Anatomical analysis of vertebral arteries in vertebrobasilar dolichoectasia: A multi-center study

Background: Vertebrobasilar dolichoectasia (VBD) is a rare disease with significant morbidity. Its propensity for posterior circulation and relationship with aneurysms is poorly understood. Here, we aimed to describe the anatomical characteristics of the vertebral arteries (VA) in patients with VBD. Methods: We conducted a multi-center retrospective cohort analysis on patients diagnosed with VBD between January 2009 and December 2022. Anatomical variables were measured after manual segmentation on CTA. Length of the VAs, basilar artery (BA), sectional diameters, and tortuosity index were measured and compared with a control group. Results: 124 patients were included: 38 patients with VBD and 86 controls. VBD patients had longer VAs (right VA 262.5 vs. 228.7 mm, p<0.01; left VA 253.4 vs. 222.1 mm, p<0.01), longer BAs (41.9 vs. 30.0 mm, p<0.01), and larger cross-sectional diameters of right V3 (5.1 vs. 4.6 mm, p<0.05) and V4 segments (4.5 vs.2.9 mm, p<0.05) and left V1-V4 segments (V1 6.1 vs. 4.2, V2 7.2 vs.4.8 mm, V3 6.4 vs.5.0 mm, V4 6.5 vs. 3.0 mm, p<0.01). Patients with VBD and fusiform aneurysms had longer VAs and BA than patients without aneurysms (p<0.01). The VAs tortuosity index was higher in VBD than controls (60.69 vs. 44.18, p<0.01). No cases of vertebral stenosis were detected. Conclusions: Our study offers an anatomical study of VBD. While the natural history is poorly understood, the higher tortuosity index with associated wall shear stress, provides a possible mechanism for disease progression. Further studies are needed to better understand the