MORPHOLOGY AND FUNCTION OF PRESERVED MICROVASCULAR ARTERIAL GRAFTS - AN EXPERIMENTAL-STUDY IN RATS

The aim of this study is to examine the morphology and function of sma ll-caliber, arterial grafts after preservation in the University of Wi sconsin solution (UW). Rat carotid arteries were stored in UW (n = 10) or in phosphate-buffered saline (PBS) (n = 10) for 1, 3, 7, and 14 da ys and were examined with light microscopy (LM) and scanning electron microscopy (SEM). Rat aortic preparations were stored in UW or PBS for 1 hour, 24 hours, 72 hours, 7 days, and 14 days and assessed for func tional responses (stimulated contraction and endothelium-dependent rel axation). Segments (5 mm) of rat carotid arteries were stored in UW or PBS for 3 days, 7 days, and 14 days and orthotopically implanted as a utografts and allografts. No immunosuppressive or anticoagulant agents were used. After 28 days of implantation, the grafts were assessed fo r patency and excised for LM and SEM. In UW, the endothelial layer rem ained intact up to 9 days of storage. In PBS, the endothelial layer sh owed deterioration after 1 day and was completely lost after 3 days. F unctional responses were demonstrated to exist for as long as 7 days s torage in UW. In PBS, no responses could be evoked after 24 hours stor age, Autografts preserved in UW for 3 days (n = 6), 7 days (n = 6), an d 14 days (n = 6) showed patency rates of 83.3%, 66.6%, and 66.6%, res pectively, whereas patency rates of allografts were 66.6%, 33.3%, and 33.3%, respectively. Autografts stored in PBS for 3 days (n = 6), 7 da ys (n = 6), and 14 days (n = 6) showed patency rates of 33.3%, 33.3%, and 50%, respectively, whereas patency rates of allografts were 16.7%, 0%, and 33.3%, respectively. The UW preserved autografts showed norma l morphology. All other groups showed vessel wall degeneration which i n the allograft groups, were accompanied by lymphocellular infiltratio n. In conclusion, the endothelial layer and vessel wall of arteries ar e adequately preserved in UW. Functional responses are retained up to 14 days storage in UW, hut, are lost after 24 hours storage in PBS. Au tograft implantation studies accordingly show good performance of arte rial segments preserved in UW, whereas allografts are subject to degra dation as a result of rejection.