Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL (R.M., A.J.B., SS., P.E., J. Collins, J. Carr, M.M.); Division of Cardiology, Northwestern University, Chicago, IL (P.K.); Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, University of Calgary, Canada (P.W.M.F.); Division of Cardiothoracic Surgery, Northwestern University, Chicago, IL (P.W.M.F., S.C.M., P.M.)); and Department Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL (M.M.).
Circulation. 2014 Feb 11;129(6):673-82. doi: 10.1161/CIRCULATIONAHA.113.003026. Epub 2013 Dec 17.
Aortic 3-dimensional blood flow was analyzed to investigate altered ascending aorta (AAo) hemodynamics in bicuspid aortic valve (BAV) patients and its association with differences in cusp fusion patterns (right-left, RL versus right-noncoronary, RN) and expression of aortopathy.
Four-dimensional flow MRI measured in vivo 3-dimensional blood flow in the aorta of 75 subjects: BAV patients with aortic dilatation stratified by leaflet fusion pattern (n=15 RL-BAV, mid AAo diameter=39.9±4.4 mm; n=15 RN-BAV, 39.6±7.2 mm); aorta size controls with tricuspid aortic valves (n=30, 41.0±4.4 mm); healthy volunteers (n=15, 24.9±3.0 mm). Aortopathy type (0-3), systolic flow angle, flow displacement, and regional wall shear stress were determined for all subjects. Eccentric outflow jet patterns in BAV patients resulted in elevated regional wall shear stress (P<0.0125) at the right-anterior walls for RL-BAV and right-posterior walls for RN-BAV in comparison with aorta size controls. Dilatation of the aortic root only (type 1) or involving the entire AAo and arch (type 3) was found in the majority of RN-BAV patients (87%) but was mostly absent for RL-BAV patients (87% type 2). Differences in aortopathy type between RL-BAV and RN-BAV patients were associated with altered flow displacement in the proximal and mid AAo for type 1 (42%-81% decrease versus type 2) and distal AAo for type 3 (33%-39% increase versus type 2).
The presence and type of BAV fusion was associated with changes in regional wall shear stress distribution, systolic flow eccentricity, and expression of BAV aortopathy. Hemodynamic markers suggest a physiological mechanism by which the valve morphology phenotype can influence phenotypes of BAV aortopathy.
通过分析主动脉 3 维血流来研究二叶式主动脉瓣（BAV）患者升主动脉（AAo）血流动力学的变化及其与瓣叶融合模式（右-左，RL 与右-非冠状动脉，RN）的差异和主动脉病变的表达的关系。
使用 4 维血流 MRI 对 75 例受试者的主动脉进行了活体 3 维血流测量：根据瓣叶融合模式分层的主动脉扩张 BAV 患者（n=15 RL-BAV，中 AAo 直径=39.9±4.4mm；n=15 RN-BAV，39.6±7.2mm）；三叶式主动脉瓣的主动脉大小对照者（n=30，41.0±4.4mm）；健康志愿者（n=15，24.9±3.0mm）。确定了所有受试者的主动脉病变类型（0-3）、收缩期血流角度、血流位移和局部壁面剪切应力。与主动脉大小对照者相比，BAV 患者偏心流出射流模式导致 RL-BAV 的右前壁和 RN-BAV 的右后壁局部壁面剪切应力升高（P<0.0125）。在大多数 RN-BAV 患者（87%）中发现仅主动脉根部扩张（1 型）或整个 AAo 和弓部扩张（3 型），而在 RL-BAV 患者中，这种情况大多不存在（87%为 2 型）。RL-BAV 和 RN-BAV 患者之间主动脉病变类型的差异与近端和中 AAo 的血流位移变化有关，1 型（42%-81%减少与 2 型）和远 AAo 的 3 型（33%-39%增加与 2 型）。
BAV 融合的存在和类型与局部壁面剪切应力分布、收缩期血流偏心性和 BAV 主动脉病变的表达变化有关。血流动力学标志物表明，瓣膜形态表型可以通过生理机制影响 BAV 主动脉病变的表型。
