BLOOD CARDIOPLEGIA REDUCES OXIDANT BURDEN IN THE ISCHEMIC AND REPERFUSED HUMAN MYOCARDIUM

In 20 patients receiving cold crystalloid cardioplegia (n = 10) or col d blood cardioplegia (n = 10) during elective coronary artery bypass g rafting, the atrial myocardium was tested for glutathione-related anti oxidant defenses and lipid peroxidation. In both groups, ischemia and reperfusion induced a significant increase in lipid peroxidation value s (p < 0.05) that was associated with a depression of nonprotein thiol compound levels (p < 0.05). Compared with the cold crystalloid cardio plegia-treated patients, the cold blood cardioplegia-treated patients showed a lower lipid peroxidation (p < 0.05) and higher values of nonp rotein thiol compounds (p < 0.05). Moreover, a significant ischemia an d reperfusion-dependent activation of glutathione transferase was obse rved only in the cold crystalloid cardioplegia-treated patients. Selen ium-dependent glutathione peroxidase and glutathione reductase activit ies did not change after release of the aortic cross-clamp and did not differ between the two groups. The highest postoperative plasma level of the myocardial-specific isoenzyme of creatine kinase was significa ntly more elevated in the cold crystalloid cardioplegia patients. Over all, these tissue biochemical features indicate a lower oxidant burden in the myocardium of cold blood cardioplegia-treated patients, a find ing suggesting superior protection for the ischemic and reperfused hum an myocardium also through antioxidant-type mechanisms, apparently med iated by the antioxidant capacity of erythrocytes and specific plasma molecules.