Associations of wall shear stress and nitric oxide distribution with vertebral artery tortuosity: A morphological and...

The vertebral artery (VA) exhibits substantial morphological variability and is prone to tortuosity and atherosclerosis at the V1 segment . This study aimed to systematically analyze sex-, laterality-, and age-related differences in the geometry and hemodynamics of the VA V1 segment, and to explore the potential role of hemodynamic factors in VA tortuosity and remodeling. Computed tomography angiography data from 53 subjects were used to reconstruct 3D models of the VA V1 segment. Geometric parameters of the subclavian artery and VA were quantified across sex, laterality, and age groups. Computational fluid dynamics was performed to evaluate key hemodynamic parameters in representative models, including velocity, time-averaged wall shear stress (TAWSS), and nitric oxide (NO) distributions. The left VA had a larger diameter and higher tortuosity propensity than the right, and VA tortuosity increased markedly with age. Left VA exhibited higher velocity, TAWSS, and NO levels, with elevated WSS localized to curved and peri-bifurcation regions. Circumferentially, TAWSS and NO showed greater magnitudes and variability in the left VA, potentially contributing to more significant vascular remodeling and tortuosity. Age-related circumferential heterogeneity of TAWSS and NO was also observed, linking to the 3D curvature development. The geometry and hemodynamics of VA exhibit significant variations associated with sex, laterality, and aging. Hemodynamic parameters-particularly TAWSS and NO spatial distribution-correlated closely with VA tortuosity and remodeling, with circumferential heterogeneity potentially driving curvature progression. These findings provide biomechanical insights into VA aging and cerebrovascular diseases, aiding clinical risk assessment and intervention planning.