Cardiogenic Shock

Background

• Cardiogenic shock is characterized by persistent hypotension due to a reduced cardiac index and in the presence of elevated pulmonary capillary wedge pressure (PCWP).
• About 7% incidence of cardiogenic shock after acute myocardial infarction, increased incidence in patients with STEMI risk factors. Non-STEMI patients with shock have increased mortality.
• Acute myocardial infarction is the most common cause of cardiogenic shock, but onset may also be more gradual due to decompensation of a chronic disorder such as ischemic or non-ischemic dilated cardiomyopathy.
• Complications include pulmonary edema, hepatic decompensation, and acute renal failure.
• Prognosis improved with emergency reperfusion strategies, but remains high for cardiogenic shock due to right coronary artery (RCA) occlusion and vessels for which flow is not restored.

Evaluation

• Suspect cardiogenic shock in patients with known or suspected acute ischemia, heart failure, or chest trauma who are hypotensive with tachycardia and that have elevated jugular venous pressure, cool extremities and/or other signs of poor organ perfusion such as mental status changes and decreased urine output.
• Initial testing should include:
  • 12-lead electrocardiogram with right-sided leads if right ventricular infarction is suspected
  • emergent transthoracic echocardiography performed at the bedside for the assessment of ventricular function and to identify potential causes of cardiogenic shock
  • blood tests, including:
    • CBC
    • complete metabolic panel
    • cardiac troponin to evaluate acute coronary syndrome as a possible cause of cardiogenic shock
    • arterial blood gas
    • lactate
    • NT-pro BNP
• Consider early invasive hemodynamic monitoring with pulmonary artery catheter to confirm the diagnosis and to guide treatment.

Management

Immediate treatment

• Administer oxygen to patients with oxygen saturation ≤ 90% and assess the potential need for intubation and mechanical ventilation.
• 100-200 mL fluid boluses may be required to optimize left ventricular filling pressures in patients with developing cardiogenic shock with clinical signs suggestive of, or hemodynamic monitoring indicative of, a pulmonary capillary wedge pressure (PCWP) < 15 mm Hg
• Avoid fluids if frank pulmonary edema is present or if PCWP is > 18 mm Hg based on invasive hemodynamic monitoring, but consider cautious administration of small fluid boluses (100-200 mL) in patients with pulmonary capillary wedge pressure (PCWP) < 15 mm Hg to optimize left ventricular filling pressures.
• Use temporary IV inotropic support to maintain systemic perfusion and to preserve end-organ performance (Strong recommendation). Examples include:
  • norepinephrine (typical dose range is 0.01 to 0.03 mcg/kg/minute)
  • dopamine (typical initial dose is 2-10 mcg/kg/minute, may increase up to 20-50 mcg/kg/minute)
  • dobutamine (typical dose range is 2-20 mcg/kg/minute)
• Consider mechanical cardiovascular support, including intra-aortic balloon pump (IABP) counterpulsation, Impella, Tanden Heart, or ECMO, which can be useful for patients with cardiogenic shock after ST-elevation myocardial infarction (STEMI) who do not quickly stabilize with pharmacological therapy. (Weak recommendation). The benefit on mortality is uncertain.
• Perform emergency revascularization with either percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) in patients with cardiogenic shock due to acute coronary syndromes (Strong recommendation).
• Perform emergent surgery as indicated in patients with papillary muscle rupture or ventricular septal rupture after STEMI as well as for ventricular free-wall rupture following STEMI.
• Consider extracorporeal membrane oxygenation (ECMO) to provide emergency biventricular support in patients with poor oxygenation due to cardiac failure or use as a bridge to transplantation or implantation of an extracorporal left ventricular or biventricular mechanical assist device (Weak recommendation).

Treatment for persistent cardiogenic shock

• Consider continuous IV inotropic support "bridge therapy" while awaiting mechanical circulatory support or cardiac transplantation in patients with stage D heart failure refractory to guideline-directed medical therapy and device therapy (Weak recommendation).
• Consider left ventricular assist devices (LVADs) for circulatory support (other than IABP) in patients with refractory cardiogenic shock and as a "bridge to recovery" or "bridge to decision" in patients with profound hemodynamic compromise (Weak recommendation).
• Offer cardiac transplantation to selected patients with cardiogenic shock refractory to guideline-directed medical therapy, device therapy, or surgical management (Strong recommendation).
• Consult palliative care team in those patients with persistent multisystem organ failure and/or a lack of social support required for a cardiac transplant or LVAD to address the goals of care.
• Consider long-term, continuous IV inotropic support as palliative therapy in select patients with stage D heart failure despite optimal guideline-directed medical therapy and device therapy who are not eligible for either mechanical circulatory support or cardiac transplantation (Weak recommendation).