[Association between basilar artery hypoplasia and posterior circulation infarction].

OBJECTIVE

To explore the relationship between basal artery hypoplasia (BAH) and posterior circulation ischemic stroke and its clinical characteristics to improve the understanding of BAH.

METHODS

A total of 328 hospitalized patients from April 2012 to April 2014 were enrolled retrospectively. With normal course and regular shape of basilar artery on brain magnetic resonance angiography (MRA), other causes of posterior circulation ischemic stroke were excluded. They were divided into BAH (n = 48) and non-BAH (n = 280) groups according to the morphology and diameter of basilar artery on head MRA. We compared the general information and intracranial vascular variations between two groups, especially the incidence rate of posterior circulation infarction and mean blood flow velocity (Vm) of basal artery by analyzing clinical information and MRI findings. Meantime, their clinical outcomes were observed through follow-ups. And detailed clinical features were discussed for the patients with posterior circulation infarction in the BAH group.

RESULTS

(1) The concurrent lesions included vertebral artery intracranial segment hypoplasia (n = 24, VAH), fetal type posterior artery (n = 18, FTPA), persistent trigeminal artery (n = 1) and giant fenestration variation on vertebral artery (n = 1) in the BAH group. In comparison, it was more liable to cranial vascular variations in the BAH group (P < 0.05). (2) The incidence rates of posterior circulation infarction for two groups were 35.4% (17/48) and 8.6% (24/280) respectively. In comparison, these cases in the BAH group were more likely to suffer from posterior circulation ischemic stroke (P < 0.05) and the Vm of basal artery in the BAH group was obviously lower than that in the non-BAH group (P < 0.05). (3) these cases with stroke in two groups had no mortality during a follow-up period of 4-28 months. There were 3 cases with recurrent posterior circulation stroke in the non-BAH group. The number of cases with mRS scoring 2 points or less in the BAH group was more than that in the non-BAH group at discharge, 30 or 90 days after discharge (P < 0.05). (4) these cases with posterior circulation stroke in the BAH group often presented as lacunar syndrome (9/17), paramedian infarction in pons (9/17) and bilateral VAH plus unilateral FTPA (8/17).

CONCLUSION

As a relatively rare disease, BAH often has other intracranial vascular variants. Posterior circulation stroke occurs due to reduced blood supply of vertebrobasilar system, especially pons infarction. Though with relatively good clinical outcomes, we still need to make an early diagnosis and strengthen stroke prevention.