Relationship Between Basilar Artery Characteristics And The Subtypes Of Pontine Infarction

Background and PurposeAccording to lesion location whether extending to the anterior surface of the pons, isolated pontine infarctions are usually classified as paramedian pontine infarction(PPI) or lacunar pontine infarction(LPI). Previous studies identified atheromatous basilar artery branch disease and small vessel lipohyalinosis leading to lacunar infarcts are the main pathologies of isolated pontine infarcts. With the development of neuroimaging, vertebral artery hypoplasia, basilar artery hypoplasia, basilar artery bending, the congenital variation of vertebrobasilar artery and vertebrobasilar dolichoectasia(VBD) gradually be taken seriously. In addition, there are many patients with isolated pontine infarcts without arterial steno-occlusion, a potential cardiac source of embolism or other rare causes. The morphological abnormalities of vertebrobasilar artery may be associated with an increased risk of cerebral posterior circulation infarction. Recent studies indicated that ectasia of the basilar artery(BA) are associated with the occurrence of PPI, seriously basilar artery curvature may be a marker for a high risk of pontine infarction, and a larger angle at the vertebrobasilar junction was found in the patients with LPI. Nonetheless, the reports of sufficient numbers of patients including vascular studies are rare. Further research is required to clarify the relationship between the basilar artery characteristics and pontine infarction type. It may help us understand the underlying mechanism of pontine infarction.Therefore, the aim of this study was to investigate the association between basilar artery morphology(diameter, height of bifurcation, transverse position) and the lesion patterns of pontine infarcts.MethodsData for this study were obtained from the First Affiliated Hospital of Zhengzhou University Stroke Registry, which is a prospective hospital-based cohort study on acute ischemic stroke. The present study included patients with isolated pontine infarcts who were enrolled in the registry from January 2011 to December 2015. Baseline clinical characteristics for patients are recorded in the standard Case Report Form. Depending on whether the lesion on magnetic resonance imaging extended to the anterior surface of the pons, isolated pontine infarctions were classified into two groups: PPI and LPI. BA diameter, BA lateral displacement, and bifurcation height were assessed using magnetic resonance angiography or computed tomography angiography source imaging. The main clinical manifestations, blood test results, morphological characteristics of the basilar artery, and stroke risk factors were compared between the groups. All data were analyzed with SPSS(version 21.0). Differences between groups were assessed using the chi-square test for categorical variables and the Student t test or Mann-Whitney U test for continuous variables. BA diameter was dichotomized using the median. Multivariate logistic regression analyses were performed to evaluate independent variables associated with the pattern of pontine infarction. The included covariates were conventional risk factors with a P value of <0.1 in the univariate analysis. All statistical analyses were performed with a 2-tailed test and P <0.05 was considered significant.ResultsA total of 2001 acute ischemic stroke patients within 14 days of the onset registered in the database, and 219 inpatients with an acute isolated pontine infarcts meeting the inclusion criteria were included in this study(72 females [32.9%] and 147 males [67.1%]. The mean age of the patients was 61.70±10.16 years(range 33-80 years). One hundred and fifty two patients were diagnosed with PPI. Sixty seven patients were diagnosed with LPI. Of these patients, 148 with hypertension(67.6%), 93 with diabetes(42.5%), 37 with coronary heart disease(16.9%), 143 with hyperlipidemia(65.3%), 64 with smoking history(29.2%), 47 with drinking history(21.5%), and 56 with previous history of stroke(25.6%) were observed. NIHSS score on admission was 2(1- 5).The basilar artery diameter ranged from 1.5 to 5.3 mm(median 3.1mm). 7 patient(3.2%) had sectasia of basal artery: 5 cases of PPI and 2 cases of LPI. The transverse position of the basilar artery was lateral to the margin of the clivus or dorsum sellae in 46 cases(21.0%). The height of bifurcation of the basilar artery was above the suprasellar cistern in 52 cases(23.7%). Only four cases(1.8%) had dolichoectasia: 3 patients of PPI, 1 cases of LPI. There were statistically significant differences in NIH stroke scale score(P <0.001), limb paralysis(P <0.001), hyperlipidemia(P = 0.038), homocysteine level(P = 0.038), basilar artery diameter(P = 0.025) between patients with PPI and LPI.After adjustment for basilar artery diameter, hyperlipidemia, homocysteine lever and lateral displacement of the basilar artery(P = 0.078), increased basilar artery diameter(OR = 2.43, 95% CI 1.25-4.70; P = 0.009), hyperlipidemia(OR = 2.02, 95% CI 1.06-3.85; P = 0.032) were independently associated with the likelihood of patients having PPI and the seriously lateral displacement of the basilar artery(OR = 0.46, 95% CI 0.22-0.96; P = 0.038) was associated with LPI.ConclusionPatients with an increased basilar artery diameter have a greater risk of developing PPI than LPI. The seriously lateral displacement of the basilar artery is positively correlated with the risk of LPI. The finding may help predict the types of acute pontine infarction.