A preclinical trial of perventricular pulmonary valve implantation: Pericardial versus aortic porcine valves mounted on self-expandable stent

Abstract

Perventricular pulmonary valve implantation (PPVI) of a xenograft valve can be a less invasive technique that avoids cardiopulmonary bypass in patients who require pulmonary valve replacement. We compared the hemodynamics, durability, and histologic changes between two different xenogenic valves (pericardial vs. aortic valve porcine xenografts) implanted into the pulmonary valve position using a PPVI technique and evaluated the safety and efficacy of PPVI as a preclinical study. In 18 sheep, pericardial (group porcine pericardial [PP], n = 9) or aortic valve (group porcine aortic valve [PAV], n = 9) xenogenic porcine valves manufactured as a stented valve were implanted using a PPVI technique. The porcine tissues were decellularized, alpha-galactosidase treated, fixed with glutaraldehyde after space-filler treatment, and detoxified to improve durability. Hemodynamic and immunohistochemical studies were performed after the implantation; radiologic and histologic studies were performed after a terminal procedure. All stented valves were positioned properly after the implantation, and echocardiography and cardiac catheterization demonstrated good hemodynamic state and function of the valves. All the anti-α-Gal IgM and IgG titers were below 0.3 optical density. Computed tomography of extracted valves demonstrated no significant differences in the degree of calcification between the two groups (P = .927). Microscopic findings revealed a minimal amount of calcification and no significant infiltration of macrophage or T-cell in both groups, regardless of the implantation duration. The PPVI is a feasible technique. Both stented valves made of PP and PAV showed no significant differences in hemodynamic profile, midterm durability, and degree of degenerative dystrophic calcification.

Keywords: animal study; congenital heart disease; pulmonary valve replacement; tissue engineering.