The Effects of Geography on Outcomes of Routine Early Versus Selective Late Revascularization Strategy in the Treatment of Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction: A Meta-Analysis of Transatlantic Randomized Controlled Trials

BACKGROUND: The optimal timing of revascularization in unstable angina (UA) or non-ST-segment elevation myocardial infarction (NSTEMI) remains uncertain. We compared routine early revascularization (REV) versus selective late revascularization (SLR) strategies and divergence in the approach of cardiologists in the United States and Europe. METHODS: Seventeen randomized controlled trials (RCTs) (15,812 patients) were extracted from PubMed, Cochrane Library, EMBASE and Web of Science databases. The data were pooled using the Der Simonian and Laird random-effect models and expressed as pooled risk ratios (RR) with 95% confidence intervals (95% CIs). RESULTS: Overall, there was no difference in all-cause mortality (RR: 1.01, 95% CI: 0.95 - 1.08, P = 0.7), myocardial infarction (MI) (RR: 0.98, 95% CI: 0.79 - 1.22, P = 0.85) or coronary artery bypass grafting (CABG) (RR: 1.33, 95% CI: 0.92 - 1.91, P = 0.12) between REV and SLR strategy. There were trends of decreased incidence of MI in REV, 13.3% (1,029/7,704) vs. 15.1% (1,108/7,314) in SLR (P = 0.007), and rate of CABG was higher in REV, 4.9% (140/2,831) vs. 3.7% (105/2,819) in SLR (P = 0.031). There were trends of lower all-cause mortality in the combined US/international trials in both REV 8.4% (390/4,624) vs. 22.8% (908/3,975) (P < 0.001) and SLR 8% (359/4,421) vs. 24% (910/3,808) (P < 0.001) compared to the European trials. There were also trends of lower rates of MI in the European trials in the REV group 20% (623/3,080) vs. 25% (712/2,893) in SLR (P = 0.001) and higher rates of CABG in REV 8.3% (96/1,144) vs. 5.7% (67/1,165) in SLR (P = 0.02); however, there were no significant effects in the pooled RR ratios even after subgroup analysis between US/international trials and European trials. CONCLUSIONS: Despite having contemporary differences in the management approach towards UA/NSTEMI patients, no significant differences in trends were observed with REV strategy in US/international trials vs. European trials.