Percutaneous revascularization of left main coronary artery (LMCA) disease has remained controversial for more than 25 years, since LMCA balloon angioplasty was first performed by Andreas Gruentzig in 1978. Summarizing his experience, Gruentzig concluded, “We have not been too successful with dilating left main stems…although the procedure is relatively simple, the potential complications are both sudden and serious.”1 Following the evolution of percutaneous catheter-based therapies to include both bare metal stent and, more recently, drug-eluting stent (DES) platforms in conjunction with advances in periprocedural and postprocedural adjunctive pharmacotherapies, interest in percutaneous LMCA revascularization, particularly unprotected left main, has been renewed. Although studies performed with bare metal stents demonstrated a low rate of in-hospital mortality, the incidence of late coronary restenosis remained high.2–6 In the Unprotected Left Main Trunk Intervention Multi-Center Assessment (ULTIMA) registry, which enrolled 279 patients with unprotected LMCA disease who had percutaneous coronary revascularization (69% bare metal stent), mortality at a 1-year follow-up was proportional to clinical risk stratification (40% in high-risk versus 3.5% in low-risk patient cohorts), and repeated revascularization was required in 34% of cases.6 The experience gleaned from these studies continued to support the American College of Cardiology/American Heart Association (ACC/AHA) guideline recommendations that in reasonable surgical candidates with LMCA disease, coronary bypass surgery is the preferred therapeutic option.7 After the introduction of DES, several small clinical series demonstrated the feasibility and short-term safety of LMCA stenting, while late clinical/angiographic outcomes appeared favorable as compared with historical (nonrandomized) patient cohorts treated with bare metal stents.3,8–11 The cumulative experience with DES treatment for LMCA demonstrated an apparent marked reduction in major adverse cardiovascular events, including target vessel revascularization, during 6 to 12 months of follow-up as compared with the precedent experience after bare metal stent deployment. Article p 2542 The clinical …