Topography of Vertebral Artery Origin Plaques: Characteristics and Determinants.

Background: Atherosclerotic plaques located at the vertebral artery ostium (VAo) are a mechanism for posterior circulation stroke, but little is known about VAo plaque topography and formation. In this study, we describe the topography of atherosclerotic plaques involving the origin of the vertebral artery (VA).

Methods: Cross-sectional analyses of extracranial duplex studies were performed, and VAo plaques were classified based on their topography in 3 groups: (1) exclusively at the VA ostium; (2) predominantly subclavian, with extension into the vertebral ostium; and (3) predominantly ostial, with extension into the subclavian artery). Chi-square and analysis of variance tests were performed to investigate the association between VAo plaque topography and continuous and categorical variables, respectively.

Results: A total of 99 of 481 (21%) ultrasound duplex studies showed VAo plaques. The majority of the plaques (60%) were found to extend from the subclavian to the ostium. Plaques occurred more frequently at the medial wall of the VAo. No vascular risk factors were associated with plaque formation; however, women were more likely to have plaques involving predominantly or exclusively the VAo (P = .004).

Conclusions: We describe 3 different patterns of VAo involvement in patients with ostial atherosclerotic VA disease. VAo plaques occurred almost exclusively at the medial wall of the vessel. Women had more plaques involving predominantly the origin. Prospective studies are needed to investigate the clinical significance of these findings.