P1824Aortic wall shear stress in bicuspid aortic valve disease - 10-year follow-up

Abstract

Abstract Introduction Bicuspid aortic valve (BAV) disease leads to deviant complex helical flow patterns in the aorta - especially in the mid-ascending (AoA) part. In association with congenital BAV, aortic wall alterations such as aortic dilatation and dissection may occur. Among others, wall shear stress (WSS) could be one parameter to contribute to the prediction of the long-term outcome of patients with BAV. 4D-flow in cardiovascular magnetic resonance has been established as a valid method to estimate WSS. Purpose The aim of this study is to reevaluate WSS and comparing it to values generated in the same patient cohort with bicuspid aortic valve disease in 2008. No one of the above had aortic dilation in 2008 but proven helical flow pattern. The long term follow-up study might show changes in WSS over the period of ten years. Methods Ten complete 4D flow datasets of patients (age at follow-up: median 34.5 years; range 19–41 years) with bicuspid aortic valve disease without enlargement of the aorta were obtained in 2008 and reevaluated in 2018/2019 in the same patient collective. Mean WSS values were calculated with identical specific software tools. All data were analyzed by two experienced investigators. Results Aortic diameters at the level of the mid AoA did not change significantly in the 10-year period. The WSS values were lower in 2018 at all levels of the ascending aorta (Table 1). Indexed aortic diameters at the level of the mid ascending aorta did not change, median difference 0.06 cm/m2 (range −0.1 cm/m2 to 0.2 cm/m2; p=0.28), absolute values of indexed AoA diameters in 2018/2019 ranged from 1.27 cm/m2 to 2.2 cm/m2 (median 1.76 cm/m2). Table 1 WSS magnitudinal [N/m2] 2008 (n=10) 2018 (n=10) Median difference p-value median range median range Level aortic bulb 0.95 0.80–1.46 0.42 0.34–0.82 −0.53 <0.01 Level mid ascending aorta 0.72 0.40–0.98 0.39 0.34–0.59 −0.33 <0.01 Level brachiocephalic trunc (BCT) 0.71 0.38–1.03 0.40 0.37–0.61 −0.31 <0.01 Conclusions Indexed AoA diameters in BAV disease did not change significantly over a 10-year period. WSS of AoA was less compared to values generated in 2008. This might be explained by a slight alteration in hemodynamic flow patterns by the aging aorta, but not by changes of the aortic diameters. Possibly a drop of WSS in BAV could serve as a marker for a benign long term course.