Non-Invasive biomechanical evaluation of implanted human cryopreserved arterial homografts: Comparison with pre-implanted cryografts and arteries from human donors and recipients

Abstract

Native vessels-grafts biomechanical mismatch (BM) is related to graft failure. The BM could be reduced using human cryopreserved/defrosted arteries (cryografts), but post-thaw cryografts´ recovery could be associated with an impaired biomechanical behavior. In vitro, we demonstrated that our cryopreservation methods do not affect arteries´ biomechanics, but only post-implant studies would allow determining the cryografts´ biomechanical performance. AIM: To characterize the biomechanical properties of implanted cryografts, and to compare them with cryografts pre-implant, recipients´ native arteries, and arteries from subjects with characteristics similar to those of the recipients and multiorgan donors (MOD) whose arteries were cryopreserved. METHODS: Native femoral arteries anastomosed to cryografts, implanted cryografts, and arteries from subjects, recipient-like and MOD-like, were studied. In vitro (pre-implant cryografts) and in vivo non-invasive studies were performed. Arterial pressure, diameter, and wall thickness were obtained to quantify local and regional biomechanical parameters, and to evaluate the arterial remodeling. CONCLUSION: Implanted cryografts were remodeled, with an increased wall thickness, wall-to-lumen ratio, and wall cross-sectional area. The proximal-distal gradual transition in stiffness remained unchanged. Implanted cryografts were stiffer than MOD-like arteries, but more compliant than recipients´ arteries. The cryografts-native arteries biomechanical differences were lesser than those described for venous grafts or expanded polytetrafluoroethylene.