Appa Harish, Park Kenneth, Bezuidenhout Deon, van Breda Braden, de Jongh Bruce, de Villiers Jandré, Chacko Reno, Scherman Jacques, Ofoegbu Chima, Swanevelder Justiaan, Cousins Michael, Human Paul, Smith Robin, Vogt Ferdinand, Podesser Bruno K, Schmitz Christoph, Conradi Lenard, Treede Hendrik, Schröfel Holger, Fischlein Theodor, Grabenwöger Martin, Luo Xinjin, Coombes Heather, Matskeplishvili Simon, Williams David F, Zilla Peter
Strait Access Technologies (SAT), University of Cape Town, Cape Town, South Africa.
Cardiovascular Research Unit, University of Cape Town, Cape Town, South Africa.
Front Cardiovasc Med. 2022 Mar 3;9:791949. doi: 10.3389/fcvm.2022.791949. eCollection 2022.
Leaflet durability and costs restrict contemporary trans-catheter aortic valve replacement (TAVR) largely to elderly patients in affluent countries. TAVR that are easily deployable, avoid secondary procedures and are also suitable for younger patients and non-calcific aortic regurgitation (AR) would significantly expand their global reach. Recognizing the reduced need for post-implantation pacemakers in balloon-expandable (BE) TAVR and the recent advances with potentially superior leaflet materials, a trans-catheter BE-system was developed that allows tactile, non-occlusive deployment without rapid pacing, direct attachment of both bioprosthetic and polymer leaflets onto a shape-stabilized scallop and anchorage achieved by plastic deformation even in the absence of calcification. Three sizes were developed from nickel-cobalt-chromium MP35N alloy tubes: Small/23 mm, Medium/26 mm and Large/29 mm. Crimp-diameters of valves with both bioprosthetic (sandwich-crosslinked decellularized pericardium) and polymer leaflets (triblock polyurethane combining siloxane and carbonate segments) match those of modern clinically used BE TAVR. Balloon expansion favors the wing-structures of the stent thereby creating supra-annular anchors whose diameter exceeds the outer diameter at the waist level by a quarter. In the pulse duplicator, polymer and bioprosthetic TAVR showed equivalent fluid dynamics with excellent EOA, pressure gradients and regurgitation volumes. Post-deployment fatigue resistance surpassed ISO requirements. The radial force of the helical deployment balloon at different filling pressures resulted in a fully developed anchorage profile of the valves from two thirds of their maximum deployment diameter onwards. By combining a unique balloon-expandable TAVR system that also caters for non-calcific AR with polymer leaflets, a powerful, potentially disruptive technology for heart valve disease has been incorporated into a TAVR that addresses global needs. While fulfilling key prerequisites for expanding the scope of TAVR to the vast number of patients of low- to middle income countries living with rheumatic heart disease the system may eventually also bring hope to patients of high-income countries presently excluded from TAVR for being too young.
瓣叶耐久性和成本问题在很大程度上限制了当代经导管主动脉瓣置换术（TAVR）仅适用于富裕国家的老年患者。易于部署、避免二次手术且也适用于年轻患者和非钙化性主动脉反流（AR）的TAVR将显著扩大其全球应用范围。认识到球囊扩张式（BE）TAVR植入后对起搏器的需求减少以及近期在潜在更优质瓣叶材料方面取得的进展，研发了一种经导管BE系统，该系统允许进行触觉式、非闭塞性部署，无需快速起搏，生物假体瓣叶和聚合物瓣叶均可直接附着于形状稳定的扇形结构上，并且即使在无钙化的情况下也可通过塑性变形实现锚定。由镍 - 钴 - 铬MP35N合金管开发出三种尺寸：小号/23毫米、中号/26毫米和大号/29毫米。带有生物假体瓣叶（三明治交联去细胞心包）和聚合物瓣叶（结合硅氧烷和碳酸酯链段的三嵌段聚氨酯）的瓣膜的压接直径与现代临床使用的BE TAVR相匹配。球囊扩张有利于支架的翼状结构，从而形成瓣环上锚定结构，其直径在腰部水平超过外径四分之一。在脉动复制器中，聚合物和生物假体TAVR显示出等效的流体动力学性能，具有出色的有效瓣口面积（EOA）、压力梯度和反流体积。部署后抗疲劳性能超过ISO要求。螺旋部署球囊在不同充盈压力下的径向力导致瓣膜从其最大部署直径的三分之二起形成完全展开的锚定轮廓。通过将一种独特的球囊扩张式TAVR系统与聚合物瓣叶相结合，该系统还适用于非钙化性AR，一种针对心脏瓣膜疾病的强大且可能具有颠覆性的技术已被纳入一种满足全球需求的TAVR中。在满足将TAVR范围扩大到大量患有风湿性心脏病的低收入和中等收入国家患者的关键先决条件的同时，该系统最终可能也会给目前因年龄太小而被排除在TAVR之外的高收入国家患者带来希望。
