Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 N Michigan Avenue, Suite 1600, Chicago, IL, 60611, USA.
Department of Cardiology, Northwestern Memorial Hospital, Chicago, IL, 60611, USA.
Int J Cardiovasc Imaging. 2022 Sep;38(9):2047-2056. doi: 10.1007/s10554-022-02593-0. Epub 2022 Mar 16.
This study investigated the impact of bicuspid aortic valve (BAV) on valve morphology and motion as well as proximal and aortic hemodynamics using a same-day echocardiography and cardiac MRI. Transthoracic echocardiography, two-dimensional cine MRI of the aortic valve, and aortic 4D flow MRI were performed on the same day in 9 normofunctional BAV patients (age = 41 ± 12, 3 female), 4 BAV with moderate to severe aortic stenosis (AS) (age = 63 ± 5, 1 female), and 36 healthy tricuspid aortic valve controls (age = 52 ± 10, 21 female). Valve opening and closing timings and transvalvular peak velocity were measured using B-mode and Doppler echocardiogram, respectively. Valve orifice morphology at a fully-opened state was characterized using cine MRI. Ascending aortic (AAo) wall shear stress (WSS) was measured using 4D flow MRI data. Valve motion timings were similar between BAV and controls. BAV was associated with an increased orifice aspect ratio (1.44 ± 0.11 vs. 1.10 ± 0.13, P < 0.001), transvalvular peak velocity (1.5 ± 0.3 vs. 1.2 ± 0.2 m/s, P < 0.001) and maximum AAo WSS (1.62 ± 0.31 vs. 0.91 ± 0.24 Pa, P < 0.001). The increased orifice aspect ratio was associated with the increase in transvalvular peak velocity (r = 0.80, P < 0.0001) and maximum AAo WSS (r = 0.83, P < 0.0001). Transvalvular peak velocity was also positively correlated with maximum AAo WSS (r = 0.83, P < 0.0001). A same-day echo and MRI imaging allows for a comprehensive assessment of the impact of aortic valve disease on valve function and hemodynamics. In this pilot application to BAV, we found increased orifice aspect ratio may be responsible for increased transvalvular peak velocity and maximum AAo WSS.
本研究通过同日进行的超声心动图和心脏 MRI，探讨了二叶式主动脉瓣（BAV）对瓣膜形态和运动以及近端和主动脉血流动力学的影响。在 9 例功能正常的 BAV 患者（年龄=41±12 岁，3 例女性）、4 例中重度主动脉瓣狭窄（AS）的 BAV 患者（年龄=63±5 岁，1 例女性）和 36 例健康三尖瓣主动脉瓣对照者（年龄=52±10 岁，21 例女性）中，同日进行经胸超声心动图、主动脉瓣二维电影 MRI 和主动脉 4D 流 MRI。使用 B 型和多普勒超声心动图分别测量瓣膜开放和关闭时间以及跨瓣峰值速度。使用电影 MRI 描述完全开放状态下的瓣膜口形态。使用 4D 流 MRI 数据测量升主动脉（AAo）壁面切应力（WSS）。BAV 与对照组的瓣膜运动时间相似。BAV 与瓣口面积率增加（1.44±0.11 比 1.10±0.13，P<0.001）、跨瓣峰值速度（1.5±0.3 比 1.2±0.2 m/s，P<0.001）和最大 AAo WSS（1.62±0.31 比 0.91±0.24 Pa，P<0.001）相关。瓣口面积率增加与跨瓣峰值速度（r=0.80，P<0.0001）和最大 AAo WSS（r=0.83，P<0.0001）的增加相关。跨瓣峰值速度与最大 AAo WSS 也呈正相关（r=0.83，P<0.0001）。同日的超声和 MRI 成像可以全面评估主动脉瓣疾病对瓣膜功能和血流动力学的影响。在这项针对 BAV 的初步应用中，我们发现瓣口面积率增加可能是导致跨瓣峰值速度和最大 AAo WSS 增加的原因。
