Effect of Leaflet Anisotropy, Coaptation Curvature, and Stent Flexibility on the Stress Concentrations and In Vitro Function of Polymer Trileaflet Heart Valves

Polymer trileaflet valves have been under investigation for the past 40–50 years in an attempt to produce a valve alternative that is both durable and non-thrombogenic. Most have met with limited success due to oxidative reactions and high dynamic stresses borne by the material [1]. With this knowledge, an oxidatively stable polyolefin, poly(styrene-b-isobutylene-b-styrene) (SIBS), was selected for the design of a fiber-reinforced polymer trileaflet heart valve. The hydrodynamic properties of prototype SIBS valves have been encouraging, but some valves failed prematurely as a result of insufficient durability during in vivo implantation in a sheep model or during accelerated in vitro fatigue.