Assessment of leaflet designs for a novel fully-polymeric transcatheter heart valve
Creators: name: Smid, Caroline Charlotte
name: Pappas, Georgios A.
name: Cesarovic, Nikola
name: Falk, Volkmar
name: Ermanni, Paolo
Publisher: name: ETH Zurich
Year: 2021

description: Approximately 30 million people from industrialized countries are estimated to be affected by heart valve diseases, which is most prevalent in the elderly [1]. Due to the increase in life expectancy worldwide, the prevalence of valvular heart disease is rising rapidly. By 2050, the demand is expected to exceed 850,000 heart valves annually [2]. Despite the continuous and considerable improvement of artificial heart valves, the replacement recurrently leads to a shift from the native valve disease to a prosthetic valve-induced disease due to design-inherent limitations and suboptimal prosthesis selection [3]. The improvement of artificial heart valves concerning functionality, durability, reliability, and cost can result in a shift from open-heart surgery as the first choice for heart valve replacement to minimally-invasive procedures and consequently, significantly reduce complications and therapy expenses for valvular disease. “Especially the reduction of the cost may drastically affect the accessibility of such devices for third world countries, where due to socio-economic circumstances the highest demand for artificial heart valves is observed (Zilla et al., 2008) and the medical equipment for open-heart surgery is not accessible.” (Schlothauer & Ermanni, 2019) Especially in the field of heart valves with large diameters, there are additional challenges, meaning that there is still a lot of need for research and development.
A fully-polymeric transcatheter heart valve combining the advantages of the two main heart valve prosthesis types, namely the mechanical and the bioprosthetic heart valve, could address the current challenges. This new heart valve concept should be applicable to all anatomical heart valve diameters in order to be able to use them for a Total Artificial Heart as a superior goal.
The hypothesis is that this concept can be enabled by a CF-PEEK composite stent and leaflets made of an ultra-stiff material. This ultra-stiff material, which is still unexplored for this application, seems promising for the durability, the hemocompatibility, and the possibility of larger atrio-ventricular heart valves. Since the material is approximately 350 times stiffer than the natural leaflet tissue, a new leaflet design is needed that reduces the flexural stiffness in order for the heart valve to exhibit good kinematics. Good kinematics is defined, among other things, by a low transvalvular pressure differential for the opening and a large orifice area in the open state. These characteristics will be investigated experimentally using a pulse duplicator. A pulse duplicator simulates the function of the heart, by generating a pulsatile flow through the heart valve placed in the circuit. In parallel, 'quasistatic' dynamic FEM simulations were performed to study the opening process of the new leaflet designs with different stiffnesses.
Preliminary results show that the pulse duplicator mimics physiological conditions and that in the FEA the new designs open at a lower pressure differential than a conventional design mimicking the native leaflets, with the same stiffness. This new heart valve concept could become the next emerging technology.


[1] Kadouch, J. and Labojka, D. (2017): Matters of the Heart: Valvular Heart disease today. Paris: The Art & Science of Risk
[2] Yacoub, M. H.; Takkenberg, J. J. M. (2005): Will heart valve tissue engineering change the world? In Nature clinical practice. Cardiovascular medicine 2 (2), pp. 60–61. DOI: 10.1038/ncpcardio0112.
[3] Pibarot, Philippe; Dumesnil, Jean G. (2009): Prosthetic heart valves: selection of the optimal prosthesis and long-term management. In Circulation 119 (7), pp. 1034–1048. DOI: 10.1161/CIRCULATIONAHA.108.778886.