Dynamics of endothelial repair in end-to-side microsurgical carotid anastomoses in rats: a scanning electron microscopic evaluation.

A scanning electron microscopic (SEM) investigation of endothelial behavior, following carotid end-to-side microsurgical anastomoses, was carried out in twenty-four Sprague-Dawley rats. From the hemodynamic point of view, the experimental model used in this study involved a bidirectional flow in the recipient vessel. Following surgery, specimens were collected at intervals varying from 15 minutes to 14 days. The thrombus formation was particularly evident in the first 45 minutes, and then gradually disappeared. Evidence showed that the new endothelial cells, covering the defect at the site of the suture, originate from the normal endothelium. Regenerated endothelial cells showed particular morphological features which are expressions of high metabolic rate and of active cell movement. Endothelial repair on the suture line began 3 days after the operation, and was completed there earlier than it was on the stitches. An accurate microsurgical technique is needed to avoid an increased thrombus formation and delayed re-endothelialization.