Aortic valve replacement after previous coronary artery bypass grafting

Background. As the population ages, an increasing number of patients with previous coronary artery bypass grafting (CABG) will require subsequent aortic valve replacement (AVR). This study examined outcome of AVR after previous CABG and reviewed possible indications for valve replacement at the time of initial myocardial revascularization. Methods. Between March 1975 and December 1994, 145 patients had AVR after previous CABG. Sixty-three patients (43%) had their initial CABG elsewhere. Reoperation for AVR was the second cardiac procedure in 137 patients and the third in 8. Redo CABG with AVR was done in 66 (46%). There were 118 men and 27 women. The mean age at CABG was 64 ± 7.9 years; for AVR this was 71 ± 7.6 years. Results. In 2 young patients accelerated calcific aortic stenosis occurred in the setting of renal failure. Significant aortic stenosis did not appear to be addressed at initial CABG in 3 patients. Transaortic valvular gradient, as measured by cardiac catheterization, increased by 10.4 ± 7.0 mm Hg/y. Twenty-four patients (16.6%) died. The mortality for AVR alone or for AVR + redo-CABG was 15 of 125 patients (12%). For patients having more complicated procedures, the mortality was 9 of 20 (45%). Nine patients (6.2%) suffered a postoperative cerebrovascular accident. Low preoperative ejection fraction measured by echocardiography, sternal reentry problems, complexity of operation, and prolonged cross-clamp and bypass times were significant factors associated with mortality. Age at AVR, interval between operations, the extent of underlying native coronary artery disease, the state of the previously placed bypass conduits, and methods of myocardial preservation were not significant predictors of operative mortality. On multivariate analysis there was only one significant value: prolonged cross-clamp time. Conclusions. Aortic valve replacement after previous CABG is associated with a mortality that is higher than that seen after repeat CABG or repeat AVR. It seems prudent, therefore, to use liberal criteria for AVR in those patients who require coronary revascularization and who, at the same time, have mild or moderate aortic valve disease.