Abstract
Many congenital heart defects and degenerative valve diseases require replacement of heart valves in children and young adults. Transcatheter xenografts degenerate over time. Tissue engineering might help to overcome this limitation by providing valves with ability for self-repair. A transcatheter decellularized tissue-engineered heart valve (dTEHV) was developed using a polyglycolic acid (PGA) scaffold. A first prototype showed progressive regurgitation after 6 months in-vivo due to a suboptimal design and misguided remodeling process. A new geometry was developed accordingly with computational fluid dynamics (CFD) simulations and implemented by adding a polyether-ether-ketone (PEEK) insert to the bioreactor during cultivation. This lead to more belly-shaped leaflets with higher coaptation areas for this second generation dTEHV. Valve functionality assessed via angiography, intracardiac echocardiography, and MRI proved to be much better when compared the first generation dTEHV, with preserved functionality up to 52 weeks after implantation. Macroscopic findings showed no thrombi or signs of acute inflammation. For the second generation dTEHV, belly-shaped leaflets with soft and agile tissue-formation were seen after explantation. No excessive leaflet shortening occurred in the second generation dTEHV. Histological analysis showed complete engraftment of the dTEHV, with endothelialization of the leaflets and the graft wall. Leaflets consisted of collagenous tissue and some elastic fibers. Adaptive leaflet remodeling was visible in all implanted second generation dTEHV, and most importantly no fusion between leaflet and wall was found. Very few remnants of the PGA scaffold were detected even 52 weeks after implantation, with no influence on functionality. By adding a polyether-ether-ketone (PEEK) insert to the bioreactor construct, a new geometry of PGA-scaffold based dTEHV could be implemented. This resulted in very good valve function of the implanted dTEHV over a period of 52 weeks.
Highlights
9 out of 1000 children are born with a congenital heart defect [1,2]
The Pulmonary valve is most frequently affected by these congenital heart defects, making it the valve that is most often replaced in people born with congenital heart disease [3,4]
T After harvesting the decellularized tissue-engineered heart valve (dTEHV) from the bioreactor, differences in geometry were clearly visible between the first and second generation of dTE-valves: Leaflets were much
Summary
9 out of 1000 children are born with a congenital heart defect [1,2]. The Pulmonary valve is most frequently affected by these congenital heart defects, making it the valve that is most often replaced in people born with congenital heart disease [3,4].Currently, there are two generally different types of valve prostheses being used for heart valve replacement: Mechanical and biological valves. 9 out of 1000 children are born with a congenital heart defect [1,2]. The Pulmonary valve is most frequently affected by these congenital heart defects, making it the valve that is most often replaced in people born with congenital heart disease [3,4]. There are two generally different types of valve prostheses being used for heart valve replacement: Mechanical and biological valves. Most common are bleeding complications for mechanical heart valves and degeneration for biological valves, leading to the necessity of new prostheses for pulmonary valve replacement [5,6]. Degeneration of biological valves occurs mainly due to their inability to promote re-endothelialization of autologous cells and tissue remodeling [7,8]
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