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How should patients with unstable angina and non-ST-segment elevation myocardial infarction be managed? A meta-analysis of randomized trials

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Abstract

Purpose

Patients with unstable angina or non-ST-segment elevation myocardial infarction (MI) may be managed with either an “invasive” or “conservative” strategy. It is unclear which of these strategies is superior.

Methods

We identified studies with MEDLINE and EMBASE searches (1966-September 2003) and by reviewing reference lists. Studies were included if they were randomized controlled trials comparing management strategies for patients in the early post-unstable angina/non-ST-segment elevation MI period and had follow-up data for at least 3 months.

Results

Seven trials that randomized a total of 9212 patients were included. The pooled odds ratio (OR) for all-cause mortality was 0.96 (95% confidence interval [CI]: 0.72 to 1.27). The occurrence of fatal or nonfatal re-infarction was reduced with an invasive strategy (OR 0.73; 95% CI: 0.61 to 0.88) as was readmission to hospital (OR 0.67; 95% CI: 0.48 to 0.94). The endpoints of nonfatal MI and the composite of death or nonfatal MI showed nonsignificant trends favoring an invasive strategy. Trials that included a higher proportion of patients with ST-segment depression on admission and trials in which a larger proportion of patients underwent revascularization showed a greater magnitude of benefit for an invasive strategy.

Conclusion

For patients with unstable angina/non-ST-segment elevation MI, an invasive strategy reduces rates of fatal or nonfatal re-infarction and hospital readmission, but not all-cause mortality, when compared with a noninvasive strategy. These results suggest that an invasive management strategy should be considered for all patients with unstable angina/non-ST-segment elevation MI and perhaps in particular those with ST-segment depression.

Section snippets

Methods

We searched the MEDLINE and EMBASE databases (Ovid Technologies, 1966-September 2003; English language) for keywords related to acute coronary syndromes (eg, coronary artery disease, myocardial infarction, unstable angina), medical therapy (eg, platelet aggregation inhibitor, antithrombotic, thrombolysis), interventional therapy (eg, angioplasty, percutaneous transluminal coronary angioplasty, coronary angiography), and risk stratification. Two investigators independently reviewed the search

Trial characteristics and methodological quality

Our initial search yielded 382 citations, of which 328 articles were excluded on the basis of an abstract review. Of the remaining 54 references, 42 were excluded because they reported trials that enrolled patients with ST-segment elevation MI, did not report the results of a clinical trial, were duplicate publications, described studies that only randomized patients with cardiogenic shock or high risk post-MI patients, were not published in English, or did not fulfill inclusion criteria for

Discussion

This meta-analysis demonstrates that when compared with a conservative strategy, an invasive management strategy reduces rates of re-hospitalization and the combined endpoint of fatal and nonfatal re-infarction for patients with unstable angina and non-ST-elevation MI. A nonsignificant trend favoring an invasive strategy for reducing the composite endpoint of death or nonfatal re-infarction was also observed, but there was no advantage of either strategy with respect to all-cause mortality or

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