Patterns and Outcomes of the Top of the Basilar Artery Syndrome: The Role of the Posterior Communicating Artery.

BACKGROUND: Clinical syndromes secondary to infarcts in the distal basilar artery (BA) area have been described as "top of the basilar" (TOB) syndrome. However, in the era of advanced imaging technology, it has been realized that the clinical and imaging features are quite diverse in patients with distal BA occlusion. The aim of the present study was to investigate the patterns and clinical outcomes of TOB assessed with modern images and categorize TOBs accordingly. Additionally, we examined the possible influence of the posterior communicating artery (PcoA) on the patterns of TOB. METHODS: Patients with distal BA occlusion on magnetic resonance angiography were categorized as TOB-A, and those with multiple lesions in the distal BA territory on diffusion-weighted magnetic resonance imaging as TOB-L. Patients with angiographically and lesion distribution-defined TOB were classified as having TOB-A&L; those with angiographically defined TOB as having TOB-A without TOB-L; and those with lesion distribution-defined TOB as having TOB-L without TOB-A. The PcoA was categorized as "textbook-type" (good P1) and "fetal-type" (absent P1). Factors associated with unfavorable short-term outcomes (modified Rankin Scale 5-6 at discharge), and 1-year and long-term mortalities, were assessed. RESULTS: Of 1,466 patients with ischemic stroke in the posterior circulation who were admitted to Asan Medical Center within 24 h of symptom onset, 124 (8.5%) had TOB, including 45 with TOB-A&L, 44 with TOB-A, and 35 with TOB-L. NIHSS scores (21 [9.5-26] vs. 6 [3-11.5] vs. 6 [3-9]; p < 0.01) and rates of motor deficit (75.6 vs. 54.5 vs. 34.4%; p < 0.01), concomitant pontine lesions (17.8 vs. 25.0 vs. 2.9%; p < 0.01), PcoA presence (44.4 vs. 68.2 vs. 25.7%; p < 0.01), and unfavorable short-term outcomes (62.2 vs. 25.0 vs. 14.3%; p < 0.01) differed significantly in the 3 patient groups. Multivariate analysis showed that textbook-type PcoA was independently associated with a lower frequency of unfavorable short-term outcomes (OR 0.15, 95% CI 0.03-0.70). Reperfusion therapy (hazard ratio [HR] 0.25, 95% CI 0.07-0.89) and the presence of textbook-type PcoA (HR 0.20, 95% CI 0.05-0.90) were associated with a lower 1-year mortality rate after stroke. CONCLUSION: Patterns and clinical outcomes of TOB vary and are affected by the hemodynamic status of the arterial system, such as BA recanalization and the presence of textbook-type PcoA.

Progressive deficit in isolated pontine infarction: the association with etiological subtype, lesion topography and outcome.

It is important to predict progressive deficit (PD) in isolated pontine infarction, a relatively common problem of clinical stroke practice. Traditionally, lacunar infarctions are known with their progressive course. However, few studies have analyzed the branch atheromatous disease subtype as a subtype of lacunar infarction, separately. There are also conflicting results regarding the relationship with the topography of lesion and PD. In this study, we classified etiological subtypes and lesion topography in isolated pontine infarction and aimed to investigate the association of etiological subtypes, lesion topography and clinical outcome with PD. We analyzed demographics, laboratory parameters, and risk factors of 120 patients having isolated pontine infarction and admitted within 24 h retrospectively. PD was defined as an increase in the National Institutes of Health Stroke scale ≥2 units in 5 days after onset. Patients were classified as following: large artery disease (LAA), basilar artery branch disease (BABD) and small vessel disease (SVD). Upper, middle and lower pontine infarcts were identified longitudinally. Functional outcome at 3 months was determined according to modified Rankin scores. Of 120 patients, 41.7% of the patients were classified as BABD, 30.8% as SVD and 27.5% as LAA. 23 patients (19.2%) exhibited PD. PD was significantly more frequent in patient with BABD (p 0.006). PD was numerically higher in patients with lower pontine infarction. PD was associated with BABD and poor functional outcome. It is important to discriminate the BABD neuroradiologically from other stroke subtypes to predict PD which is associated with poor functional outcome in patients with isolated pontine infarctions.

Risk factors and etiological subtype analysis of brainstem infarctions.

OBJECTIVE: To evaluate the features of risk factors and etiological subtypes of brainstem infarctions (BSIs) patients in China. METHODS: One hundred and ninety-nine cerebral infarction patients with brainstem involvement were categorized into five groups according to Trial of Org 10172 in Acute Stroke Treatment classification: large artery disease (LAD), cardioembolism (CE), small vessel disease (SVD), stroke of other determined etiology (SOE) or stroke of undetermined etiology (SUE). The risk factors and percentage of the different etiological subtypes were assessed. RESULT: A total of 199 patients were enrolled in this study. The number and percentage of patients in SVD, LAD, SUE, CE and SOE were 77 (38.7%), 74 (37.2%), 25 (12.6%), 23 (11.6%) and 0, respectively. There were significantly different incidences of hypertension, diabetes and coronary heart disease (CHD) without atrial fibrillation (AF) among different stroke subtypes (P=0.006, P=0.002, P=0.016, respectively). Hypertension was more prevalent in LAD than in SVD and CE (P=0.001 and P=0.039, respectively) while the incidence of diabetes in LAD was higher than those in SVD and CE (P<0.001 and P=0.015, respectively). CHD without AF was more prevalent in CE than in SVD and LAD (P=0.044 and P=0.012, respectively). LAD was significantly associated with hypertension (OR=3.18, P=0.009) and diabetes (OR=2.84, P=0.003) in BSIs. CONCLUSION: The pattern of etiological subtypes of BSIs in China has its own characteristics. It might result from the features of risk factors in Chinese patients.

Occurrence and clinicotopographical correlates of brainstem infarction in patients with diabetes mellitus.

BACKGROUND: The goal of the study was to clarify the association between diabetes mellitus (DM) and brainstem infarctions (BSIs) and to investigate the clinicotopographic characteristics of BSIs in patients with diabetes. METHODS: Data were retrospectively reviewed for 1026 consecutive patients admitted to our hospital because of acute cerebral infarctions from January 2004 to August 2010. Acute symptomatic BSIs were explored on radiologic images and classified into multiple infarctions with BSIs, multifocal BSIs, and monofocal BSIs. Isolated BSIs were further classified based on the vertical distribution into midbrain, pontine, and medullary infarctions, and on the horizontal distribution into anterior-dominant, posterior-dominant, and anterior/posterior BSIs. Neurologic symptoms of BSIs and clinical background were compared between DM and non-DM patients. RESULTS: The prevalence of BSIs was 2.6-fold higher (P < .0001) in DM patients. Logistic regression analysis including age, sex, smoking, previous stroke, atrial fibrillation, other cardiac diseases, hypertension, hyperlipidemia, and DM showed that DM was independently associated with BSIs (odds ratio [OR] 2.814; 95% confidence interval [CI] 1.936-4.090; P < .0001). Compared with non-DM patients, DM patients showed more frequent monofocal BSIs (P < .0001) and multifocal BSIs (P = .0296). Monofocal BSIs (n = 114) more frequently involved the pons (P < .0001) and medulla (P = .0212). Anterior-dominant BSIs (P < .0001) were more common in DM patients than in non-DM patients. Symptoms of BSIs included more frequent motor paresis (P = .0180) and less frequent diplopia (P = .0298) in DM patients than in non-DM patients. CONCLUSIONS: DM is important in the development of BSIs, and the associated clinical characteristics include more frequent motor paresis and less frequent diplopia.

Lateral and medial medullary infarction: a comparative analysis of 214 patients.

BACKGROUND AND PURPOSE: No large-scale study has ever compared the clinical and radiological features of lateral medullary infarction (LMI) and medial medullary infarction (MMI). The aim of this study was to investigate them through the use of cooperatively collected cases. METHODS: Medical information on all patients from 1996 to 2000 with medullary infarction (MI) proven by brain MR images at 35 stroke centers in the Tohoku district, Japan, was collected, and their clinical and radiological features were analyzed. RESULTS: A total of 214 cases of MI were registered. They included 167 cases (78%) of LMI, 41 (19%) of MMI, and 6 (3%) of LMI plus MMI. The mean age of onset and the male-to-female ratio were 60.7 years and 2.7:1 in LMI and 65.0 years and 3.6:1 in MMI, respectively. The middle medulla was most frequently affected in LMI, and the upper medulla was most frequently affected in MMI. Dissection of the vertebral artery was observed in 29% of LMI and 21% of MMI. Prognosis, assessed by the Barthel Index, was favorable in both LMI and MMI. Diabetes mellitus was more frequently associated with MMI than with LMI. CONCLUSIONS: The present study surveyed a large number of MI cases and revealed that (1) the mean age of onset of MMI is higher than that of LMI, (2) the dissection of the vertebral artery is an important cause not only of LMI but also of MMI, and (3) diabetes mellitus is frequently associated with MMI.

Bilateral medial medullary infarction.

We present a case of bilateral medial medullary infarction demonstrated by magnetic resonance imaging (MRI) and review 12 previously reported cases. We classify these 13 cases (including the present case) into two groups according to the extent of the ischemic region: type 1, the ischemic lesion developed from the medullary pyramid to the medial longitudinal fasciculus; type 2, the lesion was confined to the medullary pyramid.A 71 year old man presented with slight disturbance of consciousness, dysarthria, disturbance of leftward gaze, no gag reflex and tetraparesis. He developed nearly complete horizontal ophthalmoplegia. MRI revealed upper medial medullary infarction bilaterally that extended to the pontomedullary junction. We propose that the prognosis of type 2 bilateral medial medullary infarction is better than that of type 1. Furthermore, the prognosis of bilateral medial medullary infarction itself may be better than previously indicated.

Aspiration subsequent to a pure medullary infarction: lesion sites, clinical variables, and outcome.

BACKGROUND: Aspiration as a symptom of dysphagia and its apparent sequela, aspiration pneumonia, are common consequences of a stroke in the medulla. Previous reports that focused on dysphagia due to a medullary lesion were studies of single cases or a relatively small number of patients with multiple lesion loci. Moreover, the interval between the onset of stroke and the evaluation time of swallowing was not controlled and varied largely among patients. Thus, prediction of the swallowing status of patients with a medullary lesion has not been tenable. OBJECTIVES: To investigate the relation between the loci of pure medullary lesions and aspiration, to examine swallowing function over time, and to explore clinical variables that can predict aspiration. METHODS: We investigated 23 patients with pure medullary infarctions using the videofluoroscopic swallowing study and compared the airway status findings with the lesion location as determined with magnetic resonance imaging. The patients were classified by 6 medullary lesion-level categories (lower, lower-middle, middle, lower-middle-upper, middle-upper, and upper) and by 5 intralevel lesion loci (inferior-dorsal, large inferior-dorsolateral, para-median, midlateral, and dorsolateral). From the results of the videofluoroscopic swallowing studies, 2 patient groups were formed: one with aspiration and the other without aspiration. The clinical variables related to aspiration and outcome measures were also explored. RESULTS: Ten (44%) of the 23 patients manifested aspiration on swallowing: 9 (69%) of 13 with only middle-level lesions or lesions in multilevels, including the middle level; 1 (33%) of 3 with only upper-level lesions; and 0 (0%) of 7 with only lower-level medullary lesions. A lesion running the length of the middle and the lower medullary levels always resulted in aspiration. When an upper-level lesion was additionally involved, the incidence of aspiration depended on the horizontal extension of the lesion. We were able to discriminate the 2 patient groups with 95.7% accuracy using such variables as dysphonia, soft palate dysfunction, and facial hypesthesia. Most of the patients with aspiration symptoms due to a pure medullary infarction recovered rather quickly. CONCLUSIONS: Medullary infarctions often cause aspiration, but the occurrence may depend on the levels along the neuraxis and intralevel lesion loci. When different lesion levels and loci and their related clinical findings are considered as possible variables, aspiration becomes predictable. The outcome data prove that systematic control of evaluation time of swallowing was critical as we engaged in this study, since many aspirators with pure medullary infarctions resolve their swallowing difficulties rather quickly.