Objectives: We sought to examine, angiographically, the longterm fate of a large number of mainly venous coronary bypass grafts and to correlate graft patency and disease with patient survival and reoperation.
Background: Much is known about bypass graft patency and disease, but the precise relation between graft fate and patient outcome has not been substantiated and documented.
Methods: A total of 1,388 patients underwent a first coronary artery bypass graft procedure at a mean age of 48.9 years, 234 had a second bypass procedure at a mean age of 53.3 years, and 15 had a third bypass procedure at a mean age of 58.2 years during the 25-year period from 1969 to 1994. Most were male military personnel or veterans; 12% were < or = 39 years old. Of 5,284 grafts placed, 91% were venous and 9% arterial. Angiograms were performed on 5,065 (98% of surviving) grafts early, on 3,993 grafts at 1 year and on 1,978 grafts at 5 years after operation; other examinations were also performed up to 22.5 years after operation, and 353 grafts were examined after > or = 15 years. Grafts were graded for patency and disease. The status of all patients was known at the study's end.
Results: The perioperative mortality rate was 1.4% for an isolated first coronary bypass procedure, 6.6% for reoperation. Vein graft patency was 88% early, 81% at 1 year, 75% at 5 years and 50% at > or = 15 years; when suboptimal grafts, graded B, were excluded from calculation, the proportion of excellent grafts, graded A, decreased to 40% after > or = 12.5 years. After the early study, the vein graft occlusion rate was 2.1%/year. Internal mammary artery graft patency was significantly better but decreased with time. Vein graft disease appeared by 1 year and the rate accelerated by > or = 2.5 years, involving 48% of grafts at 5 years and 81% at > or = 15 years; 44% of the latter grafts were narrowed > 50%. Survival of all patients was 93.6% at 5 years. 81.1% at 10 years, 62.1% at 15 years, 46.7% (150 patients) at 20 years and 38.4% (25 patients) at 23 years after operation. Survival decreased as age increased, but curves approximated "normal" life expectancy for older patients. Survival curves at all ages showed a steeper decline after 7 years. The rate of reoperation increased between 5 years and 10 to 14 years, then decreased to stable levels. Coronary atheroembolism from vein grafts was the major cause of morbidity and mortality associated with reoperation. Vein graft patency and disease were temporally and closely related to reoperation and survival.
Conclusions: Coronary bypass graft disease and occlusion are common after coronary artery bypass grafting and increase with time. They are major determinants of clinical prognosis, specifically measured by reoperation rate and survival. Intraoperative graft atheroembolism was a major reoperation hazard. Reoperation is definitely worthwhile but entails identifiable risks that must be dealt with.