Systematic review: Comparing routine and selective invasive strategies for the acute coronary syndrome

Background: Patients with non-ST-segment elevation acute coronary syndrome (ACS) are managed with either a routine invasive strategy, in which all patients receive coronary angiography, or a selective invasive strategy, in which only patients with refractory or inducible ischemia receive coronary angiography. Purpose: To evaluate whether a routine invasive strategy improves cardiovascular outcomes more than a selective invasive strategy in patients with non-ST-segment elevation ACS. Data Sources: English-language publications in PubMed, EMBASE and the Cochrane Central Register of Controlled Trials from 196 to 18 September 2007. Study Selection: Two investigators independently reviewed searches and selected trials that compared death or myocardial infarction outcomes among adults with non-ST-segment elevation ACS by randomly assigning patients to either a routine invasive strategy or a selective invasive strategy. Data Extraction: Three investigators independently abstracted data from trial reports by using standardized forms. Data Synthesis: 10 trials with a total of 10 648 patients (mean age, 62 years; 71% male; median follow-up, 16.5 months) were found. Trial participants had typical symptoms of unstable angina and frequently had a positive electrocardiogram or marker evidence of myocardial ischemia. Of the 5330 participants assigned to the routine invasive strategy group, 847 had the composite outcome of death or nonfatal myocardial infarction, compared with 928 of 5318 participants assigned to the selective invasive strategy group (relative risk, 0.90 [95% CI, 0.74 to 1.08]). Four hundred thirty-eight patients in the routine invasive strategy group and 463 in the selective invasive strategy group died (relative risk, 0.95 [CI, 0.80 to 1.14)). Four hundred ninety and 569 nonfatal myocardial infarctions, respectively, occurred in the 2 groups (relative risk, 0.86 [CI, 0.68 to 1.08]). Limitations: Methodology, protocols, and outcome definitions differed substantially among the trials. The lower bound of the Cl for the pooled results did not rule out the superiority of the routine invasive strategy. Conclusion: Available trial evidence is heterogeneous and insufficient for comparing routine and selective invasive strategies. Therefore, in patients with non-ST-segment elevation ACS a routine invasive strategy cannot be proven to reduce deaths or nonfatal myocardial infarction.