In the COMPASS trial, the combination of rivaroxaban and aspirin reduced the rate of major adverse cardiovascular events (MACE) compared with aspirin alone in individuals with stable atherosclerotic vascular disease. In a pre-planned substudy (the COMPASS-CABG study), the regimens of aspirin alone, 5.0 mg of rivaroxaban alone or aspirin plus 2.5 mg of rivaroxaban were compared in 1,448 patients from the COMPASS trial undergoing CABG surgery. Neither rivaroxaban alone nor the combination of aspirin plus rivaroxaban reduced the rate of graft failure (the primary outcome) compared with aspirin alone. The combination therapy was associated with a nonsignificant reduction in the rate of MACE (HR 0.69, 95% CI 0.33–1.47, P = 0.34), whereas rivaroxaban alone was not.