Prior coronary artery bypass surgery and risk of death among patients withischemic left ventricular dysfunction

Background-Patients with ischemic LV dysfunction are at high risk of sudden death. However, no benefit from prophylactic defibrillator therapy was obs erved in a group of patients with LV dysfunction undergoing CABG (CABG Patc h trial). Thus, the effect of CABG on future risk of sudden death in patien ts with LV dysfunction is of considerable interest. Methods and Results-Mortality and modes of death in 5410 patients with isch emic LV dysfunction who were enrolled in the Studies of Left Ventricular Dy sfunction (SOLVD) trials were evaluated. Outcomes of patients with (n=1870, 35%) versus without (n=3540) history of prior CABG were compared, and stra tification by baseline ejection fraction (EF) values (<0.25, 0.25 to 0.30, and >0.30) was performed. Prior CABG was associated with a 25% (95% CI, 15% to 36%) reduction in risk of death and a 46% (95% CI, 30% to 58%) reductio n in risk of sudden death independent of EF and severity of heart failure s ymptoms. As baseline EF declined, absolute reduction in risk of sudden deat h with prior CABG increased (P <0.01). No alteration in risk of death from progressive heart failure was observed with prior CABG. When these results were applied to a group of patients with LV dysfunction who had not undergo ne prior surgery (Coronary Artery Surgery Study Registry) predicted annual rates of death (8.2%) and sudden death (2.4%) were similar to those observe d in the CABG Patch trial (7.9% and 2.3%, respectively). Conclusions-In patients with ischemic LV dysfunction, prior CABG is associa ted with a significant independent reduction in mortality. These results ap pear to account for the lack of benefit from defibrillator therapy in the C ABG Patch trial.