Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA; Sutra Medical Inc, Lake Forest, CA, USA.
Mechanical Engineering, University of South Florida, FL, USA.
Comput Biol Med. 2024 Apr;172:108191. doi: 10.1016/j.compbiomed.2024.108191. Epub 2024 Feb 19.
Bicuspid aortic valve (BAV), the most common congenital heart disease, is prone to develop significant valvular dysfunction and aortic wall abnormalities such as ascending aortic aneurysm. Growing evidence has suggested that abnormal BAV hemodynamics could contribute to disease progression. In order to investigate BAV hemodynamics, we performed 3D patient-specific fluid-structure interaction (FSI) simulations with fully coupled blood flow dynamics and valve motion throughout the cardiac cycle. Results showed that the hemodynamics during systole can be characterized by a systolic jet and two counter-rotating recirculation vortices. At peak systole, the jet was usually eccentric, with asymmetric recirculation vortices and helical flow motion in the ascending aorta. The flow structure at peak systole was quantified using the vorticity, flow rate reversal ratio and local normalized helicity (LNH) at four locations from the aortic root to the ascending aorta. The systolic jet was evaluated with the peak velocity, normalized flow displacement, and jet angle. It was found that peak velocity and normalized flow displacement (rather than jet angle) gave a strong correlation with the vorticity and LNH in the ascending aorta, which suggests that these two metrics could be used for clinical noninvasive evaluation of abnormal blood flow patterns in BAV patients.
二叶式主动脉瓣（BAV）是最常见的先天性心脏病，易发生严重的瓣膜功能障碍和主动脉壁异常，如升主动脉瘤。越来越多的证据表明，异常的 BAV 血流动力学可能导致疾病进展。为了研究 BAV 的血流动力学，我们对整个心动周期中完全耦合血流动力学和瓣膜运动的 3D 患者特定流固耦合（FSI）模拟进行了研究。结果表明，收缩期的血流动力学可以用收缩射流和两个反向旋转的再循环涡流来描述。在收缩期峰值时，射流通常是偏心的，伴有不对称的再循环涡流和升主动脉中的螺旋流运动。在主动脉根部到升主动脉的四个位置，使用涡度、流量反转比和局部归一化螺旋度（LNH）来量化收缩期峰值的流场结构。用峰值速度、归一化流量位移和射流角度来评估收缩射流。结果发现，峰值速度和归一化流量位移（而不是射流角度）与升主动脉中的涡度和 LNH 具有很强的相关性，这表明这两个指标可用于临床无创评估 BAV 患者异常血流模式。
