Posterior Circulation Ischemia Research Articles

Brain Trust

stroke, NIHSS: stroke, NIHSSFigureFigurePART 3 IN A THREE-PART SERIES The National Institutes of Health Stroke Scale is the most widely used deficit rating scale in modern neurology, but it was not meant to be a bedside rating tool. This critical piece of the neurologic exam for any suspected stroke patient, originally developed as a research tool to measure baseline data in acute stroke clinical trials, has considerable problems that may arise in clinical practice, however. The NIHSS is used as a clinical assessment tool to evaluate the acuity of stroke patients, determine appropriate treatments, and predict patient outcomes. Several scale items require intact language, however, so it gives too much weight to deficits in patients with left versus right hemispheric strokes. A left hemispheric stroke can score up to four more points than a right hemispheric stroke of similar size. Posterior circulation strokes also suffer under the NIHSS because they receive few to no points. Important elements such as diplopia, dysphagia, gait instability, nystagmus, and dizziness receive no score, and a patient with a life-changing stroke could be completely missed if the NIHSS were the only tool considered. A good correlation is seen between NIHSS and the likelihood of finding an eligible large vessel occlusion, but no specific number seems optimal for use. (Stroke 2017;48[2]:513.) Don't fall into some of these traps; the NIHSS must be used with caution in clinical practice for rating stroke severity. Most importantly, a complete and thorough neurologic examination should be second nature and should always include anterior and posterior components. Most electronic medical records will have an NIHSS template built in, and it is widely available online, but consider other online tools such as MDCalc to help calculate a score. (www.mdcalc.com.) Noncontrast CT Neuroimaging of the patient with acute ischemic stroke is used to exclude hemorrhage, assess the degree of brain injury, and identify the vascular lesion responsible for the ischemic deficit. Noncontrast CT (NCCT) of the brain has the main advantage of widespread access and speed of acquisition. It is usually ordered to exclude or confirm hemorrhage and is highly sensitive for this indication, but it is not that sensitive for ischemia before 24 hours, and it has significantly poor sensitivity for the posterior fossa structures. (J Emerg Med 2012 May;42[5]:559.) CT angiography allows visualization of the extracranial and intracranial cerebral arteries, and CTA source images are more sensitive than NCCT scans for detecting early brain infarction. The value of CTA is to identify patients with occlusion of the major vessels within the circle of Willis or extracranial cerebral arteries, but it will still not be reliable for smaller to even medium areas of ischemia, especially in the posterior circulation territory. (Stroke 2009;40[11]:3646.) Recently, the Head Impulse, Nystagmus, Test of Skew (HINTS) exam gained attention as a series of three physical exam maneuvers to differentiate peripheral and central causes of acute vestibular syndrome. A positive HINTS exam can be 100% sensitive and 96% specific for the presence of a central lesion. It is also more sensitive than general neurologic signs: 100% vs 51%. Disclaimer ahead (and it is a big one!): The HINTS exam was tested in an outpatient setting by neuro-ophthalmologists, not emergency physicians, and may not be generalizable to an ED population. (Stroke 2009;40[11]:3504.) Use of brain MRI has significantly increased for evaluating patients with acute ischemic stroke. The rationale for MRI—diffusion-weighted imaging (DWI), in particular—is that this modality has substantially higher sensitivity (88-100%) than that of NCCT for detecting ischemia, with a specificity reported to be as high as 95%-100%. MRI also identifies acute intracranial hemorrhage with similar reliability to NCCT. As if our jobs were not hard enough, emerging evidence now shows that DWI fails to identify acute ischemic stroke in a substantial minority of patients, about seven percent. These DWI-negative stroke cases fall into three categories: posterior circulation ischemia, small strokes, particularly in the brainstem, and hyperacute ischemia (MRI done within six hours of onset). (Neurology 2017;89[3]:256.) Acute ischemic stroke remains one of the most challenging diagnoses in emergency medicine. We need to continue to rise to the challenge, using clinical judgment followed by a thorough and complete neurologic exam and appropriate imaging. Our patients can't afford for us to miss the diagnosis of acute ischemic stroke because early diagnosis can lead to improved outcome, and the neurologic exam and appropriate use of imaging are our best tools.

Etiological characteristics analysis of 3 137 outpatients with vertigo or dizziness in ENT department

Objective: To analyze the etiological characteristics of patients in department of ENT with chief complaint of vertigo or dizziness in order to reduce the rate of misdiagnosis and wrong treatment. Method: A total of 3 137 patients in department of ENT with chief complaint of vertigo or dizziness from Sep 2015 to Sep 2017 were included and the etiologies were clarified retrospectively. And in which with any of the 8 kinds of disease including benign paroxysmal positional vertigo(BPPV), vestibular neuritis, vestibular migraine (VM), Meiniére disease, recurrent vestibular disease, sudden deafness with vertigo, psychogenic vertigo, posterior circulation ischemia (PCI) together 2 138 patients were further stratified analyzed by gender and age. Result: ①Etiological characteristics of patients with vertigo or dizziness：among the 3 137 patients with vertigo or dizziness in ENT department in our hosipital, the peripheral diseases of vestibular were the most common disease with a total of 1 607 cases, accounting for 51.23%. And there were 506 cases of the central diseases of vestibular accounting for 16.13%, 382 cases of other systemic diseases accounting for 12.18%, 85 cases（2.71%）of psychogenic vertigo, 557 cases （17.76%）of unknown etiology. ②Analysis of the frequent and serious causing of patients with vertigo or dizziness: among the 2 138(68.15%) patients with vertigo or dizziness, BPPV with a total of 827 cases (26.36%) was the most prevalent,while 215(25.99%) of them were diagnosed as self-cured BPPV,vestibular neuritis and VM were the second prevalent with 420 cases (13.39%) and 329 cases (10.49%) respectively, Meiniére disease, recurrent vestibular disease, sudden deafness with vertigo were the third prevalent with 209 cases (6.66%), 144 cases (4.59%), 102 cases (3.25%), respectively; well psychogenic vertigo and PCI were relatively rare, with respectively 85 cases (2.71%) and 22 cases (0.70%). Eotiology analysis stratified by age: The causes of vertigo or dizziness were ranged with age, and patients of 50-70 years old were most common with a total of 1 011 cases, accounting for 49.6%. Etiology analysis stratified by gender: There was gender difference in patients with vertigo or dizziness,such as BPPV, VM, recurrent vestibular disease, sudden deafness with vertigo and psychogenic vertigo were common in female, while PCI in male insteadly. Conclusion: ①Among the patients with vertigo or dizziness, the pheripheral diseases of vestibular are the most prevalent, in which BPPV takes the highest accidence. ②Patients ranging from 50 to 70 years old take the main parts in patients with vertigo or dizziness. And there is an obvious gender difference in patients with BPPV, VM, recurrent vestibular disease, sudden deafness with vertigo, psychogenic vertigo and PCI.

Regional and sex differences in cerebral vasomotor reactivity to carbon dioxide

Studies on cerebral vasomotor reactivity (CVMR) to carbon dioxide (CO2) are often limited to middle cerebral artery (MCA), and rarely include anterior cerebral artery (ACA) and/or vertebral artery (VA); In addition, comparison of reactivity across vessels in the same individuals is rarely performed; Moreover, sex difference in CVMR has also not been carefully investigated. Therefore, it remains unknown whether there are differences in CVMR across arterial territories and/or between females and males. Twenty‐five young healthy subjects (15 females; age: 19–37 yrs, 27±5 yrs) were enrolled. The cerebral blood flow velocities (CBFVs) at the MCA, ACA and VA were simultaneously and continuously recorded with transcranial Doppler during 3‐min resting ventilation, 2‐min inspiration of 8% CO2, 21% O2, balance nitrogen, and 2‐min mild hyperventilation, in the sitting position. The CVMR of each artery is expressed as the percent change in its CBFV per mmHg change in end‐tidal CO2, as quantified by the slope of this relationship. The results are presented as Mean±SD. The experimental protocol resulted in a variation of end‐tidal CO2 from 31.8±4.7 to 46.6±5.5 (baseline, 40.4±3.5) mmHg, with a slight variation of mean blood pressure from 92±13 to 99±13 (baseline, 94±12) mmHg. The repeated‐measures ANOVA for multiple comparisons with Bonferroni correction indicated that the CVMR slope was significantly lower in the VA (1.85±0.61 %/mmHg) than in the MCA (2.30±1.04, P = 0.023) or ACA (2.33±0.92, P = 0.004). Females generally showed steeper CVMR slope than males (2.43±0.91 vs. 1.77±0.31, P = 0.019, for the 3‐artery averaged value), with no interaction found between sex and arterial territory factors. Based on these results, the CVMR appears lower in the posterior (vertebrobasilar) circulation than in the anterior circulation. Consistent with previous data we also found females had higher CVMR values in all arteries than males. The observed regional and sex CVMR differences should play an important role when assessing the cerebral blood flow response to other physiological situations (e.g. dynamic exercise; orthostatic, hypoxia, heat or cold stress), and might explain some neurological symptoms relevant to the posterior circulation ischemia and/or sex differences, which merits further investigation. Future studies are planned to examine the pressure‐ and/or flow‐induced concurrent diameter changes of the insonated artery, when using CBFV rather than volumetric cerebral blood flow to assess the CVMR.Support or Funding InformationSupported by the War Related Illness & Injury Study Center, Veterans Administration and NIH grant R21DC009900.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hepatitis E Virus Infection in Acute Non-Traumatic Neuropathy: A Large Prospective Case-Control Study in China

Neurological manifestations are potently associated with hepatitis E virus (HEV) infection in Europe, mainly attributed to genotype (G) 3 HEV infection. We determined the frequency and causal relationship of HEV in patients with non-traumatic neurological disorders in China, where G4 HEV is prevalent. Consecutive patients diagnosed with neurological illnesses and individuals visiting the physical examination center in a hospital of eastern China were tested for HEV by serology and molecular method. 1117 patients and 1475 healthy controls were enrolled. Anti-HEV IgM antibodies were detectable in 6 (0.54%) of the patients and 10 (0.68%) of the healthy controls (P = 0.651). Serum HEV RNA was detected in all of the 16 individuals. The six patients with positive anti-HEV IgM included two viral encephalitis, two posterior circulation ischemia, one peripheral neuropathy and one Guillian-Barre syndrome. They had no symptoms of acute viral hepatitis except two patients of viral encephalitis had mildly transaminitis. Additional, 39.51% patients and 35.63% controls without acute HEV infection were anti-HEV IgG positive (P = 0.144). Anti-HEV IgG positivity was more frequent in male and elderly in both the patients and control groups, but unrelated to the incidence of any non-traumatic neurological illness, hospital stay or treatment outcome, except linking to better outcome of hemorrhagic stroke disease. These data demonstrate that HEV appears not to contribute to acute neurological disorders in China. Nevertheless, we cannot exclude a possible causative role, suggesting that testing for HEV in this population, especially in situations of unexplained deregulated liver function would be warranted. Funding Statement: This study was supported by National Natural Science Foundation of China (No. 31770186) (to Y. Wang) Declaration of Interests: The authors have declared that no competing interests exist. Ethics Approval Statement: The standard protocol, ethical approvals and registrations of this study were approved by an ethical standards committee of The First People's Hospital of Yancheng City and all patients gave informed consent that allowed future testing of archived bio-samples.

Balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.

IntroductionVertebral artery stenosis is a major cause of posterior circulation ischemia in the elderly. There is not a clear consensus on the optimal therapeutic approach for symptomatic extracranial vertebral artery stenosis.AimTo evaluate the feasibility and efficacy of balloon-expandable stent angioplasty in the treatment of vertebral artery stenosis in the V2 segment.Material and methodsFive patients with vertebral artery stenosis (V2 segment) and treatment of percutaneous transluminal stenting from July 2009 to June 2014 were retrospectively evaluated. All patients underwent color Doppler, transcranial color Doppler (TCD), CT angiography (CTA) and cerebral digital subtraction angiography (DSA) preoperatively. Whether there was osseous oppression was determined according to neck computed tomography (CT) and CTA. After the surgery, angiography was performed to determine if there was infarction or bleeding in the intracranial vertebral artery, basilar artery and posterior cerebral artery. The surgical parameters, residual stenosis, complications, etc. were recorded and evaluated. The patients were followed up accordingly.ResultsFive patients (3 males, 2 females; average age of 66 ±4.2, range of 54–75) were enrolled in the study. Balloon-expandable stents were successfully implanted in the 5 patients. The mean residual stenosis after the balloon-expandable stenting (preoperative: average, 87.0 ±6.6%, range: 75–93%) was 12.6 ±7.8% (range: 5–25%). The clinical symptoms disappeared or receded. No serious complications occurred.ConclusionsThe balloon-expandable stent angioplasty seemed to be feasible and efficacious in treating vertebral artery stenosis in the V2 segment. Further study with a large sample size is needed.

A Posterior Circulation Ischemia Risk Score System to Assist the Diagnosis of Dizziness

We aimed to establish a risk score system without radio-image examination, which could help clinicians to differentiate patients with vertigo and posterior circulation ischemia (PCI) rapidly from the other dizzy patients. We analyzed 304 patients with vertigo (50% PCI). The attributes with more significant contributions were selected as the risk factors for the PCI risk score system, and every one of them was assigned a value according to their respective odds ratio values. We also compared the respective receiver operating characteristic curves of the 3 diagnostic methods (PCI score system, ABCD2, and Essen score systems) to evaluate their prediction effectiveness. Nine risk factors were ultimately selected for PCI score system, including high blood pressure (1'), diabetes mellitus (1'), ischemic stroke (1'), rotating and rocking (-1'), difficulty in speech (5'), tinnitus (-5'), limb and sensory deficit (5'), gait ataxia (1'), and limb ataxia (5'). According to their respective PCI risk scores, the patients were divided into 3 subgroups: low risk (≤0', risk <37.4%), medium risk (1'-5'), and high risk (≥6', risk >95.0%). When 0' was selected as a cutoff point for differentiating the patients with PCI from patients without PCI, the sensitivity was 94.1%, with a specificity of 41.4%. The areas under the receiver operator curve value of PCI score system was .82 (P = .000), much higher than the areas under the receiver operator curve value of ABCD2 (.69, P = .000) and that of the Essen system (.67, P = .000) CONCLUSION: The PCI score system could help clinicians to differentiate patients with vertigo and PCI rapidly from the other dizzy patients.

Seven years' follow-up of comparative study between stenting and medication for treatment of symptomatic vertebrobasilar artery stenosis.

Objective Endovascular stent-assistant angioplasty (ESAA) is a valid treatment for symptomatic vertebrobasilar artery stenosis (SVAS), but the long-term effect and the improvement of condition compared with medication treatment are unknown. This study investigated the long-term efficacy of ESAA in patients with moderate and severe SVAS, and compared the efficacy with medication treatment. Materials and methods We conducted a retrospective analysis of clinical data of 43 patients with moderate and severe SVAS hospitalized in our department. According to different treatment methods they were divided into 29 cases in an ESAA group and 14 cases in a medication treatment group. During the follow-up period, the degree of vascular stenosis, vascular blood flow velocity, restenosis rate, recovery of neurological function and the incidence of cerebral ischemic events in the two groups were analyzed. Results The average clinical follow-up period was 89.4 ± 10.2 months. Before treatment, the stenosis rate and average blood flow velocity of the two groups were not statistically significant ( p > 0.05). During the follow-up period, both were significantly lower than the medication treatment group ( p < 0.01). In the ESAA group, three cases of stent stenosis, and three cases in the medication treatment group were completely occluded. The total ischemic events in ESAA group were three cases, compared with nine cases in the medication treatment group; the difference was statistically significant ( p < 0.05). Conclusion ESAA has a long-term effect in the treatment of symptomatic moderate and severe vertebrobasilar artery stenosis. It is superior to medication therapy in preventing posterior circulation ischemia (PCI), but a larger sample size is still needed to confirm the study.

Detecting Intracranial Vessel Wall Lesions With 7T-Magnetic Resonance Imaging: Patients With Posterior Circulation Ischemia Versus Healthy Controls.

Vessel wall magnetic resonance imaging sequences have been developed to directly visualize the intracranial vessel wall, enabling detection of vessel wall changes, including those that have not yet caused luminal narrowing. In this study, vessel wall lesion burden was assessed in patients with recent posterior circulation ischemia using 7T-magnetic resonance imaging and compared with matched healthy controls. Fifty subjects (25 patients and 25 matched healthy controls) underwent 7T-magnetic resonance imaging with an intracranial vessel wall sequence before and after contrast administration. Two raters scored the presence and contrast enhancement of arterial wall lesions in individual segments of the circle of Willis and its primary branches. Total burden and distribution of vessel wall lesions and lesion characteristics (configuration, thickening pattern, and contrast enhancement) were compared both between and within both groups. Overall, vessel wall lesion burden and distribution were comparable between patients and controls. Regarding individual arterial segments, only vessel wall lesions in the posterior cerebral artery were more frequently observed in patients (18.0%) than in controls (5.4%; P=0.003). Many of these lesions showed enhancement, both in patients (48.9%) and in controls (43.5%; P=0.41). In patients, the proportion of enhancing lesions was higher in the posterior circulation (53.3%) than in the anterior circulation (20.6%; P=0.008). Although overall intracranial vessel wall lesion burden and contrast enhancement were comparable between patients with recent posterior circulation ischemia and healthy controls, this study also revealed significant differences between the 2 groups, suggesting an association between posterior circulation lesion burden/enhancement and ischemic events. URL: http://www.trialregister.nl. Unique identifier: NTR5688.

Diagnosis of DWI-negative acute ischemic stroke: A meta-analysis.

To determine the prevalence of diffusion-weighted imaging (DWI)-negative acute ischemic stroke (AIS) and to identify clinical characteristics of patients with DWI-negative AIS. We systematically searched PubMed and Ovid/MEDLINE for relevant studies between 1992, the year that the DWI sequence entered clinical practice, and 2016. Studies were included based upon enrollment of consecutive patients presenting with a clinical diagnosis of AIS prior to imaging. Meta-analysis was performed to synthesize study-level data, estimate DWI-negative stroke prevalence, and estimate the odds ratios (ORs) for clinical characteristics associated with DWI-negative stroke. Twelve articles including 3,236 AIS patients were included. The meta-analytic synthesis yielded a pooled prevalence of DWI-negative AIS of 6.8%, 95% confidence interval (CI) 4.9-9.3. In the 5 studies that reported proportion data for DWI-negative and DWI-positive AIS based on the ischemic vascular territory (n = 1,023 AIS patients), DWI-negative stroke was strongly associated with posterior circulation ischemia, as determined by clinical diagnosis at hospital discharge or repeat imaging (OR 5.1, 95% CI 2.3-11.6, p < 0.001). A small but significant percentage of patients with AIS have a negative DWI scan. Patients with neurologic deficits consistent with posterior circulation ischemia have 5 times the odds of having a negative DWI scan compared to patients with anterior circulation ischemia. AIS remains a clinical diagnosis and urgent reperfusion therapy should be considered even when an initial DWI scan is negative.

Isolated transient vertigo: posterior circulation ischemia or benign origin?

BackgroundIsolated transient vertigo can be the only symptom of posterior circulation ischemia. Thus, it is important to differentiate isolated vertigo of a cerebrovascular origin from that of more benign origins, as patients with cerebral ischemia have a much higher risk for future stroke than do those with ‘peripheral’ vertigo. The current study aims to identify risk factors for cerebrovascular origin of isolated transient vertigo, and for future cerebrovascular events.MethodsFrom the files of 339 outpatients with isolated transient vertigo we extracted history, clinical and technical findings, diagnosis, and follow-up information on subsequent stroke or transient ischemic attack (TIA). Risk factors were analyzed using multivariate regression models (logistic or Cox) and reconfirmed in univariate analyses.ResultsOn first presentation, 48 (14.2%) patients received the diagnosis ‘probable or definite cerebrovascular vertigo’. During follow-up, 41 patients suffered stroke or TIA (event rate 7.9 per 100 person years, 95% confidence interval (CI) 5.5–10.4), 26 in the posterior circulation (event rate 4.8 per 100 person years, 95% CI 3.0–6.7). The diagnosis was not associated with follow-up cerebrovascular events. In multivariate models testing multiple potential determinants, only the presentation mode was consistently associated with the diagnosis and stroke risk: patients who presented because of vertigo (rather than reporting vertigo when they presented for other reasons) had a significantly higher risk for future stroke or TIA (p = 0.028, event rate 13.4 vs. 5.4 per 100 person years) and for future posterior circulation stroke or TIA (p = 0.044, event rate 7.8 vs. 3.5 per 100 person years).ConclusionsWe here report for the first time follow-up stroke rates in patients with transient isolated vertigo. In such patients, the identification of those with cerebrovascular origin remains difficult, and presentation mode was found to be the only consistent risk factor. Confirmation in an independent prospective sample is needed.

Value of 3D Pseudo-continuous Arterial Spin Labeling Magnetic Resonance Perfusion Imaging in Evaluating Posterior Circulation Ischemia in the Elderly.

Objective To investigate the value of 3D pseudo-continuous arterial spin labeling (3D-pCASL) magnetic resonance perfusion technique in evaluating posterior circulation ischemia (PCI) of the elderly beyond 80 years old and to offer the evidence of PCI of the elderly for clinical diagnosis. Methods Totally 53 male subjects older than 80 years were recruited in this study,including 20 subjects with clinically diagnosed PCI and 33 normal subjects. All the subjects underwent routine brain magnetic resonance imaging and 3D-pCASL sequence on a 3.0T magnetic resonance imaging system with 8 channel brain coil. Two post-labeling delay (PLD) time (PLD=1525 ms and PLD=2525 ms) of 3D-pCASL were used in this study to increase the accuracy of cerebral blood flow (CBF) change of posterior circulation region. We used SPM12 software to measure mean CBF values of bilateral occipital lobes and bilateral cerebellums. Independent sample t-test and rank-sum test were performed to evaluate the difference of CBF changes of anterior circulation and posterior circulation in two groups at two PLD time,the difference of CBF changes of bilateral occipital lobes and bilateral cerebellums in two groups of two PLD time,and the difference of increment of CBF between two PLD interval between two groups. Results In case group,the CBF value of the anterior circulation was significantly higher than that of posterior circulation at both two PLD time points (PLD=1525 ms and PLD=2525 ms)(P=0.000,P=0.000);in control group,the CBF value of the anterior circulation was significantly higher than that of the posterior circulation only at PLD=1525ms (P=0.025). The CBF values at bilateral occipital lobes and bilateral cerebellums at two PLD time points (PLD=1525 ms and PLD=2525 ms) were significantly higher in case group than in control group(P=0.003,P=0.002,P=0.000,P=0.001,P=0.000,P=0.001,P=0.002,P=0.014,respectively). Compared with the control group,the difference was statistically significant in bilateral occipital lobes and cerebellums with a smaller △CBF between two PLD interval in case group (P=0.004,P=0.001,P=0.001,P=0.025). Conclusion Multiple PLD time points need to be used in 3D-pCASL in diagnosing PCI of the elderly because the posterior circulation is slow in these patients. 3D-pCASL technique is sensitive in detecting decreased CBF in posterior circulation and therefore can be used to predict posterior circulation stroke in the elderly.

Etiological analysis on patients in department of vertigo and dizziness oriented outpatient

Objective: We aimed to explore the spectrum of causes for patients in department of vertigo and dizziness oriented outpatient, in order to provide a reference for diagnosis and treatment of patients with vertigo or dizziness. Methods: Retrospective analysis were carried out with clinical data of patients in our department of vertigo and dizziness oriented outpatient. The target group under study was diagnosed based on the uniform diagnostic criteria, and re-visiting patients were excluded. Results: This clinical study was conducted on 5 348 cases, who visited our vertigo and dizziness oriented outpatient from December 2012 to July 2015. The ratio of male to female was 1∶1.48, the age range was between 16 and 93. The frequencies of different etiology were: benign paroxysmal positional vertigo 1 902(35.56%), Chronic subjective dizziness 1 329(24.85%), vestibular migraine 624(11.67%), Meniere's disease 378(7.07%), multi-sensory neuropathy 231(4.32%), vestibular paroxysmia 177(3.31%), benign recurrent vestibulopathy 171(3.20%), presyncope 66(1.23%), posterior circulation ischemia 57(1.07%), vestibular neuritis 54(1.01%), sudden deafness complicated vertigo 36(0.67%), other reasons 68(1.27%), unknown 255(4.77%). Conclusions: Our study indicates that the precedent three causes for vertigo or dizziness are benign paroxysmal positional vertigo, chronic subjective dizziness and vestibular migraine, followed by Meniere's disease、multi-sensory neuropathy, vestibular paroxysmia and benign recurrent vestibulopathy. Presyncope, posterior circulation ischemia, vestibular neuritis and sudden deafness complicated vertigo are relatively infrequent. There are still a certain proportion of patients undetermined.

Increased risk for posterior circulation ischaemia in patients with vertebral artery hypoplasia: A systematic review and meta-analysis.

Although several study protocols reported that vertebral artery hypoplasia can predispose to posterior circulation ischaemia, the role of vertebral artery hypoplasia in the risk of posterior circulation ischaemia still remains controversial. The aim of the present meta-analysis was to investigate the association of vertebral artery hypoplasia and posterior circulation ischaemia. We performed a systematic review and random effects meta-analysis of all eligible observational study protocols reporting prevalence rates of vertebral artery hypoplasia in patients with anterior circulation ischaemia and posterior circulation ischaemia. We identified eight study protocols including a total of 3875 acute ischemic stroke patients (mean age: 64.2 years, 61.3% males) and reporting a pooled prevalence of vertebral artery hypoplasia 18.6% (95%CI: 10.8-30.0%). In the overall analysis, a significantly higher probability of vertebral artery hypoplasia presence was found in posterior circulation ischaemia patients compared to patients with anterior circulation ischaemia (risk ratio = 2.12, 95%CI: 1.60-2.82, p < 0.001). In the subsequent sensitivity analysis, vertebral artery hypoplasia was again found to be significantly more prevalent in patients with posterior circulation ischaemia compared to anterior circulation ischaemia (risk ratio = 1.81, 95%CI: 1.58-2.06, p < 0.001), with no evidence of heterogeneity (I2 = 0%, p for Cochran Q = 0.55) between included studies. The present report is a meta-analysis of retrospective observational study protocols, with all the inherent limitations of included studies. The heterogeneity on the reported rates of vertebral artery hypoplasia could be attributed to differences in population age, sex, race, imaging protocols and vertebral artery hypoplasia definition between included studies. Our meta-analysis provides further evidence for a possible causal relationship between vertebral artery hypoplasia and cryptogenic posterior circulation ischaemia, an association which undoubtedly deserves further investigation in future prospective study protocols.

Surgical treatment for fracture-dislocation of upper cervical spine complicated with vertebral artery injury

Objective To explore the perioperative management and surgical outcomes of fracture-dislocation of the upper cervical spine complicated with vertebral artery injury. Methods We ret-rospectively analyzed the clinical data of 19 patients diagnosed with fracture-dislocation of the upper cervical spine complicated with vertebral artery injury who had been treated at our department from January 2008 through December 2012. They were 14 males and 5 females, aged from 22 to 53 years (mean, 35.2 years). All the patients had fractures of the atlas and/or axis, and disordered atlanto-axial relationship as well. According to Frankel grading system, 8 cases were Grade D and 11 Grade E. The cervical posterior fixation with pedicle screws was adopted for all and hemostasis was conducted for those with bleeding from the broken vertebral artery. Their Frankel grade, Japanese Orthopedic Association (JOA) score and visual analogue scale (VAS) score were compared between preoperation and final follow-up. Results Intraoperative hemor-rhage occurred in 2 patients from the injured vertebral artery. Hemostasis was achieved through direct tamponade with bone wax and gelatin sponge in one and through endovascular intervention after bleeding control by direct tamponade in another. Neither of them presented with symptoms of posterior circulation ischemia after operation. The mean operation time was 153.5 min, and the mean blood loss was 542.1 mL. All the patients were followed up for an average time of 28 months. Bony union was obtained in all after an average time of 13.5 weeks. Follow-ups revealed no ischemic stroke in this series. Symptoms of transient ischemic attack, like transient dizziness and blurred vision, appeared in 2 patients. At the final follow-up, all the patients were assessed as Frankel Grade E. Their mean JOA and VAS scores were significantly improved from 8.1±1.2 and 7.0±1.7 preoperatively to 12.7±1.6 and 1.3±1.2, respectively (P< 0.05). Conclusions An-giography examination is routinely indicated for the patients with fracture-dislocation of the upper cervical spine perioperatively. Preoperative evaluation of the vertebral artery and its adjacent structures and effective intra-operative hemostasis can avoid uncontrollable bleeding during operation, reduce postoperative complications, and improve surgical outcomes. Key words: Cervical; Fractures, bone; Dislocation; Vertebral artery injury

Keep it simple: vascular risk factors and focal exam findings correctly identify posterior circulation ischemia in "dizzy" patients.

BackgroundDizziness is a common chief complaint of patients presenting to the Emergency Department (ED). Physicians must quickly and accurately identify patients whose etiology is most likely ischemia. Additional tools are available, but often require further training (vestibular testing) or are costly and not always readily available (magnetic resonance imaging (MRI)). This study evaluates the ability of a routine history and simple physical examination to correctly identify dizzy patients with posterior circulation ischemia, and the added utility of CT angiography (CTA).MethodsWe performed a retrospective analysis of all individuals presenting to the ED with a reported chief complaint of dizziness. Neurology was consulted and CTA ordered at the discretion of the ED provider. Demographic, medical, and radiographic variables were evaluated along with final diagnosis. Multivariable logistic regression and ROC analysis were used to determine factors associated with ischemia, the sensitivity of vascular risk factors and focal exam findings in predicting ischemia, and the additional benefit, if any, of CTA.ResultsOne thousand two-hundred sixteen individuals meeting inclusion criteria presented to the ED over a 2 year period and were included in analysis. One hundred (8.2 %) were diagnosed with posterior circulation ischemia. For the entire cohort, age (OR 1.4 per 10 years, p < 0.0001), systolic blood pressure (OR 1.3 per 10 mmHg, p < 0.0001), and focal exam findings (OR 28.69, p < 0.0001) were most significantly associated with ischemia in multivariable modeling. When age, race, sex, presence of vascular risk factors, and focal neurologic findings were entered into ROC analysis, the AUC for correctly identifying posterior circulation ischemia was 0.90. In the subset of patients who underwent CTA (n = 87), the AUC did not improve (0.78 with and without CTA in ROC analysis, p = 0.52).ConclusionsA vascular risk assessment and neurological examination are adequate for risk stratification of ischemia in the dizzy patient and should remain the standard evaluation.

Abstract WP66: Posterior Communicating Artery May Decrease the Severity of Hyperacute Posterior Circulation Ischemic Stroke and Predict Clinical Outcomes

Background and Purpose: Hyperacute posterior circulation ischemia (PCI) is known to have poor clinical outcomes. Pretreatment ischemic lesion is an outcome predictor in patients with basilar artery occlusion. When basilar artery occlusion occurs, collateral blood flow can be reversed through hemodynamic connections between posterior communicating artery (PComA), first PCA segment, and carotid artery. We hypothesized that the presence of PComA is related to less severe ischemia and favorable outcome in the patients with hyperacute PCI. Methods: We retrospectively selected patients with acute ischemic lesion in posterior circulation who had received thrombolysis from stroke registry between June 2008 and September 2013. All patients were examined by CT angiography (CTA) before treatment. The NIHSS scale was used to assess initial stroke severity. The presence of PComA was confirmed based on axial CTA source images. The outcome of patients was defined as modified Rankin Scale score (mRS) after three months. Results: Seventy-five patients (45 male; mean age: 69 years, range; 29-91 years) were treated by multimodal thrombolytic therapy (27 intravenous only, 37 intra-arterial only, 11 intravenous and intra-arterial method). Thirty-four of 75 patients (45.3%) had bilateral PComAs and 36 of 75 patients (48%) had unilateral PComA. Initial NIHSS scale was significantly lower in patients with bilateral PComAs than patients with absent or unilateral PComA (mean NIHSS scale 12.38±9.02 vs. 18.73±9.19, p=0.004). The rate of favorable outcome (mRS 0-2) was significantly higher in patients with bilateral PComAs in comparison to patients with unilateral or absent PComA (78.6% vs. 27.3%, p&lt;0.001). Conclusions: PComA is related to initial severity of hyperacute PCI. Well-developed collateral flow is associated with less severe ischemic damage, and as a consequence, leads to more favorable outcomes. Further prospective clinical trials are required to confirm the effect of PComA on clinical outcomes of hyperacute PCI.

Abstract TP226: Vertebral Artery Dissection is More Common Than Carotid Artery Dissection and More Difficult to Detect on Non-invasive Imaging

Background: Cervical artery dissections (CAD) are among the most common causes of stroke in young and middle-aged adults. In contrast to carotid dissections (CD) and anterior circulation ischemia, the clinical manifestations of vertebral dissections (VD) and posterior circulation ischemia are often nonspecific (e.g. dizziness and ataxia), and thus a high index of suspicion is necessary for diagnosis. Therefore, the reported incidence of VD in the medical literature is likely to be an underestimation. Methods: With IRB approval, we conducted a retrospective chart review study using the Neurology Database of Houston Methodist Neurological Institute to identify all patients diagnosed with CAD between August 2011 and March 2015. All patients presented with cerebral ischemia (TIA or stroke). The diagnosis of CAD was made by a stroke neurologist and was based on clinical presentation and appropriate vascular imaging studies. Patients with incidental CAD and those with questionable diagnosis of CAD clinically and radiographically were excluded. Over the studied period (32 months), a total of 677 TIA patients and 3230 stroke patients were admitted to our tertiary-care hospital. Results: Of 52 patients with CAD-related TIA or ischemic stroke, there were 34 patients (65.4%) with VD and 18 patients (34.6%) with CD. The average age of presentation is 47 years (range: 18 to 75 years) for VD patients and 51 years (range: 34 to 78 years) for CD patients. CAD was slightly more common in males, with 18 VD patients (52.9%) and 10 CD patients (55.5%) in our studied population were males. Out of 30 patients with VD who underwent both noninvasive vascular imaging (MRA or CTA) and cerebral angiogram, dissection was detected on noninvasive imaging in 10 patients (33.3%). On the other hand, out of 13 patients with CD who had both types of imaging modalities, dissection was detected on noninvasive testing in 8 patients (61.5%). Conclusions: VD was detected approximately twice as frequently as CD in our study. Both conditions are slightly more common in men with an average age of presentation is about 50 years. In addition, our data suggest that noninvasive testing is more likely to diagnose carotid dissection (in two-third of cases) than vertebral dissection (in one-third of cases).

Abstract TMP38: Vertebrobasilar Dolichoectasia is a Distinct Subtype of Intracranial Large Artery Disease: Computational Fluid Dynamics of Hemodynamic Abnormalities

Background: Imaging of stroke due to vertebrobasilar dolichoectasia may not reveal either luminal stenosis or atherosclerotic plaque, leading to misdiagnosis of stroke mechanism or etiology. We leveraged the advanced imaging capabilities of computational fluid dynamics (CFD) to disclose the hemodynamic abnormalities within these complex neurovascular lesions. Methods: CT angiography from a series of stroke patients with vertebrobasilar dolichoectasia was selected from a prospective imaging registry of posterior circulation ischemia. A 3D geometric mesh was generated from CTA source images, extending from distal V4 vertebral arteries (VA) to the P1 posterior cerebral arteries (PCA). CFD processing was conducted with Ansys (ICEM, CFX) on a Cray supercomputer. Boundary conditions applied at the VA inlets and PCA outlets were used to map intraluminal pressure changes (ΔP), blood flow velocities (V), turbulent kinetic energy (TKE) and wall shear stress (WSS). Results: 18 cases of vertebrobasilar dolichoectasia with CTA source images were processed with CFD. Focal stenoses (&gt;50%) were apparent in only 4/18 (22%) cases. Intraluminal pressure varied markedly throughout the vertebrobasilar arterial segments in 7/18 (39%) cases. Blood flow velocities were also heterogeneous, with increases in 6/18 (33%) cases and decreases in 5/18 (28%) cases. WSS was markedly abnormal in all 18 cases, revealing regions of both elevated WSS and contralateral decreases in WSS. Maximal TKE values were within expected range for arterial diameter, yet obvious eddy currents were visualized in all 18 cases. Conclusions: CFD generated from routine CTA reveals numerous hemodynamic abnormalities in vertebrobasilar dolichoectasia, even when stenosis is unapparent. WSS-induced remodeling mapped with CFD may be used to detect arteriogenesis and atherosclerotic lesion development.

Abstract TP32: Endovascular Treatment of Posterior Circulation Strokes Improves Outcome

Introduction: Patients presenting with acute ischemic stroke due to a large vessel occlusion of the anterior circulation (usually M1), are now offered thrombectomy after 6 major trials demonstrated superior results over IV tPA alone. However, there are few trials evaluating the benefit of clot retrieval in posterior circulation strokes. Our goal was to evaluate the benefit of thrombectomy for posterior circulation strokes. Methods: We conducted a comprehensive record review of patients who underwent acute endovascular intervention for posterior circulation ischemia at a community based, university affiliated comprehensive stroke center during a 5-year period (2010-2015). The initial NIHSS, discharge NIHSS and discharge mRS were abstracted. We compared discharge mRS to composite 90 DAYS mRS of six recent multi-centered prospective randomized control trials (MPRCT) for acute endovascular treatment of acute ischemic stroke involving large vessel occlusions (SWIFT PRIME, ESCAPE, MR CLEAN, EXTEND-IA, REVASCAT, THERAPY). Results: There were 2,980 patients who presented with acute ischemic stroke during the pre-specified time period. Of those 310 were posterior circulation strokes; of which, 34 underwent endovascular treatment. These were compared with 1,386 patients with proximal anterior circulation strokes included in the recent MPRCTs. The mean age was 62 (SD=12). Mean initial NIHSS was 12 (SD=11). Mean change in NIHSS was 4 (SD =6). Mean discharge NIHSS was 9 (SD=11). Mean discharge mRS was 2.6 (SD=2.1). Conclusion: The benefits of thrombectomy for posterior circulation strokes compare well with those recently achieved by the trials evaluating the treatment for anterior circulation strokes. A prospective randomized trial comparing this option with the standard of care should be attempted to better elucidate the results.

Safety of different acupuncture manipulations for posterior circulation ischemia with vertigo.

Acupuncture at Fengchi (GB20) in the posterior neck improves vertigo. However, subarachnoid hemorrhage and spinal epidural hematoma have been reported to occur after acupuncture in the posterior neck. Therefore, in the present study, we assessed the safety of acupuncture at Fengchi. Laboratory tests and adverse event reports were used to evaluate the safety of different acupuncture manipulations for the treatment of posterior circulation ischemia with vertigo. A total of 136 patients were randomly assigned to four groups. Verum acupuncture was conducted with different needle insertion directions (contralateral paropia or prominentia laryngea) and different needle twisting frequencies (60 or 120 times/minute) at Fengchi and matching acupoints (for example, Zhongwan [CV12], Qihai [CV6], Zusanli [ST36], and Fenglong [ST40]). The patients received 14 treatments over 3-4 weeks. Routine blood analysis, hepatic and renal function tests, urine and feces tests and electrocardiography were performed before the first treatment session and after the final session. Adverse events were recorded after every session. Of the 136 patients, 120 completed the study. There were no significant differences between pretreatment and posttreatment test results in any of the groups. Only five patients suffered from minor adverse events (needling pain, slight hematoma and transient chest tightness). No serious adverse events were found. Our results indicate that a 14-session course of needling at Fengchi is relatively safe for treating posterior circulation ischemia with vertigo.