Endothelium dysfunction caused by acute pressure distension of human saphenous vein used for myocardial revascularization.

OBJECTIVE To study morphofunctional alterations induced by brief pressure increases in human saphenous veins utilized in coronary artery bypass grafting. METHOD Saphenous veins of 20 patients undergoing coronary artery bypass grafting, were distributed into four experimental groups, control, 100 mmHg, 200 mmHg and 300 mmHg, and submitted to pressure distention over 15 seconds using Krebs solution. The evaluation included CD34 immunohistochemistry and an In vitro vascular reactivity study in organ chambers. RESULTS The main experimental findings were 1) From pressures of 200 mmHg there was a tendency to reduce the CD34 expression which became statistically significant at 300 mmHg; 2) There was no impairment of the contraction and relaxation as evidenced by in vitro vascular reactivity tests. CONCLUSION Although vascular reactivity impairment was not demonstrated in vitro, the CD34 expression, measured by immunohistochemistry, shows there is endothelium dysfunction at pressures of 300 mmHg.