Aortic Dilation in Bicuspid Aortic Valve Disease

Abstract

Background—: Ascending aortic dilation is important in bicuspid aortic valve (BAV) disease, with increased risk of aortic dissection. We used cardiovascular MR to understand the pathophysiology better by examining the links between 3-dimensional flow abnormalities, aortic function, and aortic dilation. Methods and Results—: A total of 142 subjects underwent cardiovascular MR (mean age, 40 years; 95 with BAV, 47 healthy volunteers). Patients with BAV had predominantly abnormal right-handed helical flow in the ascending aorta, larger ascending aortas (18.3±3.3 versus 15.2±2.2 mm/m ² ; P 2 /s; P P 2 ; P 2 /s; P P 2 ; P 2 ; P <0.05) than right–left cusp fusion (n=55). Patients with BAV with normal flow patterns had similar aortic dimensions and wall shear stress to healthy volunteers and younger patients with BAV showed abnormal flow patterns but no aortic dilation, both further supporting the importance of flow pattern in the pathogenesis of aortic dilation. Aortic function measures (distensibility, aortic strain, and pulse wave velocity) were similar across all groups. Conclusions—: Flow abnormalities may be a major contributor to aortic dilation in BAV. Fusion type affects the severity of flow abnormalities and may allow better risk prediction and selection of patients for earlier surgical intervention.