Management of mild to moderate aortic stenosis at the time of coronary artery bypass grafting.

An increasing number of patients are referred for coronary artery bypass surgery (CABG) with the presence of mild to moderate aortic stenosis (AS). It is well accepted that patients with severe AS and coronary artery disease (CAD) should undergo combined aortic valve replacement (AVR) and CABG, which carries an operative mortality of approximately 5-7%. For patients with CAD and mild AS, controversy persists regarding concomitant AVR during CABG. It has been shown that AS progresses at a rate of 5-10 mmHg per year, and the valve area decreases by about 0.1 cm2 per year. The progression of AS is more rapid in elderly patients, in the presence of CAD, and in patients with a calcific degenerative etiology. In contrast, patients with congenital bicuspid valves or rheumatic pathology demonstrate slower progression of disease. Despite these observations, it is difficult to predict reliably the progression of disease for an individual. Thus, an attempt should be made to identify patients who are likely to progress rapidly from mild to severe AS and who would therefore benefit from AVR/CABG. Our approach regarding the decision to perform an AVR/CABG is based on aortic valve gradient and area. If the gradient is >25 mmHg, AVR should be considered. If the gradient is <10 mmHg, then only CABG is performed. Severities of leaflet calcification and leaflet mobility are factors that should be taken into account when deciding to perform concomitant AVR/CABG for intermediate gradient (10-25 mmHg). Additional important variables include the etiology of aortic valve disease, the rate of progression of AS, the patient's life expectancy, and general condition. For patients with mild AS who are undergoing CABG, a tailored approach involving intraoperative transesophageal echocardiography and valve inspection is the most appropriate surgical option.