Effect of gradual reperfusion on ventricular function after 6-h preservation

This experiment was designed to determine the effect of a gradual increase in reperfusion pressure on ventricular function after 6-h preservation of the heart. Twenty-four rabbit hearts were allocated to four groups, each reperfused at different pressures: group I (80 mmHg); group II (40 mmHg for 10 min, then increased to 80 mmHg); group III (20 mmHg for 5 min, then increased by 20 mmHg at 5-min intervals); and group IV (as group III + perfusion with recombinant human superoxide dismutase). The developed pressures at balloon volumes of 1.2, 1.5 and 1.8 ml were significantly higher in groups III and IV than in group I. The values of left ventricular peak dP/dt were significantly greater in groups II, III, and IV than in group I. Light microscopical examination revealed severe interstitial oedema in group I, moderate oedema in group II, and minimal oedema in groups III and IV. Gradual reperfusion resulted in significantly better systolic function and less interstitial oedema. Use of recombinant human superoxide dismutase provided little additional benefit when combined with gradual reperfusion.