Supplementation of University of Wisconsin solution with Nitroglycerin and Nicorandil in long-term myocardial preservation: effects on the oxidative state, endothelial function and morphology.

The purpose of this study was to assess the effects of the addition of Nitroglycerin or Nicorandil to University of Wisconsin solution in long-term myocardial preservation. In a model of heterotopic heart transplantation in pigs, the donor heart was preserved for 24 hours by means of continuous perfusion in this solution, in the presence or absence of these drugs. During this period, the oxygenation and pH of the solution were measured, as were lactate concentrations and enzyme release. At regular intervals following reperfusion we measured the concentrations of enzymes, antioxidants, glutathione peroxidase, glutathione reductase, malondialdehyde, endothelin and nitrite, and, two hours later, samples of both ventricles were taken for a morphological study. In the treated groups there was a higher lactate production during preservation and, during reperfusion, the signs of contracture and the elevation of enzyme levels were more marked than in the untreated groups. In contrast, the glutathione reductase concentrations did not decrease during the first phase of reperfusion and were directly correlated with those of antioxidants, endothelin levels increased less than in the untreated groups and, in the case of nitroglycerin, the nitrite concentration was significantly greater than in the remaining groups. We conclude that nitroglycerin and nicorandil improved the oxidative state and endothelial function and did not produce substantial morphological changes, but increased cell necrosis and contracture, possibly due to the duration of ischemia.

Experimental heterotopic heart transplantation: an easier technique.

AIM: The use of heterotopic heart transplantation (HHT) in experimental surgery is an extended method to evaluate cardiac graft viability. To study endothelial injury after ischemia-reperfusion, the technique described by Matsui et al. in 1988 for HHT was chosen. A modification, which consists of replacing the atrium-to-atrium anastomosis for the tip of a 30-Fr venous cannula, was developed with the purpose of using this technique in small pigs. Both techniques were compared. METHODS: Twenty-seven consecutive HHTs in 17- to 20-kg pigs using Matsui's original technique and the modified technique were performed. Ischemia time, bleeding volume, mean gradient and anastomosis complications were measured to compare both techniques. RESULTS: Statistically significant decreases in ischemia time, bleeding volume and mean gradient with the modified technique were found. Furthermore, there were two cases of suture dehiscence with the original technique. CONCLUSIONS: The replacement of the atrium-to-atrium anastomosis for the venous cannula is a modification that statistically decreases the ischemia time, blood loss and avoids suture complications. This modification makes Matsui's technique easier, faster and safer in small pigs and it may be used in bigger animals and in any kind of non-permanent anastomosis.