Is reperfusion injury from multiple aortic cross-clamping a current myth of cardiac surgery?

Four hundred eighty adult patients undergoing cardiac operations had systemic and topical hypothermic anoxic arrest supplemented with potassium chloride pharmacological cardioplegia in a prospective randomiz ed study. Group 1 (217 patients) had continuous aortic cross-clamping and one single anoxic arrest period during the cardiac portion of the operation, which resulted in a transmural myocardial infarction rate of 8.3%, myocardial "injury" incidence of 12.4%, 4.6% cardiac-related deaths, 11.5% and 24.8% severe and malignant ventricular arrhythmias, 21.7% rate of severe vasopressor usage, a mean group serum glutamic oxaloacetic transaminase (SGOT) of 140 +/- 39 IU, and a mean group lactic dehydrogenase (LDH) of 636 +/- 78.2 IU. Group 2 (263 patients) had intermittent aortic cross-clamping with multiple reperfusion intervals, which resulted in a significantly lower incidence of transmural myocardial infarction at 1.9% (p < 0.01), rate of myocardial injury at 5.66% (p < 0.02), number of cardiac deaths at 0.76% (p < 0.02), 8.7% and 16.0% severe and malignant ventricular arrhythmias (p < 0.01), severe vasopressor utilization rate of 14.3% (p < 0.05), mean group SGOT at 72.0 +/- 3.1 IU (p < 0.01), and mean group LDH at 471.0 +/- 12.3 IU (p < 0.05) than Group 1. These results do not support the contention that intermittent aortic cross-clamping in conjunction with hypothermia and pharmacological cardioplegia leads to increased clinical cardiac damage compared with continuous aortic cross-clamping. The converse is implied, in that the anoxic heart may benefit from the physiological effects of briefly reperfused oxygenated blood.