Department of Biomedical Engineering, Stony Brook University, T8-050 Health Sciences Center, Stony Brook, NY 11794-8084.
Department of Medicine and Biomedical Engineering Sarver Heart Center, University of Arizona, Tucson, AZ 85721.
J Biomech Eng. 2022 Jun 1;144(6). doi: 10.1115/1.4054149.
Tissue-based transcatheter aortic valve (AV) replacement (TAVR) devices have been a breakthrough approach for treating aortic valve stenosis. However, with the expansion of TAVR to younger and lower risk patients, issues of long-term durability and thrombosis persist. Recent advances in polymeric valve technology facilitate designing more durable valves with minimal in vivo adverse reactions. We introduce our second-generation polymeric transcatheter aortic valve (TAV) device, designed and optimized to address these issues. We present the optimization process of the device, wherein each aspect of device deployment and functionality was optimized for performance, including unique considerations of polymeric technologies for reducing the volume of the polymer material for lower crimped delivery profiles. The stent frame was optimized to generate larger radial forces with lower material volumes, securing robust deployment and anchoring. The leaflet shape, combined with varying leaflets thickness, was optimized for reducing the flexural cyclic stresses and the valve's hydrodynamics. Our first-generation polymeric device already demonstrated that its hydrodynamic performance meets and exceeds tissue devices for both ISO standard and patient-specific in vitro scenarios. The valve already reached 900 × 106 cycles of accelerated durability testing, equivalent to over 20 years in a patient. The optimization framework and technology led to the second generation of polymeric TAV design- currently undergoing in vitro hydrodynamic testing and following in vivo animal trials. As TAVR use is rapidly expanding, our rigorous bio-engineering optimization methodology and advanced polymer technology serve to establish polymeric TAV technology as a viable alternative to the challenges facing existing tissue-based TAV technology.
基于组织的经导管主动脉瓣(AV)置换(TAVR)设备是治疗主动脉瓣狭窄的突破性方法。然而,随着 TAVR 向年轻和低风险患者的扩展,长期耐久性和血栓形成问题仍然存在。聚合物瓣膜技术的最新进展有助于设计更耐用的瓣膜,同时减少体内不良反应。我们介绍了我们的第二代聚合物经导管主动脉瓣(TAV)装置,该装置经过设计和优化,以解决这些问题。我们介绍了该装置的优化过程,其中装置部署和功能的各个方面都针对性能进行了优化,包括独特的聚合物技术考虑因素,以减少聚合物材料的体积,从而降低压缩输送轮廓。支架框架经过优化,可在较低的材料体积下产生更大的径向力,确保稳固的部署和锚固。瓣叶形状与不同的瓣叶厚度相结合,可优化减少弯曲循环应力和瓣膜的流体动力学。我们的第一代聚合物装置已经证明,其流体动力学性能在 ISO 标准和患者特定的体外场景中都满足并超过了组织装置。该瓣膜已经达到了 900×106 次加速耐久性测试,相当于患者体内超过 20 年的时间。优化框架和技术导致了第二代聚合物 TAV 设计的出现——目前正在进行体外流体动力学测试,并随后进行体内动物试验。随着 TAVR 的使用迅速扩大,我们严格的生物工程优化方法和先进的聚合物技术有助于将聚合物 TAV 技术确立为现有基于组织的 TAV 技术所面临挑战的可行替代方案。