Endothelial Preservation in Reversed and In Situ Autogenous Vein Grafts

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Abstract
The hypothesis that superior endothelial preservation occurs when in situ (as opposed to harvested and reversed) autogenous veins are used as arterial grafts was investigated in a canine model by quantitating endothelial loss as seen on scanning electron micrographs. In situ grafts were compared to atraumatically dissected, nondistended, reversed grafts and to grafts distended to 500 mmHg pressure. Two h after arterial transplantation, endothelial denudation averaged 3.9 .+-. 6.7% on in situ grafts, 18.6 .+-. 5.9% on reversed grafts (P < 0.01), and 35.3 .+-. 5.4% on reversed and distended grafts (P < 0.001). At 24 h after grafting, a significant increase (P < 0.01) in endothelial destruction on in situ grafts resulted in a smaller, yet still significant difference in endothelial preservation between in situ and reversed grafts (15.2 .+-. 9.5% vs. 25.1 .+-. 23.4%, P < 0.05). Endothelial healing was largely accomplished at 2 wk regardless of technique. No difference in endothelial fibrinolytic activity could be detected between in situ and gently handled, reversed grafts at 24 h or 6 wk after surgery. An obligatory, although modest, degree of endothelial destruction occurred on the undissected portion of in situ grafts as a consequence of exposure to arterial hemodynamics. However, in the immediate postoperative period, endothelial preservation on in situ grafts surpassed that seen in even the most gently handled reversed vein grafts.