Helical vortex arising from aberrant right subclavian artery induces occurrence of dissection tears

Aortic dissection (AD) is a life-threatening condition characterized by a tear in the aortic wall, resulting in the separation of its layers and the formation of true and false lumens. The aberrant right subclavian artery (ARSA) is frequently observed in AD patients. Structural changes to the aortic arch create abnormal hemodynamics, making ARSA a potential risk factor for AD development. This study aims to investigate the relationship between the hemodynamics of ARSA patients and AD initiation using computational fluid dynamics (CFD). A total of twelve models divided into three groups of the aortic arch were constructed based on computed tomography angiography (CTA) images. Group A consists of four models constructed based on patients with both ARSA and acute AD. Group B consists of four models modified from the ARSA models (group A) by repositioning the right subclavian artery to the brachiocephalic trunk, and group C consists of four models derived from CTA images of healthy volunteers as a control group. CFD simulations were conducted to evaluate wall shear stress (WSS), oscillatory shear index (OSI) as well as helicity and blood flow patterns within the aorta. The results reveal that ARSA leads to sustained helical blood flow, increased tangential forces, and lower OSI values in regions of tears. This study demonstrates that congenital ARSA damages aortic wall dynamics by inducing non-physiological high helical blood flow, thereby increasing the risk of AD.