Invasive versus conservative strategies in patients with non-st-elevation acute coronary syndrome: an updated meta-analysis

Abstract

Background: Early invasive approach is recommended for non-ST-segment elevation acute coronary syndromes (NSTE-ACS). However, recent guidelines propose early or deferred angiography within the routine invasive strategy. We sought to perform an updated meta-analysis to determine whether early invasive therapy improves clinical outcomes in patients with NSTE-ACS. Methods: Randomized controlled trials (RCTs) identified through search of MEDLINE, EMBASE, and the Cochrane databases (1991 through December 2012) and hand searching of cross references from original articles and reviews. Clinical trials that randomized NSTE-ACS patients to early invasive versus delayed invasive or more conservative approach were included for analysis. Major outcomes of death and myocardial infarction (MI) occurring from index hospitalization to the end of follow-up were extracted from published results of eligible studies. Secondary end points included the composite of death or MI; rehospitalization; recurrent angina; and repeat revascularization. The pooled effects were calculated using fixed-effects model (Mantel-Haenszel method) or random effects models (Dersimonian and Laird method). Results: A total of fifteen RCTs including 15,315 patients were included in this meta-analysis. No statistically significant differences in the risk of death (odds ratio [OR] 0.86, 95% confidence interval [CI] 0.70–1.06, p=0.15) or MI (OR 0.92, 95% CI 0.74–1.13, p=0.41) were detected between early invasive group versus delayed invasive or conservative approach group. Early invasive strategy significantly reduced the risk of composite of death or MI (OR 0.82, 95% CI 0.70–0.96, p=0.02), rehospitalization (OR 0.80, 95% CI 0.72–0.89, p<0.001), and recurrent angina (OR 0.75, 95% CI 0.56–0.99, p=0.04). Stratified analysis by the invasiveness suggested similar odds of mortality in studies comparing invasive versus conservative strategy (OR 0.87, 95% CI 0.68–1.11, p=0.25) and early versus late invasive approach (OR 0.81, 95% CI 0.50–1.32, p=0.41). Conclusions: Management of NSTE-ACS by early invasive strategy does not decrease the risk of death or MI at long-term follow up. However, early intervention reduces the risk of recurrent angina and rehospitalization compared with delayed intervention or conservative management.