Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8151, USA.
School of Mechanical Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel.
Ann Biomed Eng. 2019 Jan;47(1):113-125. doi: 10.1007/s10439-018-02119-7. Epub 2018 Sep 7.
Transcatheter aortic valve replacement (TAVR) is a minimally-invasive approach for treating severe aortic stenosis. All clinically-used TAVR valves to date utilize chemically-fixed xenograft as the leaflet material. Inherent limitation of the tissue (e.g., calcific degeneration) motivates the search for alternative leaflet material. Here we introduce a novel polymeric TAVR valve that was designed to address the limitations of tissue-valves. In this study, we experimentally evaluated the hemodynamic performance of the valve and compared its performance to clinically-used valves: a gold standard surgical tissue valve, and a TAVR valve. Our comparative testing protocols included: (i) baseline hydrodynamics (ISO:5840-3), (ii) complementary patient-specific hydrodynamics in a dedicated system, and (iii) thrombogenicity. The patient-specific testing system facilitated comparing TAVR valves performance under more realistic conditions. Baseline hydrodynamics results at CO 4-7 L/min showed superior effective orifice area (EOA) for the polymer valve, most-notably as compared to the reference TAVR valve. Regurgitation fraction was higher in the polymeric valve, but within the ISO minimum requirements. Thrombogenicity trends followed the EOA results with the polymeric valve being the least thrombogenic, and clinical TAVR being the most. Hemodynamic-wise, the results strongly indicate that our polymeric TAVR valve can outperform tissue valves.
经导管主动脉瓣置换术(TAVR)是一种治疗严重主动脉瓣狭窄的微创方法。迄今为止,所有临床应用的 TAVR 瓣膜均采用化学固定的异种移植物作为瓣叶材料。组织的固有局限性(例如,钙化退化)促使人们寻找替代瓣叶材料。在这里,我们介绍了一种新型聚合物 TAVR 瓣膜,旨在解决组织瓣膜的局限性。在这项研究中,我们对瓣膜的血液动力学性能进行了实验评估,并将其性能与临床应用的瓣膜进行了比较:金标准外科组织瓣膜和 TAVR 瓣膜。我们的比较测试方案包括:(i)基线流体动力学(ISO:5840-3),(ii)专用系统中的补充患者特异性流体动力学,和(iii)血栓形成。患者特异性测试系统有助于在更现实的条件下比较 TAVR 瓣膜的性能。在 CO 4-7 L/min 的基线血流动力学结果显示,聚合物瓣膜的有效瓣口面积(EOA)更高,与参考 TAVR 瓣膜相比,这一优势尤为明显。聚合物瓣膜的反流分数较高,但在 ISO 的最低要求范围内。血栓形成趋势与 EOA 结果一致,聚合物瓣膜的血栓形成最少,而临床 TAVR 的血栓形成最多。从血液动力学角度来看,结果强烈表明我们的聚合物 TAVR 瓣膜可以优于组织瓣膜。