Influence of Crossover on Mortality in a Randomized Study of Revascularization in Patients With Systolic Heart Failure and Coronary Artery Disease

Background-To assess the influence of therapy crossovers on treatment comparisons and mortality at 5 years in patients with ischemic heart disease and heart failure randomly assigned to medical therapy alone (MED) or to MED and coronary artery bypass graft (CABG) surgery in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Methods and Results-The influence of early crossover (within the first year after randomization) on 5-year mortality was assessed using time-dependent multivariable Cox models. CABG was performed in 65/602 patients (10.8%) assigned to MED, and 55/610 patients (9.0%) assigned to CABG received MED only. Common reasons for crossover from MED to CABG were progressive symptoms or acute decompensation. MED-assigned patients who underwent CABG had lower 5-year mortality than those who received MED only (25% vs 42%; hazard ratio, 0.50; 95% confidence interval, 0.30-0.85; P=0.008). The main reason for crossover from CABG to MED was patient/family decision. Five patients did not undergo their assigned CABG within a year but died before receiving surgery without status change. They were deemed crossover to MED. The CABG-to-MED crossover population had higher 5-year mortality compared with those treated with CABG per-protocol (59% vs 33%; hazard ratio, 2.01; 95% confidence interval, 1.36-2.96; P<0.001). CABG was associated with lower mortality compared with MED in per-protocol and several time-dependent analyses (all P<0.05). Conclusions-CABG reduced mortality in both the per-protocol and crossover STICH patient populations. Crossover from assigned therapy, therefore, diminished the impact of CABG on survival in STICH when analyzed by intention to treat.