Elsevier

Academic Radiology

Volume 20, Issue 1, January 2013, Pages 10-15
Academic Radiology

Original investigation
Quantitative Assessment of Asymmetric Aortic Dilation with Valve-related Aortic Disease

https://doi.org/10.1016/j.acra.2012.07.012Get rights and content

Rationale and Objectives

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.

Materials and Methods

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.

Results

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).

Conclusions

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.

Section snippets

Patient Selection

Computed tomographic and magnetic resonance angiographic images of the thorax were retrospectively reviewed to identify patients in six groups. Four groups with aortic dilation were studied: those with tricuspid aortic valves (TAVs) with and without stenosis and those with BAVs with and without stenosis. The two control groups had either TAVs or BAVs without aortic stenosis or dilation. Waiver of informed consent was obtained from our institutional review board for this retrospective study,

Patient Characteristics

A total of 105 patients were identified. Patient demographics and clinical information are described in Table 1. Among subjects with TAVs, 34 patients with and 25 controls without AsAo dilation were selected. The mean age was 69.6 ± 9.54 years for patients with dilation and 53.7 ± 17.4 years for controls (P < .01). Of the patients with TAVs and dilated ascending aortas (n = 34), nine had aortic stenosis. Among subjects with BAVs, 22 patients with and 24 controls without AsAo dilation were

Discussion

We demonstrate that asymmetric dilation of the ascending aorta, with relative bulging of the greater curvature, is not only linked to aortic stenosis but is also seen with nonstenotic BAVs. The superior 3D abilities of CTA and MRA allowed the quantification of this aortic asymmetry using a ratio of the greater to lesser AsAo curvatures.

CTA and MRA allow the evaluation of the entire ascending aorta, in contrast to echocardiography, with which the superior extent of dilation often is not

Conclusions

We used the superior 3D capabilities of CTA and MRA to demonstrate a unique, asymmetric shape of AsAo dilation that is linked to aortic valve disease. This asymmetry is seen not only in the setting of aortic stenosis but also with nonstenotic BAV. This suggests that the hemodynamic forces that contribute to aortic dilation are not fully revealed by conventional assessment of the aortic valve. Follow-up is needed to determine whether aortic morphology and assessment of underlying abnormal

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