Department of Engineering, University of Palermo, viale delle Scienze, Ed.8, 90128, Palermo, Italy.
Department for the Treatment and Study of Cardiothoracic Diseases and Cardiothoracic Transplantation, IRCCS-ISMETT, via Tricomi n.5, 90127, Palermo, Italy.
Med Eng Phys. 2020 Aug;82:40-48. doi: 10.1016/j.medengphy.2020.05.018. Epub 2020 Jul 9.
Left ventricular outflow tract (LVOT) obstruction is a feared complication of transcatheter mitral valve replacement (TMVR). This procedure leads to an elongation of LVOT in the left ventricle (namely, the neoLVOT), ultimately portending hemodynamic impairment and death. This study sought to understand the biomechanical implications of LVOT obstruction in two patients who underwent TMVR as an "off-label" application of the Edwards SAPIEN 3 (S3) Ultra transcatheter heart valve (THV). A computational framework of TMVR was developed to assess the neoLVOT area and quantify the sub-aortic flow structure. We observed that the annuloplasty ring serves as the key anchor zone of S3 Ultra THV. A good agreement was found between the numerically-predicted and CT-imaging measurements of neoLVOT area, with differences less than 10% in both patients. The pressure drop across the neoLVOT did not determine hemodynamic impairment in both patients. Quantification of structural and hemodynamic variables by computational modeling may facilitate more accurate predictions of the LVOT obstruction in TMVR, particularly for patients which are considered to have a borderline risk of obstruction.
左心室流出道（LVOT）阻塞是经导管二尖瓣置换术（TMVR）的一种可怕并发症。该手术会导致左心室 LVOT 延长（即新 LVOT），最终导致血流动力学受损和死亡。本研究旨在通过两名接受经导管心尖二尖瓣置换术（TMVR）的患者的生物力学意义，了解经导管二尖瓣置换术的生物力学意义。TMVR 的计算框架用于评估新 LVOT 区域并量化主动脉下流动结构。我们观察到，瓣环成形环是 S3 Ultra 经导管心脏瓣膜（THV）的关键锚固区。在两名患者中，新 LVOT 区域的数值预测和 CT 成像测量之间均发现了很好的一致性，差异均小于 10%。新 LVOT 跨壁压降并未导致两名患者血流动力学受损。通过计算模型对结构和血流动力学变量进行定量分析，可以更准确地预测 TMVR 中的 LVOT 阻塞，特别是对于被认为存在阻塞风险的患者。
