A benchmark for evaluating innovative treatment of left main coronary disease

Left main trunk stenosis (> or = 50%) has traditionally been treated with coronary artery bypass grafting. Improvements in coronary stents have led some to advocate percutaneous coronary intervention. To provide a benchmark of outcomes against which percutaneous coronary intervention may be compared, we (1) assessed survival and freedom from coronary reintervention after coronary artery bypass grafting in these patients and (2) identified their risk factors.

From 1971 to 1998, the first 1000 primary coronary artery bypass grafting patients (n=26,927) were followed every 5 years. Of these, 3803 had left main trunk stenosis > or = 50%. A multivariable, nonproportional hazards, time-related analysis was performed to model survival and freedom from coronary reintervention (percutaneous coronary intervention or reoperation) and to identify their risk factors. Survival at 30 days, 1, 5, 10, 15, and 20 years was 97.6%, 93.6%, 83%, 64%, 44%, and 28%, respectively, and freedom from coronary reintervention was 99.7%, 98.9%, 96.6%, 89%, 76%, and 61%, respectively. Worse left ventricular function (P<0.0001), diabetes (P<0.0001), hypertension (P<0.001), peripheral arterial disease (P=0.0002), smoking (P<0.0001), and elevated triglycerides (P=0.01) decreased survival, and younger age (P<0.0001), elevated triglycerides (P=0.005), and incomplete revascularization (P=0.003) increased coronary reintervention. Internal thoracic artery grafting of the left anterior descending improved survival and decreased coronary reintervention.

This study provides a 20-year outcome benchmark for surgical treatment of left main trunk disease. It indicates that simple comparisons of new treatments are inadequate without risk adjustment. Risk factor adjustment should be used when comparing coronary artery bypass grafting with current and future treatment innovations and when selecting the best treatment strategy for individual patients.