Among the first 400 patients undergoing saphenous vein coronary artery bypass at Stanford Medical Center, 67 (18%) met criteria for "preinfarction angina". Angina was alleviated and possible myocardial infarction was prevented utilizing these surgical technics. The overall operative mortality rate in the preinfarction angina patients was 10.4%, which contrasted strikingly with a 1.5% operative mortality for elective coronary artery bypass at Stanford. Six of the seven operative deaths resulted from myocardial infarction, two of which were related to technical factors. Operative mortality appeared to be related to degree of preoperative congestive heart failure and hypotension, pump time, sex, and number of atherosclerosis risk factors present. Fifty-two of the 60 patients leaving the hospital (87%) received good symptomatic benefit from surgery, including no late infarction, over a 6.8 month mean follow-ulp period. The late death rate was 3.3%, and the late infarction rate was 10% during the follow-up period. Angina can be alleviated and impending myocardial infarction may be prevented with aggressive surgical intervention.