Coronary artery bypass grafts in 109 autopsied patients. Statistical analysis of graft and anastomosis patency and regional myocardial injury.

The natural history of coronary artery bypass grafts (CABGs) is poorly understood. In 109 hearts with CABGs, examined after postmortem coronary arteriography and fixation in distention from patients autopsied at The Johns Hopkins Hospital, we studied the 236 grafted coronary arteries for graft and anastomosis patency and operative myocardial injury in the distribution of the distal anastomosis. Of the 30 patients who died at operation, 71 of 72 (99%) had patent grafts; of 61 who died within one month, 120 of 131 (92%) had patent grafts; and of 18 who died one to 70 months after surgery 20 of 33 (61%) had patent grafts. The distal anastomosis site was open in 184 of 211 (87%) patent grafts but in only 13 of 25 (52%) nonpatent grafts. Regional contraction-band necrosis was found in 83 of 184 (45%) with patent graft and distal anastomosis, but in only 11 of 52 (21%) that were closed. Five closed distal anastomoses, but none that were open, had coagulation necrosis. Since the introduction of cold potassium chloride cardioplegia, significantly less regional contraction-band necrosis (19 of 79) (24%) was found than before (80 of 157) (51%). The results of this study show less CABG patency in long-term survivors; association of regional contraction-band necrosis with patent grafts and of coagulation necrosis with closed grafts; and less operative myocardial injury with current surgical technique.