Polyisobutylene-Based Thermoplastic Elastomers for Manufacturing Polymeric Heart Valve Leaflets: In Vitro and In Vivo Results

Evgeny Ovcharenko,Maria Rezvova,Tatiana Glushkova,Yulia Kudryavtseva,Kirill Klyshnikov,Sergei Kostjuk,Dmitry Trebushat,Leonid Barbarash,Larisa Antonova,Evgeniya Krivikina,Pavel Nikishau,Tatiana Akentieva,Daria Shishkova

doi:10.3390/app9224773

Evgeny Ovcharenko, Maria Rezvova + Show 11 more

Open Access

https://doi.org/10.3390/app9224773

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Abstract

Superior polymers represent a promising alternative to mechanical and biological materials commonly used for manufacturing artificial heart valves. The study is aimed at assessing poly(styrene-block-isobutylene-block-styrene) (SIBS) properties and comparing them with polytetrafluoroethylene (Gore-texTM, a reference sample). Surface topography of both materials was evaluated with scanning electron microscopy and atomic force microscopy. The mechanical properties were measured under uniaxial tension. The water contact angle was estimated to evaluate hydrophilicity/hydrophobicity of the study samples. Materials’ hemocompatibility was evaluated using cell lines (Ea.hy 926), donor blood, and in vivo. SIBS possess a regular surface relief. It is hydrophobic and has lower strength as compared to Gore-texTM (3.51 MPa vs. 13.2/23.8 MPa). SIBS and Gore-texTM have similar hemocompatibility (hemolysis, adhesion, and platelet aggregation). The subcutaneous rat implantation reports that SIBS has a lower tendency towards calcification (0.39 mg/g) compared with Gore-texTM (1.29 mg/g). SIBS is a highly hemocompatible material with a promising potential for manufacturing heart valve leaflets, but its mechanical properties require further improvements. The possible options include the reinforcement with nanofillers and introductions of new chains in its structure.

Highlights

Valvular heart disease is a major cause of disability and premature mortality worldwide [1].Clinically moderate or severe valvular heart disease will double before 2050 from 1.5 million in 2015 to 3.3 million in 2056 [2] resulting in a sharp increase of heart valve replacements, either surgical or transcatheter
The formation of block copolymer was confirmed by the shifts of gel permeation chromatography (GPC)
A particular attention should be paid to styrene and isobutylene block copolymers as promising materials since they are thermoplastic, The development of polymeric heart leaflets requires the use of polymers with superior hemocompatible properties as well as those yielding the best physical and mechanical properties

Summary

Introduction

Moderate or severe valvular heart disease will double before 2050 from 1.5 million in 2015 to 3.3 million in 2056 [2] resulting in a sharp increase of heart valve replacements, either surgical or transcatheter. To date, damaged native valves are replaced with mechanical and tissue heart valves. Neither mechanical nor tissue prostheses are ideal [3,4]. Their implantation is associated with reduced quality of life. Mechanical prostheses require life-long anticoagulation therapy and are associated with a substantially high risk of bleedings [5]. Tissue heart valves are susceptible to calcification and degeneration resulting in the structural failure, requiring repeat surgery [6,7]

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