Abstract 2124: A Benchmark for Evaluating Innovative Treatment of Left Main Coronary Disease
Objectives: Left main (LM) stenosis (≥50%) has traditionally been treated with coronary artery bypass grafting (CABG), but improvements in coronary stents have led advocates of percutaneous coronary intervention (PCI) to treat it with PCI. To provide a benchmark of outcomes against which PCI and future innovations may be compared, we 1) assessed long-term survival and freedom from coronary reintervention after CABG in patients with LM stenosis, and 2) identified their risk factors.
Methods: From 1971 to 1998, the first 1,000 patients undergoing primary isolated CABG (n=26,927) were followed every 5 years. Of these, 3,803 had LM stenosis ≥50%. A multivariable, nonproportional-hazards, time-related analysis was performed to model survival and freedom from coronary reintervention (PCI or reoperation) and to identify by bootstrap bagging patient and operative factors associated with these outcomes.
Results: 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 70%. Worse left ventricular function (P<.0001), diabetes (P<.0001), hypertension (P<.001), peripheral vascular disease (P=.0002), smoking history (P<.0001), and elevated triglycerides (P=.01) decreased survival, and younger age (P<.0001), elevated triglycerides (P=.005) and incomplete revascularization (P=.003) increased coronary reintervention. Internal thoracic artery grafting of the left anterior descending improved survival and decreased coronary reintervention.
Conclusions: This study provides a 20-year benchmark of outcomes for patients with LM disease treated by CABG and indicates that simple comparisons of new treatments are inadequate without risk adjustment. Using these data, we have developed benchmark software for use in risk-adjusted evaluation of current and future treatment innovations.