Objective criteria to indicate efficacy of revascularization have been defined in a series of 100 patients followed up to 48 months. Angina was decreased in 75% of the patients. Rate of reinfarction was reduced 50% when compared to control patients, but life expectancy was less clearly affected. The gains of this operation presumably take place after the neovascular connections between the implanted artery and the coronary circulation are established. Factors favoring successful revascularition are (1) a major degree of arterial obstruction, (2) local collateral formation, and (3) myocardial lactate production. Angina pectoris is the major indication for surgery. Surgery is contraindicated by severe heart failure, widespread atherosclerosis, or poor general health. Severe proximal coronary disease constitutes an augmented although not a prohibitive risk to surgery.