Acute Coronary Syndrome and Cardiogenic Shock: Management in the Cardiac Catheterization Laboratory
Cardiogenic shock is defined as inadequate cardiac output (CO) to meet tissue perfusion, despite the presence of adequate intravascular volume. The hemodynamic criteria for cardiogenic shock include: sustained hypotension (systolic blood pressure <90 mm Hg for at least 30 min), a reduced cardiac index (<2.2 L/min/m2), and an elevated pulmonary capillary wedge pressure (PCWP) (>15 mm Hg).1
Key factors in the management of acute heart failure syndromes and cardiogenic shock in the catheterization laboratory include identification of etiology and assessment of hemodynamic stability. Common causes of acute heart failure are listed in Table 1, with acute myocardial infarction (MI) the predominant cause. Correctly diagnosing an acute coronary syndrome (ACS) is crucial because treatment for this cause of shock revolves around timely coronary reperfusion with additional hemodynamic support as needed. However, when cardiogenic shock is due to acute decompensation from a non-ACS cause, short-term support with inotropes or percutaneous devices may be necessary until recovery or to bridge patients to more long-term therapies such as open-heart surgery, cardiac transplantation, or left ventricular assist device (LVAD) implantation.
The 2 main focuses of this chapter will be treatment of ACSs in the cardiogenic shock setting, and mechanical support initiated in the cardiac catheterization laboratory. In many cases of cardiogenic shock, pharmacologic therapy alone may be inadequate and, therefore, patients may require emergent mechanical support. As the treatment of cardiogenic shock in the ACS setting revolves around coronary reperfusion, this will be discussed in detail. Furthermore, many of the principles of treating shock in the ACS setting can be applied to the other causes of shock. It is important to understand the rationale behind the current treatment of acute heart failure and implications these may have when patients present for subsequent treatment in the OR.