Long-term Behaviour of Cryopreserved Arterial Grafts Versus Prosthetic Micrografts

Abstract

All three grafts show good long-term tolerance when used in an arterial setting. Following long-term implant, autografts and cryoisografts show similar alterations that give rise to the complete loss of the muscle component of the tunica media along with the formation of a stable neointima. This new layer takes on the role of the tunica media.

Outcomes of long storage times for cryopreserved vascular grafts in outflow reconstruction in living donor liver transplantation

“…According to a literature review, a rat experiment in which arterial CVGs were used as vessel substitutes showed that general thinning of the arterial wall with delayed formation of the neointima and degeneration of the tunica media in arterial CVGs did not give rise to aneurysm formation 90 days after implantation (short term) . Another animal experiment involving arterial CVGs showed a complete loss of the muscle component of the tunica media along with the formation of a stable neointima in arterial CVGs in long‐term implants (180 days) . In LDLT, the short‐term patency of the outflow in V5 and V8 via interposition CVGs can prevent congestion of the anterior segment.…”

“…14 Another animal experiment involving arterial CVGs showed a complete loss of the muscle component of the tunica media along with the formation of a stable neointima in arterial CVGs in longterm implants (180 days). 27 In LDLT, the short-term patency of the outflow in V5 and V8 via interposition CVGs can prevent congestion of the anterior segment. Also, there is a low risk of aneurysm formation in arterial CVGs in the low-pressure system of the hepatic vein.…”

The Structural and Cellular Viability in Cryopreserved Rabbit Carotid Arteries

“…After in vitro perfusion, three parameters of mechanical properties, except for longitudinal elastic modulus, decreased further to a maximal 3ϳ4 fold decrease compared with fresh carotid arteries. These problems seriously affect the longterm patency of the cryopreserved grafts, which has mixed clinical and experimental reports thus far [63][64][65]. At the moment, cryopreserved graft has no clear advantage over the prosthetic grafts except in certain conditions [65][66][67][68].…”

Differential Functional Coupling Between Human Saphenous Cryoallografts and Arteries: Importance of the Arterial Type and the Biomechanical Parameter Evaluated

“…Nowadays, cryoallografts are used as vascular substitutes, but there are still questions related to their performance, because (i) there are no gold standards in cryopreservation techniques, making the evaluation and validation of the technique employed necessary; (ii) vessels have different susceptibilities to cryodamage, preventing generalization of the results; and (iii) damage to the wall components that determine the vascular wall dynamics has been reported, so the biomechanical and functional evaluation of the cryoallografts, overcoming the methodological limitations described earlier, is required (2,4,(7)(8)(9)15,16). Determining the cryoallografts' biomechanical and functional behaviors and their differences with the native arteries and vascular substitutes available would be important in (i) evaluating the usefulness of the cryopreservation method, (ii) identifying if the venous cryoallografts have biomechanical and functional advantages over the ePTFE, and (iii) determining if there are differences in the cryoallograft-native artery mechanical coupling that depend on the arterial type and/or on the biomechanical property considered.…”

“…Additionally, considering the recognized differences in the biomechanical behavior between the different types of arteries and the different mechanical and functional properties, the biomechanical and functional couplings should be evaluated for muscular and elastic arteries. However, most works assessed the vascular biomechanical properties in animal vessels; studied vascular rings, blades, or strips; performed statistical studies; did not characterize either the individual contribution of the different biomechanical properties or the biomechanical functions, and overlooked the regional differences among arteries (7)(8)(9)(10)(11). With reference to the biomechanical coupling, it has been quantified mainly in terms of compliance or elastic coupling, disregarding the dynamic properties, the arterial functions, and the differences in the wall dynamics of elastic and muscular arteries.…”