Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy; Department of Bioengineering Research, IRCCS-ISMETT, Palermo, Italy.
Department of Engineering, Viale delle Scienze, Università degli Studi di Palermo, Palermo, Italy.
J Biomech. 2022 Nov;144:111337. doi: 10.1016/j.jbiomech.2022.111337. Epub 2022 Oct 4.
Transcatheter mitral valve replacement (TMVR) has been used for "off-label" treatment when annuloplasty band ring for mitral repair fails. However, the complex anatomy and function of the mitral valve may lead to fatal complications as a result of the left ventricular outflow tract (LVOT) obstruction in TMVR. We report the structural and hemodynamic response of LVOT obstruction resulting from TMVR with the Edwards SAPIEN 3 Ultra (S3) device. We modified the original Living Heart Human Model (LHHM) to account for a failed mitral valve with an annuloplasty band ring and simulated the cardiac beating condition in the setting of S3 device implantation. Findings demonstrated a high dynamic behavior of the newly formed LVOT (neoLVOT) as confined by the displaced mitral valve and the interventricular septum. During the cardiac beat, the neoLVOT area oscillated from a maximum of 472.1 mm at early systole to the minimum of 183 mm at end-systole. The profile of both anchoring force and contact pressure revealed that the band ring serves as the anchoring zone while mitral valve is primally displaced by the deployed device. At early systole, computational flow dynamics highlighted hemodynamic disturbances associated with the LVOT obstruction, with a skewed flow towards the septum and a pressured drop of 4.5 mmHg between the left ventricular apex and the neoLVOT region. This study can lead to a more accurate assessment of the risk induced by the LVOT obstruction when stratifying patient anatomic suitability for TMVR.
经导管二尖瓣置换术（TMVR）已被用于二尖瓣修复的成形环环失败时的“超适应证”治疗。然而，二尖瓣的复杂解剖结构和功能可能导致左心室流出道（LVOT）阻塞的致命并发症。我们报告了经 TMVR 应用爱德华兹 SAPIEN 3 Ultra（S3）装置导致的 LVOT 阻塞的结构和血流动力学反应。我们对原始的活体心脏人体模型（LHHM）进行了修改，以模拟二尖瓣成形环环失败的二尖瓣，并在 S3 装置植入的情况下模拟心脏跳动条件。研究结果表明，新形成的 LVOT（neoLVOT）受到移位的二尖瓣和室间隔的限制，具有很高的动态行为。在心脏跳动过程中，neoLVOT 区域的面积从收缩早期的最大值 472.1mm 振荡到收缩末期的最小值 183mm。锚固力和接触压力的分布表明，成形环作为锚固区，而二尖瓣最初被展开的装置所移位。在收缩早期，计算血流动力学突出了与 LVOT 阻塞相关的血流动力学紊乱，血流向室间隔偏斜，左心室心尖和 neoLVOT 区域之间的压力下降 4.5mmHg。这项研究可以更准确地评估 TMVR 患者解剖学适宜性分层时 LVOT 阻塞引起的风险。
