Prolonged cardiac preservation. Evaluation of the University of Wisconsin preservation solution by comparison with the St. Thomas' Hospital cardioplegic solutions in the rat. The University of Wisconsin solution differs from other types of solutions used for organ preservation because it contains high-energy phosphate precursors (adenosine and phosphate), impermeants (lactobionate and raffinose), an oncotic agent (pentafraction), and antioxidants (allopurinol and glutathione). These components have the potential to enhance the preservation of ATP, reduce intracellular and extracellular edema, and attenuate free-radical-mediated injury. The University of Wisconsin solution has been demonstrated to enhance and extend the preservation of the liver, pancreas, and kidney, but its potential role in the heart remains unproven. We have evaluated the University of Wisconsin solution (Du Pont) by comparing it with the St. Thomas' Hospital cardioplegic solutions No. 1 and No. 2 (Plegisol), which are used in Europe and the United States for routine cardiac surgery and transplantation. For each solution, 10 isolated working rat hearts were arrested by 10 ml of the solution (at 4 degrees C) and then maintained immersed in the same solution for 4 hours at 4 degrees C. Mean recovery of functional indexes (expressed as a percentage of their preischemic control values) after use of the University of Wisconsin solution were as follows: peak aortic pressure, 90.6 +/- 1.0; dP/dt, 71.5 +/- 5.5; aortic flow, 81.6 +/- 4.7; coronary flow, 87.5 +/- 3.5; and cardiac output, 82.6 +/- 3.5. In contrast, the mean recoveries after St. Thomas' Hospital solution No. 1 were as follows: peak aortic pressure, 82.8 +/- 1.3; dP/dt, 49.7 +/- 3.0; aortic flow, 58.4 +/- 5.3; coronary flow, 79.6 +/- 5.9; and cardiac output, 63.0 +/- 4.9. In contrast still, mean recoveries after St. Thomas' Hospital solution No. 2 were as follows: peak aortic pressure, 83.1 +/- 1.2; dP/dt, 40.7 +/- 6.1; aortic flow, 37.0 +/- 5.1; coronary flow, 65.8 +/- 3.6; and cardiac output, 43.1 +/- 5.6. The recovery of all indexes were significantly superior (p less than 0.005) after preservation with University of Wisconsin solution compared with either of the St. Thomas' Hospital solutions. 