MYOCARDIAL INJURY DURING REOPERATION FOR CORONARY-ARTERY BYPASS-SURGERY

Objectives: To determine the incidence, triggers, and timing of myocardial injury during reoperation for coronary artery bypass surgery. Design: Prospective observational. Setting: One tertiary care university hospital. Participants: 15 patients undergoing reoperation. Interventions: Multilead electrocardiographic monitoring approximately every 3 minutes during surgery. Measurements and Main Results: The occurrence of a new ischemic ST elevation or depression on the electrocardiogram (EGG) was determined. A major deterioration in ventricular function after cardiopulmonary bypass (CPB) also was determined. Peak creatine kinase myocardial band (CK-NIB) greater than or equal to 25 IU/L was considered to be the marker of myocardial injury. Seven patients demonstrated myocardial injury, all intraoperatively. Five of these patients had new ST elevation episodes before CPB. Three of the episodes were temporally associated with an abrupt increase in the heart rate. The other two episodes were temporally associated with surgical manipulation of the heart and the old grafts. The sixth patient had a significant deterioration of ventricular function during CPB. One of the patients who had ST elevation before CPB and the seventh patient developed ST elevation towards the end of protamine administration. Conclusions; In patients undergoing reoperation, the intraoperative incidence of myocardial injury, especially before CPB, was found to be substantially higher than that previously reported. Copyright (C) 1995 by W.B. Saunders Company