Propranolol and cardiac surgery: a problem for the anesthesiologist?
Propranolol therapy has been implicated as a cause of myocardial depression and increased morbidity and mortality in patients undergoing coronary artery surgery. The authors reviewed 169 consecutive patients undergoing cardiac surgery, of whom 143 had been taking propranolol, with regard to preoperative administration of propranolol and intraoperative or postoperative complications. Patients taking propranolol until 24 hours before surgery showed no increased incidence of hypotension or bradycardia before cardiopulmonary bypass. Hypotension after bypass was no more common in patients off propranolol 12 to 48 hours than in patients who either discontinued the drug over 48 hours before operation or had never taken the drug. Myocardial contractility as measured by systolic time intervals was normal 24 to 48 hours after stopping propranolol therapy. Five patients had preoperative myocardial infarctions within 48 hours of discontinuing the drug. The operative mortality rate was 4 percent in patients taking propranolol within 48 hr of surgery and 6% in all other patients. Seven risk factors, other than propranolol, were identified in those patients requiring inotropic support. The authors conclude that propranolol can be given safely within 24 to 48 hours of coronary artery surgery provided the patient is a satisfactory candidate for myocardial revascularization.