Tracheal Homograft as Aortic Conduit: Early Phase Results

Abstract

The aim of this study was to evaluate the performance of tracheal homografts as aortic conduits. Fourteen tracheal grafts freshly procured from rats were preserved by the following two methods: cryopreservation (n = 6) and treatment with glutaraldehyde 0.2 % (n = 8). The explanted tracheae were stored for ten to twenty days prior to implantation. They were subsequently implanted into the infrarenal aorta of the recipient rats. The average length replaced was 1 to 1.5 cm. The grafts were then evaluated after a period of one (n = 6, 2 cryopreserved, 4 gluteraldehyde), two (n = 4, 2 cryopreserved, 2 glutaraldehyde), and three (n = 4, 2 cryopreserved, 2 gluteraldehyde) weeks for their performance, morphol ogy, and histopathology. The rats did well postoperatively with adequate distal perfusion. Two of the 6 rats with cryopreserved grafts had reduced flow as evidenced by lack of pulsation in the aorta distal to the graft, and histologic examination revealed incompletely occluding thrombus adherent to the luminal surface. The remaining cyropreserved and glutaraldehyde-fixed grafts had good flow and did not show any radiologic evidence of narrowing at the site of anastomosis or in the region of the graft. Histopathologic examination showed that the glutaraldehyde-treated homografts had better morphology, intact carti lage, and no or mild inflammatory response. The cryopreserved tracheal homo grafts showed degenerative changes in the cartilage. The inflammatory response was moderate, and the mucosa was either ruptured or absent. In the 2 that had reduced flow, there was marked cartilage necrosis and inflammatory response with thrombus formation in the lumen. This early phase study shows that tracheal homografts functioned well as conduits in the aortic position and gluaraldehyde treated homografts have better morphology than cryopreserved homografts.