Veterans Administration cooperative study of surgery for coronary arterial occlusive disease: view from a noncooperating hospital.

Wadsworth Veterans Administration Hospital (VA-W) dropped out of the VA Coronary Cooperative Study (VA-Coop) in 1971 because of difficulty adhering to selection criteria, and because of the lack of standardization of surgical methods. Comparison of results from 1972-1974 showed the following differences: cardiopulmonary bypass time per graft, 61 minutes (VA-Coop) vs 33 minutes (VA-W); perioperative myocardial infarction (MI), 18% vs 6%; hospital mortality, 6% vs 1%; revascularization index (patent grafts per patient determined by postoperative angiography divided by diseased arteries per patient), 0.55 (VA-Coop) vs 0.84 (VA-W). However, the slopes of the actuarial survival curves were similar after the first year. In a group of patients operated on at UCLA and VA-W (UC-VA) during 1969-1971, the 1-year survival rate was 85%, but the annual death rate thereafter was also approximately 2% per year. The survival of VA-Coop surgical patients with three-vessel disease without left main lesions was significantly better (p less than 0.05 by Wilcoxon test) than the medical group with the 6-month (surgical) mortality adjusted to a more acceptable level (5%). These results indicate that coronary bypass surgery produces an annual mortality of approximately 2% per year after the first year. Differences in survival rates are due primarily to variations in first-year mortality, which is influenced by operative mortality as well as morbidity, incomplete revascularization, and low graft patency rate. In our view, the surgical results reported by the VA Cooperative Study are representative of an intermediary step in the development of coronary bypass surgery. The data, however, still indicate that surgical treatment results in better survival in patients with multivessel coronary disease.