"Early Invasive vs. Conservative Strategy in Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction"
The New England Journal of Medicine, 2011, [Page numbers].

Contents

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 Funding
10 Further Reading

Clinical Question

In patients with unstable angina and non-ST-segment elevation myocardial infarction (NSTEMI) who are treated with aspirin, heparin, and tirofiban, does an early invasive strategy lead to better outcomes compared to a conservative strategy?

Bottom Line

For patients with unstable angina and NSTEMI treated with aspirin, heparin, and the glycoprotein IIb/IIIa inhibitor tirofiban, an early invasive strategy reduced the incidence of major cardiac events compared to a conservative strategy.

Major Points

The study demonstrated that among patients with unstable angina and NSTEMI, employing an early invasive strategy after initial treatment with aspirin, heparin, and tirofiban led to superior outcomes compared to a more conservative approach. This supports broader use of early glycoprotein IIb/IIIa inhibition in combination with early invasive intervention in such patients.

Guidelines

Current guidelines suggest that an early invasive strategy should be considered in patients with unstable angina and NSTEMI, particularly those who are at intermediate or high risk according to initial risk stratification.

Design

- Multicenter, double-blind, parallel-group, randomized, placebo-controlled trial
- N=2,220 patients with unstable angina and NSTEMI
- Early invasive strategy: routine early catheterization (4 to 48 hours after randomization) and appropriate revascularization
- Conservative strategy: catheterization for recurrent symptoms or abnormal stress test
- Setting: Various clinical centers
- Enrollment: December 1997 to December 1999
- Mean follow-up: 6 months
- Analysis: Intention-to-treat

Population

Inclusion Criteria:
- Adult patients (≥18 years old) with unstable angina or NSTEMI within the previous 24 hours
- Candidates for coronary revascularization
- At least one of the following: ST-segment or T-wave changes, elevated cardiac markers, documented coronary artery disease

Exclusion Criteria:
- Persistent ST-segment elevation, secondary angina, recent revascularization, high bleeding risk, severe heart failure or shock, other serious diseases, renal impairment, current participation in another study

Baseline Characteristics:
- Well-matched groups
- 40% aged at least 65 years
- 33% women
- 48% with ST-segment or T-wave changes
- 54% with elevated troponin T levels

Interventions

- All patients treated with 325 mg of aspirin daily, intravenous unfractionated heparin, and tirofiban.
- Invasive strategy: immediate catheterization and revascularization.
- Conservative strategy: medical therapy with catheterization reserved for recurrent ischemia or abnormal stress test.

Outcomes

Primary Outcome:
- Combined incidence of death, nonfatal myocardial infarction, or rehospitalization for an acute coronary syndrome at six months was 15.9% in the invasive group vs. 19.4% in the conservative group (P=0.025).

Secondary Outcomes:
- Death or nonfatal myocardial infarction at six months was also fewer in the invasive strategy (7.3% vs. 9.5%, P<0.05).

Funding

The study was funded by Merck.

Further Reading

- Full details of the study design, results, and analysis are available at the New England Journal of Medicine website.

Appendix
- Full list of study investigators, research coordinators, and clinical centers available online.