Older age, internal carotid artery stenosis, and female sex as factors correlated with twisted carotid bifurcation based on 457 angiographic studies and a literature review

Abstract Twisted carotid bifurcation (TCB) is a well-known anatomical variation of the carotid bifurcation in patients undergoing carotid endarterectomy. However, few investigations of TCB have focused on patients without internal carotid artery (ICA) stenosis. This study was performed to analyze the characteristics of TCB in patients with ICA stenosis and other diverse pathologies. All conventional cerebral angiographies performed in our institute for any reason from January 2012 to December 2018 were reviewed. The patients were divided into two groups, the TCB group and the anatomically normal non-TCB group, and the basic characteristics of the groups were analyzed. Both sides of the carotid bifurcation were clearly visualized in 457 patients. TCB was found in 89 of 457 patients (19.5%); among these 89 patients, 74 (83.1%) had TCB only on the right side, 8 (9.0%) only on the left side, and 7 (7.9%) bilaterally. TCB was found more frequently on the right than left [81 (17.7%) and 15 (3.3%), respectively, on each of the 457 sides (p < 0.0001)]. TCB was significantly more frequent in older patients (p = 0.02), female patients (p < 0.001), and patients with ICA stenosis or occlusion at the bifurcation (p = 0.005). The prevalence of TCB was 19.5%, and 84.4% of cases were on the right side in patients with diverse pathologies. In conclusion, older patients, female patients, and patients with ICA stenosis or occlusion are more prone to have TCB.