The pre- and postoperative course in 118 patients (104 males, mean age 62 +/- 8.1, 14 females, 60 +/- 10.7 years) who underwent coronary artery bypass surgery for significant left main coronary artery disease was studied to analyze the current management and risk factors of this lesion. Of these patients 32% (38/118) remained in hospital care from the date of diagnosis (coronary angiography) until the operation. The mean interval between diagnosis and operation was 39 days (range 0-166). Twelve patients (10%) had urgent procedures (< or = 48 hours after angiography), 25 (21%) accelerated (< or = 2 weeks), 52 (44%) anticipated (< or = 2 months) and 30 (25%) elective procedures (> 2 months). There was a significant negative correlation (p < 0.001) between the grade of stenosis and the time interval from diagnosis to operation. The operation technique did not differ from the usual procedure except for the less frequent use of the internal mammary artery as arterial conduit. Patients with stable angina received an internal mammary artery graft in 65% (80/118) as compared to 26% (6/23) of the patients with unstable angina. This differs significantly from the overall rate of 95% of the patients undergoing coronary artery bypass surgery at our institution. The rate of perioperative myocardial infarction was 18% (21/118). There was no significant relation between infarction and angina class, severity of the stenosis and the use of internal mammary artery as bypass graft. The hospital mortality was 4.2% (5/118) and thus was not different from the overall mortality of (2.5%).(ABSTRACT TRUNCATED AT 250 WORDS)