Have We Given Up on Intra‐aortic Balloon Counterpulsation in Post–Myocardial Infarction Cardiogenic Shock?

Abstract

The recently published Intra-aortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial concluded that intra-aortic counterpulsation (IACP) does not reduce 30-day mortality in patients with cardiogenic shock (CS) complicating acute myocardial infarction (AMI) for whom early revascularization strategy was planned. The study resulted in downgrading IACP in post-AMI CS patients by certain professional organizations like the European Society of Cardiology. Although this is the largest and most important CS study of this decade, it suffers from considerable shortcomings: (1) time intervals from chest-pain onset or AMI recognition to revascularization, enrollment, and IACP initiation are not disclosed; (2) 86.6% of the treatment arm initiated IACP only post-percutaneous coronary intervention (PCI), and 4.3 % did not receive IACP at all; (3) 17.4% of the control arm crossed over to IACP or other mechanical support, mostly due to protocol violations; (4) there is no adjudication of the mortality events; (5) follow-up is limited to 30 days; and (5) both methodology (especially IACP device size) and quality of IACP are not evaluated and documented. Because the study assessed mostly the efficacy and safety of IACP initiated post-PCI, the study conclusions should not be extrapolated to IACP pre-PCI or during PCI in CS. Moreover, IACP had a favorable effect on the mortality of younger patients. Intra-aortic counterpulsation should remain the first line of mechanical circulatory support for the hemodynamically compromised AMI patients with or without CS who are undergoing primary PCI. Early upgrade to more advanced mechanical circulatory support should be considered for selective suitable candidates who remain in refractory CS despite revascularization and IACP.