Showing posts with label Acute. Show all posts
Showing posts with label Acute. Show all posts

Sunday, February 23, 2014

Practice Essentials

Acute coronary syndrome (ACS) refers to a spectrum of clinical presentations ranging from those for ST-segment elevation myocardial infarction (STEMI) to presentations found in non–ST-segment elevation myocardial infarction (NSTEMI) or in unstable angina. It is almost always associated with rupture of an atherosclerotic plaque and partial or complete thrombosis of the infarct-related artery.

Essential update: Discharge safe in suspected ACS if troponin and copeptin are negative

Patients with suspected ACS who test negative for troponin and copeptin can be safely discharged from the hospital without further testing, according to a recent study, the Biomarkers in Cardiology 8 (BiC-8) trial. Copeptin, a marker of severe hemodynamic stress, can be detected immediately in acute myocardial infarction.[1]

The study involved 902 patients at low to intermediate risk of ACS; half of the patients were treated with standard care, and the other 451 patients underwent a copeptin assay. In the latter group, patients with a positive copeptin test, defined as a level of 10 pmol/L or greater, were treated with standard ACS care, while patients with a copeptin level below 10 pmol/L were discharged into ambulant care, including an outpatient visit within 72 hours.

In the 451 patients tested for troponin and treated with standard care, the 30-day rate of major adverse cardiovascular events was 5.5%, compared with 5.46% in the 451 patients tested for troponin and copeptin, a statistically insignificant difference.

Signs and symptoms

Atherosclerosis is the primary cause of ACS, with most cases occurring from the disruption of a previously nonsevere lesion. Complaints reported by patients with ACS include the following:

PalpitationsPain, which is usually described as pressure, squeezing, or a burning sensation across the precordium and may radiate to the neck, shoulder, jaw, back, upper abdomen, or either arm Exertional dyspnea that resolves with pain or restDiaphoresis from sympathetic dischargeNausea from vagal stimulationDecreased exercise tolerance

Physical findings can range from normal to any of the following:

Hypotension: Indicates ventricular dysfunction due to myocardial ischemia, myocardial infarction (MI), or acute valvular dysfunctionHypertension: May precipitate angina or reflect elevated catecholamine levels due to anxiety or to exogenous sympathomimetic stimulation DiaphoresisPulmonary edema and other signs of left heart failureExtracardiac vascular diseaseJugular venous distentionCool, clammy skin and diaphoresis in patients with cardiogenic shockA third heart sound (S3) and, frequently, a fourth heart sound (S4)A systolic murmur related to dynamic obstruction of the left ventricular outflow tractRales on pulmonary examination (suggestive of left ventricular dysfunction or mitral regurgitation)

Potential complications include the following:

Ischemia: Pulmonary edemaMyocardial infarction: Rupture of the papillary muscle, left ventricular free wall, and ventricular septum

See Clinical Presentation for more detail.

Diagnosis

Guidelines for the management of non-ST-segment elevation ACS were released in 2011 by the European Society of Cardiology (ESC).[2] The guidelines include the use of the CRUSADE risk score (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines).

In the emergency setting, electrocardiography (ECG) is the most important diagnostic test for angina. ECG changes that may be seen during anginal episodes include the following:

Transient ST-segment elevationsDynamic T-wave changes: Inversions, normalizations, or hyperacute changesST depressions: These may be junctional, downsloping, or horizontal

Laboratory studies that may be helpful include the following:

Creatine kinase isoenzyme MB (CK-MB) levelsCardiac troponin levelsMyoglobin levelsComplete blood countBasic metabolic panel

Diagnostic imaging modalities that may be useful include the following:

Chest radiographyEchocardiographyMyocardial perfusion imagingCardiac angiographyComputed tomography, including CT coronary angiography and CT coronary artery calcium scoring

See Workup for more detail.

Management

Initial therapy focuses on the following:

Stabilizing the patient’s conditionRelieving ischemic painProviding antithrombotic therapy

Pharmacologic anti-ischemic therapy includes the following:

Nitrates (for symptomatic relief)Beta blockers (eg, metoprolol): These are indicated in all patients unless contraindicated

Pharmacologic antithrombotic therapy includes the following:

AspirinClopidogrelPrasugrelTicagrelorGlycoprotein IIb/IIIa receptor antagonists (abciximab, eptifibatide, tirofiban)

Pharmacologic anticoagulant therapy includes the following:

Unfractionated heparin (UFH)Low-molecular-weight heparin (LMWH; dalteparin, nadroparin, enoxaparin)Factor Xa inhibitors (rivaroxaban, fondaparinux)

Additional therapeutic measures that may be indicated include the following:

ThrombolysisPercutaneous coronary intervention (preferred treatment for ST-elevation MI)

Current guidelines for patients with moderate- or high-risk ACS include the following:

Early invasive approachConcomitant antithrombotic therapy, including aspirin and clopidogrel, as well as UFH or LMWH

See Treatment and Medication for more detail.

Image libraryA 62-year-old woman with a history of chronic stabA 62-year-old woman with a history of chronic stable angina and a "valve problem" presents with new chest pain. She is symptomatic on arrival, complaining of shortness of breath and precordial chest tightness. Her initial vital signs are blood pressure = 140/90 mm Hg and heart rate = 98. Her electrocardiogram (ECG) is as shown. She is given nitroglycerin sublingually, and her pressure decreases to 80/palpation. Right ventricular ischemia should be considered in this patient. NextBackground

Acute coronary syndrome (ACS) refers to a spectrum of clinical presentations ranging from those for ST-segment elevation myocardial infarction (STEMI) to presentations found in non–ST-segment elevation myocardial infarction (NSTEMI) or in unstable angina. In terms of pathology, ACS is almost always associated with rupture of an atherosclerotic plaque and partial or complete thrombosis of the infarct-related artery. (See Etiology.)

In some instances, however, stable coronary artery disease (CAD) may result in ACS in the absence of plaque rupture and thrombosis, when physiologic stress (eg, trauma, blood loss, anemia, infection, tachyarrhythmia) increases demands on the heart. The diagnosis of acute myocardial infarction in this setting requires a finding of the typical rise and fall of biochemical markers of myocardial necrosis in addition to at least 1 of the following[3] (See Workup.):

Ischemic symptomsDevelopment of pathologic Q wavesIschemic ST-segment changes on electrocardiogram (ECG) or in the setting of a coronary intervention

The terms transmural and nontransmural (subendocardial) myocardial infarction are no longer used because ECG findings in patients with this condition are not closely correlated with pathologic changes in the myocardium. Therefore, a transmural infarct may occur in the absence of Q waves on ECGs, and many Q-wave myocardial infarctions may be subendocardial, as noted on pathologic examination. Because elevation of the ST segment during ACS is correlated with coronary occlusion and because it affects the choice of therapy (urgent reperfusion therapy), ACS-related myocardial infarction should be designated STEMI or NSTEMI. (See Workup.)

Attention to the underlying mechanisms of ischemia is important when managing ACS. A simple predictor of demand is rate-pressure product, which can be lowered by beta blockers (eg, metoprolol or atenolol) and pain/stress relievers (eg, morphine), while supply may be improved by oxygen, adequate hematocrit, blood thinners (eg, heparin, IIb/IIIa agents such as abciximab, eptifibatide, tirofiban, or thrombolytics), and/or vasodilators (eg, nitrates, amlodipine). (See Medications.)

In 2010, the American Heart Association (AHA) published new guideline recommendations for the diagnosis and treatment of ACS.[4]

PreviousNextEtiology

Acute coronary syndrome (ACS) is caused primarily by atherosclerosis. Most cases of ACS occur from disruption of a previously nonsevere lesion (an atherosclerotic lesion that was previously hemodynamically insignificant yet vulnerable to rupture). The vulnerable plaque is typified by a large lipid pool, numerous inflammatory cells, and a thin, fibrous cap.

Elevated demand can produce ACS in the presence of a high-grade fixed coronary obstruction, due to increased myocardial oxygen and nutrition requirements, such as those resulting from exertion, emotional stress, or physiologic stress (eg, from dehydration, blood loss, hypotension, infection, thyrotoxicosis, or surgery).

ACS without elevation in demand requires a new impairment in supply, typically due to thrombosis and/or plaque hemorrhage.

The major trigger for coronary thrombosis is considered to be plaque rupture caused by the dissolution of the fibrous cap, the dissolution itself being the result of the release of metalloproteinases (collagenases) from activated inflammatory cells. This event is followed by platelet activation and aggregation, activation of the coagulation pathway, and vasoconstriction. This process culminates in coronary intraluminal thrombosis and variable degrees of vascular occlusion. Distal embolization may occur. The severity and duration of coronary arterial obstruction, the volume of myocardium affected, the level of demand on the heart, and the ability of the rest of the heart to compensate are major determinants of a patient's clinical presentation and outcome. (Anemia and hypoxemia can precipitate myocardial ischemia in the absence of severe reduction in coronary artery blood flow.)

A syndrome consisting of chest pain, ischemic ST-segment and T-wave changes, elevated levels of biomarkers of myocyte injury, and transient left ventricular apical ballooning (takotsubo syndrome) has been shown to occur in the absence of clinical CAD, after emotional or physical stress. The etiology of this syndrome is not well understood but is thought to relate to a surge of catechol stress hormones and/or high sensitivity to those hormones.

PreviousNextPrognosis

Six-month mortality rates in the Global Registry of Acute Coronary Events (GRACE) were 13% for patients with NSTEMI ACS and 8% for those with unstable angina.

An elevated level of troponin (a type of regulatory protein found in skeletal and cardiac muscle) permits risk stratification of patients with ACS and identifies patients at high risk for adverse cardiac events (ie, myocardial infarction, death) up to 6 months after the index event.[5, 6] (See Workup.)

The PROVE IT-TIMI trial found that after ACS, a J-shaped or U-shaped curve association is observed between BP and the risk of future cardiovascular events.[7]

LeLeiko et al determined that serum choline and free F(2)-isoprostane are also predictors of cardiac events in ACS. The authors evaluated the prognostic value of vascular inflammation and oxidative stress biomarkers in patients with ACS to determine their role in predicting 30-day clinical outcomes. Serum F(2)-isoprostane had an optimal cutoff level of 124.5 pg/mL, and serum choline had a cutoff level of 30.5 µmol/L. Choline and F(2)-isoprostane had a positive predictive value of 44% and 57% and a negative predictive value of 89% and 90%, respectively.[8]

Testosterone deficiency is common in patients with coronary disease and has a significant negative impact on mortality. Further study is needed to assess the effect of treatment on survival.[9]

A study by Sanchis et al suggests renal dysfunction, dementia, peripheral artery disease, previous heart failure, and previous myocardial infarction are the comorbid conditions that predict mortality in NSTEMI ACS.[10] In patients with comorbid conditions, the highest risk period was in the first weeks after NSTEMI ACS. In-hospital management of patients with comorbid conditions merits further investigation.

Patients with end-stage renal disease often develop ACS, and little is known about the natural history of ACS in patients receiving dialysis. Gurm et al examined the presentation, management, and outcomes of patients with ACS who received dialysis before presentation for an ACS. These patients were enrolled in the Global Registry of Acute Coronary Events (GRACE) at 123 hospitals in 14 countries from 1999-2007.

NSTEMI ACS was the most common in patients receiving dialysis, occurring in 50% of patients (290 of 579) versus 33% (17,955 of 54,610) of those not receiving dialysis The in-hospital mortality rates were higher among patients receiving dialysis (12% vs 4.8%; p [11]

In a study that assessed the impact of prehospital time on STEMI outcome, Chughatai et al suggest that “total time to treatment” should be used as a core measure instead of “door-to-balloon time.”[12] This is because on-scene time was the biggest fraction of "pre-hospital time.” The study compared groups with total time to treatment of more than 120 minutes compared with 120 minutes or less and found mortalities were 4 compared with 0 and transfers to a tertiary care facility were 3 compared with 1, respectively.

PreviousNextPatient Education

Patient education of risk factors is important, but more attention is needed regarding delays in door-to-balloon time, and one major barrier to improving this delay is patient education regarding his or her symptoms. Lack of recognition of symptoms may cause tremendous delays in seeking medical attention.

Educate patients about the dangers of cigarette smoking, a major risk factor for coronary artery disease (CAD). The risk of recurrent coronary events decreases 50% at 1 year after smoking cessation. Provide all patients who smoke with guidance, education, and support to avoid smoking. Smoking-cessation classes should be offered to help patients avoid smoking after a myocardial infarction. Bupropion increases the likelihood of successful smoking cessation.

Diet plays an important role in the development of CAD. Therefore, prior to hospital discharge, a patient who has had a myocardial infarction should be evaluated by a dietitian. Patients should be informed about the benefits of a low-cholesterol, low-salt diet. In addition, educate patients about AHA dietary guidelines regarding a low-fat, low-cholesterol diet.

A cardiac rehabilitation program after discharge may reinforce education and enhance compliance.

The following mnemonic may useful in educating patients with CAD regarding treatments and lifestyle changes necessitated by their condition:

A = Aspirin and antianginalsB = Beta blockers and blood pressure (BP)C = Cholesterol and cigarettesD = Diet and diabetesE = Exercise and education

For patients being discharged home, emphasize the following:

Timely follow-up with primary care providerCompliance with discharge medications, specifically aspirin and other medications used to control symptomsNeed to return to the ED for any change in frequency or severity of symptomsPreviousProceed to Clinical Presentation , Acute Coronary Syndrome

Wednesday, February 5, 2014

Practice Essentials

Acute pericarditis is an inflammation of the pericardium characterized by chest pain, pericardial friction rub, and serial ECG changes.

Signs and symptoms

Chest pain is the cardinal symptom of pericarditis, usually precordial or retrosternal with referral to the trapezius ridge, neck, left shoulder, or arm. Common associated signs and symptoms include low-grade intermittent fever, dyspnea/tachypnea (a frequent complaint and may be severe, with myocarditis, pericarditis, and cardiac tamponade), cough, and dysphagia. In tuberculous pericarditis, fever, night sweats, and weight loss are commonly noted (80%).

Specific causes of pericarditis include the following:

Idiopathic causesInfectious conditions, such as viral, bacterial, and tuberculous infectionsInflammatory disorders, such as RA, SLE, scleroderma, and rheumatic feverMetabolic disorders, such as renal failure, hypothyroidism, and hypercholesterolemiaCardiovascular disorders, such as acute MI, Dressler syndrome, and aortic dissectionMiscellaneous causes, such as iatrogenic, neoplasms, drugs, irradiation, cardiovascular procedures, and trauma

See Clinical Presentation for more detail.

Diagnosis

Initial evaluation includes a clinical history and physical examination, ECG, echocardiography, chest radiography, and lab studies.

ECG can be diagnostic in acute pericarditis and typically shows ST elevation in all leads. The ratio of the amplitude of ST segment to the amplitude of the T wave in leads I, V4, V5, and V6 on electrocardiogram can be used to differentiate acute pericarditis (AP) from early repolarization (ER) and early repolarization of left ventricular hypertrophy (ERLVH), according to a recent study. When ST elevation was present in lead I, the ST/T ratio had the best predictive value for discriminating between AP, ER and ERLVH. The study involved 25 patients with AP, 27 with ER, and 28 with ERLVH.[1]

Echocardiography is particularly helpful if pericardial effusion is suspected on clinical or radiographic grounds, the illness lasts longer than 1 week, or myocarditis or purulent pericarditis is suspected.

A chest radiograph is only helpful for diagnosis in patients with effusions >250mL. Patients with small effusions (less than a few hundred milliliters) may present with a normal cardiac silhouette.

Lab tests may include CBC; serum electrolyte, blood urea nitrogen (BUN), and creatinine levels; erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels; and cardiac biomarker measurements, lactate dehydrogenase (LDH), and serum glutamic-oxaloacetic transaminase (SGOT; AST) levels.

See Workup for more detail.

Management

Treatment for specific causes of pericarditis is directed according to the underlying cause. For patients with idiopathic or viral pericarditis, therapy is directed at symptom relief.

Pharmacologic treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the mainstay of therapy. These agents have a similar efficacy, with relief of chest pain in about 85-90% of patients within days of treatment. A full-dose NSAID should be used, and treatment should last 7-14 days.

Colchicine, alone or in combination with an NSAID, can be considered for patients with recurrent or continued symptoms beyond 14 days.[2]

Corticosteroids should not be used for initial treatment of pericarditis unless it is indicated for the underlying disease, the patient’s condition has no response to NSAIDs or colchicine, or both agents are contraindicated.

Surgical treatment

Surgical procedures for pericarditis include pericardiectomy, pericardiocentesis, pericardial window placement, and pericardiotomy.

Pericardiectomy is the most effective surgical procedure for managing large effusions, because it has the lowest associated risk of recurrent effusions. This procedure is used for constrictive pericarditis, effusive pericarditis, or recurrent pericarditis with multiple attacks, steroid dependence, and/or intolerance to other medical management.

Patients with effusions larger than 250 mL, effusions in which size increases despite intensive dialysis for 10-14 days, or effusions with evidence of tamponade are candidates for pericardiocentesis.

Pericardial window placement is used for effusive pericarditis therapy. In critically ill patients, a balloon catheter may be used to create a pericardial window, in which only 9 cm2 or less of pericardium is resected.

Consider subxiphoid pericardiotomy for large effusions that do not resolve. This procedure may be performed under local anesthesia and has a lower risk of complications than pericardiectomy.

See Treatment and Medication for more detail.

Image libraryThis 12-lead electrocardiogram is representative oThis 12-lead electrocardiogram is representative of pericarditis. NextBackground

Acute pericarditis is an inflammation of the pericardium characterized by chest pain, pericardial friction rub, and serial electrocardiographic (ECG) changes (see an example of such an ECG below). Pericarditis and cardiac tamponade involve the potential space surrounding the heart or pericardium; pericarditis is one cause of fluid accumulation in this potential space, and cardiac tamponade is the hemodynamic result of fluid accumulation.

This 12-lead electrocardiogram is representative oThis 12-lead electrocardiogram is representative of pericarditis.

For more information, see the the Medscape Reference articles Constrictive Pericarditis, Constrictive-Effusive Pericarditis, Pediatric Infective Pericarditis, and Imaging in Constrictive Pericarditis.

For patient education information, see the Cholesterol Center and Heart Center, as well as Pericarditis, Heart Attack, and Chest Pain.

PreviousNextAnatomy

The pericardium (pericardial complex) serves as a protective barrier from the spread of infection or inflammation from adjacent structures. It is composed of the parietal pericardium (an outer fibrous layer) and the visceral pericardium (an inner serous membrane made of a single layer of mesothelial cells). The fibrous pericardium is a flask-shaped, tough outer sac with attachments to the diaphragm, sternum, and costal cartilage. The visceral pericardium is thin, adjacent to the surface of the heart, and attached to the epicardial fat; it reflects back on itself to form the parietal pericardium.

The pericardium normally contains as much as 20-50 mL of an ultrafiltrate of plasma. Approximately 90-120 mL of additional pericardial fluid can accumulate in the pericardium without an increase in pressure. The capacity of the atria and ventricles to fill is mechanically compromised with further fluid accumulation, which can result in marked increases in pericardial pressure, eliciting reduced stroke volume, decreased cardiac output, and hypotension (cardiac tamponade physiology). The rapidity of fluid accumulation influences the hemodynamic effect. Drainage occurs via the thoracic duct and the right lymphatic duct into the right pleural space.

PreviousNextPathophysiology

Pericardial physiology includes 3 main functions. First, through its mechanical function, the pericardium promotes cardiac efficiency by limiting acute dilation, maintaining ventricular compliance with preservation of the Starling curve, and distributing hydrostatic forces. The pericardium also creates a closed chamber with subatmospheric pressure that aids atrial filling and lowers transmural cardiac pressures. Second, through its membranous function, the pericardium shields the heart by reducing external friction and acting as a barrier against extension of infection and malignancy. Third, through its ligamentous function, the pericardium anatomically fixes the heart.

In most cases of acute pericarditis, the pericardium is acutely inflamed and has an infiltration of polymorphonuclear (PMN) leukocytes and pericardial vascularization. Often, the pericardium manifests a fibrinous reaction with exudates and adhesions. The pericardium may develop a serous or hemorrhagic effusion. A granulomatous pericarditis occurs with tuberculosis, fungal infections, rheumatoid arthritis (RA), and sarcoidosis.

Uremic pericarditis is thought to result from inflammation of the visceral and parietal layers of the pericardium by metabolic toxins that accumulate in the body owing to kidney failure. Other factors may be involved, however, because pericarditis also may occur in patients with chronic renal failure who are already receiving dialysis therapy.

The putative toxins suggested to precipitate uremic pericarditis when they accumulate are poorly characterized, but they may include urea, creatinine, methylguanidine, guanidinoacetate, parathyroid hormone, beta2-microglobulin, uric acid, and others. More than one toxin apparently may be involved, although considerable controversy surrounds this point.

The precise pathogenetic changes induced by these toxins when causing uremic pericarditis have not been elucidated, although a rough correlation with the degree and the duration of azotemia exists; the blood urea nitrogen (BUN) level is usually greater than 60 mg/dL (22 mmol/L). Uremic pericarditis may be associated with hemorrhagic or serous effusion, although considerable overlap exists. Hemorrhagic effusions are more common and result in part from uremia-induced platelet dysfunction.

Some authors distinguish between 2 types of pericarditis in patients with renal failure. One type is uremic pericarditis, which occurs in patients with uremia who have never received dialysis. The other type is dialysis-associated pericarditis, which occurs in patients who are already receiving dialysis. In the latter case, inadequate dialysis may usually be implicated, because aggressive dialysis often leads to resolution. Other causes of dialysis-associated pericarditis may include volume overload and bacterial or viral infections.

In an observational study that employed data from 88 maintenance hemodialysis patients, investigators found that intensive dialysis is the most effective treatment for dialysis-associated pericarditis in patients on dialysis who have diabetes and those who do not.[3] Following the intensification of hemodialysis, pericarditis improved in 85.1% of patients with diabetes and in 82.9% of those without diabetes. Among patients with diabetes, 85.1% survived without recurrence of pericarditis, 4.3% survived but did suffer recurrence, and 10.6% died, with similar outcomes recorded in the group without diabetes (87.8%, 4.9%, and 7.3%, respectively).[3]

PreviousNextEtiology

This section will first briefly discuss acute pericarditis, chronic pericarditis, and cardiac tamponade; then, several specific entities that cause pericarditis will be briefly reviewed.

Acute pericarditis

Serous pericarditis is usually caused by noninfectious inflammation such as occurs in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Fibrous adhesions rarely occur.

Fibrous and serofibrinous pericarditis represent the same basic process and are the most frequent type of pericarditis. Common causes include acute myocardial infarction (MI), postinfarction (including Dressler syndrome), uremia, radiation, RA, SLE, and trauma. Severe infections may also cause a fibrinous reaction, as does routine cardiac surgery.

Purulent or suppurative pericarditis due to causative organisms may arise from direct extension, hematogenous seeding, or lymphatic extension, or by direct introduction during cardiotomy. Immunosuppression facilitates this condition. Clinical features include fever, chills, and spiking temperatures. Constrictive pericarditis is a serious potential complication.

Hemorrhagic pericarditis involves blood mixed with a fibrinous or suppurative effusion, and it is most commonly caused by tuberculosis or direct neoplastic invasion. This condition can also occur in severe bacterial infections or in patients with a bleeding diathesis. Hemorrhagic pericarditis is common after cardiac surgery and may cause tamponade. The clinical significance is similar to suppurative pericarditis.

Until proven otherwise, caseation within the pericardial sac is tuberculous in origin. Untreated, caseous pericarditis is the most common antecedent to chronic constrictive pericarditis of a fibrocalcific nature.

Chronic pericarditis

Adhesive mediastinopericarditis is a reaction that usually follows suppurative or caseous pericarditis, cardiac surgery, or irradiation. This condition is rarely caused by a simple fibrinous exudate. The pericardial potential space is obliterated, and adhesion of the external surface of the parietal layer to surrounding structures occurs. Clinically, systolic contraction of the ribcage and diaphragm and pulsus paradoxus may be observed. The increased workload may cause massive cardiac hypertrophy and dilatation, which can mimic an idiopathic cardiomyopathy.

Constrictive pericarditis is usually caused by suppurative, caseous, or hemorrhagic pericarditis. The heart may become encased in a 0.5-cm–thick to 1-cm–thick layer of scar or calcification (concretio cordis), resembling a plaster mold. Contrary to clinical findings in adhesive mediastinopericarditis, the heart cannot become hypertrophic or dilate because of insufficient space.

Imazio et al suggest that constrictive pericarditis is a rare complication of viral or idiopathic acute pericarditis ([4]

Cardiac tamponade

Tamponade is more common in patients with malignant pericarditis. Effusions caused by tumors often progress to tamponade, eliciting bleeding in the pericardium. Blood accumulates more rapidly than a transudate or exudate and more commonly causes tamponade.

Identification of any pericardial fluid in the setting of penetrating injury to the thorax or upper abdomen requires aggressive resuscitation; penetrating cardiac injuries may occur, with hemopericardium as the most common feature. In acute massive hemopericardium, the time is insufficient for defibrination to occur. The hemopericardium organizes and may partially clot, resulting in a pericardial hematoma. The hematoma may appear echogenic instead of echo free.

Potential sources of iatrogenic cardiac perforation include central line placement, pacemaker insertion, cardiac catheterization, sternal bone marrow biopsies, and pericardiocentesis. The right atrium is the most common site of perforation from catheter placement. Perforation, as well as direct catheter infusion of fluids, can cause tamponade. In fact, a tamponade delay of hours to days has occurred secondary to catheter misplacement.

In one case report, tamponade was described as the first manifestation of dermatopolymyositis.[5]

Specific causes of pericarditis include the following and are briefly reviewed below:

Idiopathic causesInfectious conditions, such as viral, bacterial, and tuberculous infectionsInflammatory disorders, such as RA, SLE, scleroderma, and rheumatic feverMetabolic disorders, such as renal failure, hypothyroidism, and hypercholesterolemiaCardiovascular disorders, such as acute MI, Dressler syndrome, and aortic dissectionMiscellaneous causes, such as iatrogenic, neoplasms, drugs, irradiation, cardiovascular procedures, and traumaIdiopathic causes

Between 26% and 86% of cases of acute pericarditis are idiopathic in nature.[6] No clinical features distinguish idiopathic cases from viral pericarditis. It is likely that most idiopathic cases are undiagnosed viral infections. Seasonal peaks occur in spring and fall.

Chronic idiopathic pericarditis is defined as a pericardial effusion that persists more than 3 months without any apparent etiology. Pericardiocentesis alone results in resolution of large effusions; however, recurrence is common.

Viral infection

Viral infection is the most common cause of acute pericarditis and accounts for 1-10% of cases. The disease is usually a short self-limited disease that lasts 1-3 weeks and can occur as seasonal epidemics, especially coxsackievirus B and influenza.

Causative viruses include coxsackievirus B,[7] echovirus, adenoviruses, influenza A and B viruses, enterovirus, mumps virus, Epstein-Barr virus, human immunodeficiency virus (HIV), herpes simplex virus (HSV) type 1, varicella-zoster virus (VZV), measles virus, parainfluenza virus (PIV) type 2, and respiratory syncytial virus (RSV), cytomegalovirus (CMV), and hepatitis viruses A, B, and C (HAV, HBV, HCV, respectively).

Patients may have associated myocarditis. Pericardial involvement is frequent in persons with HIV, but is usually an asymptomatic pericardial effusion of small volume. Individuals with advanced HIV infection develop pericardial involvement more frequently, with one study noting right atrial diastolic compression in 5% of cases involving advanced HIV infection.[8] Symptomatic pericarditis occurs in less than 1% of cases involving HIV, and its etiology can include the usual causes, opportunistic infection, Kaposi sarcoma, and HIV.

Bacterial infection

Bacterial infections accounts for 1-8% of pericarditis cases and result from direct pulmonary extension, hematogenous spread, myocardial abscess or endocarditis, penetrating injury to chest wall from either trauma or surgery, or a subdiaphragmatic suppurative lesion. Purulent pericarditis may result from previous aseptic pericarditis, and a high percentage of patients develop constrictive pericarditis.

Organisms that have been isolated include gram-positive species such as Streptococcus pneumoniae and other Streptococcus species and Staphylococcus.[9] Isolated gram-negative species include Proteus, Escherichia coli, Pseudomonas, Klebsiella, Salmonella, Shigella, Neisseria meningitidis, and Haemophilus influenzae.

Less common organisms include Legionella, Nocardia, Actinobacillus, Rickettsia, Borrelia burgdorferi (Lyme borreliosis), Listeria, Leptospira, Chlamydophila psittaci, and Treponema pallidum (syphilis).

Anaerobes have also been isolated in 40% of patients in reviews of the pediatric population.

Previously, Pneumococcus was the predominant organism. However, in the antibiotic era, staphylococcal and gram-negative species have become more common. Most cases are now associated with thoracic surgery, renal disease, and immunosuppression.

Tuberculous infection

Tuberculosis accounts for 4% of cases and should be considered in all instances of pericarditis without a rapid course, especially in high-risk groups, such as elderly patients in nursing homes and those with acquired immunodeficiency syndrome (AIDS).[10] Approximately 50% of affected patients develop constrictive pericarditis.

Fungal and parasitic infection

Fungal organisms that may cause acute pericarditis include Histoplasma, Blastomyces, Coccidioides, Aspergillus, and Candida. Parasitic organisms include Entamoeba, Echinococcus, and Toxoplasma.

Rheumatoid arthritis

Pericarditis occurs predominantly in males with severely destructive and nodular RA. The pericardial involvement is usually clinically silent, with the diagnosis made in only 2% of adults and 6% of juveniles with RA. Rarely, pericarditis precedes the onset of RA. Autopsy studies show a pericarditis prevalence of 11-50%.

Systemic lupus erythematosus, scleroderma, sarcoidosis

Clinically evident pericarditis has been reported in 25% of patients with SLE and usually occurs in lupus flare-ups, but it may be the presenting manifestation. Autopsy series reveal pericardial involvement in 62% of lupus patients.

Pericarditis is recognized in 5-10% of patients with scleroderma, with a 70% autopsy prevalence. Pericardial effusions occur in 40% of patients with scleroderma and can be due to scleroderma, myocardial failure (restrictive cardiomyopathy), and renal failure. Restrictive cardiomyopathy and pericardial constriction can coexist. Usually, pulmonary hypertension, right heart failure, and systolic dysfunction occur.

Sarcoidosis may result in pericarditis, but this condition rarely causes cardiac tamponade or constrictive pericarditis

Rheumatic fever

Pericarditis in those with rheumatic fever occurs more commonly in lower socioeconomic groups and in children, often accompanying endocarditis and myocarditis, with a worse prognosis. Consider rheumatic fever as an etiology in any child with pericarditis. However, this disease is not a demonstrated cause of constrictive pericarditis.

In adults, pericarditis may not occur with myocardial or valvular involvement, and it is associated with a better prognosis. The pericarditis usually appears 7-10 days after the onset of fever and arthritis. Often, stage 1 electrocardiographic (ECG) findings are absent (see Electrocardiography).

Other inflammatory conditions

The following conditions may also cause acute pericarditis:

Sjögren syndromeMixed connective-tissue diseaseReiter syndromeAnkylosing spondylitisInflammatory bowel diseaseWegener granulomatosisVasculitis (eg, giant cell arteritis, polyarteritis)PolymyositisBehçet syndromeWhipple diseaseFamilial Mediterranean feverSerum sicknessRenal failure

Richard Bright described uremic pericarditis in 1836. Since that classic description, this common complication of chronic renal failure has evolved from an ominous event heralding the terminal stages of disease to an event that, with early management, is likely to have a good outcome. Furthermore, advances in dialysis technology with early and timely management of chronic renal failure have dramatically reduced the prevalence of uremic pericarditis. Uremic pericarditis has a prevalence of 6-10% in patients with acute or chronic renal failure, and it continues to be associated with significant morbidity and occasional mortality.

Renal failure accounts for approximately 12% of cases of pericarditis. In the predialysis era, pericarditis developed in 35-50% of patients with uremia who had chronic renal failure and less commonly in those with acute renal failure. Death often followed in several weeks. With dialysis, the pericarditis incidence rate is less than 10%; however, this condition occurs after the onset of dialysis in 8-12% of cases.

Asymptomatic pericardial effusions can occur in 36-62% of patients with uremia who require dialysis; these effusions are often small to moderate in size and can occur secondary to volume overload. Pericardial effusions can lead to significant hemodynamic complications during routine dialysis. Moreover, the presence of a large pericardial effusion that persists for longer than 10 days after intensive dialysis has a high likelihood of causing tamponade.

Hypothyroidism

Hypothyroidism accounts for as many as 4% of pericarditis cases. In fact, myocardial involvement is common, and pericardial involvement usually occurs with severe hypothyroidism. Patients may develop large pericardial effusions, but they rarely develop tamponade.

Cholesterol pericarditis

Cholesterol pericarditis, also called gold-paint pericarditis, is a complication of a chronic pericardial effusion exacerbated by cholesterol crystals. It usually presents with large effusions that are not hemodynamically important, and development of constriction is rare. Granulomatous pericarditis has been implicated in some cases.

Myocardial infarction

After a transmural infarction, a fibrinous pericardial exudate appears within 24 hours, begins to organize at 4-8 days, and completes organization at 4 weeks.[11, 12] Pericardial pain occurs less frequently than the friction rub, which is often detected on the second or third day after an acute MI but may be heard within 24 hours and as late as 10 days.

Before thrombolytic therapy, infarct-associated pericarditis ranges from 7% to 23% of cases. At autopsy in one study, almost all patients were noted to have localized fibrinous pericarditis overlying the area of infarction. With thrombolytic therapy and direct infarct angioplasty, the incidence of post–MI-associated pericarditis has decreased to 5-8%.

Overall, pericardial involvement indicates a larger infarction, greater incidence of left ventricular dysfunction, and greater mortality. The pericarditis usually heals without consequence; effusions may occur, but they rarely lead to tamponade.

Dressler syndrome

Dressler syndrome is now considered rare. When pericarditis associated with Dressler syndrome does occur, it is usually observed 2-3 weeks after a myocardial infarction. Initially, the syndrome was described in as many as 4% of patients following and acute MI. Later studies suggested a much lower incidence. Dressler syndrome is rarely described with pulmonary embolism.

This syndrome may be a unique autoimmune-mediated phenomenon to myocardial antigens, or it may merely be an unrecognized post–MI pericarditis. Patients may develop pulmonary infiltrates and large pericardial effusions.

Because of the risk of hemorrhagic pericarditis, anticoagulant therapy should be stopped in patients with Dressler syndrome.

Aortic dissection and Takotsubo cardiomyopathy

Aortic dissection accounts for 1% of cases of acute pericarditis, especially for cases with hemorrhage into the pericardium.

Takotsubo cardiomyopathy is a transient cardiac syndrome that involves left ventricular apical akinesis and mimics acute coronary syndrome.

Neoplasm

Malignancy account for 5-17% of pericarditis cases; in patients presenting with acute pericarditis or pericardial effusion, 4-7% have an unsuspected malignancy. Primary neoplasm of the heart and pericardium is rare; most cases of neoplasm-related pericarditis are a result of metastatic disease. Autopsy studies have noted that approximately 10% of patients with cancer develop cardiac involvement, and it is often clinically silent. The neoplastic cells reach the pericardium through the bloodstream, through the lymphatic system, or via local growth.

Neoplastic disease, particularly advanced disease, is the most frequent cause of tamponade in the hospital. Occasionally, the tumor encases the heart and causes constrictive pericarditis rather than tamponade.

Pericardial mesothelioma and angiosarcoma are lethal malignancies with aggressive local spread that respond poorly to treatment. Infants and children can present with a teratoma in the pericardial space. These can often be successfully removed.

Lung cancer, including adenocarcinoma and squamous and small cell carcinoma, accounts for approximately 33% of cases; breast cancer accounts for 25%; leukemia and lymphoma, including Hodgkin and non-Hodgkin, account for 15% of cases; and malignant melanoma represents another 5%. Almost all other malignancies, except primary brain, comprise the rest of the cases. Kaposi sarcoma has also become a more prominent cause of neoplastic disease with the AIDS epidemic.

Drugs

Some medications, including penicillin and cromolyn sodium, induce pericarditis through a hypersensitivity reaction. The anthracycline antineoplastic agents, such as doxorubicin and cyclophosphamide, have direct cardiac toxicity and can cause acute pericarditis and myocarditis.

Pericarditis can also develop from a drug-induced lupus syndrome caused by medications including procainamide, hydralazine, methyldopa, isoniazid, mesalazine, and reserpine. Methysergide causes constrictive pericarditis through mediastinal fibrosis. Dantrolene, phenytoin, and minoxidil produce pericarditis through an unknown mechanism.

Smallpox vaccination infrequently leads to myocarditis. In a review of a large vaccination program in the US military, approximately 12 per 100,000 vaccinated troops developed myopericarditis within 14 days of vaccination.[13, 14] Whether this was due to a direct viral cytopathic effect or an immune-mediated phenomenon is unclear.

Irradiation

Pericardial disease is the most common cardiac toxicity from radiation therapy. Others are coronary artery disease, conduction disturbance, and myocardial and valvular disease.[15] A high incidence of such toxicity occurs with high doses, especially those greater than 4000 rad.

Radiation pericarditis can present as acute pericarditis, with or without effusion; chronic constrictive pericarditis; or effusive-constrictive pericarditis.

Invasive cardiac procedures

Electrophysiologic studies, radiofrequency ablation, pacemaker implantation, and percutaneous coronary intervention are among several invasive cardiac procedures that can cause pericarditis.

Postpericardiotomy syndrome is similar to Dressler syndrome, except that postpericardiotomy syndrome occurs after cardiac surgery. Several series note an incidence rate of 10-40%; approximately 1% of patients with postpericardiotomy syndrome develop tamponade.

Pericardial effusions can occur in the absence of typical features of postpericardiotomy syndrome. In one study, 56% developed pericardial effusions early after cardiac surgery, without correlation to pericarditis or tamponade. The effusions were more common after heavy postoperative bleeding.

Trauma

Approximately 1% of cases of acute pericarditis are caused by trauma, such as penetrating and nonpenetrating cardiac trauma. Also consider esophageal rupture or perforation and pancreatitis.

PreviousNextEpidemiology

Epidemiologic data on the incidence of acute pericarditis are lacking, likely because this condition is frequently inapparent clinically, despite its presence in numerous disorders. Lorell noted a diagnosis of acute pericarditis in approximately 1 per 1000 hospital admissions.[16] In addition, acute pericarditis comprises 1% of emergency room visits in patients with ST-segment elevation.[17] In fact, the reported incidence of acute pericardial tamponade is approximately 2% of penetrating trauma; however, this condition is rarely seen in blunt chest trauma.

Uremic pericarditis may occur in 6-10% of patients with advanced renal failure before initiation of dialysis. When patients with large effusions are studied, uremia may account for up to 20% of cases in some series. The widespread availability of dialysis has reduced the incidence of uremic pericarditis.

Malignant disease is the most common cause of pericardial effusion with tamponade in developed countries; However, tuberculosis should be considered in endemic areas.

Acute pericarditis is more common in men than in women. However, although this condition is more common in adults than in children, adolescents are more commonly affected than young adults. Nonetheless, Merce et al found no difference in etiology, clinical course, and prognosis between elderly and younger patients with moderate and large pericardial effusions.[18]

PreviousNextPrognosis

The prognosis in individuals with pericarditis depends on the etiology of this condition, as well as the presence of a pericardial effusion and/or tamponade. Idiopathic and viral etiologies usually have a self-limited course, without any risk of evolution toward constrictive pericarditis.[19, 20] Most post–MI cases have a benign course; however, pericarditis is associated with larger infarcts, and therefore, overall long-term mortality may be increased.

Patients with scleroderma or children with rheumatic fever and pericarditis have a poor prognosis, and purulent, tuberculous, and neoplastic pericardial involvement have more complicated courses with worse outcomes. Purulent pericarditis is associated with a mortality rate nearing 100% for untreated persons and a mortality rate of 12-40% for treated patients. The mortality rate in tuberculous pericarditis approaches 50%.

Uremic pericarditis continues to be associated with significant morbidity and occasional mortality. Of patients with uremic pericarditis, 3-5% may develop hemorrhagic pericarditis.

For penetrating injuries, the prognosis depends heavily on the rapid identification of tamponade. Mortality may occur in 3-5% of cases resulting from cardiac tamponade or arrhythmias. Favorable factors include minor perforations, isolated right ventricular wounds, systolic blood pressure more than 50 mm Hg, and the presence of tamponade.

PreviousProceed to Clinical Presentation , Acute Pericarditis

Sunday, February 2, 2014

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