We read with great interest a meta-analysis by Lee et al (including 2,905 patients) of 8 clinical studies (2 randomized trials and 6 nonrandomized studies) comparing coronary artery bypass grafting (CABG) to percutaneous coronary intervention (PCI) with drug-eluting stents (DES) in patients with unprotected left main coronary artery disease, which demonstrated no significant difference between the CABG and DES groups in the risk for death at 1-year follow-up (odds ratio [OR] 1.12, 95% confidence interval [CI] 0.80 to 1.56). We have several concerns regarding their meta-analysis.

First, citation errors exist: patient numbers in the CABG and DES groups were not 302 and 312 but 348 and 357 in the Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery (SYNTAX) trial and not 161 and 98 but 154 and 94, respectively, in the Bologna Registry of Palmerini et al. Second, although ORs as well as 95% CIs were calculated on the basis of rates comparing CABG to DES for each study in the analysis, the most appropriate way of summarizing time-to-event data is to use methods of survival analysis and express the intervention effect as a hazard ratio (HR). Third, although the investigators extracted and combined not adjusted but unadjusted ORs from not only randomized trials but also nonrandomized studies, it is usually appropriate for nonrandomized studies to analyze adjusted rather than unadjusted effect estimates that are limited by publication bias, treatment bias, confounders, and a tendency to overestimate treatment effect.

We recently performed a meta-analysis (including 2,841 patients) that combined not unadjusted ORs but adjusted HRs from 7 nonrandomized studies, which suggested that PCI with DES or bare-metal stents might increase late (2- to 4-year) mortality relative to CABG in patients with unprotected left main coronary artery disease (PCI vs CABG: HR 1.35, 95% CI 1.04 to 1.75; CABG vs DES: HR 0.74, 95% CI 0.57 to 0.96). Although our meta-analysis included patients receiving not only DES but also bare-metal stents, a meta-regression analysis in an unrestricted maximum-likelihood model revealed that the percentage of patients receiving DES was not associated with improved PCI treatment estimates.

Despite the results of the meta-analysis by Lee et al, in terms of late mortality, CABG would be preferred to PCI with DES or bare-metal stents in patients with unprotected left main coronary artery disease.