Heart Valves from Polyester Fibers vs. Biological Tissue: Comparative Study In Vitro

Transcatheter aortic valve implantation (TAVI) has become a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in TAVI procedures for over a decade, with over 100,000 implantations to date. However, with only 6 years follow up, little is known about the long-term durability of biological tissue. Moreover, the high cost of tissue harvesting and chemical treatment procedures favor the development of alternative synthetic valve leaflet materials. Textile polyester is one such material which provides outstanding folding and strength properties combined with proven biocompatibility, and could therefore be considered as a candidate to replace the biological valve leaflets in TAVI procedures. For that purpose, in addition to the mechanical properties, the hemodynamic properties of the synthetic material should be comparable to the properties of biological tissue. An ideal replacement heart valve would provide low static and dynamic regurgitation, ensure laminar flow across the valve, and limit the turbidity of flow downstream of the valve. The purpose of the present work is to compare in vitro the mechanical and hemodynamic performances of textile woven polyester valves with biological ones. Testing results indicate that textile valves trade elasticity for superior mechanical strength, relative to biological tissue. Despite this, the dynamic flexibility of textile valve leaflets strongly resembled what was seen with biological leaflets. Regurgitation, as well as slightly modified turbulent patterns, in textile valves was higher than biological valves due to the increased porosity, but, rapid tissue ingrowth post-implantation would likely mitigate this effect. Together these findings provide additional evidence favoring the use of textile polyester as a synthetic heart valve leaflet material.