The purpose of our study was to evaluate the cytotoxicity of incubation solutions used in heart surgery to endothelial cells. The endothelial layer of human saphenous veins (HSV) and bovine internal mammary arteries (BMA) and veins (BMV) were studied after a two-hour storage interval and compared with control vessel segments prepared immediately after harvesting. To visualize the endothelial cell damage, specimens were stained with a silver nitrate technique. The surface covered by light-microscopically intact endothelial cells was computed in percent. In the control HSV segments 70.8 +/- 4.6% of the endothelium were found to be morphologically intact. The results for stored HSV segments were 50.0 +/- 4.2% (Bretschneider's solution), 14.8 +/- 4.5% (physiological saline), 0.45 +/- 0.1% (physiological saline with heparin), 16.7 +/- 4.7% (Ringer's lactate) and 37.2 +/- 5.3% (heparinized blood). Comparable values obtained with BMA specimens were 98.3 +/- 0.7% (controls), 78.1 +/- 4.7% (Bretschneider's solution), 39.2 +/- 3.3% (physiological saline), 8.4 +/- 2.0% (physiological saline with heparin), 11.3 +/- 1.7% (Ringer's lactate) and 67.8 +/- 6.2% (heparinized blood). A similar trend was found with BMV segments: 85.2 +/- 4.7% (controls), 75.6 +/- 6.0% (Bretschneider's solution), 49.5 +/- 8.9% (physiological saline), 5.95 +/- 0.7% (physiological saline with heparin), 6.2 +/- 0.7% (Ringer's lactate) and 54.3 +/- 5.1% (heparinized blood). In conclusion, Bretschneider's solution proved to be superior for storage of bypass grafts in comparison to all other tested solutions in this series.

Bretschneider's is the most suitable of the solutions studied as a graft storage medium in bypass and cardiothoracic surgery, but a solution causing even less damage is desireable.