Intraaortic Balloon Support for Myocardial Infarction With Cardiogenic Shock - IABP-SHOCK II

Description:

The goal of the trial was to evaluate treatment with intra-aortic balloon counterpulsation (IABP) compared with no IABP among patients with acute myocardial infarction (AMI) and cardiogenic shock.

Hypothesis:

IABP will improve survival.

Study Design

  • Randomized
  • Parallel
  • Stratified

Patient Populations:

  • Patients with AMI complicated by cardiogenic shock and early planned revascularization
  • Definition of cardiogenic shock:
    - Systolic blood pressure <90 mm Hg for at least 30 minutes or the need for catecholamine infusion to support systolic blood pressure >90 mm Hg and
    - Pulmonary congestion and
    - Impaired end-organ perfusion (altered mental status, cold/clamming skin/extremities, oliguria with urine output <30 cc/hour, or serum lactate >2 mmol/L)

    Number of screened applicants: 790
    Number of enrollees: 600
    Duration of follow-up: 30 days
    Mean patient age: 70 years (median)
    Percentage female: 33%
    Ejection fraction: 35%

Exclusions:

  • More than 30 minutes of resuscitation
  • No intrinsic heart action
  • Coma with fixed dilated pupils
  • Mechanical cause of cardiogenic shock or alternative cause of shock
  • Massive pulmonary embolism
  • Severe peripheral arterial disease
  • At least moderate aortic regurgitation
  • Age >90 years
  • Life expectancy <6 months

Primary Endpoints:

  • All-cause mortality at 30 days

Secondary Endpoints:

  • Major bleeding
  • Peripheral ischemic complications
  • Sepsis
  • Stroke

Drug/Procedures Used:

Patients with AMI and cardiogenic shock were randomized to IABP (n = 301) versus no IABP (n = 299). All patients received early revascularization and best available medical therapy.

IABP was placed immediately before or after percutaneous coronary intervention (PCI).

Principal Findings:

Overall, 600 patients were randomized. The median age was 70 years, 33% were women, 35% had diabetes, 24% had prior myocardial infarction, 32% had a qualifying non-ST-elevation MI, 42% had been resuscitated before randomization, median left ventricular ejection fraction was 35%, median blood pressure as 89/55 mm Hg, 96% received primary PCI (42% with drug-eluting stents), 30% received immediate PCI of nonculprit vessels, 3.5% underwent immediate bypass surgery, 5.5% received a ventricular assist device, and median duration of IABP support was 3 days.

At 30 days, all-cause mortality had occurred in 39.7% of the IABP group versus 41.3% of the no IABP group (p = 0.69). There was no difference in subgroups, except for patients with no prior MI where there was relatively more benefit than among patients with prior MI.

- Reinfarction in hospital: 3.0% versus 1.3% (p = 0.16)
- Stent thrombosis in hospital: 1.3% versus 1.0% (p = 0.71)
- Major bleeding: 3.3% versus 4.4% (p = 0.51)
- Peripheral ischemic complications requiring intervention: 4.3% versus 3.4% (p = 0.53)
- Sepsis: 15.7% versus 20.5% (p = 0.15)
- Stroke: 0.7% versus 1.7% (p = 0.28)

Serum lactate and renal function remained similar between the groups.

Interpretation:

Among patients with AMI and cardiogenic shock, the use of IABP did not reduce mortality. This was also true among patients who received IABP support immediately prior to PCI, which is frequently done in an effort to make PCI safer. Overall mortality was slightly lower than expected, which could have contributed to the null finding. Also, the hemodynamic improvement from IABP may be too modest to affect mortality. It is unknown if a ventricular assist device would have resulted in different outcomes.

Despite no benefit on the primary outcome, there were no important safety concerns from the use of IABP. This multicenter study will likely temper the current class I recommendation for this support device in MI and cardiogenic shock.

References:

Thiele H, Zeymer U, Neumann FJ, et al., on behalf of the IABP-SHOCK II Trial Investigators. Intraaortic Balloon Support for Myocardial Infarction With Cardiogenic Shock. N Engl J Med 2012;367:1287-96.

Presented by Dr. Holger Thiele at the European Society of Cardiology Congress, Munich, August 27, 2012.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support

Keywords: Myocardial Infarction, Stroke, Follow-Up Studies, Drug-Eluting Stents, Heart-Assist Devices, Catecholamines, Blood Pressure, Cold Temperature, Oliguria, Percutaneous Coronary Intervention, Lactates, Shock, Cardiogenic, Thrombosis, Stroke Volume, Intra-Aortic Balloon Pumping, Diabetes Mellitus


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