The effect of controlled reperfusion in porcine hearts submitted to three hours of cold global ischemia.

Abstract

At present, many investigations of myocardial function following ischemic insults concentrate on the modalities of reperfusion rather than on the mode of preservation. In this study, we tried to define the effect of reperfusion using warm blood cardioplegia (WBC) after medium-term (3 h) cold global ischemia, as required in cardiac transplantation. Twenty-one porcine hearts were harvested after preservation with cold cardioplegia (St. Thomas Hospital solution) and topical cooling. Normothermic reperfusion with blood was initiated after 3 h of ischemia utilizing a special extracorporeal pump circuit. Twelve hearts served as controls (group A), while substrate-enriched WBC was applied during the initial 20 min of reperfusion in nine hearts (group B). Hearts in both groups were then studied for myocardial function and metabolism under both working and nonworking conditions for a maximum of 180 min. In the nonworking mode, left ventricular dp/dt was significantly higher in group B than in group A at 15 min (2201 +/- 785 mm Hg/sec vs 1515 +/- 732 mm Hg/sec) and at 180 min (1730 +/- 471 mm Hg/sec vs 836 +/- 147 mm Hg/sec; P less than 0.05). After 3 h, lactate production was significantly higher in group A (371 +/- 45 mg/dl) than in group B (108 +/- 44 mg/dl; P less than 0.05). Creatine kinase release into the coronary sinus was also significantly elevated in group A at 15 min (2807 +/- 1478 IU/l vs 1148 +/- 1272 IU/l; P less than 0.05). Similarly, the hemodynamic data obtained under working conditions in group B were superior to those in group A.(ABSTRACT TRUNCATED AT 250 WORDS)