tension is proportional to the pressure times the radius of the arterial conduit (T = P x R). As diameter increases, wall tension increases, which contributes to increasing diameter. As tension increases, risk of rupture increases. Increased pressure (systemic hypertension) and increased aneurysm size aggravate wall tension and therefore increase the risk of rupture.

Aneurysm formation is probably the result of multiple factors affecting that arterial segment and its local environment.

PreviousNextPresentation

Most patients with aortic aneurysms are asymptomatic at the time of discovery. Thoracic aneurysms are usually found incidentally after chest radiographs or other imaging studies. Abdominal aortic aneurysms may be discovered incidentally during imaging studies or a routine physical examination as a pulsatile abdominal mass.

The most common complication of abdominal aortic aneurysms is rupture with life-threatening hemorrhage manifesting as pain and hypotension. The triad of abdominal pain, hypotension, and a pulsatile abdominal mass is diagnostic of a ruptured abdominal aortic aneurysm, and emergent operation is warranted without delay for imaging studies.

Patients with a variant of abdominal aortic aneurysm may present with fever and a painful aneurysm with or without an obstructive uropathy. These patients may have an inflammatory aneurysm that can be treated with surgical repair.

Other presentations of abdominal aortic aneurysm include lower extremity ischemia, duodenal obstruction, ureteral obstruction, erosion into adjacent vertebral bodies, aortoenteric fistula (ie, GI bleed), or aortocaval fistula (caused by spontaneous rupture of aneurysm into the adjacent inferior vena cava [IVC]). Patients with aortocaval fistula present with abdominal pain, venous hypertension (ie, leg edema), hematuria, and high output cardiac failure.

Patients with thoracic aneurysms are often asymptomatic. Most patients are hypertensive but remain relatively asymptomatic until the aneurysm expands. Their most common presenting symptom is pain. Pain may be acute, implying impending rupture or dissection, or chronic, from compression or distension. The location of pain may indicate the area of aortic involvement, but this is not always the case. Ascending aortic aneurysms tend to cause anterior chest pain, while arch aneurysms more likely cause pain radiating to the neck. Descending thoracic aneurysms more likely cause back pain localized between the scapulae. When located at the level of the diaphragmatic hiatus, the pain occurs in the mid back and epigastric region.

Large ascending aortic aneurysms may cause superior vena cava obstruction manifesting as distended neck veins. Ascending aortic aneurysms also may develop aortic insufficiency, with widened pulse pressure or a diastolic murmur, and heart failure. Arch aneurysms may cause hoarseness, which results from stretching of the recurrent laryngeal nerves. Descending thoracic aneurysms and thoracoabdominal aneurysms may compress the trachea or bronchus and cause dyspnea, stridor, wheezing, or cough. Compression of the esophagus results in dysphagia. Erosion into surrounding structures may result in hemoptysis, hematemesis, or gastrointestinal bleeding. Erosion into the spine may cause back pain or instability. Spinal cord compression or thrombosis of spinal arteries may result in neurologic symptoms of paraparesis or paraplegia. Descending thoracic aneurysms may thrombose or embolize clot and atheromatous debris distally to visceral, renal, or lower extremities.

Patients who present with ecchymoses and petechiae may be particularly challenging because these signs probably indicate disseminated intravascular coagulation (DIC). The risk of significant perioperative bleeding is extremely high, and large amounts of blood and blood products must be available for resuscitative transfusion.

The most common complications of thoracic aortic aneurysms are acute rupture or dissection. Some patients present with tender or painful nonruptured aneurysms. Although debate continues, these patients are thought to be at increased risk for rupture and should undergo surgical repair on an emergent basis.

PreviousNextIndications

Indications for surgery of thoracic aortic aneurysms are based on size or growth rate and symptoms. Because the risk of rupture is proportional to the diameter of the aneurysm, aneurysmal size is the criterion for elective surgical repair. Elefteriades published the natural history of thoracic aortic aneurysms and recommends elective repair of ascending aneurysms at 5.5 cm and descending aneurysms at 6.5 cm for patients without any familial disorders such as Marfan syndrome.[13, 14] These recommendations are based on the finding that the incidence of complications (rupture and dissection) exponentially increased when the size of the ascending aorta reached 6.0 cm (31% risk of complications) or when the size of the descending aorta reached 7.0 cm (43% risk).[15, 14] Patients with Marfan syndrome or familial aneurysms should undergo earlier repair, when the ascending aorta grows to 5.0 cm or the descending aorta grows to 6.0 cm.

In addition, relative aortic aneurysm size in relation to body surface area may be more important than absolute aortic size in predicting complications.[16] Using the aortic size index (ASI) of aortic diameter (in cm) divided by body surface area (m2), patients are stratified into 3 groups: ASI 2 are at low risk for rupture (4%/y), ASI 2.75-4.25 cm/m2 are at moderate risk (8%/y), and ASI >4.25cm/m2 are at high risk (20-25%/y).[16, 17]

Rapid expansion is also a surgical indication. Growth rates average 0.07 cm/y in the ascending aorta and 0.19 cm/y in the descending aorta.[14] A growth rate of 1 cm/y or faster is an indication for elective surgical repair.

Symptomatic patients should undergo aneurysm resection regardless of size. Acutely symptomatic patients require emergent operation. Emergent operation is indicated in the setting of acute rupture. Rupture of the ascending aorta may occur into the pericardium, resulting in acute tamponade. Rupture of the descending thoracic aorta may cause a left hemothorax.

Patients with acute aortic dissection of the ascending aorta require emergent operation. They may present with rupture, tamponade, acute aortic insufficiency, myocardial infarction, or end-organ ischemia. Acute dissection of the descending aorta does not require surgical intervention, unless complicated by rupture, malperfusion (eg, visceral, renal, neurologic, leg ischemia), progressive dissection, persistent recurrent pain, or failure of medical management.

Patients who undergo surgery for symptomatic aortic insufficiency or stenosis with an associated enlarged aneurysmal aorta should have concomitant aortic replacement if the aorta reaches 5 cm in diameter. Concomitant aortic replacement should be consider for patients with bicuspid aortic valves with an aorta >4.5 cm in diameter.

As one may imagine, the quality of data and level of evidence supporting these recommendations widely vary. Given this discrepancy and important subject matter, in 2010, a joint task force spearheaded by the American College of Cardiology Foundation and the American Heart Association, and composed of members of many professional societies specializing in treatment of diseases of the thoracic aorta, produced an Executive Summary detailing guidelines for diagnosis and management of this disease, which will be annually updated.[18]

Summary of indicationsAortic size Ascending aortic diameter ≥5.5 cm or twice the diameter of the normal contiguous aortaDescending aortic diameter ≥6.5 cmSubtract 0.5 cm from the cutoff measurement in the presence of Marfan syndrome, family history of aneurysm or connective tissue disorder, bicuspid aortic valve, aortic stenosis, dissection, patient undergoing another cardiac operation Growth rate ≥1 cm/ySymptomatic aneurysmTraumatic aortic ruptureAcute type B aortic dissection with associated rupture, leak, distal ischemiaPseudoaneurysmLarge saccular aneurysmMycotic aneurysmAortic coarctationBronchial compression by aneurysmAortobronchial or aortoesophageal fistulaPreviousNextRelevant Anatomy

Ascending aortic aneurysms occur as proximally as the aortic annulus and as distally as the innominate artery. They may compress or erode into the sternum and ribs, causing pain or fistula. They also may compress the superior vena cava or airway. When symptomatic by rupture or dissection, they may involve the pericardium, aortic valve, or coronary arteries. They may rupture into the pericardium, causing tamponade. They may dissect into the aortic valve, causing aortic insufficiency, or into the coronary arteries, causing myocardial infarction.

Aortic arch aneurysms involve the aorta where the innominate artery, left carotid, and left subclavian originate. They may compress the innominate vein or airway. They may stretch the left recurrent laryngeal nerve, causing hoarseness.

Descending thoracic aneurysms originate beyond the left subclavian artery and may extend into the abdomen. Thoracoabdominal aneurysms are stratified based on the Crawford classification. Type I involves the descending thoracic aorta from the left subclavian artery down to the abdominal aorta above the renal arteries. Type II extends from the left subclavian artery to the renal arteries and may continue distally to the aortic bifurcation. Type III begins at the mid-to-distal descending thoracic aorta and involves most of the abdominal aorta as far distal as the aortic bifurcation. Type IV extends from the upper abdominal aorta and all or none of the infrarenal aorta. Descending thoracic aneurysms and thoracoabdominal aneurysms may compress or erode into surrounding structures, including the trachea, bronchus, esophagus, vertebral body, and spinal column.

PreviousNextContraindications

Aneurysm surgery has no strict contraindications. The relative contraindications are individualized, based on the patient's ability to undergo extensive surgery (ie, the risk-to-benefit ratio). Patients at higher risk for morbidity and mortality include elderly persons and individuals with end-stage renal disease, respiratory insufficiency, cirrhosis, or other comorbid conditions. For descending thoracic aneurysms, endovascular stent grafting is less invasive and is an ideal alternative (with appropriate anatomic considerations) to open repair for patients at high risk for complications of open repair. Stent grafts are also a reasonable alternative (with the appropriate anatomy) to open repair in patients who are not at high risk for complications. Patients must understand that life-long follow-up is required and that long-term durability is unknown.

PreviousProceed to Workup , Thoracic Aortic Aneurysm

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Emergent Management of Abdominal Aortic Aneurysm Rupture

Introduction to AAA

The decision to treat an unruptured abdominal aortic aneurysm (AAA) is a complex one, based on operative risk, the risk of rupture, and the patient’s estimated life expectancy. Ruptured AAA is a life-threatening condition that requires emergent surgery. For other discussions on AAA, see Abdominal Aortic Aneurysm and Bedside Ultrasonography Evaluation of Abdominal Aortic Aneurysm.

History of the procedure

Vesalius described the first AAA in the 16th century. Before the development of a surgical intervention for the process, attempts at medical management failed. The initial attempts at surgical control used ligation of the aorta, with the expected consequences.

In 1923, Matas performed the first successful aortic ligation on a patient. Attempts were made to induce thrombosis by inserting intraluminal wires. In 1948, Rea wrapped reactive cellophane around the aneurysm in order to induce fibrosis and limit expansion. This technique was used on Albert Einstein in 1949, and he survived 6 years before succumbing to rupture. In 1951, Charles Dubost performed the first AAA repair using a homograft.

Prior to this, aortic aneurysms were treated using a variety of methods, including ligation, intraluminal wiring, and cellophane wrapping. Unfortunately, early homografts became aneurysmal because of preservation techniques. In 1953, Blakemore and Voorhees repaired a ruptured AAA using a Vinyon-N graft (ie, nylon). Later, these grafts were replaced by Dacron and GORE-TEX (ie, polytetrafluoroethylene [PTFE]) fabrics. The final advance was abandonment of silk sutures, which degenerate, in favor of braided Dacron, polyethylene, and PTFE (ie, GORE-TEX) sutures, all of which retain tensile strength.

Postoperative surgical mortality rates initially remained high (>25%) because the aneurysm sac generally was excised. Nearly simultaneously in 1962, Javid and Creech reported the technique of endoaneurysmorrhaphy (see the images below). This advancement dramatically reduced mortality. Today, operative mortality rates range from 1.8-5%.

Aneurysm with retroperitoneal fibrosis and adhesion of the duodenum and fibrosis. Endoaneurysmorrhaphy.

In the late 1980s, Parodi et al described endovascular repair using a large Palmaz stent and unilateral aortofemoral and femorofemoral crossover Dacron grafts.[1] Currently, many devices are used for the endovascular treatment of AAA (see the image below).

Endovascular grafts. NextEpidemiologyUnited States statistics

Ruptured abdominal aortic aneurysm (AAA) causes an estimated 15,000 deaths per year. The frequency of rupture is 4.4 cases per 100,000 persons. The reported incidence of rupture varies from 1-21 cases per 100,000 person-years.

International statistics

The frequency of rupture is 6.9 cases per 100,000 persons in Sweden, 4.8 cases per 100,000 persons in Finland, and 13 cases per 100,000 persons in the United Kingdom.

PreviousNextPrognosis

The prognosis is guarded in patients who suffer AAA rupture prehospital. More than 50% do not survive to the ED; of those who do, survival rate drops by about 1% per minute. However, survival rate is good in the subset of patients who are not in severe shock and who receive timely, expert surgical intervention.

In 1988, 40,000 surgical reconstructions for abdominal aortic aneurysm (AAA) were performed in the US, with substantial mortality differences between elective versus emergency operations. As elective aneurysm repair has a mortality rate drastically lower than that associated with rupture, the emphasis must be on early detection and repair free from complications.

The long-term prognosis is related to associated comorbidities. Long-term survival is shortened by chronic heart failure and chronic obstructive pulmonary disease. Rupture of associated thoracic aneurysms is also an important cause of late death. Overall, AAA repair is very durable, with few long-term complications ([2, 3]

PreviousNextPathophysiology

Aneurysm diameter is an important risk factor for rupture. In general, abdominal aortic aneurysms (AAAs) gradually enlarge (0.2-0.8 mm/y) and eventually rupture. Hemodynamics play an important role. Areas of high stress have been found in AAAs and appear to correlate with the site of rupture. Computer-generated geometric factors have demonstrated that aneurysm volume is a better predictor of areas of peak wall stress than aneurysm diameter. This may have implications in determining which AAAs require surgical repair.

AAA rupture is believed to occur when the mechanical stress acting on the wall exceeds the strength of the wall tissue. Wall tension can be calculated using the Laplace Law for wall tension: P × R/W, where P = mean arterial pressure (MAP), R = radius of the vessel, and W = wall thickness of the vessel.

AAA wall tension is a significant predictor of pending rupture. The actual tension in the AAA wall appears to be a more sensitive predictor of rupture than aneurysm diameter alone. For these reasons, the clinician may wish to achieve acute blood pressure control in patients with AAA and elevated blood pressure.

PreviousNextClinical Presentation

Persons with abdominal aortic aneurysms (AAAs) that have ruptured may present in many ways. The most typical manifestation of rupture is abdominal or back pain with a pulsatile abdominal mass. However, the symptoms may be vague, and the abdominal mass may be missed. Symptoms may include groin pain, syncope, paralysis, or flank mass. The diagnosis may be confused with renal calculus, diverticulitis, incarcerated hernia, or lumbar spine disease.

Transient hypotension should prompt consideration of rupture because this finding can progress to frank shock over a period of hours. Temporary loss of consciousness is also a potential symptom of rupture.

Patients with a ruptured AAA may present in frank shock as evidenced by cyanosis, mottling, altered mental status, tachycardia, and hypotension. At least 65% of patients with ruptured AAA die from sudden cardiovascular collapse before arriving at a hospital.

It is important to note progressive symptoms (eg, abdominal or back pain, vomiting, syncope, claudication). These should alert the clinician to the possibility of expansion with imminent rupture.

Peripheral emboli and claudication

Atheroemboli from small AAAs produce livedo reticularis of the feet or blue toe syndrome (see the image below). Occasionally, small AAAs thrombose, producing acute claudication.

Atheroemboli from small abdominal aortic aneurysms produce livedo reticularis of the feet (ie, blue toe syndrome). Aortocaval fistulae

AAAs may rupture into the vena cava, producing large arteriovenous fistulae. In this case, symptoms include tachycardia, congestive heart failure (CHF), leg swelling, abdominal thrill, machinery-type abdominal bruit, renal failure, and peripheral ischemia.

Aortoduodenal fistulae

Finally, an AAA may rupture into the fourth portion of the duodenum. These patients may present with a herald upper gastrointestinal bleed followed by an exsanguinating hemorrhage.

PreviousNextIndications

Even patients who do not have symptoms from their abdominal aortic aneurysms (AAAs) may eventually require surgical intervention because the result of medical management in this population is a mortality rate of 100% over time due to rupture. In addition, these patients have a high likelihood of limb loss from peripheral embolization.

The decision to treat an unruptured abdominal aortic aneurysm (AAA) is based on operative risk, the risk of rupture, and the patient’s estimated life expectancy. In 2003, the Society for Vascular Surgery (SVS) published a series of guidelines for the treatment of AAAs based on these principles.[4] The operative risk is based on patients’ comorbidities and hospital factors.

Abdominal ultrasonography can provide a preliminary determination of aneurysm presence, size, and extent. Rupture risk is in part indicated by the size of the aneurysm (see Table 1, below).

Table 1. Abdominal Aortic Aneurysm Size and Estimated Annual Risk of Rupture (Open Table in a new window)

AAA Diameter (cm) Rupture Risk (%/y) 04-50.5-55-63-156-710-207-820-40>830-50

In addition to aneurysm diameter, risk of rupture is also an expression of sex, aneurysm expansion rate, family history, and chronic obstructive pulmonary disease (COPD) (see Table 2, below).

Table 2. Risk of Abdominal Aortic Aneurysm Rupture (Open Table in a new window)

Low Risk Average Risk High Risk Diameter5-6 cm>6 cmExpansion0.3-0.6 cm/y>0.6 cm/ySmoking/COPDNone, mildModerateSevere/steroidsFamily historyNo relativesOne relativeNumerous relativesHypertensionNormal blood pressureControlledPoorly controlledShapeFusiformSaccularVery eccentricWall stressLow (35 N/cm2Medium (40 N/cm2High (45 N/cm2)Sex...MaleFemale

The operative risk (see Table 3, below) is based on patients’ comorbidities and hospital factors. Patient characteristics, including age, sex, renal function, and cardiopulmonary disease are perhaps the most important. However, lower-volume hospitals and surgeons are associated with higher mortality.[5]

Table 3. Operative Mortality Risk of Open Repair of Abdominal Aortic Aneurysm (Open Table in a new window)

Lowest RiskModerate RiskHigh RiskAge Age 70-80 yAge 80 yPhysically activeActiveInactive, poor staminaNo clinically overt cardiac diseaseStable coronary disease; remote MI;

LVEF >35%

Significant coronary disease; recent MI;

frequent angina; CHF; LVEF
No significant comorbiditiesMild COPDLimiting COPD; dyspnea at rest; O2

dependency; FEV1
...Creatinine 2.0-3.0 mg/dL...Normal anatomyAdverse anatomy or AAA

characteristics

Creatinine >3 mg/dLNo adverse AAA characteristics...Liver disease (↑ PT; albumin Anticipated operative mortality, 1%-3%Anticipated operative mortality, 3%-7%Anticipated operative mortality, at least

5%-10%; each comorbid condition

adds ~3%-5%

mortality risk

CHF – chronic heart failure; COPD – chronic obstructive pulmonary disease; LVEF – left ventricular ejection fraction; MI – myocardial infarction; PT – prothrombin time

With AAAs smaller than 5.5 cm, elective repair has not been shown to improve survival.[6]

Prospective studies have concluded that following aneurysms larger than 5.5 cm with serial ultrasounds or CT scans is safe. A slightly higher rupture rate in women exists, and this threshold may be lower.

Thus, the decision to repair an AAA is a complex one in which the patient must play an important role. In some very elderly patients or patients with limited life expectancy, aneurysm repair may not be appropriate. In these patients, the consequences of rupture should be frankly discussed. If rupture occurs, no intervention should be performed.

PreviousNextContraindications

Contraindications for operative intervention of abdominal aortic aneurysms (AAAs) include severe chronic obstructive pulmonary disease (COPD), severe cardiac disease, active infection, and medical problems that preclude operative intervention. These patients may benefit best from endovascular stenting of the aneurysm.

In many patients, the decision to operate is a balance between risks and benefits. In an elderly patient (>80 y) with significant comorbidities, surgical repair may not be indicated. However, the decision to intervene should not be based on age alone, even with rupture. The decision is best based on the patient's overall physical status, including a positive attitude toward the surgery.

Patients with known cancer that has an indolent course (eg, prostate cancer) may merit aneurysm repair if their estimated survival is 2 years or longer.

PreviousNextWorkupLaboratory studies

A complete blood count with differential is used to assess transfusion requirements and the possibility of infection. A metabolic panel (including kidney and liver function tests) is indicated for ascertaining the integrity of renal and hepatic function, in order to assess operative risk and guide postoperative management.

Type and crossmatch blood to prepare for the possibility of transfusion, including clotting factors and platelets.

Because synthetic material is used in the intervention, assess and eliminate potential foci of infection preoperatively by urinalysis.

Assessment of pulmonary function is part of the preoperative workup, to determine operative risk and postoperative care. Patients who can climb a flight of stairs without excessive shortness of breath generally do well. If the patient's pulmonary status is in question, blood gas measurement and pulmonary function tests are helpful.

Chest radiography

Chest radiography is used to gain a preliminary assessment of the status of the heart and lungs. Concurrent pulmonary or cardiac disease may need to be addressed prior to treating the aneurysm.

Computed tomography

Preoperative CT scanning helps more clearly define the anatomy of the aneurysm and other intra-abdominal pathologies. Nonenhanced CT scanning is used to size aneurysms.[7] Although sizing the aneurysm is important, the anatomic relationships important to surgery are also determined. These include the location of the renal arteries, length of the aortic neck, condition of the iliac arteries, and anatomic variants such as a retroaortic left renal vein or horseshoe kidney.

Enhanced spiral CT scanning of the abdomen and pelvis with multiplanar reconstruction and CT angiography is the test of choice for preoperative evaluation for open and endovascular repair (see the image below).

Enhanced spiral CT scans with multiplanar reconstruction and a CT angiogram.

Of AAA cases, 10-20% have focal outpouchings or blebs visible on CT scans that are thought to contribute to the potential for rupture. The wall of the aneurysm becomes laminated with thrombus as the blebs enlarge. This can give the appearance of a relatively normal intraluminal diameter in spite of a large extraluminal size.

Magnetic resonance angiography

Magnetic resonance angiography (MRA) is quickly replacing the traditional angiographic assessment of aneurysms. The study provides excellent anatomical definition and 3-dimensional assessment of the problem. Gadolinium-enhanced MRA can provide excellent images, even though regional variations in quality are reported.

Conventional angiography

Angiography remains the criterion standard for the diagnosis of AAA, and it is indicated in the presence of associated renal or visceral involvement, peripheral occlusive disease, or aneurysmal disease. Angiography is also essential with any renal abnormality (eg, horseshoe kidney, pelvic kidney). (See the image below.)

Angiography is used to diagnose the renal area. In this instance, an endoleak represented continued pressurization of the sac. Echocardiography

Because of the fluid shift involved during the operative repair of AAA, cardiac function should be assessed using echocardiography. By ascertaining the ejection fraction of the patient, the operative intervention can be planned and cardiac protective measures can be instituted as needed. This study is particularly indicated in patients with a history of CHF or known cardiac enlargement.

Pulmonary assessment

Assessment of pulmonary function is of paramount importance in these patients. Because surgical intervention requires an abdominal incision, preoperative assessment of the patient's pulmonary status allows for tailored postoperative care.

Cardiac assessment

Assess cardiac status in all patients with vascular disease. If one vascular bed is involved with an atherosclerotic process, then consider that others also may be involved. Electrocardiography findings provide a baseline assessment of cardiac rhythm and old disease processes.

A stress test can be performed to uncover unsuspected cardiac ischemia. Significant coronary disease may need to be addressed before the AAA can be repaired.

PreviousNextTreatment & Management

Abdominal aortic aneurysms (AAAs) are typically repaired by an operative intervention. The possible approaches are the traditional open laparotomy, newer minimally invasive methodologies, or by the placement of endovascular stents.

Preoperative details

Preoperatively, obtain a careful history and perform a physical examination and laboratory assessment. These basic assessments provide the information for estimating perioperative risk and life expectancy after the proposed procedure.

Carefully consider whether the patient's current quality of life is sufficient to justify the operative intervention. In the case of elderly persons who may be debilitated or may have mental deterioration, this decision is made in conjunction with the patient and family.

Once the decision is made, identify comorbidities and risk factors that increase the operative risk or decrease survival. Ascertain the patient's activity level, stamina, and stability of health. Perform a thorough cardiac assessment tailored to the patient's history, symptoms, and results from preliminary screening tests such as the electrocardiogram and stress test.

Because COPD is an independent predictor of operative mortality, assess lung function by performing a room-air arterial blood gas measurement and pulmonary function tests. In patients with abnormal test results, preoperative intervention in the form of bronchodilators and pulmonary toilet often can reduce operative risks and postoperative complications.

Preoperative intravenous antibiotics (usually a cephalosporin) are administered to reduce the risk of infection. Arranging for appropriate intravenous accesses to accommodate blood loss, arterial pressure monitoring through an arterial line, and Foley catheter placement to monitor urine output are routine preparations for surgery.

For patients at high risk because of cardiac compromise, a Swan-Ganz catheter is placed to assist with cardiac monitoring and volume assessment. Transesophageal echocardiography can be useful to monitor ventricular volume and cardiac wall motion and to provide a guide with respect to fluid replacement and pressor use.

Prepare for blood replacement. The patient should have blood available for transfusion. Intraoperative Cell Saver use and preoperative autologous blood donation have become popular.

Maintain a normal body temperature during the operative intervention to prevent coagulopathy and maintain normal metabolic function. To prevent hypothermia, place a recirculating, warm forced-air blanket on the patient and warm any intravenous fluids and blood before administration.

In summary, the following are standard preoperatively:

Type and crossmatch bloodAdminister prophylactic antibiotics (cefazolin, 1 g intravenous piggyback)Insert a Foley catheterEstablish large-bore intravenous accessMonitor central venous pressure or establish Swan-Ganz catheterization (if indicated)Prepare the skin from the nipples to the mid thighAdminister general anesthesia (with or without epidural anesthesia)Cell Saver use has become popularInsert a nasogastric tubeIntraoperative details

The aorta may be approached either transabdominally or through the retroperitoneal space. Approach juxtarenal and suprarenal aortic aneurysms from the left retroperitoneal space.

Self-retaining retractors are used. Keep the bowel warm and, if possible, not exteriorized. The abdomen is explored for abnormalities (eg, gallstones, associated intestinal or pancreatic malignancy).

Depending on the patient's anatomy, the aorta can be reconstructed with a tube graft, an aortic iliac bifurcation graft, or an aortofemoral bypass.

For proximal infrarenal control, first identify the left renal vein. Occasionally (

Regarding pelvic outflow, in most instances, the inferior mesenteric artery is sacrificed. Therefore, to prevent colon ischemia, make every attempt to restore at least one hypogastric (internal iliac) artery perfusion. If the hypogastric arteries are sacrificed (associated aneurysms), reimplant the inferior mesenteric artery.

For supraceliac aortic control, first divide the ligaments to the left lateral segment of the liver and then retract the segment. The crura of the diaphragm are separated, and the aorta is bluntly dissected. Supraceliac control is recommended for inflammatory aneurysms.

The aorta is reconstructed from within using PTFE or Dacron. The aneurysm sac is closed, and the graft is put into the duodenum to prevent erosion.

Special considerations

Inflammatory aneurysms require supraceliac control, minimal dissection of the duodenum, and balloon occlusion of the iliac arteries. In patients with inflammatory aneurysms or large iliac artery aneurysms, identify the ureters; occasionally, ureteral stents are recommended in patients with inflammatory aneurysms.

Prevention of distal embolization

The patient is heparinized (5000 U intravenously) prior to aortic cross-clamping. If significant intraluminal debris, juxtarenal thrombus, or prior peripheral embolization is present, the distal arteries are clamped first, followed by aortic clamping.

Before restoring lower extremity blood flow, both forward flow (aortic) and back flow (iliac) are allowed to remove debris. The graft is also irrigated to flush out debris.

The colon is inspected prior to closure, and the femoral arteries are palpated. Before the patient leaves the operating room, determine lower extremity circulation. If a clot was dislodged at the time of aortic clamping, it can be removed with a Fogarty embolectomy catheter. Heparin reversal is not usually required.

PreviousNextPostoperative Details

Fluid shifts are common following aortic surgery. Fluid requirements may be high in the first 12 hours, depending on the amount of blood loss and fluid resuscitation in the operating room. Monitor the patient in the surgical intensive care unit for hemodynamic stability, bleeding, urine output, and peripheral pulses. A postoperative electrocardiogram and chest radiograph are needed. Prophylactic antibiotics (eg, cefazolin at 1 g) are administered for 24 hours.

The patient is seen in 1-2 weeks for suture or skin staple removal, then yearly thereafter.

PreviousNextPatient Education

For patient education information, see the Circulatory Problems Center and Cholesterol Center, as well as Aortic Aneurysm, High Cholesterol, and Cholesterol FAQs.

PreviousNextComplications

The following are potential complications of abdominal aortic aneurysms:

Death - 1.8-5% if elective and 50% if rupturedPneumonia - 5%Myocardial infarction - 2-5%Groin infection - Less than 5%Graft infection - Less than 1%Colon ischemia - Less than 1% if elective and 15-20% if rupturedRenal failure related to preoperative creatinine level, intraoperative cholesterol embolization, and hypotensionIncisional hernia - 10-20%Bowel obstructionAmputation from major arterial occlusionBlue toe syndrome and cholesterol embolization to feetImpotence in males - Erectile dysfunction and retrograde ejaculation (>30%)Paresthesias in thighs from femoral exposure (rare)Lymphocele in groin - Approximately 2%Late graft enteric fistulaPreviousNextEndovascular Stent Grafts

Endovascular stent grafts for the treatment of abdominal aortic aneurysm (AAA) are a less invasive form of treatment. Patients are discharged 1-2 days following surgery. The graft is placed through 2 small incisions. In September 2000, 2 grafts were approved by the US Food and Drug Administration (FDA). Since then, several more devices have received FDA approval.[8] Recently, the FDA has recommended careful follow-up because of persistent endoleaks and late ruptures.

In some instances, endoleaks represent continued pressurization of the sac (see image below). Aneurysm sacs may also demonstrate elevated pressure despite the absence of a demonstrable endoleak. This has been described as "endotension."

Persistently elevated aneurysm sac pressure, whether secondary to endoleak or endotension, is worrisome because it may progress to AAA rupture. Early data demonstrated a need for secondary interventions, via endovascular techniques, in as many as 10% of patients per year following endovascular aneurysm repair, compared with 2% in the first 5 years for open repair. Improvement has been made in the rate of secondary interventions following endovascular repair, but long-term durability has yet to be determined.

Angiography is used to diagnose the renal area. In this instance, an endoleak represented continued pressurization of the sac.

Informing the patient about these potential problems is important prior to implanting these grafts. In addition, patients with endografts require follow-up evaluation with serial CT scanning on a schedule that demands more office visits than are required for patients who receive conventional grafts.

Currently, endovascular repair is advocated for patients at increased risk for open aneurysm repair, but until results from randomized controlled trials are available, patient preference is the strongest determinant in deciding between endovascular and open aneurysm repair.

Previous, Emergent Management of Abdominal Aortic Aneurysm Rupture

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Aortic Stenosis

Practice Essentials

Aortic stenosis is the obstruction of blood flow across the aortic valve. Among symptomatic patients with medically treated moderate-to-severe aortic stenosis, mortality from the onset of symptoms is approximately 25% at 1 year and 50% at 2 years. Symptoms of aortic stenosis usually develop gradually after an asymptomatic latent period of 10-20 years.

Essential update: Expanded FDA labeling for transcatheter valve allows alternative access sites

In September 2013, the FDA approved new labeling for the Sapien transcatheter valve, which eliminates references to specific access sites used when implanting the valves (ie, transfemoral and transapical approaches) and allows the use of alternative access sites (eg, subclavian approach).[1, 2] The change in labeling was supported by data from the Transcatheter Valve Therapy Registry and European registries.

Signs and symptoms

The classic triad of symptoms in patients with aortic stenosis is as follows[3] :

Chest pain: Angina pectoris in patients with aortic stenosis is typically precipitated by exertion and relieved by restHeart failure: Symptoms include paroxysmal nocturnal dyspnea, orthopnea, dyspnea on exertion, and shortness of breathSyncope: Often occurs upon exertion when systemic vasodilatation in the presence of a fixed forward stroke volume causes the arterial systolic blood pressure to decline

Systolic hypertension can coexist with aortic stenosis. However, a systolic blood pressure higher than 200 mm Hg is rare in patients with critical aortic stenosis.

In severe aortic stenosis, the carotid arterial pulse typically has a delayed and plateaued peak, decreased amplitude, and gradual downslope (pulsus parvus et tardus).

Other symptoms of aortic stenosis include the following:

Pulsus alternans: Can occur in the presence of left ventricular systolic dysfunctionHyperdynamic left ventricle: Unusual; suggests concomitant aortic regurgitation or mitral regurgitationSoft or normal S1Diminished or absent A2: The presence of a normal or accentuated A2 speaks against the existence of severe aortic stenosisParadoxical splitting of the S2: Resulting from late closure of A2Accentuated P2: In the presence of secondary pulmonary hypertensionEjection click: Common in children and young adults with congenital aortic stenosisProminent S4: Resulting from forceful atrial contraction into a hypertrophied left ventricleSystolic murmur: The classic crescendo-decrescendo systolic murmur of aortic stenosis begins shortly after the first heart sound; the intensity increases toward midsystole and then decreases, with the murmur ending just before the second heart sound

See Clinical Presentation for more detail.

Diagnosis

The following studies are used in the diagnosis and assessment of aortic stenosis:

Serum electrolyte levelsCardiac biomarkersComplete blood countB-type natriuretic peptide: May provide incremental prognostic information for predicting symptom onset in asymptomatic patients with severe aortic stenosis[4] Electrocardiography: Serial ECG can demonstrate the progression of aortic stenosisChest radiographyEchocardiography: 2-dimensional and DopplerCardiac catheterization: Can be used if clinical findings are inconsistent with echocardiogram resultsCoronary angiographyRadionuclide ventriculography: May provide information on LV functionExercise stress testing: Contraindicated in symptomatic patients with severe aortic stenosis

See Workup for more detail.

Management

The only definitive treatment for aortic stenosis is aortic valve replacement. The development of symptoms due to this condition provides a clear indication for replacement.[5, 6]

Emergency care

A patient presenting with uncontrolled heart failure should be treated supportively with oxygen, cardiac and oximetry monitoring, intravenous access, loop diuretics, nitrates (remembering the potential nitrate sensitivity of patients with aortic stenosis), morphine (as needed and tolerated), and noninvasive or invasive ventilatory support (as indicated). Patients with severe heart failure due to aortic stenosis that is resistant to medical management should be considered for urgent surgery.

Pharmacologic therapy

Agents used in the treatment of patients with aortic stenosis include the following:

Digitalis, diuretics, and angiotensin-converting enzyme (ACE) inhibitors: Can be cautiously used in patients with pulmonary congestion Vasodilators: May be used for heart failure and for hypertension but should also be employed with extreme cautionDigoxin, diuretics, ACE inhibitors, or angiotensin receptor blockers[6] : Recommended by the European Society of Cardiology (ESC)/European Association for Cardio-Thoracic Surgery (EACTS) guidelines for patients with heart failure symptoms who are not suitable candidates for surgery or transcatheter aortic valve implantation

Aortic valve replacement

According to American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, candidates for aortic valve replacement include the following patients[7] :

Symptomatic patients with severe aortic stenosisPatients with severe aortic stenosis undergoing coronary artery bypass surgeryPatients with severe aortic stenosis undergoing surgery on the aorta or other heart valvesPatients with severe aortic stenosis and LV systolic dysfunction (ejection fraction

Percutaneous balloon valvuloplasty

Percutaneous balloon valvuloplasty is used as a palliative measure in critically ill adult patients who are not surgical candidates or as a bridge to aortic valve replacement in critically ill patients.

See Treatment and Medication for more detail.

Image libraryCalcific aortic stenosis (parasternal long-axis and short-axis views). NextBackground

Aortic stenosis is the obstruction of blood flow across the aortic valve. Aortic stenosis has several etiologies, including congenital (unicuspid or bicuspid valve), calcific (due to degenerative changes), and rheumatic. Degenerative calcific aortic stenosis is now the leading indication for aortic valve replacement. The favorable long-term outcome following aortic valve surgery and the relatively low operative risk emphasize the importance of an accurate and timely diagnosis (see Prognosis).

Stenotic valves are shown in the images below. Symptoms of aortic stenosis usually develop gradually after an asymptomatic latent period of 10-20 years. Exertional dyspnea or fatigue is the most common initial complaint. Ultimately, most patients experience the classic triad of chest pain, heart failure, and syncope (see History).

Two-dimensional (2D) Doppler echocardiography is the imaging modality of choice to diagnose and estimate the severity of aortic stenosis and localize the level of obstruction (see Workup). The only definitive treatment for aortic stenosis is aortic valve replacement (see Treatment and Management).

Go to Pediatric Valvar Aortic Stenosis, Pediatric Subvalvar Aortic Stenosis, and Pediatric Supravalvar Aortic Stenosis for more complete information on these topics.

PreviousNextPathophysiology

When the aortic valve becomes stenotic, resistance to systolic ejection occurs and a systolic pressure gradient develops between the left ventricle and the aorta. This outflow obstruction leads to an increase in left ventricular (LV) systolic pressure. As a compensatory mechanism to normalize LV wall stress, LV wall thickness increases by parallel replication of sarcomeres, producing concentric hypertrophy. At this stage, the chamber is not dilated and ventricular function is preserved, although diastolic compliance is reduced.

Eventually, however, LV end-diastolic pressure (LVEDP) rises, which causes a corresponding increase in pulmonary capillary arterial pressures and a decrease in cardiac output due to diastolic dysfunction. The contractility of the myocardium may also diminish, which leads to a decrease in cardiac output due to systolic dysfunction. Ultimately, heart failure develops.

In most patients with aortic stenosis, LV systolic function is preserved and cardiac output is maintained for many years despite an elevated LV systolic pressure. Although cardiac output is normal at rest, it often fails to increase appropriately during exercise, which may result in exercise-induced symptoms.

Diastolic dysfunction may occur as a consequence of impaired LV relaxation and/or decreased LV compliance, as a result of increased afterload, LV hypertrophy, or myocardial ischemia. LV hypertrophy often regresses following relief of valvular (also called valvular) obstruction. However, some individuals develop extensive myocardial fibrosis, which may not resolve despite regression of hypertrophy.

In patients with severe aortic stenosis, atrial contraction plays a particularly important role in diastolic filling of the left ventricle. Thus, development of atrial fibrillation in aortic stenosis often leads to heart failure due to an inability to maintain cardiac output.

Increased LV mass, increased LV systolic pressure, and prolongation of the systolic ejection phase all elevate the myocardial oxygen requirement, especially in the subendocardial region. Although coronary blood flow may be normal when corrected for LV mass, coronary flow reserve is often reduced.

Myocardial perfusion is thus compromised by the relative decline in myocardial capillary density and by a reduced diastolic transmyocardial (coronary) perfusion gradient due to elevated LV diastolic pressure. Therefore, the subendocardium is susceptible to underperfusion, which results in myocardial ischemia.

Angina results from a concomitant increased oxygen requirement by the hypertrophic myocardium and diminished oxygen delivery secondary to diminished coronary flow reserve, decreased diastolic perfusion pressure, and relative subendocardial myocardial ischemia.

PreviousNextEtiology

Most cases of aortic stenosis are due to the obstruction at the valvular level. Common causes are summarized in Table 1.

Table 1. Common Causes of Aortic Stenosis Among Patients Requiring Surgery (Open Table in a new window)

Age Age >70 years (n=322) Bicuspid AV (50%)

Postinflammatory (25%)

Degenerative (18%)

Unicommissural (3%)

Hypoplastic (2%)

Indeterminate (2%)

Degenerative (48%)

Bicuspid (27%)

Postinflammatory (23%)

Hypoplastic (2%)

Valvular aortic stenosis can be either congenital or acquired.

Congenital valvular aortic stenosis

Congenitally unicuspid, bicuspid, tricuspid, or even quadricuspid valves may be the cause of aortic stenosis. In neonates and infants younger than 1 year, a unicuspid valve can produce severe obstruction and is the most common anomaly in infants with fatal valvular aortic stenosis. In patients younger than 15 years, unicuspid valves are most frequent in cases of symptomatic aortic stenosis.

In adults who develop symptoms from congenital aortic stenosis, the problem is usually a bicuspid valve. Bicuspid valves do not cause significant narrowing of the aortic orifice during childhood. The altered architecture of the bicuspid aortic valve induces turbulent flow with continuous trauma to the leaflets, ultimately resulting in fibrosis, increased rigidity and calcification of the leaflets, and narrowing of the aortic orifice in adulthood.

A cohort study by Tzemos et al of 642 ambulatory adults with bicuspid aortic valves found that during the mean follow-up duration of 9 years, survival rates were not lower than for the general population. However, young adults with bicuspid aortic valve had a high likelihood of eventually requiring aortic valve intervention.[8]

Congenitally malformed tricuspid aortic valves with unequally sized cusps and commissural fusion (“functionally bicuspid” valves) can also cause turbulent flow leading to fibrosis and, ultimately, to calcification and stenosis. Clinical manifestations of congenital aortic stenosis in adults usually appear after the fourth decade of life.

Acquired valvular aortic stenosis

The main causes of acquired aortic stenosis include degenerative calcification and, less commonly, rheumatic heart disease.

Degenerative calcific aortic stenosis (also called senile calcific aortic stenosis) involves progressive calcification of the leaflet bodies, resulting in limitation of the normal cusp opening during systole. This represents a consequence of long-standing hemodynamic stress on the valve and is currently the most frequent cause of aortic stenosis requiring aortic valve replacement. The calcification may also involve the mitral annulus or extend into the conduction system, resulting in atrioventricular or intraventricular conduction defects.

Risk factors for degenerative calcific aortic stenosis include hypertension, hypercholesterolemia, diabetes mellitus, and smoking. The available data suggest that the development and progression of the disease are due to an active disease process at the cellular and molecular level that shows many similarities with atherosclerosis, ranging from endothelial dysfunction to, ultimately, calcification.[9]

In rheumatic aortic stenosis, the underlying process includes progressive fibrosis of the valve leaflets with varying degrees of commissural fusion, often with retraction of the leaflet edges and, in certain cases, calcification. As a consequence, the rheumatic valve often is regurgitant and stenotic. Coexistent mitral valve disease is common.

Other, infrequent causes of aortic stenosis include obstructive vegetations, homozygous type II hypercholesterolemia, Paget disease, Fabry disease, ochronosis, and irradiation.

It is worthwhile to note that although differentiation between tricuspid and bicuspid aortic stenosis is frequently made, it is often difficult to determine the number of aortic valve leaflets. A study comparing operatively excised aortic valve structure evaluation by cardiac surgeon versus pathologist found that valve structure determination was frequently incongruous.[10]

PreviousNextEpidemiology

Severe aortic stenosis is rare in infancy, occurring in 0.33% of live births, and is due to a unicuspid or bicuspid valve. Most patients with a congenitally bicuspid aortic valve who develop symptoms do not do so until middle age or later. Patients with rheumatic aortic stenosis typically present with symptoms after the sixth decade of life.

Aortic sclerosis (aortic valve calcification without obstruction to blood flow, considered a precursor of calcific degenerative calcific aortic stenosis) increases in incidence with age and is present in 29% of individuals older than 65 years and in 37% of individuals older than 75 years. In elderly persons, the prevalence of aortic stenosis is between 2% and 9%.

Degenerative calcific aortic stenosis usually manifests in individuals older than 75 years and occurs most frequently in males.[5]

PreviousNextPrognosis

Patients with severe aortic stenosis may be asymptomatic for many years despite the presence of severe LV outflow tract obstruction (LVOTO). LVOTOs have been associated with “high heritability.” One study suggests that 20% of patients with isolated LVOTO had an affected first-degree relative with undetected bicuspid aortic valves.[11]

Asymptomatic patients, even with critical aortic stenosis, have an excellent prognosis for survival, with an expected death rate of less than 1% per year; only 4% of sudden cardiac deaths in severe aortic stenosis occur in asymptomatic patients. A new proposed aortic stenosis grading classification that integrates valve area and flow-gradient patterns has been found to allow for better characterization of the clinical outcome among patients with asymptomatic severe aortic stenosis.[12]

Although the presence of low-gradient "severe stenosis" (defined as aortic valve area 2 and mean gradient 40 mm Hg) is considered by some to be associated with a poor prognosis, the prospective Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study found that such patients have an outcome similar to that of patients with moderate stenosis.[13]

Among symptomatic patients with medically treated, moderate-to-severe aortic stenosis, mortality rates from the onset of symptoms are approximately 25% at 1 year and 50% at 2 years. More than 50% of deaths are sudden. In patients in whom the aortic valve obstruction remains unrelieved, the onset of symptoms predicts a poor outcome with medical therapy; the approximate time interval from the onset of symptoms to death is 1.5-2 years for heart failure, 3 years for syncope, and 5 years for angina.

Although the obstruction tends to progress more rapidly in degenerative calcific aortic valve disease than in congenital or rheumatic disease, predicting the rate of progression in individual patients is not possible. Catheterization and echocardiographic studies suggest that, on average, the valve area declines 0.1-0.3 cm2 per year; the systolic pressure gradient across the valve can increase by as much as 10-15 mm Hg per year. Obstruction progresses more rapidly in elderly patients with coronary artery disease and chronic renal insufficiency.

PreviousNextPatient Education

For patient education information, see eMedicineHealth's patient education article Angina Pectoris.

PreviousProceed to Clinical Presentation  Contributor Information and DisclosuresAuthor

Xiushui (Mike) Ren, MD  Cardiologist, The Permanente Medical Group; Associate Director of Research, Cardiovascular Diseases Fellowship, California Pacific Medical Center
Xiushui (Mike) Ren, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, and American Society of Echocardiography
Disclosure: Nothing to disclose.

Chief Editor

Richard A Lange, MD  Professor and Executive Vice Chairman, Department of Medicine, Director, Office of Educational Programs, University of Texas Health Science Center at San Antonio
Richard A Lange, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American Heart Association, and Association of Subspecialty Professors
Disclosure: Nothing to disclose.

Additional Contributors

Jerry Balentine, DO Professor of Emergency Medicine, New York College of Osteopathic Medicine; Executive Vice President, Chief Medical Officer, Attending Physician in Department of Emergency Medicine, St Barnabas Hospital

Jerry Balentine, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American College of Physician Executives, American Osteopathic Association, and New York Academy of Medicine

Disclosure: Nothing to disclose.

Edward Bessman, MD, MBA Chairman and Clinical Director, Department of Emergency Medicine, John Hopkins Bayview Medical Center; Assistant Professor, Department of Emergency Medicine, Johns Hopkins University School of Medicine

Edward Bessman, MD, MBA is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

David FM Brown, MD Associate Professor, Division of Emergency Medicine, Harvard Medical School; Vice Chair, Department of Emergency Medicine, Massachusetts General Hospital

David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Steven J Compton, MD, FACC, FACP, FHRS Director of Cardiac Electrophysiology, Alaska Heart Institute, Providence and Alaska Regional Hospitals

Steven J Compton, MD, FACC, FACP, FHRS is a member of the following medical societies: Alaska State Medical Association, American College of Cardiology, American College of Physicians, American Heart Association, American Medical Association, and Heart Rhythm Society

Disclosure: Nothing to disclose.

Daniel P Lombardi, DO Clinical Assistant Professor, New York College of Osteopathic Medicine; Attending Physician, Associate Department Director and Program Director, Department of Emergency Medicine, St Barnabas Hospital

Daniel P Lombardi, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, and American Osteopathic Association

Disclosure: Nothing to disclose.

John A McPherson, MD, FACC, FAHA, FSCAI Associate Professor of Medicine, Division of Cardiovascular Medicine, Director of Cardiovascular Intensive Care Unit, Vanderbilt Heart and Vascular Institute

John A McPherson, MD, FACC, FAHA, FSCAI is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American Heart Association, Society for Cardiac Angiography and Interventions, Society of Critical Care Medicine, and Tennessee Medical Association

Disclosure: Abbott Vascular Corp. Consulting fee Consulting

Bekir H Melek, MD, FACC Assistant Professor of Clinical Medicine, Department of Medicine, Section of Cardiology, Tulane University School of Medicine

Disclosure: Nothing to disclose.

Gary Setnik, MD Chair, Department of Emergency Medicine, Mount Auburn Hospital; Assistant Professor, Division of Emergency Medicine, Harvard Medical School

Gary Setnik, MD is a member of the following medical societies: American College of Emergency Physicians, National Association of EMS Physicians, and Society for Academic Emergency Medicine

Disclosure: SironaHealth Salary Management position; South Middlesex EMS Consortium Salary Management position; ProceduresConsult.com Royalty Other

James V Talano, MD, MM, FACC Director of Cardiovascular Medicine, SWICFT Institute

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

References

Wood S. Expanded FDA indication for Sapien valve. Medscape Medical News [serial online]. September 24, 2013;Accessed October 1, 2013. Available at http://www.medscape.com/viewarticle/811544.

FDA approval expands access to artificial heart valve for inoperable patients [press release]. Food and Drug Administration; September 23, 2013. [Full Text].

Tintinalli JE, Kelen GD, Stapczynski JS, eds. Valvular emergencies. In: 6th ed. Emergency Medicine: A Comprehensive Study Guide. New York: McGraw-Hill; 2004:54.

Bergler-Klein J. Natriuretic peptides in the management of aortic stenosis. Curr Cardiol Rep. Mar 2009;11(2):85-93. [Medline].

Townsend CM, et al. Sabiston Textbook of Surgery. 18th ed. Saunders; 2008:1841-1844..

Vahanian A, Alfieri O, Andreotti F, Antunes MJ, Barón-Esquivias G, Baumgartner H, et al. Guidelines on the management of valvular heart disease (version 2012): The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. Oct 2012;33(19):2451-96. [Medline].

[Guideline] Bonow RO, Carabello BA, Chatterjee K, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing Committee to Revise the 1998 guidelines for the management of patients with valvular heart disease) developed in collaboration with the Society of Cardiovascular Anesthesiologists endorsed by the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons. J Am Coll Cardiol. Aug 1 2006;48(3):e1-148. [Medline].

Tzemos N, Therrien J, Yip J, Thanassoulis G, Tremblay S, Jamorski MT, et al. Outcomes in adults with bicuspid aortic valves. JAMA. Sep 17 2008;300(11):1317-25. [Medline].

Hughes BR, Chahoud G, Mehta JL. Aortic stenosis: is it simply a degenerative process or an active atherosclerotic process?. Clin Cardiol. Mar 2005;28(3):111-4. [Medline].

Roberts WC, Vowels TJ, Ko JM. Comparison of interpretations of valve structure between cardiac surgeon and cardiac pathologist among adults having isolated aortic valve replacement for aortic valve stenosis (+/- aortic regurgitation). Am J Cardiol. Apr 15 2009;103(8):1139-45. [Medline].

Kerstjens-Frederikse WS, Du Marchie Sarvaas GJ, et al. Left ventricular outflow tract obstruction: should cardiac screening be offered to first-degree relatives?. Heart. Aug 2011;97(15):1228-32. [Medline].

Lancellotti P, Magne J, Donal E, et al. Clinical outcome in asymptomatic severe aortic stenosis insights from the new proposed aortic stenosis grading classification. J Am Coll Cardiol. Jan 17 2012;59(3):235-43. [Medline].

Jander N, Minners J, Holme I, et al. Outcome of patients with low-gradient "severe" aortic stenosis and preserved ejection fraction. Circulation. Mar 1 2011;123(8):887-95. [Medline].

Rodrigues Tda R, Sternick EB, Moreira Mda C. Epilepsy or syncope? An analysis of 55 consecutive patients with loss of consciousness, convulsions, falls, and no EEG abnormalities. Pacing Clin Electrophysiol. Jul 2010;33(7):804-13. [Medline].

Topol EJ, Califf RM, et al, eds. Aortic valve disease. In: Textbook of Cardiovascular Medicine. Section Two. 3rd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2007:Chap 23.

Zegdi R, Ciobotaru V, Huerre C, Allam B, Bouabdallaoui N, Berrebi A, et al. Detecting aortic valve bicuspidy in patients with severe aortic valve stenosis: high diagnostic accuracy of colour Doppler transoesophageal echocardiography. Interact Cardiovasc Thorac Surg. Jan 2013;16(1):16-20. [Medline]. [Full Text].

Zamorano JL, Badano LP, Bruce C, et al. EAE/ASE recommendations for the use of echocardiography in new transcatheter interventions for valvular heart disease. Eur Heart J. Sep 2011;32(17):2189-214. [Medline].

Piérard LA, Lancellotti P. Stress testing in valve disease. Heart. Jun 2007;93(6):766-72. [Medline]. [Full Text].

Messika-Zeitoun D, Aubry MC, Detaint D, Bielak LF, Peyser PA, Sheedy PF, et al. Evaluation and clinical implications of aortic valve calcification measured by electron-beam computed tomography. Circulation. Jul 20 2004;110(3):356-62. [Medline].

Shah RG, Novaro GM, Blandon RJ, Whiteman MS, Asher CR, Kirsch J. Aortic valve area: meta-analysis of diagnostic performance of multi-detector computed tomography for aortic valve area measurements as compared to transthoracic echocardiography. Int J Cardiovasc Imaging. Aug 2009;25(6):601-9. [Medline].

Bergler-Klein J, Klaar U, Heger M, Rosenhek R, Mundigler G, Gabriel H, et al. Natriuretic peptides predict symptom-free survival and postoperative outcome in severe aortic stenosis. Circulation. May 18 2004;109(19):2302-8. [Medline].

Brown DW, Dipilato AE, Chong EC, Gauvreau K, McElhinney DB, Colan SD, et al. Sudden unexpected death after balloon valvuloplasty for congenital aortic stenosis. J Am Coll Cardiol. Nov 30 2010;56(23):1939-46. [Medline].

Agarwal A, Kini AS, Attanti S, Lee PC, Ashtiani R, Steinheimer AM, et al. Results of repeat balloon valvuloplasty for treatment of aortic stenosis in patients aged 59 to 104 years. Am J Cardiol. Jan 1 2005;95(1):43-7. [Medline].

Rahimtoola SH. Choice of prosthetic heart valve in adults an update. J Am Coll Cardiol. Jun 1 2010;55(22):2413-26. [Medline].

[Best Evidence] Stassano P, Di Tommaso L, Monaco M, Iorio F, Pepino P, Spampinato N, et al. Aortic valve replacement: a prospective randomized evaluation of mechanical versus biological valves in patients ages 55 to 70 years. J Am Coll Cardiol. Nov 10 2009;54(20):1862-8. [Medline].

Leon MB, Smith CR, Mack M, Miller DC, Moses JW, Svensson LG, et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med. Oct 21 2010;363(17):1597-607. [Medline].

Clavel, MA, et al. Comparison Between Transcatheter and Surgical Prosthetic Valve Implantation in Patients With Severe Aortic Stenosis and Reduced Left Ventricular Ejection Fraction. Circulation. Nov 9 2010Vol;. 122 No.19.

Smith CR, Leon MB, Mack MJ, et al. Transcatheter versus surgical aortic-valve replacement in high-risk patients. N Engl J Med. Jun 9 2011;364(23):2187-98. [Medline].

Daneault B, Kirtane AJ, Kodali SK, et al. Stroke associated with surgical and transcatheter treatment of aortic stenosis: a comprehensive review. J Am Coll Cardiol. Nov 15 2011;58(21):2143-50. [Medline].

Herrmann HC, Pibarot P, Hueter I, Gertz ZM, Stewart WJ, Kapadia S, et al. Predictors of Mortality and Outcomes of Therapy in Low-Flow Severe Aortic Stenosis: A Placement of Aortic Transcatheter Valves (PARTNER) Trial Analysis. Circulation. Jun 11 2013;127(23):2316-26. [Medline].

Hahn RT, Pibarot P, Stewart WJ, et al. Comparison of transcatheter and surgical aortic valve replacement in severe aortic stenosis: a longitudinal study of echocardiography parameters in cohort A of the PARTNER Trial (Placement of Aortic Transcatheter Valves). J Am Coll Cardiol. Jun 25 2013;61(25):2514-21. [Medline].

[Guideline] Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA. May 21 2003;289(19):2560-72. [Medline].

[Guideline] Nishimura RA, Carabello BA, Faxon DP, et al. ACC/AHA 2008 Guideline Update on Valvular Heart Disease: Focused Update on Infective Endocarditis: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Journal of the American College of Cardiology. August 2008;52:676-85. [Medline].

Moura LM, Ramos SF, Zamorano JL, Barros IM, Azevedo LF, Rocha-Gonçalves F, et al. Rosuvastatin affecting aortic valve endothelium to slow the progression of aortic stenosis. J Am Coll Cardiol. Feb 6 2007;49(5):554-61. [Medline].

Chan KL, Teo K, Dumesnil JG, Ni A, Tam J. Effect of Lipid lowering with rosuvastatin on progression of aortic stenosis: results of the aortic stenosis progression observation: measuring effects of rosuvastatin (ASTRONOMER) trial. Circulation. Jan 19 2010;121(2):306-14. [Medline].

Rossebo AB, Pedersen TR, Boman K, et al. Intensive lipid lowering with simvastatin and ezetimibe in aortic stenosis. N Engl J Med. Sep 25 2008;359(13):1343-56. [Medline].

Cowell SJ, Newby DE, Prescott RJ, et al. A randomized trial of intensive lipid-lowering therapy in calcific aortic stenosis. N Engl J Med. Jun 9 2005;352(23):2389-97. [Medline].

[Guideline] Wann LS, Curtis AB, Ellenbogen KA, et al. 2011 ACCF/AHA/HRS Focused Update on the Management of Patients With Atrial Fibrillation (Update on Dabigatran): A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation. Mar 15 2011;123(10):1144-50. [Medline]. [Full Text].

[Best Evidence] Bagur R, Webb JG, Nietlispach F, Dumont E, De Larochellière R, Doyle D, et al. Acute kidney injury following transcatheter aortic valve implantation: predictive factors, prognostic value, and comparison with surgical aortic valve replacement. Eur Heart J. Apr 2010;31(7):865-74. [Medline]. [Full Text].

Eltchaninoff H, Prat A, Gilard M et al,. Transcatheter aortic valve implantation: early results of the FRANCE (FRench Aortic National CoreValve and Edwards) registry. Eur Heart Jl. 2011;32:191–197.

Lefevre T, Kappetein AP, Wolner E, et al. One year follow-up of the multi-centre European PARTNER transcatheter heart valve study. Eur Heart Jl. 2011;32:148–157.

Leon MB, Smith CR, Mack M, et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med. Oct 21 2010;363(17):1597-607. [Medline].

Prasad Y, Bhalodkar NC. Aortic sclerosis--a marker of coronary atherosclerosis. Clin Cardiol. Dec 2004;27(12):671-3. [Medline].

[Best Evidence] Rosenhek R, Zilberszac R, Schemper M, Czerny M, Mundigler G, Graf S, et al. Natural history of very severe aortic stenosis. Circulation. Jan 5 2010;121(1):151-6. [Medline].

Tamburino C, Capodanno D, Ramondo A, Petronio AS, Ettori F, Santoro G, et al. Incidence and predictors of early and late mortality after transcatheter aortic valve implantation in 663 patients with severe aortic stenosis. Circulation. Jan 25 2011;123(3):299-308. [Medline].

Zahn R, Gerckens U, EGrube E et al. Transcatheter aortic valve implantation: first results from a multi-centre real-world registry. Eur Heart Jl. 2011;32:198–204.

Zajarias A, Cribier AG. Outcomes and safety of percutaneous aortic valve replacement. J Am Coll Cardiol. May 19 2009;53(20):1829-36. [Medline].

  Calcific aortic stenosis (parasternal long-axis and short-axis views). Stenotic aortic valve (macroscopic appearance). Table 1. Common Causes of Aortic Stenosis Among Patients Requiring SurgeryTable 2. ACC/AHA Recommendations for Echocardiography (Imaging, Spectral, and Color Doppler) in Aortic StenosisTable 3. Criteria for Determining Severity of Aortic StenosisTable 4. Recommendations for Cardiac Catheterization in Aortic StenosisTable 5. Recommendations for Aortic Valve Replacement in Aortic StenosisTable 1. Common Causes of Aortic Stenosis Among Patients Requiring SurgeryAge Age >70 years (n=322) Bicuspid AV (50%)

Postinflammatory (25%)

Degenerative (18%)

Unicommissural (3%)

Hypoplastic (2%)

Indeterminate (2%)

Degenerative (48%)

Bicuspid (27%)

Postinflammatory (23%)

Hypoplastic (2%)

Table 2. ACC/AHA Recommendations for Echocardiography (Imaging, Spectral, and Color Doppler) in Aortic StenosisIndication Class Diagnosis and assessment of severity of aortic stenosisIAssessment of LV size, function, and/or hemodynamicsIReevaluation of patients with known aortic stenosis with changing symptoms or signsIAssessment of changes in hemodynamic severity and ventricular function in patients with known aortic stenosis during pregnancyIReevaluation of asymptomatic patients with severe aortic stenosisIReevaluation of asymptomatic patients with mild to moderate aortic stenosis and evidence of LV dysfunction or hypertrophyIIaRoutine reevaluation of asymptomatic adult patients with mild aortic stenosis who have stable physical signs and normal LV size and function IIITable 3. Criteria for Determining Severity of Aortic StenosisSeverity Mean gradient (mm Hg) Aortic valve area (cm2) Mild>1.5Moderate25-401-1.5Severe>40
(or 2/m2 body surface area)

Critical>80Table 4. Recommendations for Cardiac Catheterization in Aortic StenosisIndication Class Coronary angiography before aortic valve replacement in patients at risk for coronary artery diseaseIAssessment of severity of aortic stenosis in symptomatic patients when aortic valve replacement is planned or when noninvasive tests are inconclusive or a discrepancy exists in the clinical findings regarding the severity of aortic stenosis or the need for surgery ICoronary angiography before aortic valve replacement in patients for whom a pulmonary autograft (Ross procedure) is contemplated and the origin of the coronary arteries was not identified by noninvasive tests IWith infusion of dobutamine, can be useful for evaluation of patients with low-flow/low-gradient aortic stenosis and LV dysfunctionIIaNot recommended for hemodynamic measurements for assessment of aortic stenosis severity when noninvasive techniques are adequate and concord with clinical findings IIINot recommended for hemodynamic measurements for assessment of LV function and aortic stenosis severity in asymptomatic patientsIIITable 5. Recommendations for Aortic Valve Replacement in Aortic StenosisIndication Class Symptomatic patients with severe aortic stenosisIPatients with severe aortic stenosis undergoing coronary artery bypass surgeryIPatients with severe aortic stenosis undergoing surgery on the aorta or other heart valvesIPatients with severe aortic stenosis and LV systolic dysfunction (ejection fraction IPatients with moderate aortic stenosis undergoing coronary artery bypass surgery or surgery on the aorta or other heart valvesIIaPatients with mild aortic stenosis undergoing coronary artery bypass surgery when there is evidence that progression may be rapid, such as moderate-to-severe valve calcificationIIbAsymptomatic patients with severe aortic stenosis and abnormal response to exercise (eg, hypotension)IIbAsymptomatic patients with severe aortic stenosis and a high likelihood of rapid progression (based on age, calcification, and coronary artery disease) or if surgery might be delayed at the time of symptom onsetIIbAsymptomatic patients with extremely severe aortic stenosis (valve area less than 0.6 cm2, mean gradient greater than 60 mm Hg, and jet velocity greater than 5 m per second) if the patient’s expected operative mortality is 1% or lessIIbAVR is not useful for prevention of sudden death in asymptomatic patients with none of the findings listed under asymptomatic patients with severe aortic stenosisIII View Table List  Read more about Aortic Stenosis on MedscapeRelated Reference Topics
Aortic Stenosis Pathology
Pediatric Supravalvar Aortic Stenosis
Pediatric Valvar Aortic Stenosis
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Medscape Reference © 2011 WebMD, LLC, Aortic Stenosis

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