[Morphological comparison between arterial grafts and venous grafts].

We have extendedly used arterial grafts in coronary bypass surgery because of their better patency rate. We have operated 134 cases of coronary bypass during recent 27 months. Postoperative angiography showed high patency rate in arterial grafts, such as 97% (59/61) of right internal thoracic artery (RITA), 98% (107/109) of left internal thoracic artery (LITA), 96% (83/86) of right gastroepiploic artery (RGEA), comparing with 86% (26/30) of saphenous vein graft (SVG). Pathological examination was done by specimens of grafts obtained during operation. Vasa vasorum was poorly developed in ITA and RGEA. ITA had several layers of elastic fiber in media and RGEA had smooth muscular media. Both arterial grafts showed low atherosclerotic scores (intima/media), 7.1% in RITA, 7.3% in LITA and 6.8% in RGEA. But some cases with hyperlipidemia and/or diabetes showed high score of atherosclerosis in arterial grafts. Endothelial cells were well preserved in both arterial grafts after harvesting, in contrast with poor endothelial preservation in SVG. Endothelial appearance of RGEA was similar to that of the coronary artery and different from that of ITA. RGEA is superior grafts for CABG as coronary bypass because of their structural superiority.