Department of Radiology, University of California, San Francisco, San Francisco, CA 94143-0628, USA.
Acad Radiol. 2013 Jan;20(1):10-5. doi: 10.1016/j.acra.2012.07.012. Epub 2012 Aug 28.
Previous work suggests that ascending aortic (AsAo) dilation can be asymmetric and is potentially related to valve-related blood flow abnormalities. The aim of this study was to investigate the relationship between the aortic valve and AsAo dilation using a quantitative, three-dimensional assessment of aortic shapes.
Computed tomographic and magnetic resonance images of the thorax were retrospectively reviewed. Four groups with aortic dilation were studied: those with tricuspid aortic valves (TAVs) with and without stenosis and those with bicuspid aortic valves (BAVs) with and without stenosis. Controls had either TAVs or BAVs but no aortic stenosis or dilation. In additional to standard orthogonal diameters, a unique measurement of AsAo asymmetry was used: the ratio of the greater to lesser curvatures measured using three-dimensional reformats in a "candy-cane" orientation.
A total of 105 patients were identified. Ratios of greater to lesser curvature in patients with aortic dilation and nonstenotic TAVs were not significantly different from those in controls (1.69 vs 1.55, P > .20), but the asymmetry reflected by this ratio was markedly increased in patients with aortic dilation and stenotic TAVs (1.94, P < .001). Patients with aortic dilation and BAVs had significantly elevated ratios regardless of the status of the aortic valve (1.96 for nonstenotic and 2.05 for stenotic vs 1.53 for controls, P < .001).
Asymmetric AsAo dilation with relative bulging of the greater curvature is linked to aortic stenosis, but it is also seen with nonstenotic BAVs. This suggests that the hemodynamic forces that contribute to aortic dilation are not fully revealed by conventional assessment of the aortic valve.
既往研究提示升主动脉（AsAo）扩张可能呈不对称性，且与瓣相关血流异常有关。本研究旨在采用主动脉形态的定量三维评估方法来探究主动脉瓣与升主动脉扩张之间的关系。
回顾性分析胸部 CT 和磁共振成像资料。研究了四组升主动脉扩张患者：三尖瓣主动脉瓣（TAV）伴或不伴狭窄组，以及二叶式主动脉瓣（BAV）伴或不伴狭窄组。对照组患者具有 TAV 或 BAV，但无主动脉瓣狭窄或扩张。除了标准的正交直径外，还采用了一种独特的升主动脉不对称测量方法：使用三维重建在“棒棒糖”方位测量大、小曲率的比值。
共纳入 105 例患者。升主动脉扩张且非狭窄性 TAV 患者的大、小曲率比值与对照组相比无显著差异（1.69 比 1.55，P＞.20），但反映该比值的不对称性在升主动脉扩张且狭窄性 TAV 患者中明显增加（1.94，P＜.001）。无论主动脉瓣状态如何，升主动脉扩张且 BAV 患者的比值均显著升高（非狭窄性为 1.96，狭窄性为 2.05，对照组为 1.53，均 P＜.001）。
相对大曲率向外膨隆的不对称性升主动脉扩张与主动脉瓣狭窄有关，但也可见于非狭窄性 BAV。这提示导致主动脉扩张的血流动力学因素并未通过对主动脉瓣的常规评估得到充分揭示。
