Computational Fluid Dynamic Analysis of the Left Atrial Appendage to Predict Thrombosis Risk.
Computational Fluid Dynamic Analysis of the Left Atrial Appendage to Predict Thrombosis Risk.
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DOI：
10.3389/fcvm.2018.00034
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发表时间：
2018
影响因子：
3.6
通讯作者：
Burriesci G Burriesci
中科院分区：
文献类型：
--
作者：
Bosi GM;Cook A;Rai R;Menezes LJ;Schievano S;Torii R;Burriesci G Burriesci
在房颤（AF）期间，超过90%的导致血栓栓塞事件的左心房血栓起源于左心耳（LAA），LAA是从左心房（LA）突出的复杂小囊。目前可用于预防血栓栓塞事件的治疗方法有口服抗凝剂、手术LAA隔绝术或经皮LAA闭塞术。然而，左心耳血栓形成的机制尚不清楚。这项工作的目的是分析四种典型LAA形态-“鸡翅”，“仙人掌”，“风向袋”和“花椰菜”-的血流动力学行为，以确定不同形状和血栓事件风险之间的潜在关系。对4例无左心房病变的患者的计算机断层扫描（CT）图像进行分割，以得出左心耳和左心房的3D解剖形状。根据患者特定解剖结构进行计算流体动力学（CFD）分析，同时施加健康和AF流动条件。速度和剪切应变率（SSR）进行了分析。不同LAA区域的停留时间通过虚拟造影剂洗脱来估计。计算流体动力学结果表明，在心动周期的每个瞬间，速度和SSR均沿左心耳沿着减小，从左心耳口到头端，从而使左心耳头端更容易发生液体停滞，从而形成血栓。速度和SSR也从正常到AF条件降低。四个心动周期后，花椰菜形态的造影剂洗脱率最低（AF中残留造影剂的3.27%），Windsock形态的最高（AF中残留造影剂的0.56%）。这表明，与文献中的临床报告一致，预计前者与血栓形成的风险较高相关。所提出的计算模型突出了左心耳形态在正常和房颤条件下对血流动力学的主要作用，揭示了数值分析可以在血栓形成风险患者分层中提供的潜在支持，以实现个性化的患者护理。
During Atrial Fibrillation (AF) more than 90% of the left atrial thrombi responsible for thromboembolic events originate in the left atrial appendage (LAA), a complex small sac protruding from the left atrium (LA). Current available treatments to prevent thromboembolic events are oral anticoagulation, surgical LAA exclusion, or percutaneous LAA occlusion. However, the mechanism behind thrombus formation in the LAA is poorly understood. The aim of this work is to analyse the hemodynamic behaviour in four typical LAA morphologies - “Chicken wing”, “Cactus”, “Windsock” and “Cauliflower” - to identify potential relationships between the different shapes and the risk of thrombotic events. Computerised tomography (CT) images from four patients with no LA pathology were segmented to derive the 3D anatomical shape of LAA and LA. Computational Fluid Dynamic (CFD) analyses based on the patient-specific anatomies were carried out imposing both healthy and AF flow conditions. Velocity and shear strain rate (SSR) were analysed for all cases. Residence time in the different LAA regions was estimated with a virtual contrast agent washing out. CFD results indicate that both velocity and SSR decrease along the LAA, from the ostium to the tip, at each instant in the cardiac cycle, thus making the LAA tip more prone to fluid stagnation, and therefore to thrombus formation. Velocity and SSR also decrease from normal to AF conditions. After four cardiac cycles, the lowest washout of contrast agent was observed for the Cauliflower morphology (3.27% of residual contrast in AF), and the highest for the Windsock (0.56% of residual contrast in AF). This suggests that the former is expected to be associated with a higher risk of thrombosis, in agreement with clinical reports in the literature. The presented computational models highlight the major role played by the LAA morphology on the hemodynamics, both in normal and AF conditions, revealing the potential support that numerical analyses can provide in the stratification of patients under risk of thrombus formation, towards personalised patient care.
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影响因子：
2.1
作者：
Dentamaro, Ilaria;Vestito, Domenico;Colonna, Paolo
通讯作者：
Colonna, Paolo
DOI：
10.1161/circoutcomes.110.958165
发表时间：
2011-05-01
影响因子：
6.9
作者：
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通讯作者：
Schulman, Kathy L.
DOI：
10.1016/j.jtcvs.2011.07.052
发表时间：
2011-11-01
影响因子：
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作者：
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