This study compared the outcomes of combined coronary artery bypass grafting (CABG)/aortic valve replacement (AVR) and CABG alone in patients with moderate aortic stenosis and determined the possible indications for AVR at the time of CABG. Between December 1988 and January 2001, in Tenri Hospital, 41 patients with aortic stenosis underwent CABG: 26 patients underwent the combined procedure and 15 patients underwent CABG alone. The patients who underwent CABG alone were separated them into 2 groups on the basis of the results of annual echocardiography: the rapid progression group, defined by an increase of deltaP by >/=10 mmHg/year, and the slow progression group. Of the 15 patients who underwent CABG alone, the probability of survival at the end of the study in 2001 was 92% at 5 years and 74% at 10 years, and the respective event-free rates were 65% and 50%. Patients less than 70 years old and who were in the rapid progression group had a greater risk for re-operation. The study suggests that patients younger than 70 years old with risk factors for rapid progression should undergo CABG/AVR, and conversely, those older than 70 years old without the risk factors can undergo CABG only.