Coronary bypass surgery for stable angina and unstable angina pectoris.

Large randomized trials have shown that surgical revascularization is more effective than medical therapy in relieving angina and improving exercise tolerance. Development of atherosclerosis in the vein grafts plus progression of disease in the native vessels, however, results in a return of angina in a substantial proportion of patients 5 to 10 years after the procedure. The better myocardial protection, more complete revascularization, and improved graft patency rates that have occurred in the last decade imply that survival following coronary artery bypass may be improved in a broader spectrum of coronary artery disease patients than documented in the randomized trials. Patients with unstable angina have higher operative mortality but clearly benefit symptomatically from revascularization. There is a need for randomized trials to compare the relative risks and benefits of angioplasty versus surgical revascularization.