Reza Symon, Kovarovic Brandon, Bluestein Danny
Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, USA.
medRxiv. 2025 May 6:2025.05.04.25326961. doi: 10.1101/2025.05.04.25326961.
Transcatheter aortic valve replacement (TAVR) is increasingly used to treat aortic stenosis, including in low-risk patients. However, post-procedural cardiac conduction abnormalities (CCA), often requiring permanent pacemaker implantation (PPI), remain a concern. This study investigates how the volume and distribution of aortic leaflet calcium deposits influence the risk of post-TAVR CCA.
An electromechanically coupled four-chamber beating heart model was used to simulate TAVR with a self-expandable Evolut 26 mm device. Five virtual patient scenarios were modeled with varying calcium volumes and distributions: no calcium, uniform distribution (3 Calc), and isolated calcification on the left coronary leaflet (LCL), right coronary leaflet (RCL), or non-coronary leaflet (NCL). Electrical conduction was simulated using a monodomain model and coupled with structural mechanics to evaluate tissue-device interactions. Metrics included principal stress, contact pressure, and contact pressure index (CPI) over three cardiac cycles.
Larger calcium volumes and specific leaflet distributions increased stress and contact pressure near the atrioventricular node. The LCL model exhibited the highest mechanical stress and peak contact pressure (13.1 kPa), while the NCL model showed the lowest (6.42 kPa). The RCL model had intermediate values. Elevated contact pressure and stress in the LCL case suggest an increased risk of conduction disruption and PPI.
Leaflet calcium deposit volume and distribution significantly influence mechanical stress and contact dynamics near the conduction system following TAVR. These insights support the integration of clinical data, such as leaflet calcium volume and distribution into pre-procedural planning to personalize risk assessment and improve patient outcomes.
经导管主动脉瓣置换术（TAVR）越来越多地用于治疗主动脉瓣狭窄，包括低风险患者。然而，术后心脏传导异常（CCA），通常需要植入永久起搏器（PPI），仍然是一个问题。本研究调查主动脉瓣叶钙沉积的体积和分布如何影响TAVR术后CCA的风险。
使用机电耦合的四腔跳动心脏模型，用可自膨胀的Evolut 26 mm装置模拟TAVR。模拟了五种虚拟患者情况，钙体积和分布各不相同：无钙、均匀分布（3 Calc），以及左冠状动脉瓣叶（LCL）、右冠状动脉瓣叶（RCL）或无冠状动脉瓣叶（NCL）的孤立钙化。使用单域模型模拟电传导，并与结构力学相结合，以评估组织与装置的相互作用。指标包括三个心动周期的主应力、接触压力和接触压力指数（CPI）。
更大的钙体积和特定的瓣叶分布增加了房室结附近的应力和接触压力。LCL模型表现出最高的机械应力和峰值接触压力（13.1 kPa），而NCL模型显示最低（6.42 kPa）。RCL模型的值居中。LCL情况下接触压力和应力的升高表明传导中断和PPI的风险增加。
瓣叶钙沉积的体积和分布显著影响TAVR术后传导系统附近的机械应力和接触动态。这些见解支持将临床数据，如瓣叶钙体积和分布纳入术前规划，以个性化风险评估并改善患者预后。
