AIMS Aortic dilation in bicuspid aortic valve (BAV) might extend to the proximal arch. Arch flow dynamics and their relationship with this segment dilation are still unexplored. Using 4D-flow cardiovascular magnetic resonance, we analysed flow dynamics in the arch for each BAV morphotype and their association with this segment dilation. METHODS AND RESULTS One hundred and eleven BAV patients (aortic diameters ≤55 mm, non-severe valvular disease), 21 age-matched tricuspid aortic valve (TAV) patients with dilated arch and 24 healthy volunteers (HV) underwent 4D-flow. BAV were classified per fusion morphotype: 75% right-left (RL-BAV), and per arch dilation: 57% dilated, mainly affecting the right-noncoronary (RN) BAV (86% dilated vs. 47% in RL-BAV). Peak velocity, jet angle, normalized displacement, in-plane rotational flow (IRF), wall shear stress, and systolic flow reversal ratio (SFRR) were calculated along the thoracic aorta. ANCOVA and multivariate linear regression analyses were used to identify correlates of arch dilation. BAV had higher rotational flow and eccentricity than TAV in the proximal arch. Dilated compared with non-dilated BAV had higher IRF being more pronounced in the RN-morphotype. RN-BAV, IRF, and SFRR were independently associated with arch dilation. Aortic stenosis and male sex were independently associated with arch dilation in RL-BAV. Flow parameters associated with dilation converged to the values found in HV in the distal arch. CONCLUSION Increased rotational flow could explain dilation of the proximal arch in RN-BAV and in RL-BAV patients of male sex and with valvular stenosis. These patients may benefit from a closer follow-up with cardiac magnetic resonance or computed tomography.

中文翻译：

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近端主动脉弓旋转流量增加与其在二尖瓣主动脉瓣疾病中的扩张有关。

AIMS双尖瓣主动脉瓣（BAV）中的主动脉扩张可能延伸至近端弓。拱流动力学及其与该段扩张的关系尚待探索。使用4D流心血管磁共振，我们分析了每种BAV形态类型在足弓中的血流动力学及其与该节段扩张的关系。方法和结果110例BAV患者（主动脉直径≤55mm，非严重瓣膜疾病），21例年龄相匹配的三尖瓣扩张型三尖瓣主动脉（TAV）患者和24例健康志愿者（HV）接受了4D流动。BAV按融合形态类型分类：右-左（RL-BAV）占75％，每弓扩张：57％扩张，主要影响右-非冠状动脉（RN）BAV（扩张86％，而RL-BAV占47％） 。峰值速度，射流角，归一化位移，平面内旋转流（IRF），壁切应力，沿胸主动脉计算收缩压逆转率（SFRR）。ANCOVA和多元线性回归分析用于确定弓扩张的相关性。在近端弓形中，BAV比TAV具有更高的旋转流量和偏心率。与未扩张的BAV相比，扩张的IRF更高，在RN形态型中更明显。RN-BAV，IRF和SFRR与弓扩张独立相关。在RL-BAV中，主动脉瓣狭窄和男性性别与弓扩张独立相关。与扩张相关的流量参数收敛于远侧弓形中的HV值。结论旋转流量增加可能解释了RN-BAV和RL-BAV男性和瓣膜狭窄患者的近端弓扩张。