Effect of cannula position in the thoracic aorta with continuous left ventricular support: four-dimensional flow-sensitive magnetic resonance imaging in an in vitro model
Effect of cannula position in the thoracic aorta with continuous left ventricular support: four-dimensional flow-sensitive magnetic resonance imaging in an in vitro model
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DOI：
10.1093/ejcts/ezt095
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发表时间：
2013-09-01
影响因子：
3.4
通讯作者：
Jung, Bernd
中科院分区：
文献类型：
--
作者：
Benk, Christoph;Mauch, Alexander;Jung, Bernd
左心室辅助装置（LVAD）已成为心力衰竭患者的重要治疗选择。然而，改变的血流模式被怀疑会影响主动脉中的灌注或引起主动脉根部的结构变化，导致反流和瓣膜功能障碍或血栓形成。为了利用四维流敏磁共振成像技术评价离体心脏模型系统中的血流模式，建立了一个与磁共振兼容的模型系统，该模型系统由主动脉和模拟心脏脉动流的VAD组成。LVAD通过三个不同的插管位置连接到主动脉模型。评估了整个系统的血流模式以及预定义位置的流速，以降低和零心输出量。插管位置影响整个胸主动脉的血流模式和流速。对于残余心输出量，与降主动脉中的较小吻合或插管位置相比，较大吻合和LAVD流速降低导致升主动脉中的流速较高和逆行血流较小。在降主动脉插管位置观察到显著的主动脉血流动力学，在心输出量减少的情况下，如LVAD治疗患者中常见的那样，流出插管与升主动脉的大吻合在主动脉根部诱导了最小的不利血流模式。我们的方法可能有助于更好地理解LVAD引起的血流模式变化。插管位置和吻合口的优化可能有助于防止主动脉瓣反流和血栓形成的进展。
Left ventricular assist devices (LVADs) have become an important treatment option for heart failure patients. However, altered blood flow patterns are suspected to affect perfusion in the aorta or cause structural changes to the aortic root, leading to regurgitation and valve dysfunction or thrombus formation. The purpose of this study was to evaluate flow patterns in a realistic in vitro model system using four-dimensional flow-sensitive magnetic resonance imaging.A magnetic resonance compatible model system was developed consisting of an aorta connected to a VAD simulating the pulsatile flow of the native heart. An LVAD was connected to the aorta model via three different cannula positions. Flow patterns in the entire system as well as flow rates in predefined positions for reduced and zero cardiac output were evaluated.Cannula position influences flow patterns and flow rates in the entire thoracic aorta. For a residual cardiac output, a larger anastomosis and a decreased flow rate of the LAVD result in a higher flow rate and smaller retrograde flow in the ascending aorta when compared with a smaller anastomosis or a cannula position in the descending aorta. Pronounced flow turbulences in the aorta were observed for the cannula position in the descending aorta.In the setting of reduced cardiac output, as commonly observed in patients on LVAD therapy, a large anastomosis to the ascending aorta for the outflow cannula induces the least-adverse flow patterns in the aortic root. Our approach may aid in a better understanding of LVAD-induced flow-pattern changes. Optimization of the cannula position and anastomosis may help to prevent the progression of aortic valve-regurgitation and thrombus formation.