Cardiogenic shock in acute myocardial infarction.

D espite the marked reduction in mortality from acute myocardial infarction (AMI), which may be as low as 3% to 4% with today’s national guidelines for rapid, catheter-based revascularization to open the infarct-related artery, cardiogenic shock remains the leading cause of death from AMI, occurring in as many as 10% of all myocardial infarctions (1). Unfortunately, the outcome with current treatment approaches remains very poor, with mortality as high as 40% to 50% before hospital discharge (2,3). The intra-aortic balloon pump (IABP), which was developed >4 decades ago, was the first device for mechanical support of the circulation in patients with cardiogenic shock, often when due to an AMI (4). The early and persistent enthusiasm for its use was on the basis of nonrandomized trials and registry data. However, this limited, but encouraging dataset led to endorsement of IABP use in national guidelines as a Class I indication, in part because of its appealing enhancement of coronary perfusion and the absence of other alternatives. However, when subjected to meta-analyses (5,6), as well as in the recently reported 600-patient randomized, controlled, prospective IABP-SHOCK II (Intraaortic Balloon Pump in Cardiogenic Shock II) trial (7), use of the IABP for AMI shock failed to demonstrate a significant difference in mortality over standard therapy at either 30 days or 1 year. The study (7) provided no guidelines for use of