MODIFYING MYOCARDIAL MANAGEMENT IN CARDIAC-SURGERY - A RANDOMIZED TRIAL

Among the 160 patients randomly assigned to one of eight protocols of myocardial management, all of which included controlled aortic root reperfusion, no important differences were found between protocols as to the prevalence of death (0 instances), use of an intra-aortic balloon pump (no instances), use of catecholamines, elaboration of CK-MB isoenzymes, new Q-waves, abnormal wall motion scores, or postoperative atrial fibrillation. Ventricular defibrillation was required more often in patients in the protocol with noncardioplegic blood reperfusate. Cardiac index was highest in the operating room in the group receiving hyperkalemic cold cardioplegia and initial hyperkalemic reperfusion. The reperfusion flow at the controlled pressures had initially a low flow rate (pressure 30 mmHg for 2 min; thereafter 50 mmHg), which increased to reach a peak flow rate at about 3 min after the start of reperfusion, followed by a declining flow rate reflecting changes in coronary resistance. Comparison of the overall randomly assigned group with a historical control group of 100 patients operated upon prior to the randomized trial showed no differences except for a higher rate of postoperative atrial fibrillation (25%) in the historical control group than in the randomized protocols with initial cardioplegic reperfusion (14%). The controlled reperfusion technique was found to be easy to use and is now used routinely.