Percutaneous coronary intervention versus coronary bypass surgery for unprotected left main disease: a meta-analysis of randomized controlled trials

Background: This meta-analysis of randomized controlled trials (RCTs) was aimed at comparing coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for the treatment of unprotected left main coronary disease. Methods: All RCTs randomizing patients to any type of PCI with stents vs. CABG for left main disease (LMD) were included. Primary outcome was a composite of follow-up death/myocardial infarction/stroke/repeat revascularization. Secondary outcomes were peri-procedural mortality and the individual components of the primary outcome. Incidence rate ratio (IRR) or odds ratio (OR) and 95% confidence intervals (CIs) were pooled using a generic inverse variance method with random effects model. Subgroup analyses were done based on: (I) type of PCI [bare metal stents (BMS) vs. drug-eluting stents (DES)] and; (II) mean SYNTAX score tertiles. Leave one-out analysis and meta-regression were performed. Results: Six trials were included (4,700 patients; 2,349 PCI and 2,351 CABG). Follow-up ranged from 2.33 to 5 years. PCI was associated with higher risk of follow-up death/myocardial infarction/stroke/repeat revascularization (IRR = 1.328, 95% CI, 1.114-1.582, P= 0.002) and of repeated revascularization (IRR = 1.754, 95% CI, 1.470-2.093, P< 0.001). The risk of peri-procedural mortality (OR = 0.866, 95% CI, 0.460-1.628, P= 0.654), follow-up mortality (IRR = 0.947, 95% CI, 0.711-1.262, P= 0.712), myocardial infarction (IRR = 1.342, 95% CI, 0.827-2.179, P= 0.234) and stroke (IRR = 0.800, 95% CI, 0.374-1.710, P= 0.565) were similar between groups. No differences were found between DES and BMS subgroups. The risk of followup death/myocardial infarction/stroke/repeat revascularization with PCI was higher in all SYNTAX tertiles, with a progressive increase from the 1st to the 3rd tertile. At meta-regression, higher mean SYNTAX score was associated with higher risk for the primary outcome in the PCI group (beta = 0.02, P= 0.05), whereas no association was found with female gender, mean age, or diabetes. Conclusions: CABG remains the therapy of choice for the treatment of unprotected LMD, especially for patients with a high SYNTAX score.