Mosbahi Selim, Mickaily-Huber Elizabeth, Charbonnier Dominique, Hullin Roger, Burki Marco, Ferrari Enrico, von Segesser Ludwig K, Berdajs Denis A
Department of Cardiovascular Surgery, University Hospital Lausanne, Lausanne, Switzerland.
CFS Engineering, Lausanne, Switzerland.
Interact Cardiovasc Thorac Surg. 2014 Oct;19(4):611-6. doi: 10.1093/icvts/ivu202. Epub 2014 Jun 19.
The reconstruction of the right ventricular outflow tract (RVOT) with valved conduits remains a challenge. The reoperation rate at 5 years can be as high as 25% and depends on age, type of conduit, conduit diameter and principal heart malformation. The aim of this study is to provide a bench model with computer fluid dynamics to analyse the haemodynamics of the RVOT, pulmonary artery, its bifurcation, and left and right pulmonary arteries that in the future may serve as a tool for analysis and prediction of outcome following RVOT reconstruction.
Pressure, flow and diameter at the RVOT, pulmonary artery, bifurcation of the pulmonary artery, and left and right pulmonary arteries were measured in five normal pigs with a mean weight of 24.6 ± 0.89 kg. Data obtained were used for a 3D computer fluid-dynamics simulation of flow conditions, focusing on the pressure, flow and shear stress profile of the pulmonary trunk to the level of the left and right pulmonary arteries.
Three inlet steady flow profiles were obtained at 0.2, 0.29 and 0.36 m/s that correspond to the flow rates of 1.5, 2.0 and 2.5 l/min flow at the RVOT. The flow velocity profile was constant at the RVOT down to the bifurcation and decreased at the left and right pulmonary arteries. In all three inlet velocity profiles, low sheer stress and low-velocity areas were detected along the left wall of the pulmonary artery, at the pulmonary artery bifurcation and at the ostia of both pulmonary arteries.
This computed fluid real-time model provides us with a realistic picture of fluid dynamics in the pulmonary tract area. Deep shear stress areas correspond to a turbulent flow profile that is a predictive factor for the development of vessel wall arteriosclerosis. We believe that this bench model may be a useful tool for further evaluation of RVOT pathology following surgical reconstructions.
使用带瓣管道重建右心室流出道（RVOT）仍然是一项挑战。5年再次手术率可高达25%，且取决于年龄、管道类型、管道直径和主要心脏畸形。本研究的目的是提供一个计算机流体动力学实验台模型，以分析RVOT、肺动脉、其分叉以及左右肺动脉的血流动力学，未来这可能作为分析和预测RVOT重建术后结果的工具。
对5只平均体重为24.6±0.89kg的正常猪测量RVOT、肺动脉、肺动脉分叉以及左右肺动脉处的压力、流量和直径。所获数据用于对血流状况进行三维计算机流体动力学模拟，重点关注从肺动脉干到左右肺动脉水平的压力、流量和剪切应力分布。
在0.2、0.29和0.36m/s处获得了三种入口稳定血流分布，分别对应RVOT处1.5、2.0和2.5l/min的流速。RVOT至分叉处的流速分布恒定，在左右肺动脉处降低。在所有三种入口流速分布中，在肺动脉左壁、肺动脉分叉处以及两根肺动脉开口处均检测到低剪切应力和低速区域。
这个计算流体实时模型为我们提供了肺道区域流体动力学的真实图像。深部剪切应力区域对应于湍流分布，这是血管壁动脉硬化发展的一个预测因素。我们认为这个实验台模型可能是进一步评估手术重建后RVOT病理状况的有用工具。
