Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 387 Technology Circle NW, Suite 200, Atlanta, GA, 30313, USA.
Ann Biomed Eng. 2019 Feb;47(2):381-391. doi: 10.1007/s10439-018-02154-4. Epub 2018 Oct 17.
While transcatheter mitral valve (TMV) replacement technology has great clinical potential for surgically inoperable patients suffering from mitral regurgitation, no TMV has yet achieved regulatory approval. The diversity of devices currently under development reflects a lack of consensus regarding optimal design approaches. In Part I of this two-part study, a test system was developed for the quantification of paravalvular leakage (PVL) following deployment of a TMV or TMV-like device in pressurized, explanted porcine hearts (N = 7). Using this system, PVL rate was investigated as a function of steady trans-mitral pressure (ΔP), TMV shape, and TMV-annular oversizing, using a series of "mock TMV plug" devices. Across all devices, PVL was found to approximately trend with the square of ΔP. PVL rates were approximately 0-15 mL/s under hypotensive pressure, 10-40 mL/s under normotension, and 30-85 mL/s under severe hypertension. D-shaped devices significantly reduced PVL vs. circular devices; however, this effect was diminished upon oversizing to the annulus by 6 mm inter-trigonal distance. In conclusion, this steady pressure, in vitro test system was effective to compare PVL performance across TMV-like designs. PVL exhibited complex dynamics in terms of its response to transvalvular pressure and TMV profile.
尽管经导管二尖瓣置换术（TMV）技术在二尖瓣反流且无法进行手术的患者中具有巨大的临床潜力，但尚无 TMV 获得监管批准。目前正在开发的各种设备反映出对于最佳设计方法缺乏共识。在这项两部分研究的第一部分中，开发了一种测试系统，用于在加压的、已取出的猪心脏中部署 TMV 或 TMV 样装置后定量测量瓣周漏（PVL）（N=7）。使用该系统，使用一系列“模拟 TMV 塞”装置，研究了 PVL 率与稳定的经二尖瓣压力（ΔP）、TMV 形状和 TMV-瓣环过大之间的关系。在所有装置中，PVL 大约与ΔP 的平方趋势一致。在低血压下，PVL 率约为 0-15 mL/s；在正常血压下，约为 10-40 mL/s；在严重高血压下，约为 30-85 mL/s。D 形装置与圆形装置相比显著降低了 PVL；然而，当瓣环过大 6mm 时，这种效果会减弱。总之，这种稳定压力的体外测试系统可有效地比较 TMV 样设计之间的 PVL 性能。PVL 表现出对跨瓣压力和 TMV 轮廓的复杂反应。
