THE SCIENTIFIC BASIS FOR HYPOCALCEMIC CARDIOPLEGIA AND REPERFUSION INCARDIAC-SURGERY

The scientific rationale for avoiding the use of calcium-enriched card ioplegic solutions and calcium supplementation during cardioplegic ind uction and the early phase of reperfusion in open heart surgical proce dures is reviewed. The role of the extracellular and intracellular fre e ionized calcium concentrations during ischemia and reperfusion is ex plored and the biochemical effects of ischemia on calcium fluxes, aden osine triphosphate levels, and mitochondrial function are discussed. T he role of calcium in causing myocardial stunning and the biochemical basis of reperfusion injury are also addressed. Both prolonged ischemi a and an increased concentration of Ca2+ during reperfusion have prove d to be deleterious. I conclude on the basis of my review that there i s no justification for the use of calcium chloride before and during t he early phase of reperfusion and that hypocalcemic perfusion is an ef fective and easily controllable means of myocardial protection.