Myocardial damage in combined valvular and coronary bypass surgery.

The incidence of perioperative myocardial infarction (MI) and acute ischemic injury was determined in 44 patients having aortic valve replacement plus aortocoronary vein grafts (AVR + CABG) and in 22 patients having mitral valve repair or replacement plus aortocoronary vein grafts (MVR + CABG). These data were correlated with aortic cross-clamp time, fibrillation time, presence of left ventricular hypertrophy, and, in selected cases, left ventricular biopsy. Perioperative MI occurred in 21% (9/44) of the AVR + CABG patients and 5% (1/22) of MVR + CABG patients. In contrast, the MI rate for isolated valve replacement was 7% (15/213), and for isolated CABG 14% (16/112). In the AVR + CABG group, 100% (5/5) of patients with combined cross-clamp and fibrillation times greater than 120 minutes suffered MI. These results indicate that patients with combined AVR + CABG are subject to substantially greater risk of perioperative myocardial damage than the other groups. Excessive aortic cross-clamp times and fibrillation plus aortic cross-clamp times should be avoided in AVR + CABG patients.