Clinical Question: Is a routine or selective invasive strategy more effective in the treatment of patients with acute coronary syndrome?
Setting: Various (meta-analysis)
Study Design: Meta-analysis (randomized controlled trials)
Synopsis: Optimal treatment for patients with unstable angina or non–ST-segment elevation myocardial infarction (MI) remains controversial. Investigators comprehensively searched MEDLINE, the Cochrane Registry of Controlled Trials, abstracts from major cardiology meetings, and cross-references from original articles and reviews for relevant trials comparing the benefits and risks of routine versus selective invasive treatment strategies. A routine invasive strategy was defined as all patients with unstable angina or non–ST-segment elevation MI undergoing immediate coronary angiography followed by revascularization when appropriate. A selective invasive strategy was defined as all patients initially being treated pharmacologically, followed by angiography and revascularization only for those with persistent symptoms or evidence of ongoing ischemia. Only randomized trials with adequate concealment and follow-up were included in the review. Two persons independently assessed the individual trials and extracted pertinent data. Of 84 articles initially identified, only seven involving 9,208 patients met inclusion criteria. Follow-up occurred for a mean of 17 months.
The mortality rate increased significantly during the initial hospitalization in the routine invasive strategy group (1.8 versus 1.1 percent in the selective invasive strategy group), but after discharge the routine strategy was associated with a significantly lower rate of mortality (3.8 versus 4.9 percent). Overall, the composite outcome of death or recurrent MI was lower in patients in the routine group than in the selective group (12.2 versus 14.4 percent; number needed to treat = 45; 95% confidence interval, 28 to 119). Patients at higher risk who had elevated cardiac biomarkers (e.g., troponin and creatine kinase levels) at baseline benefited the most from the routine invasive strategy, but there was no benefit to the routine strategy for patients with negative biomarkers. There was some heterogeneity in the outcomes of the various trials, but the authors speculate that it was related to the concurrent use of other medications in some, but not all, trials. Trials published after 1999 demonstrated the most benefit to routine invasive strategy, suggesting a positive impact of improved treatment protocols.
Bottom Line: High-risk patients with unstable angina or non–ST-segment elevation MI and positive cardiac biomarkers benefit from immediate coronary angiography and revascularization when appropriate. Similar patients with negative cardiac biomarkers appear to do as well with initial pharmacologic treatment, reserving angiography and revascularization for those with evidence of ongoing ischemia. (Level of Evidence: 1a–)