Patients with unprotected left main coronary artery stenosis were assigned to either CABG or PCI with sirolimus-eluting stents. At 1 year, with a wide prespecified noninferiority margin, PCI was found to be noninferior to CABG. Anumber of registry reports, as well as a substudy from a large, randomized trial, have indicated that percutaneous coronary intervention (PCI) may be an acceptable alternative to coronary-artery bypass grafting (CABG) in some patients with unprotected left main coronary artery stenosis. 1 – 11 Recent clinical guidelines have accordingly stated that elective PCI can be considered for patients who have unprotected left main coronary artery disease, although they suggest that the aggregated evidence favors CABG. 12 , 13 Whether the outcomes after PCI are similar to those after CABG remains uncertain, however, owing to the lack of large, randomized clinical trials. Registry results have . . .