Sequential vein bypass grafting: tactics and long-term results

Abstract

The sequential bypass grafting technique has many advantages over coronary artery bypass grafting with single grafts. The aim of this study was to evaluate the consequences of sequential bypass graft failure. Between 1 January 1984 and 31 December 1996, 3846 patients underwent primary coronary artery bypass vein grafting. A total of 3490 patients received sequential vein bypass grafts and 356 patients received single vein bypass grafts (9%). There were 6177 sequential bypass grafts (3490 postero-lateral grafts (56%) and 2687 in the antero-lateral position (44%)) and 1468 single grafts (972 vein grafts and 496 internal thoracic artery grafts). Overall, there were 80 hospital deaths (2.1%). Mortality in relation to type of grafts used was: 13 deaths in 356 patients with only single graft (3.7%) and 67 deaths in 3490 patients who received sequential vein grafts (1.9%). Of 3766 hospital survivors, 3731 were followed for an average of 76 months. During follow-up, 85 patients died (2.3%), 15 patients (0.4%) underwent cardiac transplantation and 52 (1.4%) had re-do coronary artery bypass vein grafting. Graft-percutaneous transluminal coronary angioplasty was performed in 56 patients (1.5%), 37/1390 single bypass grafts (2.7%) and 19/6023 sequential bypass grafts (0.3%). There were 272/6023 symptomatic sequential graft occlusions (4.5%) (182 were in postero-lateral position and 90 in the antero-lateral position). There were 66/667 single vein graft occlusions (9.9%) and 15 symptomatic internal thoracic artery graft occlusions (2.1%) during follow-up. In 97% of patients, presenting symptoms of postero-lateral sequential bypass graft occlusion took the form of a renewed angina with a myocardial infarction rate of 3% and a mortality rate of 7%. Corresponding figures for antero-lateral sequential bypass grafts were 22, 78 and 68%, and anterior single vein bypass grafts were 70, 30 and 15%, respectively. The overall 10-year survival rate in patients with sequential bypass grafts was 81.2% and the cumulative patency rate (1464 angio-controls of 2576 sequential vein grafts) was 72.2%. A symptomatic occlusion of a postero-lateral sequential vein bypass results in a low incidence of myocardial infarction with low mortality, when the terminal anastomosis is connected to a high flow vessel. An antero-lateral sequential vein bypass graft has better long-term patency than single vein bypass, but should occlusion occur, it would usually be associated with a higher myocardial infarction and mortality rates than a single vein graft. The highest risk for failure of a sequential graft in the antero-lateral position occurs when the left anterior descending artery (LAD) is small or severely diseased. In this situation the single graft technique with internal thoracic artery appears to be safer.