二叶式主动脉瓣环：采用标准化方法测量瓣环平面定义来评估心脏周期期间的几何形状和大小变化。

PURPOSE: Bicuspid aortic valve (BAV) is a complex malformation affecting not merely the aortic valve. However, little is known regarding the dynamic physiology of the aortic annulus in these patients and whether it is similar to tricuspid aortic valves (TAV). Determining the BAV annular plane is more challenging than for TAV. Our aim was to present a standardized methodology to determine BAV annulus and investigate its changes in shape and dimensions during the cardiac cycle. METHODS: BAV patients were prospectively included and underwent an ECG-gated cardiac CTA. The annulus plane was manually identified on reconstructions at 5% intervals of the cardiac cycle with a new standardized method for different BAV types. Based on semi-automatically defined contours, maximum and minimum diameter, area, area-derived diameter, perimeter, asymmetry ratio (AR), and relative area were calculated. Differences of dynamic annular parameters were assessed also per BAV type. RESULTS: Of the 55 patients included (38.4 ± 13.3 years; 58% males), 38 had BAV Sievers type 1, 10 type 0, and 7 type 2. The minimum diameter, perimeter, area, and area-derived diameter were significantly higher in systole than in diastole with a relative change of 13.7%, 4.8%, 13.7%, and 7.2% respectively (all p < 0.001). The AR was ≥ 1.1 in all phases, indicating an elliptic shape, with more pronounced flattening in diastole (p < 0.001). Different BAV types showed comparable dynamic changes. CONCLUSIONS: BAV annulus undergo significant changes in shape during the cardiac cycle with a wider area in systole and a more elliptic conformation in diastole regardless of valve type. KEY POINTS: • A refined method for the identification of the annulus plane on CT scans of patients with bicuspid aortic valves, tailored for the specific anatomy of each valve type, is proposed. • The annulus of patients with bicuspid aortic valves undergoes significant changes during the cardiac cycle with a wider area and more circular shape in systole regardless of valve type. • As compared to previously published data, the bicuspid aortic valve annulus has physiological dynamics similar to that encountered in tricuspid valves but with overall larger dimensions.

目的：二叶式主动脉瓣（BAV）是一种复杂的畸形，不仅影响主动脉瓣。然而，对于这些患者主动脉瓣环的动态生理学知之甚少，也不知道它是否与三叶式主动脉瓣（TAV）相似。确定 BAV 瓣环比确定 TAV 瓣环更具挑战性。我们的目的是提出一种标准化的方法来确定 BAV 瓣环，并研究其在心动周期中形状和尺寸的变化。

方法：前瞻性纳入 BAV 患者，并进行 ECG 门控心脏 CTA。瓣环平面在心动周期的 5%间隔的重建上手动识别，对于不同的 BAV 类型采用一种新的标准化方法。基于半自动定义的轮廓，计算最大和最小直径、面积、面积衍生直径、周长、不对称比（AR）和相对面积。还根据 BAV 类型评估了动态瓣环参数的差异。

结果：共纳入 55 例患者（38.4±13.3 岁；58%为男性），38 例为 BAV Sievers 1 型，10 例为 0 型，7 例为 2 型。最小直径、周长、面积和面积衍生直径在收缩期显著高于舒张期，相对变化分别为 13.7%、4.8%、13.7%和 7.2%（均 p<0.001）。AR 在所有相位均≥1.1，表明呈椭圆形，舒张期更明显变平（p<0.001）。不同的 BAV 类型显示出相似的动态变化。

结论：BAV 瓣环在心动周期中形状发生显著变化，收缩期面积较宽，舒张期呈更椭圆形。无论瓣叶类型如何，这与舒张期更明显的扁平化有关。

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