Coronary Bypass Surgery versus Coronary Stenting

Chicago—After 4 years, patients with coronary heart disease who underwent coronary artery bypass grafting (CABG) had a significantly lower mortality rate compared with those who had percutaneous coronary intervention (PCI), according to a large observational study. William S. Weintraub, MD, the study’s lead investigator and chair of cardiology at Christiana Care Health System in Newark, Delaware, discussed the study at the ACC meeting during a late-breaking clinical trial session. Results were simultaneously published online in the New England Journal of Medicine [doi:10.1056/NEJMoa1110717]. The ASCERT (ACCF-STS Database Collaboration on the Comparative Effectiveness of Revascularization Strategies) trial found that the mortality rate at 4 years was 16.4% in the CABG group and 20.8% in the PCI group (risk ratio, 0.79; 95% confidence interval [CI], 0.76-0.92). The study, a collaboration between the American College of Cardiology Foundation (ACCF) and the Society of Thoracic Surgeons (STS), examined databases from both organizations as well as from the Centers for Medicare & Medicaid Services. It was funded by the National Institute of Health’s National Heart, Lung, and Blood Institute. Coronary heart disease is the leading cause of death in the United States, according to Dr. Weintraub. Previous trials had shown the procedures had similar long-term outcomes or that CABG was more effective. However, Dr. Weintraub said PCI is chosen more often than CABG because it is less invasive. “This moves the bar along,” Dr. Weintraub said. “Perhaps it will lead us to some rethinking of our approaches...But I don’t think anyone would say, ‘Well, now with the results of ASCERT it’s completely changed the way we do things,’ except it may help us do things better and lead to better studies in the future.” Between January 1, 2004, and December 31, 2007, the authors examined 1,542,872 claims for PCI and 581,036 claims for CABG from a total of 1,943,653 patients. The final analysis included patients ≥65 years of age who had 2- or 3-vessel coronary artery disease without acute myocardial infarction: 103,549 patients underwent PCI and 86,244 patients underwent CABG. At 1 year, the mortality rate was 6.2% in the CABG group and 6.6% in the PCI group (risk ratio, 0.95; 95% CI, 0.90-1.00). By year 4, there was a benefit of CABG in all subgroups based on sex, age, presence or absence of diabetes, body mass index, presence or absence of chronic lung disease, ejection fraction, and glomerular filtration rate. “What was really quite striking was how consistent these data were across our subgroups,” Dr. Weintraub said. Dr. Weintraub acknowledged that ASCERT’s observational design led to treatment selection bias, but he said that he and the other investigators “looked at that quite carefully” and tried to minimize the bias by using advanced statistical techniques. Randomized trials improve the selection bias, but Dr. Weintraub said they are also expensive, take longer to conduct, and are more difficult to generalize the results to a broader population. Observational studies are larger and more easily developed, he added.