Long-term patency of saphenous veins for coronary bypass grafting.

The patency of 871 aortocoronary saphenous vein grafts in 438 patients was evaluated for a mean (+/- SEM) of 12.1 +/- 0.3 months after operation. Second studies were performed in 62 patients (134 grafts) at a mean of 42 +/- 1.3 months postoperatively (range, 13 to 61 months). The 1-year patency rate was 79.4% and increased from 76% for 546 grafts placed in 1970-1973 (Period I) to 85% for 325 grafts in 1974-1976 (period II) (P = 0.001). Overall patency was highest (82%) for grafts to the anterior descending system and lowest (76%) for the right system. These patency rates also increased between periods I and II from 79 to 88% (P < 0.05) for the anterior descending and 72 to 83% (P < 0.05) for the right system. For 47 right coronary arteries having associated distal manual endarterectomy, the graft patency rate was 62% vs 78% for those not endarterectomized (P < 0.05). Of 116 grafts patent at the initial study, five were occluded at the second study, a late failure rate of 3.7% and a mean annual attrition rate of 1.7% between 12 and 42 months after operation. High-grade (> 50%) stenoses were present in three of the five grafts at initial study. Development of late stenosis was observed in two grafts (1.7%). These data document improved 1-year patency rates for grafts in period II and a low incidence of late failure and development of late stenosis for up to 61 months following operation. Continued use of saphenous vein grafts to all three coronary arterial systems appears justified.