Effect of dominant vertebral artery angle on basilar artery curvature and plaque

BACKGROUND: Quantification of vertebral arteries can provide insights into basilar curvature and plaque. Therefore, this retrospective study aimed at identifying the dominant vertebral artery (VA) causing basilar artery (BA) curvature and to further quantify the effect of dominant VA angle on BA curvature and BA plaque using high-resolution magnetic resonance imaging (HRMRI) and 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA). METHODS: This retrospective analysis included 521 participants who underwent HRMRI in the China-Japan Friendship Hospital from November 2015 to October 2021 for neurological symptoms or signs. The VA angle more related to BA curvature was defined as the dominant VA angle. Multivariable linear regression analysis was used to evaluate the relationship between the dominant VA angle and mid-BA angle, while multivariable logistics regression was used to evaluate the influence of the dominant VA angle and clinical risk factors on BA plaque. RESULTS: In total, 259 participants were included in this study (mean age 53.71±13.12 years; 146 males). The balanced-type participants had a significantly lower probability of BA plaques (P<0.001). The Chi-squared test showed that the BA curvature direction was significantly associated with the side with larger VA diameter (P<0.001) and larger VA angle (P<0.001). As a result, the VA angle on the side with the larger diameter or the larger VA angle when the diameters were similar was considered to be the dominant VA angle. The dominant VA angle was independently correlated with the mid-BA angle (P<0.001). In addition, the dominant VA angle was also an independent risk factor for BA plaque. Additionally, 80° was the cutoff value of the dominant VA angle, and when the dominant VA angle was greater than 80°, the risk of BA plaque increased about 18-fold [odds ratio, 18.951; 95% confidence interval (CI): 4.545–79.026; P<0.001]. CONCLUSIONS: The dominant VA angle was independently associated with BA plaque, and a dominant VA angle greater than 80° may be a marker for a high risk of posterior circulation atherosclerosis.