Preoperative management of proximal lesions of the left coronary artery system: surgical implications

Between January 1975 and December 1978, a total of 67 consecutive patients with left main coronary disease had coronary bypass operations at Pacific Medical Center in San Francisco. Of these, 54 were men and 13 women. The mean age was 59 years (range 44 to 77 years). Three groups were identified retrospectively. Sex ratio, age, symptoms, and coronary pathology and hemodynamics were comparable in all groups. Group 1 (24 patients) received no propranolol or had it discontinued at least two weeks preoperatively. Group 2 (28 patients) received propranolol up until two days before the operation. Group 3 (15 patients) received propranolol until the morning of the bypass operation. The overall mortality was 2.9 percent (2 patients). In Group 1, 33 percent (8 patients) had unstable angina preoperatively, while 50 percent (14 patients) in group 2 and 40 percent (6 patients) in group 3 had unstable angina. Perioperative infarction occurred in 12.5 percent (3 patients) in group 1, 25 percent (7 patients) in group 2 and 13 percent (2 patients) in group 3. Creatine phosphokinase myocardial band fractions in the postoperative period were lowest in group 3 but were notably elevated in group 2. Postoperative inotropic support was required in one patient (4 percent) in group 1, four patients (14 percent) in group 2, while none required support in group 3. The decreased incidence of perioperative infarction and reduced need for postoperative inotropic support in group 3 suggests that if propranolol is to be part of the pharmacological preoperative regimen, it can and should be continued up to the time of operation. Propranolol should not be discontinued in the immediate preoperative period.