article19

SHOCK

"Early Revascularization in Acute Myocardial Infarction Complicated by Cardiogenic Shock".The New England Journal of Medicine. 1999. 341(9):625-634.PubMed•Full text•PDFContents

1 Clinical Question
2 Bottom Line
3 Major Points
4 Guidelines
5 Design
6 Population
6.1 Inclusion Criteria
6.2 Exclusion Criteria
6.3 Baseline Characteristics
7 Interventions
8 Outcomes
8.1 Primary Outcome
8.2 Secondary Outcomes
9 Criticisms
10 Funding
11 Further Reading

Clinical Question

Does early revascularization improve survival in patients with acute myocardial infarction complicated by cardiogenic shock?

Bottom Line

Early revascularization in patients with acute myocardial infarction complicated by cardiogenic shock did not significantly reduce overall 30-day mortality but did result in a significant survival benefit at six months.

Major Points

Cardiogenic shock is the leading cause of death in patients hospitalized for acute myocardial infarction. Previous studies suggested that revascularization could improve outcomes, but these were non-randomized and potentially biased. This randomized controlled trial did not find a significant reduction in 30-day mortality with emergency revascularization compared to initial medical stabilization. However, revascularization did result in a significant survival benefit after six months, suggesting early revascularization should be strongly considered for these patients.

Guidelines

Contemporary guidelines recommend early revascularization for patients with cardiogenic shock due to myocardial infarction, based on this trial's longer-term survival benefits.

Design

- Multicenter, randomized trial.
- N=302 patients with acute myocardial infarction and cardiogenic shock.
- Emergency revascularization: 152 patients.
- Initial medical stabilization: 150 patients.
- Inclusion criteria included ST-segment elevation, Q-wave infarction, new left bundle-branch block, or posterior infarction with anterior ST-segment depression, plus shock due to left ventricular failure.
- Exclusion criteria included severe systemic illness, other causes of shock, severe valvular disease, and unsuitability for revascularization.
- Primary endpoint: Mortality at 30 days.
- Secondary endpoint: Six-month survival.

Population

- Mean age: 66±10 years.
- 32% women.
- 55% transferred from other hospitals.

Inclusion Criteria
- Recent MI with ST-segment elevation, new Q-wave, new left bundle-branch block, or anterior ST depression with posterior MI.
- Cardiogenic shock confirmed by clinical and hemodynamic criteria.

Exclusion Criteria
- Severe concurrent illness.
- Non-cardiogenic shock.
- Severe valvular disease.
- Ineligibility for revascularization.

Baseline Characteristics
- Similar between revascularization and medical therapy groups.

Interventions

- Revascularization: Urgent coronary angiography followed by angioplasty or bypass surgery.
- Medical stabilization: Intensive medical therapy, recommended thrombolytic therapy, and intra-aortic balloon counterpulsation.

Outcomes

Primary Outcome
- 30-day mortality: 46.7% for revascularization group, 56.0% for medical therapy group (P=0.11).

Secondary Outcomes
- Six-month mortality: Significantly lower in the revascularization group (50.3%) compared to the medical therapy group (63.1%) (P=0.027).

Criticisms

- The study was designed to detect a 20% absolute mortality difference at 30 days; not powered for smaller differences.
- The small number of very early randomizations precludes inferences about benefits of very early revascularization.
- Small number of elderly patients included limits conclusions for this subgroup.

Funding

- National Heart, Lung, and Blood Institute.
- American Heart Association, New York Affiliate.