Filip Schröter, Immanuel-Klinik Bernau Herzzentrum Brandenburg, Germany
Objectives: Polymeric valves constructed from synthetic materials were amongst the first implanted artificial heart valves. They were intended to combine the advantageous hemodynamics of biological valves with the longevity of mechanical prostheses. While some of the implanted prostheses stayed functional over impressive time periods, they were hampered by material limitations and finally phased out in favor of the biological and mechanical valves used today.
Recent progress in material science led to the creation of polymers with increased longevity and biocompatibility, rebirthing the idea of polymeric heart valve prostheses. Beside imitation the natural valve form, this opens up the possibility to create new construction principles that might be more compatible with these new materials or the limitations posed by suture rings and stents necessary for implantation. This led to our currently investigated design, the TRISKELION valve.
Methods: Our prototypes were developed in a continuous and ongoing design processes and consists of a flexible cylindrical SEBS (Styrol-Ethylen-Butylen-Styrol) leaflet forming 3 or 4 openings with a rigid inner polystyrol support structure. The latter supports the unidirectional closing of the leaflets and is intended to direct the fluid flow. The basis of the prototype is currently build from stainless steel wire but is intended to be replaced by a conventional suture ring.
All our prototypes were tested using a hemodynamic pulse duplicator of the type HKP 2.0 (LB Engineering GbR, Berlin, Germany) to identify advantageous variants and compare them with commonly used biological and mechanical prostheses.
Results: Paravalvular pressure gradients of both TRISKELION valves (3 openings: 7.52 ± 0.64, 4 openings: 6.91 ± 0.62 mmHg) were comparable to a biological (8.18 ± 0.90 mmHg) and mechanical valve (10.53 ± 0.63 mmHg) currently in use. Some increased paravalvular leakage compared to these types remained and will be addressed in the prospective design process.
Conclusions: We could show that this newly designed construction principle for a polymeric heart valve shows promising performance compared to common prostheses. In a next step newly developed, highly biocompatible materials and further adjustment to the design should be used to pave the way towards a potential alternative to conventional prostheses.