1ST RESULTS ON THE FUNCTIONAL-CHARACTERISTICS OF CRYOPRESERVED HUMAN SAPHENOUS-VEIN

In current surgical practice, autologous vein is the conduit of choice for bypass of small vessel occlusive disease. Unfortunately, autologous tissue is not always available or suitable for such use because of venous disease, inadequate vessel size, surgical stripping, or previous arterial grafting procedures. Recent improvements in cryopreservation techniques have renewed interest in cryopreserved human allografts as a possible alternative to autologous tissue. However, the initial clinical results with cryopreserved vein grafts have been inconsistent. While the mechanisms of cryopreserved vein graft failure remain imprecisely defined, it has been suggested that an accelerated atherosclerotic process may be involved. In an effort to more precisely define these mechanisms, we utilized an ex vivo organ perfusion system to explore the acute response of human cryopreserved saphenous vein to an arterial hemodynamic environment. Specimens were examined for their biomechanical, morphologic, and the low density lipoprotein (LDL) metabolic adaptation during a twenty hour exposure to arterial pressures and flows. Our results suggest that cryopreserved human saphenous veins accumulate LDL-cholesterol at an accelerated rate when compared to our native tissue controls, due in part to the absence of an intact endothelial layer. Both of these factors may contribute to the poor patency rates seen in the sparsely reported clinical trials.