Randomized, controlled trial of coronary artery bypass surgery versus percutaneous coronary intervention in patients with multivessel coronary artery disease: six-year follow-up from the Stent or Surgery Trial (SoS).

BACKGROUND: The Stent or Surgery Trial is a randomized, controlled trial comparing percutaneous coronary intervention with coronary artery bypass grafting (CABG) for patients with multivessel disease. Initial results at a median follow-up of 2 years showed a survival advantage for patients randomized to CABG. This article reports survival outcome at a median follow-up of 6 years. METHODS AND RESULTS: A total of 988 (n=488 percutaneous coronary intervention, n=500 CABG) patients were randomized at 53 centers during the period from 1996 to 1999. Investigators established survival status from hospital or community medical records or national databases or by direct contact with patients and their relatives. All-cause mortality was compared with hazard ratios and confidence intervals calculated from Cox proportional hazards models. Prespecified subgroup analyses for diabetes mellitus, angina grade, and angiographic severity of coronary disease at baseline were performed with tests for interaction. At a median follow-up of 6 years, 53 patients (10.9%) died in the percutaneous coronary intervention group compared with 34 (6.8%) in the CABG group (hazard ratio 1.66, 95% confidence interval 1.08 to 2.55, P=0.022). Little evidence was found that the treatment effect on mortality differed between subgroups according to baseline angina grade (interaction test P=0.52), the severity of coronary disease (P=0.92), or diabetic status (P=0.15). CONCLUSIONS: At a median follow-up of 6 years, a continuing survival advantage was observed for patients managed with CABG, which is not consistent with results from other stent-versus-CABG studies.