Influence of several solutions used in bypass surgery on the permeability of the endothelium of carotid arteries in New Zealand rabbits.

BACKGROUND: Alteration of endothelial permeability by perfusion solutions used may influence the outcome of bypass grafts. METHOD: Carotid arteries of New Zealand rabbits were locally perfused in situ for 20 or 60 min with various solutions used in bypass surgery. After restoring normal circulation, horseradish peroxidase was injected in the ear vein. Endothelial permeability was measured by electronmicroscopy as the peroxidase accumulation in the subendothelial space during 6min circulation. RESULTS: The density indices (mean standard deviation) as a parameter for permeability in comparison to the control vessels were significantly greater than 100% for all solutions: for physiological saline 254+/-22% and 358+/-15%, for Ringer's lactate 206+/-26% and 302+/-17%, for St. Thomas' Hospital solution 163+/-15 % and 252+/-29%, and for Bretschneider's HTK solution 130+/-15% (p=0.003) and 169+/-26%, after 20 and 60 min perfusion. Addition of heparin (50IU/ml) caused a significant increase in endothelial permeability (p<0.05). CONCLUSIONS: 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.

Damage to arterial and venous endothelial cells in bypass grafts induced by several solutions used in bypass surgery.

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.

Anatomo-experimental study for lace fixation of winged scapula in muscular dystrophy.

Winging of the scapula is one of the major features of the rare facio-scapulo-humeral muscular dystrophy. Several methods of retention and fixation of the scapulae have been published, but most have technical disadvantages or complications. A modified method of operative fixation of the scapula to the chest using three polyester laces is described with the results of cadaveric studies on the stability of this system. In order to determine the optimal region for the scapula fixation using polyester laces we performed pull-out tests on twenty cadaver scapulae. Four points of insertion in the inferior part of the scapula were tested. The lateral margin showed the best results with regard to the tensile strength and the morphology of the resulting fractures. The elongation of the laces was measured as well. Compared to scapulothoracic arthrodesis interscapulo-scapulocostal scapulopexy leads to greater preserved mobility between the scapula and the chest wall and conserves vital capacity.

Cytotoxicity of various crystalloid solutions to the endothelial cells of autologous grafts.

Harvesting and storage may influence the early failure of autologous grafts. We studied the endothelial layer of human saphenous veins (HSV) and bovine internal mammary arteries (BMA) after a two-hour storage period in comparison to vessel segments prepared immediately after harvesting. The storage solutions were 0.92% NaCl, 0.9% NaCL heparinized, Ringer's Lactate (RL), heparinized blood or Bretschneider's cardioplegic solution. To visualize the endothelial cell damage, specimens were stained with silver nitrate. The surface covered by morphologically intact endothelial cells was computed in percent. In a perfusion model using the carotid artery of rabbits, the increase of the permeability of the endothelium after two hours' perfusion was investigated (n = 5 each). In native HSV-segments 70.8 +/- 4.5% of the endothelium were found to be morphologically intact. The figures for stored grafts were: 14.7 +/- 4.4% (NaCl), 0.5 +/- 0.3% (hep. NaCl), 16.0 +/- 4.6% (RL), 37.2 +/- 5.3% (hep. blood) and 50.0 +/- 4.2% (Bretschneider). Comparable results were found with BMA specimens. BMA: 98.3 +/- 2.1% (native), 39.2 +/- 3.3% (NaCl), 8.4 +/- 3.5% (hep. NaCl), 11.2 +/- 4.8% (RL). 67.0 +/- 6.1% (hep. blood) and 78.1 +/- 4.7% (Bretschneider). In accordance with these results the increase of the permeability of the endothelial cell layer of the carotid artery of rabbits was significantly less after perfusion with Bretschneider's solution. The condition of the endothelial cells of autologous grafts at the time of implantation was found to be clearly dependent on the type of solutions used for perfusion and immersion. In comparison to all crystalloids studied in this series, Bretschneider's cardioplegic solution proved to be superior.

[Early and late damage in bypass vessels induced by crystalloid and cardioplegic solutions]. / Früh- und Spätschäden in Bypass-Gefässen induziert durch kristalloide und kardioplege Lösungen.

Veins and arteries grafted into the aorto-to-coronary position undergo degenerative processes, subintimal fibrous hyperplasia and diffuse atherosclerosis. We examined the influence of various crystalloid and cardioplegic solutions on the endothelium of human saphenous veins and internal mammary arteries, bovine internal mammary veins and arteries and rabbit carotid arteries, using light microscopy, TEM, SEM, immunological techniques and quantitative permeability measuring methods. Immersion or perfusion of vessel segments for various periods of time led to an ultrastructural endothelial cell damage, to an increased endothelial permeability for macromolecules, partly to an endothelial cell loss. Addition of high concentrations of heparin impaired this effect. Under influence of various solutions an increased plaque development under stimulation with atherogenic stimuli was observed.