Cardiogenic Shock

Practice Essentials

The clinical definition of cardiogenic shock is decreased cardiac output and evidence of tissue hypoxia in the presence of adequate intravascular volume. Cardiogenic shock is the leading cause of death in acute MI, with mortality rates of up to 70-90% in the absence of aggressive, highly experienced technical care.

Essential update: Extracorporeal membrane oxygenation for cardiogenic shock after cardiotomy

In an analysis of 77 patients (mean age, 60 years) who received peripheral extracorporeal membrane oxygenation therapy (ECMO) for cardiac failure that developed after surgery for acquired heart disease, the overall 30-day mortality rate was 70%. However, the rate improved to 52% in patients who were successfully weaned from ECMO. The only preoperative factor that independently predicted 30-day mortality was older age. Postoperative predictive factors were higher blood lactate levels after 24 hours of ECMO therapy, a longer duration of ECMO support, and the development of ECMO-related or gastrointestinal complications.[1]

Signs and symptoms

The diagnosis of cardiogenic shock can sometimes be made at the bedside by observing the following:

HypotensionAbsence of hypovolemiaClinical signs of poor tissue perfusion (ie, oliguria, cyanosis, cool extremities, altered mentation)

Findings on physical examination include the following:

Skin is usually ashen or cyanotic and cool; extremities are mottledPeripheral pulses are rapid and faint and may be irregular if arrhythmias are presentJugular venous distention and crackles in the lungs are usually (but not always) present; peripheral edema also may be presentHeart sounds are usually distant, and third and fourth heart sounds may be presentThe pulse pressure may be low, and patients are usually tachycardicPatients show signs of hypoperfusion, such as altered mental status and decreased urine outputUltimately, patients develop systemic hypotension (ie, systolic blood pressure below 90 mm Hg or a decrease in mean blood pressure by 30 mm Hg)

See Clinical Presentation for more detail.

Diagnosis

Laboratory studies

Biochemical profileCBCCardiac enzymes (eg, creatine kinase and CK-MB, troponins, myoglobin, LDH)Arterial blood gasesLactateBrain natriuretic peptide

Imaging studies

Echocardiography should be performed early to establish the cause of cardiogenic shockChest radiographic findings are useful for excluding other causes of shock or chest pain (eg, aortic dissection, tension pneumothorax, pneumomediastinum) Ultrasonography can be used to guide fluid managementCoronary angiography is urgently indicated in patients with myocardial ischemia or MI who also develop cardiogenic shock

Electrocardiography

Perform electrocardiography immediately to help diagnose MI and/or myocardial ischemiaA normal ECG, however, does not rule out the possibility of acute MI

Invasive hemodynamic monitoring

Swan-Ganz catheterization is very useful for helping exclude other causes and types of shock (eg, volume depletion, obstructive shock, and shock) The hemodynamic measurements of cardiogenic shock are a pulmonary capillary wedge pressure (PCWP) greater than 15 mm Hg and a cardiac index less than 2.2 L/min/m2The presence of large V waves on the PCWP tracing suggests severe mitral regurgitationA step-up in oxygen saturation between the right atrium and the right ventricle is diagnostic of ventricular septal ruptureHigh right-sided filling pressures in the absence of an elevated PCWP, when accompanied by ECG criteria, indicate right ventricular infarction

See Workup for more detail.

Management

Cardiogenic shock is an emergency requiring the following:

Fluid resuscitation to correct hypovolemia and hypotension, unless pulmonary edema is presentPrompt initiation of pharmacologic therapy to maintain blood pressure and cardiac outputAdmission to an intensive care setting (eg, cardiac catheterization suite or ICU or critical care transport to a tertiary care center) Early and definitive restoration of coronary blood flow; at present, this represents standard therapy for patients with cardiogenic shock due to myocardial ischemia Correction of electrolyte and acid-base abnormalities (eg, hypokalemia, hypomagnesemia, acidosis)

Invasive procedures include the following:

Placement of a central line may facilitate volume resuscitation, provide vascular access for multiple infusions, and allow invasive monitoring of central venous pressure An arterial line may be placed to provide continuous blood pressure monitoringAn intra-aortic balloon pump may be placed as a bridge to percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)

Pharmacologic therapy

Patients with MI or acute coronary syndrome are given aspirin and heparinInotropic and/or vasopressor drug therapy may be necessary in patients with inadequate tissue perfusion and adequate intravascular volume, so as to maintain mean arterial pressure (MAP) of 60 or 65 mm Hg Diuretics are used to decrease plasma volume and peripheral edema

Features of dopamine are as follows:

Dopamine is the drug of choice to improve cardiac contractility in patients with hypotensionDopamine may increase myocardial oxygen demandDopamine is usually initiated at a rate of 5-10 mcg/kg/min IVThe infusion rate is adjusted according to the blood pressure and other hemodynamic parametersOften, patients may require doses as high as 20 mcg/kg/min

Features of dobutamine are as follows:

Dobutamine may be preferable to dopamine if the systolic blood pressure is higher than 80 mm HgCompared with dopamine, dobutamine has less effect on myocardial oxygen demandTachycardia from dobutamine may preclude its use in some patients

If the patient remains hypotensive despite moderate doses of dopamine, a direct vasoconstrictor may be administered, as follows:

Norepinephrine is started at a dose of 0.5 mcg/kg/min and titrated to maintain an MAP of 60 mm HgThe dose of norepinephrine may vary from 0.2-1.5 mcg/kg/minDoses as high as 3.3 mcg/kg/min have been used

Phosphodiesterase inhibitors (eg, inamrinone [formerly amrinone], milrinone) are inotropic agents with vasodilating properties and long half-lives that are beneficial in patients with cardiac pump failure, but they may require concomitant vasopressor administration

PCI and CABG

Either PCI or CABG is the treatment of choice for cardiogenic shockPCI should be initiated within 90 minutes after presentationPCI remains helpful, as an acute intervention, within 12 hours after presentationThrombolytic therapy is second best but should be considered if PCI and CABG are not immediately available

See Treatment and Medication for more detail.

Image libraryPatient with an acute anterolateral myocardial infarction who developed cardiogenic shock. Coronary angiography images showed severe stenosis of the left anterior descending coronary artery, which was dilated by percutaneous transluminal coronary angioplasty. NextBackground

Cardiogenic shock is a physiologic state in which inadequate tissue perfusion results from cardiac dysfunction, most often systolic. It is a major, and frequently fatal, complication of a variety of acute and chronic disorders, occurring most commonly following acute myocardial infarction (MI). (See Pathophysiology, Etiology, and Prognosis.)

Although ST-segment elevation MI (STEMI, previously termed Q-wave MI) is encountered in most patients, cardiogenic shock may also develop in patients with non ̶ ST-segment elevation acute coronary syndrome (NSTEMI, NSTACS, or unstable angina). (See the images below.)

Patient with an acute anterolateral myocardial infarction who developed cardiogenic shock. Coronary angiography images showed severe stenosis of the left anterior descending coronary artery, which was dilated by percutaneous transluminal coronary angioplasty. Echocardiogram image from a patient with cardiogenic shock shows enlarged cardiac chambers; the motion study showed poor left ventricular function. Courtesy of R. Hoeschen, MD.

The clinical definition of cardiogenic shock is decreased cardiac output and evidence of tissue hypoxia in the presence of adequate intravascular volume. Hemodynamic criteria for cardiogenic shock are sustained hypotension (systolic blood pressure 2) in the presence of elevated pulmonary capillary wedge pressure (>15 mm Hg). (See DDx, Workup.)

Cardiogenic shock continues to be a difficult clinical problem; the management of this condition requires a rapid and well-organized approach. (See Prognosis, Treatment, and Medication.)

The diagnosis of cardiogenic shock can sometimes be made at the bedside by observing hypotension, absence of hypovolemia, and clinical signs of poor tissue perfusion, which include oliguria, cyanosis, cool extremities, and altered mentation. These signs usually persist after attempts have been made to correct hypovolemia, arrhythmia, hypoxia, and acidosis. (See Presentation, DDx.)

Types of circulatory shock

Shock is identified in most patients based on findings of hypotension and inadequate organ perfusion, which may be caused by either low cardiac output or low systemic vascular resistance (SVR). Circulatory shock can be subdivided into 4 distinct classes based on the underlying mechanism and characteristic hemodynamic findings. In all patients, before establishing a definite diagnosis of septic shock, the following 4 classes of shock should be considered and systematically differentiated. (See Pathophysiology, Etiology, Presentation and Workup.)

Cardiogenic shock

Cardiogenic shock characterized by primary myocardial dysfunction renders the heart to be unable to maintain adequate cardiac output. These patients demonstrate clinical signs of low cardiac output, with adequate intravascular volume. The patients have cool and clammy extremities, poor capillary refill, tachycardia, narrow pulse pressure, and low urine output.

Hypovolemic shock

Hypovolemic shock results from loss of blood volume, the possible reasons for which include gastrointestinal bleeding, extravasation of plasma, major surgery, trauma, and severe burns.

Obstructive shock

Obstructive shock results from impedance of circulation by an intrinsic or extrinsic obstruction. Pulmonary embolism, dissecting aneurysm, and pericardial tamponade all result in obstructive shock.

Distributive shock

Distributive shock is caused by conditions producing direct arteriovenous shunting and is characterized by decreased SVR or increased venous capacitance because of the vasomotor dysfunction. These patients have high cardiac output, hypotension, high pulse pressure, low diastolic pressure, and warm extremities with good capillary refill. Such findings upon physical examination strongly suggest a working diagnosis of septic shock.

Patient education

Patients should receive instruction regarding the early warning signs of acute MI and how to access the emergency medical system (eg, calling 911).

Patients must also be instructed on cardiac risk factors, particularly those that are reversible and subject to change (eg, smoking, diet, exercise).

For patient education information, see the First Aid and Injuries Center and the Healthy Living Center, as well as Shock and Cardiopulmonary Resuscitation (CPR).

PreviousNextPathophysiology

Cardiogenic shock is recognized as a low cardiac output state secondary to extensive left ventricular infarction, development of a mechanical defect (eg, ventricular septal defect or papillary muscle rupture), or right ventricular infarction.

Disorders that can result in the acute deterioration of cardiac function and lead to cardiogenic shock include myocardial infarction (MI) or myocardial ischemia, acute myocarditis, sustained arrhythmia, severe valvular dysfunction, and decompensation of end-stage cardiomyopathy from multiple etiologies. Autopsy studies show that cardiogenic shock is generally associated with the loss of more than 40% of the left ventricular myocardial muscle.

Myocardial pathology

Cardiogenic shock is characterized by systolic and diastolic dysfunction. Patients who develop cardiogenic shock from acute MI consistently have evidence of progressive myocardial necrosis with infarct extension. Decreased coronary perfusion pressure and increased myocardial oxygen demand play a role in the vicious cycle that leads to cardiogenic shock.

Patients suffering from cardiogenic shock often have multivessel coronary artery disease with limited coronary blood flow reserve. Ischemia remote from the infarcted zone is an important contributor to shock. Myocardial diastolic function is also impaired, because ischemia causes decreased myocardial compliance, thereby increasing left ventricular filling pressure, which may lead to pulmonary edema and hypoxemia.

Cellular pathology

Tissue hypoperfusion, with consequent cellular hypoxia, causes anaerobic glycolysis, the accumulation of lactic acid, and intracellular acidosis. Also, myocyte membrane transport pumps fail, which decreases transmembrane potential and causes intracellular accumulation of sodium and calcium, resulting in myocyte swelling.

If ischemia is severe and prolonged, myocardial cellular injury becomes irreversible and leads to myonecrosis, which includes mitochondrial swelling, the accumulation of denatured proteins and chromatin, and lysosomal breakdown. These events induce fracture of the mitochondria, nuclear envelopes, and plasma membranes.

Additionally, apoptosis (programmed cell death) may occur in peri-infarcted areas and may contribute to myocyte loss. Activation of inflammatory cascades, oxidative stress, and stretching of the myocytes produces mediators that overpower inhibitors of apoptosis, thus activating the apoptosis.

Reversible myocardial dysfunction

Large areas of myocardium that are dysfunctional but still viable can contribute to the development of cardiogenic shock in patients with MI. This potentially reversible dysfunction is often described as myocardial stunning or as hibernating myocardium. Although hibernation is considered a different physiologic process than myocardial stunning, the conditions are difficult to distinguish in the clinical setting and they often coexist.

Myocardial stunning represents postischemic dysfunction that persists despite restoration of normal blood flow. By definition, myocardial dysfunction from stunning eventually resolves completely. The mechanism of myocardial stunning involves a combination of oxidative stress, abnormalities of calcium homeostasis, and circulating myocardial depressant substances.

Hibernating myocardium is a state of persistently impaired myocardial function at rest, which occurs because of the severely reduced coronary blood flow. Hibernation appears to be an adaptive response to hypoperfusion that may minimize the potential for further ischemia or necrosis. Revascularization of the hibernating (and/or stunned) myocardium generally leads to improved myocardial function.

Consideration of the presence of myocardial stunning and hibernation is vital in patients with cardiogenic shock because of the therapeutic implications of these conditions. Hibernating myocardium improves with revascularization, whereas the stunned myocardium retains inotropic reserve and can respond to inotropic stimulation.

Cardiovascular mechanics of cardiogenic shock

The main mechanical defect in cardiogenic shock is a shift to the right for the left ventricular end-systolic pressure-volume curve, because of a marked reduction in contractility. As a result, at a similar or even lower systolic pressure, the ventricle is able to eject less blood volume per beat. Therefore, the end-systolic volume is usually greatly increased in persons with cardiogenic shock.

The stroke volume is decreased, and to compensate for this, the curvilinear diastolic pressure-volume curve also shifts to the right, with a decrease in diastolic compliance. This leads to increased diastolic filling, which is associated with an increase in end-diastolic pressure. The attempt to enhance cardiac output by this mechanism comes at the cost of having a higher left ventricular diastolic filling pressure, which ultimately increases myocardial oxygen demand and causes pulmonary edema.

As a result of decreased contractility, the patient develops elevated left and right ventricular filling pressures and low cardiac output. Mixed venous oxygen saturation falls because of the increased tissue oxygen extraction, which is due to the low cardiac output. This, combined with the intrapulmonary shunting that is often present, contributes to substantial arterial oxygen desaturation.

Systemic effects

When a critical mass of left ventricular myocardium becomes ischemic and fails to pump effectively, stroke volume and cardiac output are curtailed. Myocardial ischemia is further exacerbated by compromised myocardial perfusion due to hypotension and tachycardia.

The pump failure increases ventricular diastolic pressures concomitantly, causing additional wall stress and thereby elevating myocardial oxygen requirements. Systemic perfusion is compromised by decreased cardiac output, with tissue hypoperfusion intensifying anaerobic metabolism and instigating the formation of lactic acid, which further deteriorates the systolic performance of the myocardium.

Depressed myocardial function also leads to the activation of several physiologic compensatory mechanisms. These include sympathetic stimulation, which increases the heart rate and cardiac contractility and causes renal fluid retention, hence augmenting the left ventricular preload. The raised heart rate and contractility increases myocardial oxygen demand, further worsening myocardial ischemia.

Fluid retention and impaired left ventricular diastolic filling triggered by tachycardia and ischemia contribute to pulmonary venous congestion and hypoxemia. Sympathetically mediated vasoconstriction to maintain systemic blood pressure amplifies myocardial afterload, which additionally impairs cardiac performance. Finally, excessive myocardial oxygen demand with simultaneous inadequate myocardial perfusion worsens myocardial ischemia, initiating a vicious cycle that ultimately ends in death, if uninterrupted.

Usually, a combination of systolic and diastolic myocardial dysfunction is present in patients with cardiogenic shock. Metabolic derangements that impair myocardial contractility further compromise systolic ventricular function. Myocardial ischemia decreases myocardial compliance, thereby elevating left ventricular filling pressure at a given end-diastolic volume (diastolic dysfunction), which leads to pulmonary congestion and congestive heart failure.

Shock state

Shock state, irrespective of the etiology, is described as a syndrome initiated by acute systemic hypoperfusion that leads to tissue hypoxia and vital organ dysfunction. All forms of shock are characterized by inadequate perfusion to meet the metabolic demands of the tissues. A maldistribution of blood flow to end organs begets cellular hypoxia and end organ damage, the well-described multisystem organ dysfunction syndrome. The organs of vital importance are the brain, heart, and kidneys.

A decline in higher cortical function may indicate diminished perfusion of the brain, which leads to an altered mental status ranging from confusion and agitation to flaccid coma. The heart plays a central role in propagating shock. Depressed coronary perfusion leads to worsening cardiac dysfunction and a cycle of self-perpetuating progression of global hypoperfusion. Renal compensation for reduced perfusion results in diminished glomerular filtration, causing oliguria and subsequent renal failure.

PreviousNextEtiology

Cardiogenic shock can result from the following types of cardiac dysfunction:

Systolic dysfunctionDiastolic dysfunctionValvular dysfunctionCardiac arrhythmiasCoronary artery diseaseMechanical complications

The vast majority of cases of cardiogenic shock in adults are due to acute myocardial ischemia. Indeed, cardiogenic shock is generally associated with the loss of more than 40% of the left ventricular myocardium, although in patients with previously compromised left ventricular function, even a small infarction may precipitate shock. Cardiogenic shock is more likely to develop in people who are elderly or diabetic or in persons who have had a previous inferior myocardial infarction (MI).

Complications of acute MI, such as acute mitral regurgitation, large right ventricular infarction, and rupture of the interventricular septum or left ventricular free wall, can result in cardiogenic shock. Conduction abnormalities (eg, atrioventricular blocks, sinus bradycardia) are also risk factors.

Many cases of cardiogenic shock occurring after acute coronary syndromes may be due to medication administration. The use of beta blockers and angiotensin-converting enzyme (ACE) inhibitors in acute coronary syndromes must be carefully timed and monitored.[2, 3, 4]

In children, preceding viral infection may cause myocarditis. In addition, children and infants may have unrecognized congenital structural heart defects that are well compensated until there is a stressor. These etiologies plus toxic ingestions make up the 3 primary causes of cardiogenic shock in children.

A systemic inflammatory response syndrome–type mechanism has also been implicated in the etiology of cardiogenic shock. Elevated levels of white blood cells, body temperature, complement, interleukins, and C-reactive protein are often seen in large myocardial infarctions. Similarly, inflammatory nitric oxide synthetase (iNOS) is also released in high levels during myocardial stress. Nitric oxide production induced by iNOS may uncouple calcium metabolism in the myocardium resulting in a stunned myocardium. Additionally, iNOS leads to the expression of interleukins, which may themselves cause hypotension.

Left ventricular failure

Systolic dysfunction

The primary abnormality in systolic dysfunction is abated myocardial contractility. Acute MI or ischemia is the most common cause; cardiogenic shock is more likely to be associated with anterior MI. The causes of systolic dysfunction leading to cardiogenic shock can be summarized as follows:

Ischemia/MIGlobal hypoxemiaValvular diseaseMyocardial depressant drugs - Eg, beta blockers, calcium channel blockers, and antiarrhythmicsMyocardial contusionRespiratory acidosisMetabolic derangements - Eg, acidosis, hypophosphatemia, and hypocalcemiaSevere myocarditisEnd-stage cardiomyopathy - Including valvular causesProlonged cardiopulmonary bypass.Cardiotoxic drugs - Eg, doxorubicin (Adriamycin)

Diastolic dysfunction

Increased left ventricular diastolic chamber stiffness contributes to cardiogenic shock during cardiac ischemia, as well as in the late stages of hypovolemic shock and septic shock. Increased diastolic dysfunction is particularly detrimental when systolic contractility is also depressed. The causes of cardiogenic shock due primarily to diastolic dysfunction can be summarized as follows:

IschemiaVentricular hypertrophyRestrictive cardiomyopathyProlonged hypovolemic or septic shockVentricular interdependenceExternal compression by pericardial tamponade

Greatly increased afterload

Increased afterload, which can impair cardiac function, can be caused by the following:

Aortic stenosisHypertrophic cardiomyopathyDynamic aortic outflow tract obstructionCoarctation of the aortaMalignant hypertension

Valvular and structural abnormality

Valvular dysfunction may immediately lead to cardiogenic shock or may aggravate other etiologies of shock. Acute mitral regurgitation secondary to papillary muscle rupture or dysfunction is caused by ischemic injury. Rarely, acute obstruction of the mitral valve by a left atrial thrombus may result in cardiogenic shock by means of severely decreased cardiac output. Aortic and mitral regurgitation reduce forward flow, raise end-diastolic pressure, and aggravate shock associated with other etiologies.

Valvular and structural abnormalities associated with cardiogenic shock include the following:

Mitral stenosisEndocarditisMitral aortic regurgitationObstruction due to atrial myxoma or thrombusPapillary muscle dysfunction or ruptureRuptured septum or free wall arrhythmiasTamponade

Decreased contractility

Reduced myocardial contractility can result from the following:

Right ventricular infarctionIschemiaHypoxiaAcidosisRight ventricular failure

Greatly increased afterload

Afterload increase associated with right ventricular failure can result from the following:

Pulmonary embolismPulmonary vascular disease - Eg, pulmonary arterial hypertension and veno-occlusive diseaseHypoxic pulmonary vasoconstrictionPeak end-expiratory pressureHigh alveolar pressureAcute respiratory distress syndromePulmonary fibrosisSleep disordered breathingChronic obstructive pulmonary disease

Arrhythmias

Ventricular tachyarrhythmias are often associated with cardiogenic shock. Furthermore, bradyarrhythmias may cause or aggravate shock due to another etiology. Sinus tachycardia and atrial tachyarrhythmias contribute to hypoperfusion and aggravate shock.

PreviousNextEpidemiologyOccurrence in the United States

The incidence rate of cardiogenic shock ranges from 5-10% in patients with acute myocardial infarction (MI). In the Worcester Heart Attack Study, a community-wide analysis, the reported incidence rate was 7.5%.[5] The literature contains few data on cardiogenic shock in patients without ischemia.

Cardiogenic shock occurs in 8.6% of patients with ST-segment elevation MI (STEMI), with 29% of those presenting to the hospital already in shock. It occurs only in 2% of patients with non ̶ ST-segment elevation acute coronary syndrome (NSTACS).

International occurrence

Several multicenter thrombolytic trials in Europe reported a prevalence rate of cardiogenic shock following MI of approximately 7%.

Race-, sex-, and age-related demographics

Race-stratified mortality rates from cardiogenic shock are as follows (race-based mortality differences disappear with revascularization):

Hispanics - 74%African Americans - 65%Whites - 56%Asians/others - 41%

The overall incidence of cardiogenic shock is higher in men than in women, with females accounting for 42% of patients with cardiogenic shock. This difference results from the increased prevalence of coronary artery disease in males. However, a higher percentage of female patients with MI develop cardiogenic shock than do males with MI.

Median age for cardiogenic shock mirrors the bimodal distribution of disease. For adults, the median age ranges from 65-66 years. For children, cardiogenic shock presents as a consequence of fulminant myocarditis or congenital heart disease.

PreviousNextPrognosis

Cardiogenic shock is the leading cause of death in acute myocardial infarction (MI). In the absence of aggressive, highly experienced technical care, mortality rates among patients with cardiogenic shock are exceedingly high (up to 70-90%). The key to achieving a good outcome is rapid diagnosis, prompt supportive therapy, and expeditious coronary artery revascularization in patients with myocardial ischemia and infarction.[6, 7, 8]

The overall in-hospital mortality rate for patients with cardiogenic shock is 57%. For persons older than 75 years, the mortality rate is 64.1%; for those younger than 75 years, it is 39.5%. Mortality rates are similar for patients with cardiogenic shock secondary to STEMI or NSTACS.

Evidence of right ventricular dilation on echocardiogram may indicate a worse outcome in patients with cardiogenic shock, as may right ventricular infarction on a right-sided electrocardiogram.[9] The prognosis for patients who survive cardiogenic shock is not well studied but may be favorable if the underlying cause of shock is expeditiously corrected.

Morbidity and mortality

Complications of cardiogenic shock may include the following:

Cardiopulmonary arrestDysrhythmiaRenal failureMultisystem organ failureVentricular aneurysmThromboembolic sequelaeStrokeDeath

The following predictors of mortality were identified from the Global Utilization of Streptokinase and Tissue-Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial[10] :

Increasing agePrior MIAltered sensoriumCold, clammy skinOliguria

Echocardiographic findings such as left ventricular ejection fraction and mitral regurgitation are independent predictors of mortality. An ejection fraction of less than 28% is associated with a survival rate of 24% at 1 year, compared with a survival rate of 56% with a higher ejection fraction. Moderate or severe mitral regurgitation was found to be associated with a 1-year survival rate of 31%, compared with a survival rate of 58% in patients with no regurgitation.

Outcomes in cardiogenic shock significantly improve only when rapid revascularization can be achieved. The SHOCK (Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock?) trial demonstrated that overall mortality when revascularization occurs is 38%.[11] When rapid revascularization is not attempted, mortality rates approach 70%. Rates vary depending on the procedure (eg, percutaneous transluminal coronary angioplasty, stent placement, thrombolytic therapy).

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