Ventricular flow dynamics with varying LVAD inflow cannula lengths: In-silico evaluation in a multiscale model
Ventricular flow dynamics with varying LVAD inflow cannula lengths: In-silico evaluation in a multiscale model
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DOI：
10.1016/j.jbiomech.2018.02.038
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发表时间：
2018-04-27
影响因子：
2.4
通讯作者：
Gregory, Shaun D.
中科院分区：
文献类型：
--
作者：
Liao, Sam;Neidlin, Michael;Gregory, Shaun D.
左心室辅助装置与血栓栓塞症有关，血栓栓塞症可能是由室内血流改变引起的。由于患者的可变性，心尖壁厚度的差异会影响插管的长度，潜在地促进不利的脑室内血流模式，这被认为与血栓形成的风险有关。本研究旨在利用商业软件Ansys建立左心室(LV)的三维多尺度计算流体动力学模型，并评估在严重扩张的LV中不同流入管插入长度时血栓形成的风险。根据HeartWare HVAD流入导管，5、19、24和50 mm的插入长度分别代表心尖肥厚的情况、典型的心尖厚度范围和实验长度。根据血液冲刷、停留时间、瞬时血液停滞和搏动指数来评估血栓形成的风险。通过引入新鲜血液置换LV内原有血液，在5个心动周期后，插入长度分别为5、19、24和50 mm的原有血液的存留率分别为46.7%、45.7%、45.1%和41.8%。与50 mm插入相比，5 mm、19 mm和24 mm插入长度的血液滞留时间分别高出9%、7%和6%。E波后未观察到心尖部的瞬时停滞。插管长度越短，插管附近的搏动指数越大。对于所研究的特定场景，相对于左心室大小较长的插入长度可能有利于通过增加左心室冲洗和减少血液停留时间来最大限度地减少血栓形成。(C)2018爱思唯尔有限公司。保留所有权利。
Left ventricular assist devices are associated with thromboembolic events, which are potentially caused by altered intraventricular flow. Due to patient variability, differences in apical wall thickness affects cannula insertion lengths, potentially promoting unfavourable intraventricular flow patterns which are thought to be correlated to the risk of thrombosis. This study aimed to present a 3D multiscale computational fluid dynamic model of the left ventricle (LV) developed using a commercial software, Ansys, and evaluate the risk of thrombosis with varying inflow cannula insertion lengths in a severely dilated LV. Based on a HeartWare HVAD inflow cannula, insertion lengths of 5, 19, 24 and 50 mm represented cases of apical hypertrophy, typical ranges of apical thicknesses and an experimental length, respectively. The risk of thrombosis was evaluated based on blood washout, residence time, instantaneous blood stagnation and a pulsatility index. By introducing fresh blood to displace pre-existing blood in the LV, after 5 cardiac cycles, 46.7%, 45.7%, 45.1% and 41.8% of pre-existing blood remained for insertion lengths of 5, 19, 24 and 50 mm, respectively. Compared to the 50 mm insertion, blood residence time was at least 9%, 7% and 6% higher with the 5, 19 and 24 mm insertion lengths, respectively. No instantaneous stagnation at the apex was observed directly after the E-wave. Pulsatility indices adjacent to the cannula increased with shorter insertion lengths. For the specific scenario studied, a longer insertion length, relative to LV size, may be advantageous to minimise thrombosis by increasing LV washout and reducing blood residence time. (C) 2018 Elsevier Ltd. All rights reserved.