Textile Heart Valve Prosthesis: The Effect of Fabric Construction Parameters on Long-term Durability

The rapid development and success of percutaneous vascular surgery over the last two decades, with the now common stent graft implantation, make this non-invasive technique attractive today even for heart valve replacement. Less traumatic for the patient and also less time consuming, this technique is however in its infancy and restricted to advanced age or terminally ill patients. A major requirement for the use of the method is that the heart valve prosthesis is flexible enough to be folded into the lumen of a small diameter catheter. A standard material used for the construction of arterial grafts and which could also be suitable for engineering heart valve prosthesis is polyester textile fabric. However no data is available in the published technical literature on the long-term durability of this or any other fabric used as a heart valve. The purpose of this research is to study the long-term fatigue behavior of woven polyester fabrics of different yarn and construction factors. In the novel in vitro technique used, a fabric specimen is subjected to combined flexural and tensile fatigue generated by fluid flow under physiological heart valve working conditions. The results obtained show how flexural properties change with fatigue time, which reflects directly on the suitability of a given fabric in such devices. The results also show trends that one can use to develop criteria for designing a fabric most highly suited for use in heart valve application.