The effect of oxygen free radical scavengers on the recovery of regional myocardial function after acute coronary occlusion and surgical reperfusion

This study investigated the effects of the exygen free radical scavengers superoxide dismutase and catalase, the peroxide ion inhibitor, in crystalloid potassium cardioplegic solution on infarct size and global and regional myocardial function after occlusion of the left anterior descending artery and surgical reperfusion in young sheep on cardiopulmonary bypass. After 1 hour of occlusion, the animals were randomized to receive either routing potassium cardioplegia or cardioplegia with superoxide dismutase and catalase. Global hemodynamics measured by maximum rate of pressure rise showed significant improvement after 5 hours or reperfusion in the group treated with superoxide dismutase and catalase (1843 ± 163 versus 979 ± 192, p < 0.001). Regional myocardial function was measured by ultrasonic crystals, implanted in the ischemica area and in a nonischemic control segment. The percent systolic shortening or bulging was calculated. At end of reperfusion in the animals treated with superoxide dismutase and catalase, there was active shortening in the ischemic area after reperfusion of +9.2% ± 0.4% versus 2.1% ± 0.8% in untreated animals (p <0.001). Infarct size measured by triphenyltetrazolium chloride staining showed significant difference (p < 0.001) between animals treated with superoxide dismutase and catalase (0.9% ± 0.1%) and control animals (61% ± 70%). Superoxide dismutase and catalase given in the cardioplegic solution before reperfusion of an acutely ischemic area of myocardium enhances recovery of contractile function and results in a significant reduction in infarct size, which suggests improved salvage of the ischemic myocardium.