Mechanisms of bioprosthetic XXXX .

@entity1 @entity730 @entity460 @entity35 @entity340 @entity528
BACKGROUND: Cryopreserved @entity1 heart valves are used in approximately 20% of the tissue heart valve procedures performed annually. The pathophysiology of allograft failure is not fully understood. The authors proposed the hypothesis that the rapid deterioration observed in some allograft heart valve recipients is caused by disruptive interstitial ice damage that occurs during cryopreservation and subsequently leads to accelerated @entity528 on implantation. METHODS: This hypothesis was tested by comparison of the standard commercial heart valve freezing method of cryopreservation and an ice-free, vitrification method of cryopreservation with fresh controls in a subcutaneous, juvenile @entity35 implant model of @entity730 . @entity460 concentration in explants was determined by atomic absorption spectroscopy. RESULTS: Statistically significant @entity730 (P<0.05) was observed in both syngeneic and allogeneic cryopreserved valves relative to fresh valves. The ice-free cryopreservation method demonstrated significant reduction of allogeneic @entity340 (P<0.01). Comparison of fresh syngeneic and allogeneic grafts at the 3-week time point demonstrated significantly higher @entity460 content in allograft valve explants (P<0.005). CONCLUSIONS: These findings demonstrate that allogeneic valve @entity730 is influenced by two factors, the cryopreservation method used and immunogenicity. Alternative cryopreservation methods that avoid ice formation may improve the in vivo performance of cryopreserved allogeneic heart valves.
