Abstract 13472: Aortic Valve Reconstruction Using In-body Tissue-Engineered Collagenous Connective Tissue Membranes,BIOSHEETs, in a 3-month Goat Model

Abstract

Background and Purpose: Autologous pericardium is widely used for a plastic material in intracardiac structures, pulmonary artery, or aortic valve leaflets. Also in aortic valve reconstruction (AVRec: Ozaki Procedure), inducing excellent clinical results over 6 years, autologous pericardium is used after fixation with glutaraldehyde. In-body tissue architecture (IBTA) based on the tissue encapsulation phenomenon of foreign materials can prepare autologous prosthetic tissues. In this study, we used an IBTA-based collagenous connective tissue sheet (Biosheet) as an aortic valve leaflet material for glutaraldehyde-free AVRec to compare the in vivo valve function and the tissue regeneration with original AVRec in a goat model. Methods and Results: AVRec was performed using two materials, glutaraldehyde-fixed autologous pericardium or Biosheets. The Biosheets were prepared by 2-month embedding of the plastic molds in the dorsal subcutaneous spaces of goats, obtained as completely autologous connective tissue with collagen and fibroblasts, and stored in alcohol before implantaion. AVRec procedure: The heart was exposed via a left thoracotomy at the fourth costal bed. Cardiopulmonary bypass was established with aortic and right atrial cannulations. After resection of native aortic valve cusps, the distance between each commissure was measured using a self-developed sizing instrument. Biosheet or autologous pericardium was trimmed with a self-developed template corresponding to the measured value. The annular margin of the leaflets was sutured to each annulus with monofilament sutures. In a Biosheet model, postoperative echocardiography after surgery showed smooth movement of the leaflets with little regurgitation, similar to that in an autologous pericardium model. Three month after Biosheet implantation, the valve leaflets was very smooth and covered partially with a thin neointima, including endothelial cells without thrombus formation. Biosheet was assimilated in an aortic root than autologous pericardium. Conclusion: An IBTA-based autologous connective sheet, Biosheet, without glutalaldehyde could be used for an AVRec material with high regeneration performance, suggesting that Biosheets have potential clinical use.