Persistence of improved exercise tolerance and degree of revascularization after coronary bypass surgery. A prospective randomized study

Coronary bypass surgery in stable angina pectoris. A randomized study of the effects on morbidity, mortality and employment

The effects of coronary bypass surgery on morbidity, mortality and employment were assessed in a randomized prospective 5-year study. Exercise tolerance showed an immediate, striking improvement, which was maintained throughout the follow-up period. Corresponding patients treated with medical therapy showed no change. More than 40 percent of patients in the surgical group were free from symptoms over the five years. The annual mortality of the surgical patients was 0.8 percent as compared with 4.0 percent in the medical patients (p less than 0.05). The annual mortality of the intensively treated medical patients with multivessel disease was not significantly higher than the 3.1 percent for a group of patients with single-vessel disease followed concomitantly. The rate of work at 5 years after bypass surgery was 47 percent as compared with only 18 percent in the randomized medically treated group (p less than 0.01). It is concluded that coronary bypass surgery reduces morbidity and mortality and improves employment.

Long-term results of coronary bypass surgery. Analysis of 1698 patients followed 15 to 20 years

Between 1968 and 1975, 1698 patients underwent coronary artery bypass with autogenous saphenous vein and were followed for up to 20 years. Age at operation was 53.9 +/- 8.4 years, and 1485 were men (88%). Angina was present in 1637 patients (96%). There was single-vessel disease in 306 patients (18%), double-vessel in 642 (38%), triple-vessel in 550 patients (32%) and left main stenosis in 200 (12%). Preoperative left ventricular quality was good in 1185 (70%), poor in 508 (30%), and unknown in five patients. Survival at 20 years was as follows: for single-vessel disease, 40%; double-vessel, 26%; triple-vessel, 20%; and left main, 25%. At 20 years of follow-up, 67% of surviving patients were asymptomatic and 26% were improved. Antianginal drug therapy consisted of nitrates in 49% of patients and beta-blockers in 26%. Graft patency at 0 to 5 years was 633 of 780 grafts (81%); at 6 to 10 years, 415 of 606 grafts (68%); at 11 to 15 years, 271 of 449 grafts (60%); and at 16 to 20 years, 65 of 140 grafts (46%). Coronary bypass reoperation was performed in 324 patients (19%) and survival of these patients was 62% compared to 37% for nonreoperation patients (p less than 0.05). Cox analysis demonstrated that the major determinants of survival related to age at operation, extent of coronary disease, quality of ventricle, history of stroke, and preoperative congestive heart failure. At 20 years of follow-up of this early experience with coronary bypass, 76% of surviving patients had one or more patent grafts and the probability of freedom from reoperation was 0.62.

The case of cardiovascular disease: evaluating complex health programs targeted at prevention, remediation, and rehabilitation

This report analyzes the complexities of evaluating prevention, remediation, and rehabilitation treatments for cardiovascular disease. A comparison of treatments revealed that distinct differences exist in terms of motivation of subjects to participate and steps required for a maximum treatment effect. Large-scale prevention programs are generally the most complex of all interventions to complete. If complex health programs are initially subdivided into their detailed planning and implementation steps, proper assessments of each step will lead to a much less difficult comprehensive evaluation.

Computer-derived treadmill exercise score quantifies the degree of revascularization and improved exercise performance after coronary artery bypass surgery

A computer-derived treadmill exercise score (TES) that quantifies the severity of the ischemic ST response to exercise was used to detect noninvasively graft occlusion or the progression of new lesions after coronary artery bypass surgery. Three months after surgery TES completely normalized in 68% of patients and improved by more than 70% in another 18% of patients, thus reflecting excellent improvement in exercise-induced ischemia in 87% of patients. Surgical results correlated well with completeness of revascularization as shown by repeat coronary angiography. When TES, done serially up to 4 years after surgery, remained unchanged, grafts were patent and no new critical lesions had occurred. Deterioration in TES always predicted either late graft occlusion or appearance of new, high-grade lesions in the native vessels. Thus TES provides a new, accurate method that quantifies the ischemic response to exercise and detects graft occlusion or new obstructive lesions in the native coronary arteries.

Persistent improvement after coronary bypass surgery: ergometric and angiographic correlations at 5 years

One hundred patients with angina pectoris who fulfilled specific entry criteria were randomly assigned to either medical therapy or bypass surgery. These groups were subjected to annual exercise testing during a 5-year follow-up period. The degree of revascularization was assessed by graft and native vessel angiography at 3 weeks, 1 year and 5 years after the operation. The exercise tolerance of the medical group remained largely unchanged during the follow-up. Eighty-five to 95% of the patients were using beta-blocking compounds at the successive testing situations. The surgical group exhibited a sustained improvement in exercise tolerance: Total work increased by 39-66% (p less than 0.02-0.001) and maximal ergometric load by 23-35% (p less than 0.01-0.001), and maximal ST depression decreased by 39-61% (p less than 0.05-0.001). The use of beta-blocking compounds in the surgical group steadily increased, from 44% at 6 months after operation to 63% of patients at 5 years. Division of the surgical group into subsets of complete and incomplete revascularization revealed that the improvement was confined to complete revascularization. Thus, the improved exercise tolerance after bypass surgery was a result of successful reestablishment of effective coronary perfusion; despite graft attrition (15% in 5 years) and new lesions in the native arteries, this improvement persisted for 5 years with appropriate medical therapy.