The incidence and prognostic impact of major bleeding (MB) after percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for left main coronary artery disease (LMCAD) are unknown.

The goal of this study was to investigate the rates and outcomes of MB after LMCAD revascularization.

In the EXCEL (Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial, 1,905 patients with unprotected LMCAD were randomized to undergo PCI (n = 948) or CABG (n = 957) and followed up for 5 years. MB was defined as TIMI major or minor bleeding, BARC (Bleeding Academic Research Consortium) types 3 to 5 bleeding, or any overt bleeding requiring blood transfusion. The association between MB and subsequent mortality was assessed in time-adjusted Cox regression models.

At 5 years, 217 patients (11.4%) had at least 1 MB event. Rates of 5-year MB were 7.9% after PCI vs 14.8% after CABG (OR: 0.48; 95% CI: 0.36-0.65; P < 0.0001). However, in-hospital MB was lower after PCI (3.8% vs 13.5%; OR: 0.25; 95% CI: 0.17-0.37), whereas postdischarge MB was lower after CABG (4.5% vs 2.0%; OR: 2.33; 95% CI: 1.33-3.09; P_interaction < 0.0001). All 41 postdischarge MB events after PCI occurred in patients receiving dual antiplatelet therapy. MB events within 5 years were associated with a higher subsequent risk of all-cause mortality (adjusted HR: 2.71; 95% CI: 1.95-3.77; P < 0.0001), whether in-hospital or postdischarge (P_interaction = 1.00) and after both PCI and CABG (P_interaction = 0.95), driven both by increased cardiovascular and non-cardiovascular mortality.

In the EXCEL trial, CABG resulted in higher 5-year rates of all MB and in-hospital MB, although postdischarge MB was more frequent after PCI. MB after both procedures was associated with increased cardiovascular and noncardiovascular mortality within 5 years.