Chair of Medical Materials and Implants, TUM School of Engineering and Design and Munich Institute of Biomedical Engineering, Technical University of Munich, Garching, Germany.
Department of Cardiology, University Hospital Bonn, Bonn, Germany.
Clin Res Cardiol. 2024 Oct;113(10):1405-1418. doi: 10.1007/s00392-023-02228-x. Epub 2023 Jun 9.
Device-related thrombus (DRT) after left atrial appendage occlusion (LAAO) is potentially linked to adverse events. Although clinical reports suggest an effect of the device type and position on the DRT risk, in-depth studies of its mechanistic basis are needed. This in silico study aimed to assess the impact of the position of non-pacifier (Watchman) and pacifier (Amulet) LAAO devices on surrogate markers of DRT risk.
The LAAO devices were modeled with precise geometry and virtually implanted in different positions into a patient-specific left atrium. Using computational fluid dynamics, the following values were quantified: residual blood, wall shear stress (WSS) and endothelial cell activation potential (ECAP).
In comparison to an ostium-fitted device position, deep implantation led to more residual blood, lower average WSS and higher ECAP surrounding the device, especially on the device's atrial surface and the surrounding tissue, suggesting increased risk for potential thrombus. For the non-pacifier device, an off-axis device orientation resulted in even more residual blood, higher ECAP and similar average WSS as compared to an ostium-fitted device position. Overall, the pacifier device showed less residual blood, higher average WSS and lower ECAP, compared to the non-pacifier device.
In this in silico study, both LAAO device type and implant position showed an impact on potential markers of DRT in terms of blood stasis, platelet adhesion and endothelial dysfunction. Our results present a mechanistic basis for clinically observed risk factors of DRT and the proposed in silico model may aid in the optimization of device development and procedural aspects.
左心耳封堵（LAAO）术后与器械相关的血栓（DRT）可能与不良事件有关。尽管临床报告提示器械类型和位置对 DRT 风险有影响，但需要深入研究其机制基础。本计算机模拟研究旨在评估非填塞式（Watchman）和填塞式（Amulet）LAAO 器械位置对 DRT 风险替代标志物的影响。
用精确的几何形状对 LAAO 器械进行建模，并将其虚拟植入到特定患者的左心房的不同位置。通过计算流体动力学，量化了以下值：残余血液、壁面剪切应力（WSS）和内皮细胞激活潜能（ECAP）。
与吻合口植入的器械位置相比，深部植入导致器械周围残余血液更多、平均 WSS 更低、ECAP 更高，尤其是在器械的心房表面和周围组织上，提示潜在血栓形成风险增加。对于非填塞式器械，器械的偏心位置导致残余血液更多、ECAP 更高，与吻合口植入的器械位置相比平均 WSS 相似。总体而言，与非填塞式器械相比，填塞式器械的残余血液更少、平均 WSS 更高、ECAP 更低。
在本计算机模拟研究中，LAAO 器械类型和植入位置均对血液淤滞、血小板黏附和内皮功能障碍等 DRT 潜在标志物产生影响。我们的结果为临床上观察到的 DRT 风险因素提供了机制基础，提出的计算机模拟模型可能有助于器械开发和手术方面的优化。
