Increased Carotid Siphon Tortuosity Is a Risk Factor for Paraclinoid Aneurysms

Shilin Liu; Yu Jin; Xukou Wang; Yang Zhang; Luwei Jiang; Guanqing Li; Xi Zhao; Tao Jiang

doi:10.3389/fneur.2022.869459

Increased Carotid Siphon Tortuosity Is a Risk Factor for Paraclinoid Aneurysms

Front Neurol. 2022 May 10:13:869459. doi: 10.3389/fneur.2022.869459. eCollection 2022.

Authors

Shilin Liu¹, Yu Jin², Xukou Wang³, Yang Zhang¹, Luwei Jiang³, Guanqing Li², Xi Zhao⁴, Tao Jiang^{1

3

5}

Affiliations

¹ Department of Neurosurgery, The Second Affiliated Hospital of Anhui Medical University, Hefei, China.
² Department of Neurology, Bozhou City Peoples Hospital, Bozhou, China.
³ Department of Neurosurgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
⁴ Philips Healthcare China, Shanghai, China.
⁵ Anhui Provincial Institute of Translational Medicine, Hefei, China.

Abstract

Background: Geometrical factors associated with the surrounding vasculature can affect the risk of aneurysm formation. The aim of this study was to determine the association between carotid siphon curvature and the formation and development of paraclinoid aneurysms of the internal carotid artery.

Methods: Digital subtraction angiography (DSA) data from 42 patients with paraclinoid aneurysms (31 with non-aneurysmal contralateral sides) and 42 age- and gender-matched healthy controls were analyzed, retrospectively. Morphological characteristics of the carotid siphon [the posterior angle (α), anterior angle (β), and Clinoid@Ophthalmic angle (γ)] were explored via three-dimensional rotational angiography (3D RA) multiplanar reconstruction. The association between carotid siphon morphology and the formation of paraclinoid aneurysms was assessed through univariate analysis. After this, logistic regression analysis was performed to identify independent risk factors for aneurysms.

Results: Significantly smaller α, β, and γ angles were reported in the aneurysmal carotid siphon group when compared with the non-aneurysmal contralateral healthy controls. The β angle was best for discriminating between aneurysmal and non-aneurysmal carotid siphons, with an optimal threshold of 18.25°. By adjusting for hypertension, smoking habit, hyperlipidemia, and diabetes mellitus, logistic regression analysis demonstrated an independent association between the carotid siphons angles α [odds ratio (OR) 0.953; P < 0.05], β (OR 0.690; P < 0.001), and γ (OR 0.958; P < 0.01) with the risk of paraclinoid aneurysms.

Conclusions: The present findings provide evidence for the importance of morphological carotid siphon variations and the likelihood of paraclinoid aneurysms. These practical morphological parameters specific to paraclinoid aneurysms are easy to assess and may aid in risk assessment in these patients.

Keywords: carotid siphon; internal carotid artery; morphology; paraclinoid aneurysm; risk factor.