Anatomopathological and Immunohistochemical Study of Explanted Cryopreserved Arteries

Background: The aim of the study was to analyze the mechanism of deterioration of implanted arteries. Methods: Eleven patients were included. Samples of vascular segments obtained from multiorgan donors and samples of the same vascular segments after explantation in the recipient were analyzed. Blood group, time of cold and warm ischemia, cause of death, time spent in the intensive care unit, time of storage of the cryopreserved grafts, and anatomopathological and immunohistochemical studies were analyzed using the preimplant samples obtained from the multiorgan donor. For samples obtained from the recipient, blood group, duration for which the tissue from the donor has been implanted, reason for graft explantation, and anatomopathological and immunohistochemical studies were analyzed. Results: Histopathologically, the main finding has been the substitution of the muscular cap of the arterial wall by an intense fibrosis, in most of the cases, of a symmetrical nature. Besides this degeneration of myocytes, there is marked perivascular fibrosis and fibrointimal thickening also exists. The T lymphocytes suggest the importance of the immunological mechanism in the distortion of the architecture of the arteries. The atherosclerosis plays a less relevant role. Conclusions: Evidence of immune-mediated injury was found, and this mechanism seems to be responsible for the degenerative process in cryopreserved homografts.