Intra-Aortic Balloon Counterpulsation in Acute Myocardial Infarction Complicated by Cardiogenic Shock (IABP-SHOCK II): Final 12 Month Results of a Randomized, Open-Label Trial

Study Questions:

What are the longer-term outcomes with intra-aortic balloon pump (IABP) use for cardiogenic shock complicating acute myocardial infarction (AMI)?

Methods:

The IABP-SHOCK II trial was a randomized, open-label, multicenter trial. Patients with cardiogenic shock complicating AMI who were undergoing early revascularization and optimum medical therapy were randomly assigned (1:1) to IABP versus control via a central web-based system. The primary efficacy endpoint was 30-day all-cause mortality, but 6- and 12-month follow-up was done in addition to quality-of-life assessment for all survivors with the Euroqol-5D questionnaire. A masked central committee adjudicated clinical outcomes. Patients and investigators were not masked to treatment allocation. Analysis was by intention to treat.

Results:

Between June 16, 2009, and March 3, 2012, 600 patients were assigned to IABP (n = 301) or control (n = 299). Of 595 patients completing 12-month follow-up, 155 (52%) of 299 patients in the IABP group and 152 (51%) of 296 patients in the control group had died (relative risk [RR], 1.01; 95% CI, 0.86-1.18; p = 0.91). There were no significant differences in reinfarction (RR, 2.60; 95% CI, 0.95-7.10; p = 0.05), recurrent revascularization (RR, 0.91; 0.58-1.41; p = 0.77), or stroke (RR, 1.50; 0.25-8.84; p = 1.00). For survivors, quality-of-life measures including mobility, self-care, usual activities, pain or discomfort, and anxiety or depression did not differ significantly between study groups.

Conclusions:

The authors concluded that in patients undergoing early revascularization for MI complicated by cardiogenic shock, IABP did not reduce 12-month all-cause mortality.

Perspective:

This prospective, randomized trial of patients with cardiogenic shock complicating AMI reported that IABP support did not increase 6- and 12-month survival compared with control, supporting the short-term 30-day follow-up data. Despite early revascularization and optimum medical therapy in both groups, mortality was still slightly higher than 50% at 1-year follow-up. Nevertheless, for survivors, the self-reported quality of life was moderate to good. Although one cannot entirely rule out the possibility that a potential beneficial effect of IABP on clinical endpoints is confined to patients in whom the support was started before revascularization, routine use of IABP does not appear justified in all patients with cardiogenic shock.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Aortic Surgery, Cardiac Surgery and Heart Failure, Mechanical Circulatory Support, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Survivors, Myocardial Infarction, Depressive Disorder, Stroke, Follow-Up Studies, Coronary Angiography, Shock, Heart-Assist Devices, Cardiovascular Diseases, Intra-Aortic Balloon Pumping, Angioplasty, Counterpulsation


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