In vivo evaluation of the effects of a new ice-free cryopreservation process on autologous vascular grafts

Conventionally cryopreserved vascular grafts have performed poorly as arter ial grafts. One possible mechanism that causes the poor function is the ext racellular ice damage in tissue. We used a novel new ice-free cryopreservat ion (namely, vitrification) method for prevention of ice formation in cryop reserved venous grafts. This study was designed to evaluate the in vivo eff ects of the vitrification process on autologous vascular grafts using a sho rt-term transplantation model and to examine the morphology and patency of vitrified grafts in correlation with control grafts. New Zealand White rabb its underwent a right common carotid interposition bypass graft. Fresh and vitrified reversed ipsilateral external jugular veins were used as autologo us grafts. Animals were sacrificed at either 2 or 4 weeks after implantatio n, and fresh and vitrified vein grafts were harvested for histology studies . The results, comparing the patency of fresh and vitrified grafts, demonst rated similar short-term patency rates (similar to 90%). There were no sign s of media disruption, aneurysm, or graft stenosis in vitrified vein grafts . Vitrification had not altered the pathophysiological cascade of events th at occur when a vein graft is inserted into the arterial system. The vitrif ication process had no adverse effects locally or systemically in vivo. In addition, vitrification has preserved endothelial cell and smooth muscle ce ll integrity posttransplantation. In conclusion, this study, using an autol ogous animal model, clearly demonstrated a significant benefit of vitrifica tion for preservation of graft function, and vitrification may be an accept able approach for preservation of blood vessels or engineered tissue constr ucts.