Physical and Hydrodynamic Equivalency of Wild Type and alpha-Gal Free GTKO Porcine Pericardium; A New Source Material For Bioprosthetic Heart Valves
Christopher GA McGregor, Benyamin Rahmani, Guerard W. Byrne, Gaetano Burriesci.
University College London, London, United Kingdom.
OBJECTIVE: Bioprosthetic heart valves (BHV) made from glutaraldehyde fixed animal tissues are an effective durable therapy in older patients (> 60 years) but exhibit age-dependent structural valve degeneration (SVD) in younger patients (< 60 years). SVD is principally caused by BHV calcification. Immune injury contributes to age-dependent SVD through the interaction of galactose alpha-1,3 galactose (Gal), a dominant xenogeneic antigen present on commercial BHVs and universally abundant human anti-Gal antibody. There is growing interest in using Gal-free animal tissues from Gal knockout pigs (GTKO), as these tissues would not be affected by anti-Gal antibody mediated injury.
METHODS: In this study we compare the composition, biophysical characteristics, hydrodynamic and durability performance of BHVs made from glutaraldehyde fixed porcine pericardium from standard and GTKO pigs.
RESULTS: We show that, with the exception of the Gal antigen which is only present in standard pig tissue, both GTKO and standard pig tissue have the same general morphology and collagen content. Uniaxial mechanical characterization and suture retention testing indicate that the tissues are equivalent in strength. Assessment of prototypes of stented porcine pericardial heart valves has shown that valves produced from standard and GTKO pericardium exhibit equivalent hydrodynamic performance. GTKO pericardial valves have also reached excellent durability, beyond 200 million cycles, meeting regulatory requirements.
CONCLUSIONS: These studies indicate that genetic disruption of the alpha-galactosyltransferase (GGTA-1) which blocks synthesis of the Gal antigen has no significant impact on the structural integrity of porcine pericardium and suggest that this tissue could substitute standard pig pericardium in biomedical devices such as bioprosthetic heart valves.
Back to 2018 Posters