How yarn orientation limits fibrotic tissue ingrowth in a woven polyester heart valve scaffold: a case report

Transcatheter Aortic Valve Implantation (TAVI) has become today a popular alternative technique to surgical valve replacement for critical patients. However, with only six years follow up on average, little is known about the long-term durability of transcatheter implanted biological tissue. Moreover, the high cost of tissue harvesting and chemical treatment procedures favor the development of alternative synthetic valve leaflet materials. In that context, thin, strong and flexible woven fibrous constructions could be considered as interesting candidates. However, the interaction of textile material with living tissue should be comparable to biological tissue, and the Foreign Body Reaction (FBR) in particular should be controlled. Actually, the porosity of textile materials tends to induce exaggerated tissue ingrowth which may prevent the implants from remaining flexible. The purpose of this preliminary animal case study is to investigate the influence of the valve leaflet yarn orientation on the fibrotic tissue ingrowth. For that purpose the in vivo performances of 45° inclined yarn woven valve leaflets implanted in juvenile sheep model were assessed after three months implantation. Results bring out that in the frame of this case study the development of fibrosis is limited with a woven fabric valve obtained from 45° inclined yarns.