Basilar artery bending length, vascular risk factors, and pontine infarction

Background: Patients exhibiting basilar artery (BA) curvature (not dolichoectasia) are at an increased risk of posterior circulation ischemic stroke. In this study, pontine infarction patients were analyzed to assess the effect of BA bending length (BL) together with other vascular factors on pontine stroke risk.

Methods: Acute pontine infarction patients were divided into BA bending and non-BA bending groups by magnetic resonance angiography (MRA). Patients with BA bending who reported symptoms of dizziness or vertigo but who had not suffered brain infarction constituted the control group. The diameter of the vertebral artery (VA) and BL were measured using MRA. Based on the bilateral VA diameter data in vertebral artery-dominant (VAD) patients, the study participants were divided into three classes for VA diameter: class one, 0.30-0.80 mm (20 cases); class two, 0.81-1.37 mm (20 cases); and class three, 1.38-3.24 mm (20 cases). The measured BL in VAD cases allowed division of patients into three levels for BL: level one, 1.02-2.68 mm (21 cases); level two, 2.69-3.76 mm (20 cases); and level three, 3.77-7.25 mm (19 cases). Vascular risk factors were compared among the three groups. Correlations of BL and VA diameter differences were studied, and multivariate analysis was applied to search for predictors of ischemic stroke in BA bending patients.

Results: Among BA bending, non-BA bending, and control groups, VA dominance (VAD) proved to be a significant differentiator. For all three groups, a patient age of ≥ 65 years, the occurrence of hypertension, smoking, high homocysteine levels, high cholesterol, and a history of type 2 diabetes, were all statistically significant factors (P<0.05). After adjusting for other relevant factors, multivariate analysis shows that BL of level 3 was an independent risk factor for pontine infarction (OR=2.74; 95% CI, 1.27 to 4.48). Both BL and diameter differences between the VAs were positively correlated with risk with statistical significance (r=0.769, P<0.001).

Conclusions: Both BL and diameter differences between the VAs are positively correlated with the risk of pontine infarction. When BA bending was coupled with other vascular risk factors, the probability of pontine infarction increased. BA bending with a BL greater than 3.77 mm was an independent predictor of pontine infarction.