Utility and limitation of sequential saphenous vein graft for complete revascularization in coronary artery surgery

Multiple bypass grafting in complete myocardial revascularization requires frequently the use of sequential saphenous vein grafts as well as arterial grafts. To expect the favorable good clinical results of revascularization, therefore, refined surgical technique for saphenous vein grafting and proper selection of suitable coronary arteries for bypass are important. Between January 1989 and April 1990, 91 patients underwent CABG utilizing internal thoracic arteries (ITA) in 79% and SVG in 99% of the patients with an average of 3.3 anastomoses per patients. Postoperative angiography was performed 4 or 8 weeks after surgery. Early patency rates were 92% (204/221) in overall anastomotic sites, 96% (52/54) in ITA and 91% (152/167) in SVG respectively. There was no difference in patency rates between individual (90%) and sequential (92%) grafts. In sequential grafting, however, patency rate of side-to-side anastomosis was higher than that of end-to-side anastomosis. Patency rates of the grafts were also evaluated in terms of the sizes of coronary arteries and intraoperative graft flows. These studies lead to the following conclusions: In individual grafting, the acceptable patency rate can be expected when the graft flow exceeds 30 ml/min even if the internal diameter of coronary artery is less than 1.5 mm. In sequential grafting, on the other hand, a diameter more than 1.5 mm is desirable for the coronary artery at the site of end-to-side anastomosis.