State of the vein grafts, native coronary arteries, and myocardium and principal cause of death in patients dying after aortocoronary bypass grafting.

Fifty five patients with 108 coronary bypass saphenous vein grafts were studied at necropsy. The mean duration of the grafts was 153 days (SD 516). The luminal narrowing of the native coronary arteries proximal to, at, and distal to the vein graft anastomoses and the narrowing of the non-grafted arteries were evaluated planimetrically. Twenty nine per cent of coronary arteries distal to graft anastomoses showed at least 76% narrowing and 50-75% occlusion was seen in 39% of such arteries. Fifty three per cent of non-grafted arteries showed at least 76% luminal narrowing and 26% had 50-75% narrowing. Six patients (11%) had surgically induced dissection of coronary arteries. Seventy seven vein grafts (71%) showed no appreciable luminal narrowing. Problems related to operative technique caused 30% of the deaths.