Coronary artery bypass grafting in elderly patients. Comparative results in a consecutive series of 469 patients older than 75 years. A consecutive series of 7104 patients undergoing isolated coronary artery bypass grafting during an 18-year period (1971 to 1988) included 469 patients older than 75 years. Results were analyzed to determine comparative risk factors for morbidity, early and late survival, and functional outcome. Patients younger than 75 years (group I) and patients older than 75 years (group II) were identical for ejection fraction and standard hemodynamic indices. Mean number of grafts and crossclamp time were greater for group II patients (p less than 0.01). Mean age of group I was 58.6 years and group II, 77.6 years (p less than 0.01). Women composed 19.7% (1308/6635) of group I and 36.2% (170/469) of group II patients (p less than 0.05). Mammary grafts were placed in 57.7% (3830/6635) of group I and 41.6% (195/469) of group II patients (p less than 0.05). Overall perioperative mortality rate was 2.1% for group I and 6.8% for group II (p less than 0.05). Perioperative myocardial infarction rate was similar for the two groups. Ventricular and supraventricular arrhythmias, renal insufficiency, neurologic complications, prolonged ventilatory support, increased hospital cost, and prolonged hospitalization were significantly more prevalent (all p less than 0.05) in patients older than 75 years. Five and 10 years postoperatively, there were no significant differences between groups I and II with regard to event-free status including angina, myocardial infarction, and reoperation. The 5-year survival rate was 92% for group I and 80% for group II (p less than 0.05), similar to that of age-matched control subjects. The significantly increased potential for complications and expense of coronary bypass in patients over 75 years of age mandates judicious patient selection and preoperative counseling. Despite a significantly increased early mortality and an anticipated decreased long-term survival paralleling normal life table survival curves, good intermediate functional improvement can be realized in patients older than 75 years, comparable with that expected in a much younger age group. 