Intraoperative myocardial protection: a comparison of blood and asanguineous cardioplegia.

Cardiac arrest was achieved in 84 patients using asanguineous cardioplegia and in 97 patients using cold blood potassium cardioplegia. The patient groups were similar in age, sex ratio, and preoperative risk factors. Other than the cardioplegic solution used, the conduct of each operation was identical. There were no differences in mean total pump time (118 minutes for the asanguineous cardioplegia group versus 117 minutes for the cold blood cardioplegia group) or cross-clamp time (73.5 versus 70 minutes, respectively). However, the blood cardioplegia group had a greater number of distal anastomoses per patient (3.9 versus 3.7; p less than 0.05). Myocardial protection was assessed clinically and by serial electrocardiograms. Cellular integrity was determined by release of the myocardial isoenzyme of serum creatine kinase (CK-MB). Cellular morphology was studied in 6 randomly selected patients in each group by electron microscopic examination of left ventricular myocardial samples obtained before and after bypass. Three patients given blood cardioplegia and 5 given asanguineous cardioplegia required intraaortic balloon counterpulsation at termination of bypass. There were no ultrastructural changes in either group. Electrocardiographic changes (Minnesota code) occurred in 12 of 84 patients receiving asanguineous cardioplegia versus 12 of 97 patients receiving cold blood potassium cardioplegia. To maintain a satisfactory cardiac index (greater than 2.0 L/min/m2), 38 of 84 patients given asanguineous cardioplegia versus 25 of 97 patients given blood cardioplegia required inotropic support up to 24 hours postoperatively (p less than 0.05). Infarct size determined from CK-MB release was significantly greater (p less than 0.05) in patients given asanguineous cardioplegia (36.27 gm-equivalents) than in those given blood cardioplegia (26.7 gm-equivalents).(ABSTRACT TRUNCATED AT 250 WORDS)