The study sought to contrast risk profiles and compare outcomes of patients with severe aortic stenosis (AS) and coronary artery disease (CAD) who underwent aortic valve replacement (AVR) and coronary artery bypass grafting (AS+CABG) with those of patients with isolated AS who underwent AVR alone.In patients with severe AS, CAD is often an incidental finding with underappreciated survival implications.From October 1991 to July 2010, 2,286 patients underwent AVR+CABG and 1,637 AVR alone. A propensity score was developed and used for matched comparisons of outcomes (1,082 patient pairs). Analyses of long-term mortality were performed for each group, then combined to identify common and unique risk factors.Patients with AS+CAD versus isolated AS were older, more symptomatic, and more likely to be hypertensive, and had lower ejection fraction and greater arteriosclerotic burden but less severe AS. Hospital morbidity and long-term survival were poorer (43% vs. 59% at 10 years). Both groups shared many mortality risk factors; however, early risk among AS+CAD patients reflected effects of CAD; late risk reflected diastolic left ventricular dysfunction expressed as ventricular hypertrophy and left atrial enlargement. Patients with isolated AS and few comorbidities had the best outcome, those with CAD without myocardial damage had intermediate outcome equivalent to propensity-matched isolated AS patients, and those with CAD, myocardial damage, and advanced comorbidities had the worst outcome.Cardiovascular risk factors and comorbidities must be considered in managing patients with severe AS. Patients with severe AS and CAD risk factors should undergo early diagnostics and AVR+CABG before ischemic myocardial damage occurs.