CORONARY REVASCULARIZATION SURGERY AFTER MYOCARDIAL-INFARCTION - IMPACT OF BYPASS-SURGERY ON SURVIVAL AFTER THROMBOLYSIS

Objectives. This study sought to investigate the impact of surgical re vascularization on outcome after myocardial infarction. Background. Sm all variations in rates of coronary artery bypass graft surgery (CABG) were noted among thrombolytic regimens in the Global Utilization of S treptokinase and Tissue Plasminogen Activator for Occluded Coronary Ar teries (GUSTO) trial, prompting the question of whether survival diffe rences were partly related to differences in CABG rates, Methods. Pati ents in the GUSTO trial were randomized to one of four thrombolytic st rategies, Of 40,861 patients with complete data, 3,526 underwent surgi cal revascularization during their initial hospital admission, Thirty- day and 1-year mortality rates were estimated using Kaplan-Meier techn iques, and the impact of CABG as a time dependent covariate on death w as evaluated using a Cox survival model, adjusting for baseline progno stic factors. Results, The median time from study enrollment to CABG w as 7 days across treatment groups, A 15% reduction in mortality for th e tissue-type plasminogen activator (t-PA)-treated group was evident b y the seventh day, Bypass surgery was a significant independent predic tor of 30 day mortality (risk ratio 1.87) and a weaker predictor of 1- year mortality (risk ratio 1.21), Operative mortality was highest in p atients with acute mitral regurgitation, ventricular septal defect or poor left ventricular function and in those undergoing CABG within the first 4 days of randomization, Conclusions. The survival benefit of a ccelerated t-PA was not related to surgical revascularization, Bypass surgery was associated with excess mortality in the first gear, but th e added short term mortality associated with CABG mag be balanced by a nticipated long-term benefit in specific groups of patients. (C) 1997 by the American College of Cardiology.