Transcatheter Pulmonary Valve Replacement by Hybrid Approach Using a Novel Polymeric Prosthetic Heart Valve: Proof of Concept in Sheep

Abstract

BackgroundSince 2000, transcatheter pulmonary valve replacement has steadily advanced. However, the available prosthetic valves are restricted to bioprosthesis which have defects like poor durability. Polymeric heart valve is thought as a promising alternative to bioprosthesis. In this study, we introduced a novel polymeric transcatheter pulmonary valve and evaluated its feasibility and safety in sheep by a hybrid approach.MethodsWe designed a novel polymeric trileaflet transcatheter pulmonary valve with a balloon-expandable stent, and the valve leaflets were made of 0.1-mm expanded polytetrafluoroethylene (ePTFE) coated with phosphorylcholine. We chose glutaraldehyde-treated bovine pericardium valves as control. Pulmonary valve stents were implanted in situ by a hybrid transapical approach in 10 healthy sheep (8 for polymeric valve and 2 for bovine pericardium valve), weighing an average of 22.5±2.0 kg. Angiography and cardiac catheter examination were performed after implantation to assess immediate valvular functionality. After 4-week follow-up, angiography, echocardiography, computed tomography, and cardiac catheter examination were used to assess early valvular function. One randomly selected sheep with polymeric valve was euthanized and the explanted valved stent was analyzed macroscopically and microscopically.FindingsImplantation was successful in 9 sheep. Angiography at implantation showed all 9 prosthetic valves demonstrated orthotopic position and normal functionality. All 9 sheep survived at 4-week follow-up. Four-week follow-up revealed no evidence of valve stent dislocation or deformation and normal valvular and cardiac functionality. The cardiac catheter examination showed the peak-peak transvalvular pressure gradient of the polymeric valves was 11.9±5.0 mmHg, while that of two bovine pericardium valves were 11 and 17 mmHg. Gross morphology demonstrated good opening and closure characteristics. No thrombus or calcification was seen macroscopically.ConclusionsThis design of the novel ePTFE transcatheter pulmonary valve is safe and effective to deploy in sheep by hybrid approach, and the early valvular functionality is good.

Bioinspired Engineering of Poly(ethylene glycol) Hydrogels and Natural Protein Fibers for Layered Heart Valve Constructs

“…34 The microstructures and mechanical properties play an important role in the functions of heart valve leaflets, which can undergo opening and closing for about 3 billion cycles during an adult lifetime. 6 For example, collagen fibers in the fibrosa layer of aortic valve leaflet are the major stress-bearing components, providing the strength to maintain coaptation during diastole. The elastin fibers in the ventricularis layer extend in diastole and recoil during systole.…”

“…All these current devices have significant limitations with risks of further morbidity and mortality. For example, MVs may cause hemorrhage and thromboembolism, and require anticoagulation for the lifetime of the patients. , BHVs show better hemodynamic behavior due to the composition and structural similarity to native heart valves when compared to MVs; however, they do show limited durability because of calcification and progressive degeneration. , Thus, polymeric heart valve (PHV) prostheses combining the advantages of MVs and BHVs with long-term durability and no necessity for permanent anticoagulation are of great interest and show potential applications in advanced transcatheter devices. , …”

“…3,4 Thus, polymeric heart valve (PHV) prostheses combining the advantages of MVs and BHVs with long-term durability and no necessity for permanent anticoagulation are of great interest 5 and show potential applications in advanced transcatheter devices. 6,7 The heterogenic composition and orientation of extracellular matrices (ECMs) play important roles in heart valve functions.…”

Development of Tissue Engineered Heart Valves for Percutaneous Transcatheter Delivery in a Fetal Ovine Model

“…The hemodynamic performance of the TEHV was assessed in a dedicated right heart pulse duplicator. Although no true control valve of similar size is available for comparison, the peak PG reported for the TEHV was 20 mm Hg, while peak PGs reported in children receiving a Melody valve (Medtronic, Minneapolis, Minnesota) or SAPIEN valve (Edwards Lifesciences, Irvine, California) in pulmonary conduits were 13.5 mm Hg (by catheterization at time of implant) and 18.7 mm Hg (by echocardiogram at 1-month follow-up), respectively ( 34 , 35 , 36 ). Postoperative pressure gradients of surgical valves implanted in the pulmonary position in pediatric patients (determined by echocardiogram) were reported as 16 to 44 mm Hg ( 37 ).…”

Polymeric Heart Valve Prostheses: Condition and Perspectives

“…Полимерные транскатетерные клапаны на основе ePTFE, модифицированного сополимером 2-метакрилоксиэтилфосфорилхолина и бутилметакрилата, были имплантированы 8 овцам в легочную позицию. Результаты эксперимента показали хорошую раннюю функцию протеза и отсутствие кальцификации и тромбообразования при макроскопическом изучении [48]. С целью улучшения характеристик и расширения спектра применения медицинских изделий из PTFE поверхность полимера модифицируют различными способами: покрывают сополимерами на основе акриловой кислоты, 4-винилпиридина, 1-винилимидазола [49,50], коллагеном [50], гепарином [51], фибронектином и фосфорилхолином [52] и др.…”