Fiber heart valve prosthesis: Early in vitro fatigue results

Abstract

Transcatheter aortic valve replacement has become today a largely considered alternative technique to surgical valve replacement in patients with high risk for open chest surgery. Biological valve tissue used in the transcatheter devices has shown success over 5 years now, but the procedure remains expensive. Moreover, different studies point out potential degradations that the tissue can undergo when folded to lower diameter and released in calcified environment with irregular geometry, which may jeopardize the durability of the device. The use of synthetic materials, like textile in particular, to replace biological valve leaflets would help reducing the procedure costs, and limit the degradations when the valve is crimped. Textile polyester material has been extensively used in the vascular surgery and is characterized by outstanding folding and strength properties combined with proven biocompatibility. However, the friction effects that occur between filaments and between yarns within a fabric under flexure loading could be critical for the resistance of the material on the long term. The purpose of this study was to assess the early fatigue performances of textile valve prototypes under accelerated cyclic loading up to 200 Mio cycles. Durability tests show that the fibrous material undergoes rearrangements between fibrous elements within the textile construction and the mechanical properties are modified on the long term. But testing is not complete with 200 Mio cycles. The material should be tested up to a higher number of cycles in future work to test the effective long-term durability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 986-992, 2016.

Transcatheter Heart Valves: A Biomaterials Perspective

“…[ 77 ] This is observed in polyester‐based prostheses where cycling loading reduces the crystalline phase of the polymer and lowers the ultimate strength and strain at failure. [ 78 ] For leaflets made from tunable polymers, various material characterization techniques are implemented to ensure superior mechanical properties. Table 2 shows the several ways materials are analyzed during THV development.…”

“…[ 90b ] In general, the reported frequency for in vitro AWT for THVR ranges between 5 and 15 Hz. [ 78,93 ]…”

“…The polyester fibers also seem to rearrange after undergoing millions of cyclic loads with decreasing crystallinity and the ultimate strength. [ 78 ] As demonstrated in an in vivo model, there appears to be a link between hemocompatibility and fabric design. THV with monofilament textile leaflets has less calcium deposition than multifilament ones, but the latter appears to attract less fibrotic ingrowth.…”

Fibrous biomaterials: Effect of textile topography on foreign body reaction

“…The case of woven material, largely used for hernia mesh and vascular graft applications has been only poorly considered in literature. Recent work has investigated the potential of PET woven textile as heart valve leaflet material 19‐22 and prototypes tested in vivo have confirmed that exaggerated fibrotic proliferation related to FBR can occur if the textile design is not appropriate 6,23 . Consequently, a more systematic study about the influence of the pore and fiber size on the in vivo behavior of a woven implant would be necessary to help optimizing the design of these devices.…”

Textile transcatheter heart valve prosthesis: state of the art

“…10 Figures 5(a) and 5(b) represent the surface SEM images of sample A at the beginning and after 200 Mio cycles, respectively. At the microscopic level, two observations can be made.…”