Previous coronary artery bypass grafting is not a risk factor for aortic valve replacement

The risk of aortic valve replacement (AVR) after previous coronary artery bypass grafting (CABG) is controversial. Its magnitude influences the threshold for recommending this procedure and has been cited in arguments regarding the optimal management of mild aortic stenosis at primary CABG. We therefore reviewed our experience with reoperative AVR +/- CABG and the primary combined procedure.

Between January 1, 1985, and June 30, 1996, 427 patients underwent primary AVR+CABG, and 52 underwent AVR +/- CABG after prior CABG. Demographics, operative characteristics, and operative results were compared between groups. Data for all patients were pooled and analyzed collectively for risk factors influencing mortality.

The extent of native coronary artery disease and the incidence of prior myocardial infarction and stroke were greater in the reoperative group. Aortic cross-clamp and cardiopulmonary bypass times were slightly shorter, and fewer distal anastomoses were performed in the reoperative group. Operative mortality (primary group, 6.3% versus reoperative group, 7.4%) and morbidity were similar. Stepwise multivariate logistic regression analysis identified age, perioperative myocardial infarction, intraaortic balloon support, ventricular arrhythmia, perioperative stroke, and development of renal failure or acute respiratory distress syndrome, but not reoperative status, as predictors of mortality.

The risk of AVR after previous CABG is similar to that for primary AVR+CABG. Valve replacement should, therefore, be pursued despite prior CABG when hemodynamically significant aortic stenosis develops. Furthermore, a circumspect approach to "prophylactic" AVR for mild aortic stenosis at primary CABG seems warranted.