Oxygen-derived free radical scavengers for amelioration of reperfusion damage in heart transplantation

In this study we tried to define the possible benefits of the oxygen-derived free radical scavengers after 3 hours of cold myocardial global ischemia, as required in the setting of cardiac transplantation. Twenty-one pig hearts were harvested after preservation with a cold cardioplegic solution (St. Thomas' Hospital solution) and topical cooling. Normothermic reperfusion with blood was achieved with a special heart-lung machine preparation, which allows the heart to beat in a working or nonworking mode. Twelve hearts served as control hearts (group I), and nine (group II) were subjected to superoxide dismutase and catalase. Superoxide dismutase was applied at a dose of 40 U/ml of cardioplegic solution and 1500 U/kg body weight with the start of reperfusion. Catalase was added to the cardioplegic solution in a dose of 100 U/kg and 3500 U/kg body weight with the start of reperfusion. After 15 minutes of retrograde reperfusion, both left ventricular developed pressure and its first derivative were significantly higher in group II (137 +/- 7.6 mm Hg, 2467 +/- 162 mm Hg/sec) than in group I (105 +/- 6 mm Hg, 1676 +/- 231 mm Hg/sec, p less than 0.05 for each). In addition, a considerably higher coronary blood flow was observed in group II throughout the 180-minute period of reperfusion (p = 0.047). We therefore conclude that the combined administration of superoxide dismutase and catalase during the initial period of cardioplegic arrest and during early reperfusion of donor hearts submitted to 3 hours of cold ischemia has a beneficial effect on myocardial performance.