模拟收缩左心室二尖瓣运动的流固耦合计算模型。

Fluid structure computational model of simulating mitral valve motion in a contracting left ventricle.

机构信息

College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia; Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.

Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia.

出版信息

Comput Biol Med. 2022 Sep;148:105834. doi: 10.1016/j.compbiomed.2022.105834. Epub 2022 Jul 5.

DOI:10.1016/j.compbiomed.2022.105834

PMID:35816854

Abstract

BACKGROUND

Fluid structure interaction simulations h hold promise in studying normal and abnormal cardiac function, including the effect of fluid dynamics on mitral valve (MV) leaflet motion. The goal of this study was to develop a 3D fluid structure interaction computational model to simulate bileaflet MV when interacting with blood motion in left ventricle (LV).

METHODS

The model consists of ideal geometric-shaped MV leaflets and the LV, with MV dimensions based on human anatomical measurements. An experimentally-based hyperelastic isotropic material was used to model the mechanical behaviour of the MV leaflets, with chordae tendineae and papillary muscle tips also incorporated. LV myocardial tissue was prescribed using a transverse isotropic hyperelastic formulation. Incompressible Navier-Stokes fluid formulations were used to govern the blood motion, and the Arbitrary Lagrangian Eulerian (ALE) method was employed to determine the mesh deformation of the fluid and solid domains due to trans-valvular pressure on MV boundaries and the resulting leaflet movement.

RESULTS

The LV-MV generic model was able to reproduce physiological MV leaflet opening and closing profiles resulting from the time-varying atrial and ventricular pressures, as well as simulating normal and prolapsed MV states. Additionally, the model was able to simulate blood flow patterns after insertion of a prosthetic MV with and without left ventricular outflow tract flow obstruction. In the MV-LV normal model, the regurgitant blood flow fraction was 10.1 %, with no abnormality in cardiac function according to the mitral regurgitation severity grades reported by the American Society of Echocardiography.

CONCLUSION

Our simulation approach provides insights into intraventricular fluid dynamics in a contracting LV with normal and prolapsed MV function, as well as aiding in the understanding of possible complications after transcatheter MV implantation prior to clinical trials.

摘要

背景

流固耦合模拟在研究正常和异常心脏功能方面具有广阔的前景，包括流体动力学对二尖瓣（MV）瓣叶运动的影响。本研究的目的是开发一种 3D 流固耦合计算模型，以模拟左心室（LV）中 MV 与血液运动相互作用时的双瓣叶 MV。

方法

该模型由理想几何形状的 MV 瓣叶和 LV 组成，MV 尺寸基于人体解剖测量值。采用基于实验的各向同性超弹性材料来模拟 MV 瓣叶的力学行为，并将腱索和乳头肌尖端也纳入其中。LV 心肌组织采用横观各向同性超弹性公式来规定。采用不可压缩纳维-斯托克斯流体公式来控制血液运动，并用任意拉格朗日欧拉（ALE）方法来确定由于 MV 边界上跨瓣压力和由此产生的瓣叶运动导致的流体和固体域的网格变形。

结果

LV-MV 通用模型能够再现由于心房和心室压力的时变而导致的 MV 瓣叶正常打开和关闭的生理轮廓，同时还能够模拟正常和脱垂的 MV 状态。此外，该模型还能够模拟在插入人工 MV 后有无左心室流出道阻塞的血流模式。在 MV-LV 正常模型中，反流血液流量分数为 10.1%，根据美国超声心动图学会报告的二尖瓣反流严重程度分级，心脏功能无异常。