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Intra-aortic balloon pump (IABP) counterpulsation has become widely used for blood pressure support in the treatment of acute myocardial infarction (MI) complicated by cardiogenic shock. It is strongly recommended in these patients by guidelines from American College of Cardiology and American Heart Association (Circulation 2008 Jan 15;117(2):296) and from the European Society of Cardiology (Eur Heart J 2008 Dec;29(23):2909) despite a lack of high quality evidence supporting its use. A new report of a large randomized trial with 600 patients casts serious doubt on the efficacy of IABP in this scenario.
Patients with acute MI and cardiogenic shock (median age 70 years) who were expected to have a revascularization procedure were randomized to IABP vs. no IABP. In the IABP group, the balloon pump was inserted either before or immediately after the revascularization procedure, at the discretion of the investigator. The choice of revascularization procedure was at the discretion of the surgeon. Exclusion criteria included resuscitation for > 30 minutes, onset of shock > 12 hours before screening and mechanical cause of cardiogenic shock. Crossover to IABP treatment was allowed in the control group in cases of mechanical complications including ventricular septal defect or papillary muscle rupture, and occurred in about 10% of controls.
There were no significant differences in any clinical outcomes in the intention-to-treat analysis (level 1 [likely reliable] evidence). Comparing IABP vs. no IABP, 30-day mortality was 39.7% vs. 41.3%, major bleeding occurred in 3.3% vs. 4.4%, and reinfarction occurred in 3% vs. 1.4%. There were also no significant differences in the rates of peripheral ischemic complications, stroke, or sepsis. In the IABP group, 30-day mortality was 36.4% of 37 patients who received the pump before revascularization and 36.8% of 240 patients who received it after revascularization (not significant) (N Engl J Med 2012 Oct 4;367(14):1287).
For more information, see the Cardiogenic shock and ST-elevation myocardial infarction (STEMI) topics in DynaMed.