Reza Symon, Kovarovic Brandon, Bluestein Danny
Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794-8084, USA.
Biomech Model Mechanobiol. 2025 Feb;24(1):29-45. doi: 10.1007/s10237-024-01893-9. Epub 2024 Oct 3.
Transcatheter aortic valve replacement (TAVR) has rapidly displaced surgical aortic valve replacement (SAVR). However, certain post-TAVR complications persist, with cardiac conduction abnormalities (CCA) being one of the major ones. The elevated pressure exerted by the TAVR stent onto the conduction fibers situated between the aortic annulus and the His bundle, in proximity to the atrioventricular (AV) node, may disrupt the cardiac conduction leading to the emergence of CCA. In this study, an in silico framework was developed to assess the CCA risk, incorporating the effect of a dynamic beating heart and preprocedural parameters such as implantation depth and preexisting cardiac asynchrony in the new onset of post-TAVR CCA. A self-expandable TAVR device deployment was simulated inside an electromechanically coupled beating heart model in five patient scenarios, including three implantation depths and two preexisting cardiac asynchronies: (i) a right bundle branch block (RBBB) and (ii) a left bundle branch block (LBBB). Subsequently, several biomechanical parameters were analyzed to assess the post-TAVR CCA risk. The results manifested a lower cumulative contact pressure on the conduction fibers following TAVR for aortic deployment (0.018 MPa) compared to nominal condition (0.29 MPa) and ventricular deployment (0.52 MPa). Notably, the preexisting RBBB demonstrated a higher cumulative contact pressure (0.34 MPa) compared to the nominal condition and preexisting LBBB (0.25 MPa). Deeper implantation and preexisting RBBB cause higher stresses and contact pressure on the conduction fibers leading to an increased risk of post-TAVR CCA. Conversely, implantation above the MS landmark and preexisting LBBB reduces the risk.
经导管主动脉瓣置换术（TAVR）已迅速取代了外科主动脉瓣置换术（SAVR）。然而，某些TAVR术后并发症仍然存在，心脏传导异常（CCA）是主要并发症之一。TAVR支架对位于主动脉瓣环和希氏束之间、靠近房室（AV）结的传导纤维施加的压力升高，可能会扰乱心脏传导，导致CCA的出现。在本研究中，开发了一个计算机模拟框架来评估CCA风险，该框架纳入了动态跳动心脏的影响以及术前参数，如植入深度和TAVR术后新出现的CCA中的既往心脏不同步情况。在五个患者场景中，在一个机电耦合的跳动心脏模型内模拟了自膨胀TAVR装置的部署，包括三个植入深度和两种既往心脏不同步情况：（i）右束支传导阻滞（RBBB）和（ii）左束支传导阻滞（LBBB）。随后，分析了几个生物力学参数以评估TAVR术后的CCA风险。结果表明，与标称情况（0.29MPa）和心室部署（0.52MPa）相比，主动脉部署的TAVR术后传导纤维上的累积接触压力较低（0.018MPa）。值得注意的是，与标称情况和既往LBBB（0.25MPa）相比，既往RBBB表现出更高的累积接触压力（0.34MPa）。更深的植入和既往RBBB会导致传导纤维上更高的应力和接触压力，从而增加TAVR术后CCA的风险。相反，在MS标志上方植入和既往LBBB会降低风险。
