Posterior Vascular Territories Research Articles

IL-1 Beta-A Biomarker for Ischemic Stroke Prognosis and Atherosclerotic Lesions of the Internal Carotid Artery.

Background and Objectives: Stroke is a leading cause of mortality and morbidity worldwide. Treatment of this pathology is still under development and its risk factors remain to be determined. Therefore, we aim to determine the role of interleukin-1 beta in atherosclerotic lesions of the internal carotid artery as a risk factor for stroke and the role of this biomarker in stroke prognosis. Materials and Methods: This study enrolled 56 patients diagnosed with ischemic stroke in the anterior vascular territory (AVT) and posterior vascular territory (PVT). All the patients had venous blood collected at admission and 7 days after the onset of the cerebral ischemia in order to determine the plasma concentration of interleukin-1 beta. At the same time, an extracranial carotid ultrasound was performed. Results: The interleukin-1 beta collected at admission was positively correlated with the NIHSS at admission (Pearson index 0.424), and both measurements were correlated with carotid stenosis (Spearmen correlation index of 0.529 and 0.653, respectively). Conclusions: Interleukin-1 beta could be a reliable biomarker for stroke prognosis and the development of atherosclerotic lesions of the internal carotid.

High posterior cerebral artery flow predicts ischemia recurrence in patients with internal carotid artery occlusion.

Recurrent stroke is a dreaded complication of symptomatic internal carotid artery occlusion (ICAO). Transcranial Duplex (TCD)-derived increased flow velocity in the ipsilateral posterior cerebral artery (PCA)-P2 segment indicates activated leptomeningeal collateral recruitment and hemodynamic impairment. Leptomeningeal collaterals are pial vascular connections between the anterior and posterior vascular territories. These secondary collateral routes are activated when primary collaterals via the Circle of Willis are insufficient. Our goal was to test the TCD parameter PCA-P2 flow for prediction of ipsilateral ischemia recurrence. We retrospectively analyzed clinical and ultrasound parameters in patients with ICAO. Together with clinical variables, we tested systolic PCA-P2 flow velocity as predictor of a recurrent ischemic event using logistic regression models. Of 111 patients, 13 showed a recurrent ischemic event within the same vascular territory. Increased flow in the ipsilateral PCA-P2 on transcranial ultrasound (median and interquartile range [IQR]: 60 cm/s [IQR 26] vs. 86 cm/s [IQR 41], p = <0.001), as well as previous transient ischemic attack (TIA) and low NIHSS were associated with ischemia recurrence. Combined into one model, accuracy of these parameters to predict recurrent ischemia was 89.2%. Our data suggest that in patients with symptomatic ICAO, flow increases in the ipsilateral PCA-P2 suggest intensified compensatory efforts when other collaterals are insufficient. Together with the clinical variables, this non-invasive and easily assessable duplex parameter detects ICAO patients at particular risk of recurrent ischemia.

Clinical and functional characteristics of women after stroke, fallers and non-fallers: a longitudinal study

BACKGROUND: Occurrence of falls is among the most frequent complications presented by the elderly and individuals with neurological diseases. It is known that in the elderly, there is a greater frequency of falls in women. However, in individuals after stroke, this relationship is not established. The purpose of this study was to differentiate the clinical and functional characteristics of fallers and non-fallers women after stroke and to verify the association between functional mobility and functional capacity in these women. DESIGN AND SETTING: This is a longitudinal prospective study conducted in Salvador, Bahia, Brazil. METHODS: Women with independent gait assisted in a reference outpatient clinic were included. Sociodemographic and clinical data were collected, and the National Institutes of Health Stroke Scale, Modified Barthel Index, Timed Up and Go (TUG), and European quality of life were applied. The level of significance was set at 5%. RESULTS: A total of 68 women with a mean age of 56 (± 13.7) years were selected; 51% of the women fell in the follow-up, the latter was younger than 55 years (± 13.4), with greater severity of the stroke. Impairment in the posterior vascular territory was more evident among falling women (P = 0.009), but all falling and non-falling women presented impaired functional mobility (TUG = 15seconds). However, the total sample was classified as totally independent or with slight dependence on the activities of daily living (ADLs) (MBI = 49). The correlation between TUG time and MBI was negative and significant (R = -0.702, P ? 0.001). CONCLUSIONS: The involvement of posterior circulation is an important predictor of falls, an important indicator in the monitoring of women after stroke. It also emphasizes that the lower functional mobility impacted women's functional capacity.

White matter damage due to pulsatile versus steady blood pressure differs by vascular territory: A cross-sectional analysis of the UK Biobank cohort study

Small vessel disease is associated with age, mean blood pressure (MAP) and blood pressure pulsatility (PP). We used data from the UK Biobank cohort study to determine the relative importance of MAP versus PP driving white matter injury within individual white matter tracts, particularly in the anterior and posterior vascular territory. The associations between blood pressure and diffusion indices in 27 major tracts were analysed using unadjusted and fully-adjusted general linear models and mixed-effect linear models. Blood pressure and neuroimaging data were available for 37,041 participants (mean age 64+/−7.5 years, 53% female). In unadjusted analyses, MAP and PP were similarly associated with diffusion indices in the anterior circulation. In the posterior circulation, the associations were weaker, particularly for MAP. In fully-adjusted analyses, MAP remained associated with all diffusion indices in the anterior circulation, independently of age. In the posterior circulation, the effect of MAP became protective. PP remained associated with greater mean diffusivity and extracellular free water diffusion in the anterior circulation and all diffusion indices in the posterior circulation. There was a significant interaction between PP and age. This implies discordant mechanisms for chronic white matter injury in different brain regions and potentially in the associated stroke risks.

External validation of the recurrent falls risk scale in community-dwelling stroke individuals

ObjectiveTo externally validate the Recurrent Fall Risk Scale (ReFR) in community-dwelling stroke survivors. MethodsCohort of stroke survivors with independent gait ability recruited from a reference outpatient stroke clinic. Besides sociodemographic and clinical data, the following scales were used: Modified Barthel Index (mBI), ReFR scale and National Institutes of Health Stroke Scale (NIHSS). Participants were followed up for 12 months to record the incidence of falls. Accuracy of the ReFR scale was measured by the area under the ROC curve. ResultsOne hundred and thirteen individuals were recruited between April 2016 and November 2016: mean age 54 years (± 14), 55% women, median time since the last stroke 24 months (range 12 –48 months), posterior vascular territory affected in 35% of the sample. Median NIHSS was 3 (range 1 to 6), median mBI 49 (range 46–50), median ReFR 3 (range 2 to 5). During the follow-up period, 32 (33%) subjects had at least one fall and 18 (19%) were recurrent fallers (two or more falls). The accuracy of ReFR scale was 0.67 (95% CI = 0.54–0.79), p = 0.026. ConclusionThis study externally validated the ReFR as a tool to predict recurrent falls in individuals after stroke.

Posterior Reversible Encephalopathy Syndrome and Azathioprine.

Posterior reversible encephalopathy syndrome should be considered in patients with sudden onset of headache, altered consciousness and seizures.Recognition of this entity and identification of the trigger are essential for reversal of the clinical picture.Autoimmune diseases and some immunosuppressive drugs have been identified as causative, but reports of an association with azathioprine are very rare.

Posterior Reversible Encephalopathy Syndrome and Azathioprine

Posterior reversible encephalopathy syndrome (PRES) is a rare syndrome that presents with neurological manifestations, often associated with arterial hypertension. Magnetic resonance imaging (MRI) shows bilateral white matter oedema in the posterior vascular territories. Immunosuppression, (pre) eclampsia and autoimmune diseases can be implicated. A 27-year-old woman, with mixed connective tissue disease under azathioprine, was admitted in the emergency room in status epilepticus and with severe hypertension. The MRI showed bilateral oedema in a pattern compatible with PRES. There was clinical improvement after azathioprine suspension. PRES is typically reversible with prompt recognition of the syndrome and its trigger. The association with azathioprine is rare.

Study of Renal and Kidney Tumor Vascularization Using Data from Preoperative Three-dimensional Arteriography Prior to Partial Nephrectomy

BackgroundIn a cadaveric model with healthy kidneys, it has recently been highlighted that a single renal segment could be supplied by one or more arterial branches originating from an artery supplying another segment. ObjectiveTo demonstrate occurrences of anatomical variations of renal vascularization and to analyze vascularization of renal tumors. Design, setting, and participantsThis prospective monocentric study included all patients treated for a renal tumor between May 2015 and June 2017 by laparoscopic partial nephrectomy after superselective tumor embolization in a hybrid operating room. InterventionThree-dimensional renal and tumoral arteriography with cone-beam computed tomography scan was performed, coupled with preoperative cross-sectional imaging. This procedure provided an accurate vascular anatomical mapping of the kidney and allowed further analysis of tumor vascularization. Outcome measurements and statistical analysisRelation between anatomical variations of the vascularization and perioperative data was assessed. A χ2 test or Fisher’s test was used for qualitative variables, and a Student t test was used for quantitative variables. Results and limitationsOut of the 60 patients included, only 25 (42%) presented a standard vascular subdivision. In 26 patients (43%), tumors were supplied by more than one branch and in 20 patients (33%), there was a branch supplying the tumor from another segment. In these cases of multiple or multi-segmental tumor vascularization, tumor size, operative duration, and duration of embolization were significantly higher than in the case of standard vascularization. These complex tumors were more often located at the upper pole of the kidney or at the junction of the anterior and posterior vascular territories of the kidney. Limitations of this study include the low number of patients and its monocentricity. ConclusionsThis study confirms that renal vascularization frequently differs from Graves’ reference model and that tumor vascularization can depend on several segmental branches. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy. Patient summaryWe studied renal and tumor vascularization using three-dimensional preoperative arteriography data on tumor kidneys. We have shown that there is great variability in renal vascularization and that tumors can be vascularized branches that originate from an artery leading to another segment. This vascular complexity explains surgical difficulties and must be taken into consideration when segmental arterial clamping is considered during partial nephrectomy.

The Correlation between Cerebral Blood Flow Measured by Bedside Xenon-CT and Brain Chemistry Monitored by Microdialysis in the Acute Phase following Subarachnoid Hemorrhage.

Cerebral microdialysis (MD) may be used in patients suffering from subarachnoid hemorrhage (SAH) to detect focal cerebral ischemia. The cerebral MD catheter is usually placed in the right frontal lobe and monitors the area surrounding the catheter. This generates the concern that a fall in cerebral blood flow (CBF) and ischemic events distant to the catheter may not be detected. We aimed to investigate if there is a difference in the association between the MD parameters and CBF measured around the MD catheter compared to global cortical CBF and to CBF in the vascular territories following SAH in the early acute phase. MD catheter was placed in the right frontal lobe of 30 SAH patients, and interstitial glucose, lactate, pyruvate, glycerol, and lactate/pyruvate ratio were measured hourly. CBF measurements were performed during day 0–3 after SAH. Global cortical CBF correlated strongly with CBF around the microdialysis catheter (CBF-MD) (r = 0.911, p ≤ 0.001). This was also the case for the anterior, middle, and posterior vascular territories in the right hemisphere. A significant negative correlation was seen between lactate and CBF-MD (r = −0.468, p = 0.009). The same relationship was observed between lactate and CBF in anterior vascular territory but not in the middle and posterior vascular territories. In conclusion, global CBF 0–3 days after severe SAH correlated strongly with CBF-MD. High lactate level was associated with low global CBF and low regional CBF in the right anterior vascular territory, when the MD catheter was placed in the right frontal lobe.

Cerebral vasculitis complicating postoperative meningitis: the role of steroids revisited

Meningitis due to Streptococcus pneumoniae is a rare complication of trans-sphenoidal surgery. We present the case of a patient who developed pneumococcal meningitis with associated bacteraemia after elective endoscopic trans-sphenoidal resection of a pituitary macro-adenoma. After initial treatment with ceftriaxone and dexamethasone, the patient made a good recovery and dexamethasone was discontinued. Two days later the patient's condition deteriorated rapidly, presenting focal and diffuse neurological deficits. Cerebral MRI revealed widespread punctate ischaemic-type lesions affecting both anterior and posterior vascular territories bilaterally and involving features consistent with cerebral vasculitis. Antibiotic treatment was broadened to include meropenem and dexamethasone was restarted, but the patient remained in a comatose state and died 14 days later. Steroid treatment may play a dual role in this poorly characterised infectious complication of trans-sphenoidal pituitary surgery. This possibility is discussed and the options for prophylaxis are reviewed.

Role of sympathetic nervous system in activity-induced cerebral perfusion

Several studies have suggested that autonomic neural control plays a role in regulation of cerebral blood flow (CBF), although the exact role of the sympathetic nervous system on CBF remains debated. The effects of sympathetic innervation on activity-induced cerebral perfusion changes in humans have not been studied. The aims of this study were therefore (a) to investigate patients with an "intrinsic" sympathetic deficit after stroke and healthy controls with regard to activity-induced cerebral perfusion changes, and (b) to investigate possible differences in functional CBF regulation between the anterior and posterior circulation. Cerebral blood flow velocity in the medial cerebral artery (MCA) and posterior cerebral artery (PCA) was investigated in 21 healthy controls and 17 patients with Wallenberg's syndrome using transcranial Doppler sonography during cortical activation of MCA and PCA territories, respectively. Patients with a central sympathetic deficit had a prolonged decrease of resistance in the MCA and showed a slower and less pronounced decrease of resistance in the PCA upon cortical activation. No difference was observed between the side with and without sympathetic deficit. Results suggest that (a) sympathetic efferents are involved in economisation of activity-induced changes of cerebral perfusion in the anterior circulation, (b) activity-induced sympathetic regulation of blood flow differs between the anterior and posterior vascular territories in humans and (c) a possible resting sympathetic tonus on extraparenchymal vessel might exist in the posterior circulation.

Resolution of Tracheal Aspiration After the Acute Phase of Stroke-Related Oropharyngeal Dysphagia

We set out to ascertain the evolution and the clinical and videofluoroscopic (VFS) prognostic factors of aspiration recovery and return to oral intake in patients with stroke and VFS diagnosis of tracheal aspiration. Twenty patients with stroke and VFS diagnosis of tracheal aspiration were prospectively evaluated. Clinical evaluation of oropharyngeal dysphagia and VFS examination were performed at admission and repeated at 1, 3, 6 and 12 months of follow-up. At admission, videofluoroscopy showed 40% of patients to have an increase in oral transit time and 65% impaired tongue control; in the pharyngeal phase, mean pharyngeal transit time was increased in 70% of patients and the time required to trigger the swallowing reflex was delayed in 70%. During follow-up, an improvement was observed, and the number of patients with aspiration decreased progressively (the most significant change occurred at 6 months). Evolution was related to the vascular territory affected: at 1 year, aspiration persisted in 12% of anterior territory lesions vs. 58% of posterior territory lesions. Also, the number of silent aspirators decreased from 35% at baseline to no patients after 3 months. Persistent aspiration at 1 year of follow-up significantly correlated with the following baseline variables: vascular territory, gag reflex abolition, palatoglossal seal alteration and pharyngeal delay time. Swallowing physiology in stroke greatly improved during follow-up, mainly between 3 and 6 months, and the number of aspirations decreased progressively. Prognostic factors for persisting aspiration are posterior vascular territory lesions, oropharyngeal reflex abolition, palatoglossal seal alteration and pharyngeal delay time at baseline.

Internal carotid artery stenosis with ipsilateral persistent hypoglossal artery presenting as a multiterritorial embolic infarction: a case report

Persistent hypoglossal artery (PHA) is a relatively rare vascular anomaly of persistent carotid-basilar anastomosis. We have treated a patient with stenosis of the internal carotid artery which was combined with PHA and who presented with multiple small embolic infarcts in multiple vascular territories. It is important to know that a persistent carotid-basilar anastomosis could be one of the causes bringing about acute infarction in both the anterior and posterior vascular territories, mimicking cardioembolism.

Cerebral infarction immediately after ingestion of hydrogen peroxide solution.

We report the clinical and neuroimaging findings of a patient who sustained multiple cerebral infarcts after the ingestion of concentrated hydrogen peroxide solution sold as a "health food" product. An 84-year-old man sustained focal neurological deficits immediately after ingesting 30 mL of 35% hydrogen peroxide solution. Physical examination disclosed a left hemiparesis, frontal release signs, and cerebellar dysfunctions. Magnetic resonance imaging revealed multiple cerebral and cerebellar infarctions in the anterior, middle, and posterior vascular territories. The likely mechanism of pathogenesis involves cerebral oxygen gas embolization. The use of hyperbaric therapy should be considered in treating hydrogen peroxide poisoning.

Usefulness of single-photon emission computed tomography of thallium-201 uptake after dipyridamole infusion for detection of coronary artery disease

The diagnostic performance of single-photon emission computed tomography (SPECT) and planar imaging of thallium-201 uptake for the detection of coronary artery disease (CAD) was compared in 79 patients who underwent both dipyridamole thallium-201 scintigraphy and coronary angiography. Clinical subgroups were assigned by severity of CAD, presence of a prior myocardial infarction and the number of narrowed coronary arteries. The overall detection of CAD was 89% for SPECT and 67% for planar (p < 0.001). For the anterior vascular territory, sensitivities for SPECT and planar imaging were 69 and 44% (p < 0.01), respectively; for the posterior vascular territory, sensitivities were 80 and 54% (p < 0.01). Receiver-operating characteristic analysis, using a 5-point evaluation scale, was performed for the anterior and posterior vascular territories. Receiver-operating characteristic curves generated for SPECT and planar studies demonstrated improved diagnostic performance by SPECT in the anterior vascular territory, but showed similar performance in the posterior territory because of lower SPECT specificity despite higher sensitivity at clinically relevant decision thresholds. In each clinical subgroup of patients, the detection of CAD by SPECT was significantly superior to that by planar imaging, regardless of the severity of stenosis or the number of significantly narrowed coronary arteries, or whether a myocardial infarction was present. Thus, SPECT thallium-201 scintigraphy is an important and necessary clinical tool for detecting CAD after dipyridamole infusion.

Brainstem Auditory Evoked Potentials in Alternating Hemiplegia: Ictal vs Interictal Assessment in One Case

The authors report a case of alternating hemiplegia (AH) in a 3yr 6m old boy who had presented, from the age of 4 months on, episodes of alternating hemi- or quadriplegia. Brainstem auditory evoked potentials were recorded both in the interictal state and, for the first time, during an attack. There was no significant difference between the two states. These findings suggest that a massive involvement of the posterior vascular territory is not likely to be associated with attacks in AH.

SEM studies of the functional morphology of the ciliary process vasculature in the cynomolgus monkey: Reactions after application of epinephrine

In the ciliary processes of the cynomolgus monkey three vascular territories with discrete arterioles and venules were found by means of scanning electron micrographs of vascular resin casts. The first vascular territory, which is located at the anterior end of the major processes, is drained posteriorly by long isolated venules, which pass the ciliary body without greater connections to the venules of the major ciliary processes, whereas the second and third territories comprise the vasculature of the major and minor ciliary processes drained posteriorly by veins which are located at the internal edge of the ciliary processes. With the functional resin casting method it could be demonstrated that 15 min after application of 20 μg of epinephrine into the conjunctival sac the terminal arterioles supplying the first vascular territory constricted most intensely, whereas the terminal arterioles related to the middle and posterior vascular territory of the ciliary processes constricted to a lesser extent. Twenty-five minutes after topical application of epinephrine only the posterior vascular territory and the capillaries of the ciliary muscle appeared filled in the resin casts. The vasculature of the anterior territories remained empty because of strong vasoconstriction of the supplying arterioles. The three morphologically different vascular territories with their different sensitivities to epinephrine may reflect a functional differentiation in respect to aqueous humour formation and resorption.