Wall Shear Stress Predicts Aortic Dilation in Patients With Bicuspid Aortic Valve

OBJECTIVES This study sought to assess the predictive value of wall shear stress (WSS) for colocalized ascending aorta (AAo) growth rate (GR) in patients with bicuspid aortic valve (BAV). BACKGROUND BAV is associated with AAo dilation, but there is limited knowledge about possible predictors of aortic dilation in patients with BAV. An increased WSS has been related to aortic wall damage in patients with BAV, but no previous prospective study tested its predictive value for dilation rate. Recently, a registration-based technique for the semiautomatic mapping of aortic GR has been presented and validated. METHODS Forty-seven patients with BAV free from valvular dysfunction prospectively underwent 4-dimensional flow cardiac magnetic resonance to compute WSS and subsequent follow-up with 2 electrocardiogram-gated high-resolution contrast-enhanced computed tomography angiograms for GR assessment. RESULTS During a median follow-up duration of 43 months, mid AAo GR was 0.24 mm/year. WSS and its circumferential component showed statistically significant association with mid AAo GR in bivariate (P = 0.049 and P = 0.014, respectively) and in multivariate analysis corrected for stroke volume and either baseline AAo diameter (P = 0.046 and P = 0.014, respectively) or z-score (P = 0.036 and P = 0.012, respectively). GR mapping further detailed that GR was heterogeneous in the AAo and that circumferential WSS, but not WSS magnitude, showed statistically significant positive associations with GR in the regions with the fastest growth. CONCLUSIONS 4D flow cardiac magnetic resonance-derived WSS and, in particular, its circumferential component predict progressive dilation of the ascending aorta in patients with BAV. Thus, the assessment of WSS may be considered in the follow-up of these patients. (J Am Coll Cardiol Img 2022;15:46-56) (c) 2022 by the American College of Cardiology Foundation.

Automated summary

This study assessed the predictive value of wall shear stress (WSS) for the growth rate (GR) of the ascending aorta (AAo) in patients with bicuspid aortic valve (BAV). The results showed a positive correlation between WSS and its circumferential component with AAo GR. Therefore, the evaluation of WSS may be helpful in the follow-up of these patients.