Favorable scanning electron microscopic findings of stapled saphenous veincarotid artery anastomoses

Background. In the progress toward "off-pump" endoscopic coronary artery su rgical procedures, new techniques for coronary artery anastomoses are being developed. One such approach is the use of nonpenetrating titanium clips. We evaluated the quality of anastomoses achieved using this technique in a porcine model of saphenous vein-carotid artery grafting using scanning elec tron microscopy. Methods. Bilateral saphenous vein-carotid artery interposition grafts were implanted in 10 "white race" pigs, using the nonpenetrating clips in one si de of the neck and conventional hand suturing on the opposite side. One wee k after operation, the grafts were harvested. Results. All grafts were patent 7 days after operation, and 40 anastomoses underwent scanning electron microscopic study. In all samples, the luminal surfaces of both the carotid artery and vein graft were covered by a contin uous layer of endothelial cells up to the anastomosis. Anastomotic sites in all clipped samples and most of the sutured anastomoses were completely en dothelialized, and anastomotic clefts were indistinguishable. However, in 2 5% of sutured specimens, the suture material remained clearly visible insid e the lumen of the vessel, and the subendothelial matrix remained exposed, with extensive fibrin, red blood cells, and platelet deposition on its surf ace. Conclusions. Because the endothelial coverage consistently appeared to be c omplete and the subendothelial matrix was not exposed, it is likely that th e risk of early anastomotic thrombosis is reduced by using the nonpenetrati ng titanium clips. (C) 1999 by The Society of Thoracic Surgeons.