bluuebunny/crossref_metadata_2025 huggingface dataset:
Impaired Pial Arteriolar Reactivity to Hypercapnia During Hyperammonemia Depends on Glutamine Synthesis
Authors: Hirata Takahiko , Koehler Raymond C. , Kawaguchi Tetsu , Brusilow Saul W. , Traystman Richard J.
Published: June 2011

Background and Purpose
Acute hyperammonemia causes glutamine and water accumulation in astrocytes and loss of the cerebral blood flow response selectively to CO
2
. We tested whether extraparenchymal pial arterioles not subjected directly to mechanical compression by swollen astrocyte processes also lose hypercapnic reactivity and whether any such loss can be attenuated by inhibiting glutamine synthesis during hyperammonemia.

Methods
Pentobarbital-anesthetized rats were pretreated intravenously with either saline vehicle, methionine sulfoximine (0.83 mmol/kg), which inhibits glutamine synthetase and potentially γ-glutamylcysteine synthetase, or buthionine sulfoximine (4 mmol/kg), which inhibits γ-glutamylcysteine synthetase. Three hours after pretreatment, cohorts received an intravenous infusion of either sodium or ammonium acetate for 6 hours. Pial arteriolar diameter was measured through a closed cranial window, and blood flow was measured with radiolabeled microspheres during normocapnia and 10 minutes of hypercapnia.

Results
With sodium acetate infusion, pial arteriolar diameter increased during hypercapnia in groups pretreated with vehicle (23±3% [mean±SE]; n=6), methionine sulfoximine (37±11%; n=5), and buthionine sulfoximine (32±3%; n=5). With ammonium acetate infusion, pial arteriolar diameter increased only in the group pretreated with methionine sulfoximine (31±4%; n=8) but not in those pretreated with vehicle (−2±4%; n=8) or buthionine sulfoximine (4±4%; n=6). Methionine sulfoximine, but not buthionine sulfoximine, also prevented loss of the cerebral blood flow response to hypercapnia, an increase in cortical tissue water content, and an increase in pressure under the cranial window during normocapnia in hyperammonemic rats. In contrast to hypercapnia, hypoxemia increased arteriolar diameter 30±7% (n=5) during ammonium acetate infusion.

Conclusions
Loss of the blood flow response to hypercapnia during acute hyperammonemia is not due simply to swollen astrocyte processes passively impeding blood flow because extraparenchymal resistance arterioles also lose their reactivity selectively to hypercapnia. Lost reactivity depends on glutamine synthesis rather than on ammonium ions per se and may reflect indirect effects of astrocyte dysfunction associated with glutamine accumulation or possibly effects of glutamine on nitric oxide production.
Aspirin in Ischemic Cerebrovascular Disease
Authors: Patrono Carlo , Roth Gerald J.
Published: June 2011

Background
A vast consensus exists in defining a narrow range of recommended daily doses of aspirin, ie, 75 to 160 mg, for the prevention of myocardial infarction, stroke, and vascular death in patients with different manifestations of coronary heart disease. In contrast, for patients with cerebrovascular disease, a much larger degree of uncertainty still exists, with recommendations ranging from 30 to 1300 mg daily.

Summary of Comment
The contention that higher doses of aspirin (650 to 1300 mg) are more effective than lower doses in stroke prevention is based on indirect and selective comparisons of different trial data, mini-meta-analyses, or subgroup analyses of individual trials. In the absence of definitive evidence from direct randomized comparisons of low-dose versus high-dose aspirin in trials of adequate size to detect a moderate difference between the two, the biological hypotheses that underpin the suggestion of greater efficacy of higher aspirin doses in cerebrovascular disease patients are reviewed and disputed. Practical implications of the use of higher doses of aspirin are also assessed on the basis of theoretical calculations of absolute benefits and risks.

Conclusions
Until additional information from ongoing trials is available, good clinical practice should dictate the use of the lowest dose of aspirin shown effective in the prevention of stroke and death in patients with ischemic cerebrovascular disease, ie, 75 mg daily.
Age-Related Changes in Stroke Risk in Men With Hypertension and Normal Blood Pressure
Authors: Curb J. David , Abbott Robert D. , MacLean Charles J. , Rodriguez Beatriz L. , Burchfiel Cecil M. , Sharp Dan S. , Ross G. Webster , Yano Katsuhiko
Published: June 2011

Background and Purpose
Stroke is a major contributor to total morbidity and mortality in older individuals, and hypertension is an important risk factor for stroke. Relatively few data exist on whether this relationship changes with age.

Methods
To examine age-related changes in the relationships between risk of stroke and hypertension, we examined the 6-year incidence of stroke among men aged 45 to 81 years using updated blood pressure data from three examinations of Japanese-American men from the Honolulu Heart Program.

Results
Both the prevalence of hypertension (systolic blood pressure ≥160 mm Hg or diastolic blood pressure ≥95 mm Hg or the use of antihypertensive medication) and the 6-year incidence of stroke increased significantly with increasing age (
P
<.01). The increase in thromboembolic stroke incidence with age was more marked in those who were normotensive at baseline (2.7/1000 in those aged 45 to 54 years to 23.9/1000 in those ≥65 years;
P
<.001) than in hypertensive men (20.6/1000 in those aged 45 to 54 years to 33.5/1000 in those ≥65 years;
P
<.01). The age-related increase in risk of thromboembolic stroke among normotensive men resulted in a decrease in the percentage of strokes attributable to hypertension (50% in those aged 45 to 54 years to 18% in those ≥65 years;
P
<.05). Similar trends were seen for hemorrhagic stroke. There were no age-related changes in the relationships of other major atherosclerotic risk factors with stroke. The hypertension/stroke relationships were present after multivariate adjustment for age, smoking, cholesterol, and other factors.

Conclusions
In view of the greater prevalence of hypertension and the proven efficacy of treatment in the elderly, these findings do not negate the value of aggressive screening and treatment of hypertension in this age group. However, it appears that other unidentified factors have an increasing role in the causation of stroke with advancing age.
Genetic Basis of Variation in Carotid Artery Wall Thickness
Authors: Duggirala Ravindranath , Villalpando Clicerio González , O’Leary Daniel H. , Stern Michael P. , Blangero John
Published: June 2011

Background and Purpose
Other than the documented associations of risk factors and carotid artery wall thickness, the genetic basis of variation in carotid artery intimal-medial thickness (IMT) is unknown. The purpose of this study was to examine the extent to which variation in common carotid artery (CCA) IMT and internal carotid artery (ICA) IMT are under genetic control.

Methods
The sibship data used for this analysis were part of an epidemiological survey in Mexico City. The CCA and ICA analyses were based on 46 and 44 sibships of various sizes, respectively. The CCA and ICA IMTs were measured with carotid ultrasonography. Using a robust variance decomposition method, we performed genetic analyses of CCA IMT and ICA IMT measurements with models incorporating several cardiovascular risk factors (eg, lipids, diabetes, blood pressure, and smoking) as covariates.

Results
After accounting for the effects of covariates, we detected high heritabilities for CCA IMT (h
2
=0.92±0.05,
P
=.001) and ICA IMT (h
2
=0.86±0.13,
P
=.029). Genes accounted for 66.0% of the total variation in CCA IMT, whereas 27.7% of variation was attributable to covariates. For ICA IMT, genes explained a high proportion (74.9%) of total phenotypic variation. The covariates accounted for 11.5% of variation in ICA IMT.

Conclusions
Our results suggest that substantial proportions of phenotypic variance in CCA IMT and ICA IMT are attributable to shared genetic factors.
Functional Outcome in Patients With Lacunar Infarction
Authors: Samuelsson Margareta , Söderfeldt Björn , Olsson Gun Britt
Published: June 2011

Background and Purpose
Little is known about the prognosis and the predictive factors for functional outcome after lacunar infarction. Our aim was to analyze this issue in more detail and with a longer follow-up than in previous reports.

Methods
Functional outcome was assessed in 81 consecutive patients with a first-ever stroke and clinical and MRI findings compatible with lacunar infarction. We measured impairment (motor, sensory, and cognitive function), disability (Katz’s Index of Activities of Daily Living [ADL] and four instrumental activities), and handicap (Oxford Handicap Scale). The patients were followed up for 3 years.

Results
During follow-up, 6% of the patients died and 21% had recurrent strokes, mostly new lacunar infarcts. A fast initial recovery was found in most patients. At 1 year, 12% were dependent in personal ADL, which after 3 years had increased to 24%, mostly as a result of the effects of recurrent strokes. In a logistic multivariate regression model, moderate or severe hemiparesis 1 month after stroke onset was the strongest predictor of physical dependence or death at 3 years (
P
<.001), followed by white matter hyperintensities on MRI (
P
<.01). Age, vascular risk factors, and recurrent stroke were not statistically significant independent predictors of functional outcome.

Conclusions
Functional outcome regarding physical independence was favorable in most patients. Motor impairment and white matter disease were the strongest predictors of a poor functional outcome. Recurrent stroke increased disability and handicap but was not a statistically significant independent risk factor. Measurements of personal ADL alone were insensitive in detecting the consequences of stroke in many patients with preserved self-care ability, who still experienced disability and handicap.
Risk of Stroke in a Cohort of 815 Patients With Calcification of the Aortic Valve With or Without Stenosis
Authors: Boon Arthur , Lodder Jan , Cheriex Emile , Kessels Fons
Published: June 2011

Background and Purpose
We sought to establish the possible role of calcification of the aortic valve with or without stenosis as a risk factor for stroke.

Methods
Occurrences of stroke, stroke subtypes, and concomitant cardiovascular risk factors were prospectively analyzed in 300 patients with echocardiographic evidence of aortic valve calcification, 515 patients with calcified aortic valve stenosis, and 562 control subjects.

Results
Twenty-four patients with aortic valve calcification, 24 patients with calcified aortic valve stenosis, and 27 control subjects had a stroke during follow-up. Using Cox proportional hazards models, we found that strokes were not significantly associated with aortic valve calcification with or without stenosis, but hypertension and any carotid stenosis were associated. On multiple logistic regression analysis, we did not find any association between one of the two valve lesions and indirect possible indications of cardiogenic embolism such as territorial as opposed to small deep brain infarcts or the presence of silent brain infarcts.

Conclusions
Aortic valve calcification with or without stenosis is not a risk factor for stroke.
Do Silent Brain Infarctions Predict the Development of Dementia After First Ischemic Stroke?
Authors: Bornstein N. M. , Gur A. Y. , Treves T. A. , Reider-Groswasser I. , Aronovich B. D. , Klimovitzky S. S. , Varssano D. , Korczyn A. D.
Published: June 2011

Background and Purpose
Silent brain infarctions (SBI) are common findings in advanced age, but their relationship to dementia is still uncertain. The present study was designed to evaluate whether SBI predict the development of dementia after first clinical ischemic stroke.

Methods
We blindly studied admission CT scans of 175 consecutive nondemented patients presenting with ischemic stroke that clinically was their first stroke episode. SBI were defined as CT evidence of infarcts not compatible with the acute event. The patients were subsequently followed for their mental state for 5 years. Survival analysis, wherein onset of dementia was the end point, was performed on the total sample population and conducted separately on those with and without SBI at admission.

Results
Dementia developed in 56 patients (32%), including 22 of the 63 (35%) with SBI and 34 of the 112 (30%) without SBI. Thus, dementia was not related to SBI.

Conclusions
Our data indicate that SBI do not predict the development of dementia after stroke.
Stretch-Induced Injury of Cultured Neuronal, Glial, and Endothelial Cells
Authors: McKinney J.S. , Willoughby K.A. , Liang S. , Ellis E.F.
Published: June 2011

Background and Purpose
There is abundant evidence that after in vivo traumatic brain injury, oxygen radicals contribute to changes in cerebrovascular structure and function; however, the cellular source of these oxygen radicals is not clear. The purpose of these experiments was to use a newly developed in vitro tissue culture model to elucidate the effect of strain, or stretch, on neuronal, glial, and endothelial cells and to determine the effect of the free radical scavenger polyethylene glycol–conjugated superoxide dismutase (PEG-SOD; pegorgotein, Dismutec) on the response of each cell type to trauma.

Methods
Rat brain astrocytes, neuronal plus glial cells, and aortic endothelial cells were grown in cell culture wells with 2-mm-thick silastic membrane bottoms. A controllable, 50-millisecond pressure pulse was used to transiently deform the silastic membrane and thus stretch the cells. Injury was assessed by quantifying the number of cells that took up the normally cell-impermeable dye propidium iodide. Some cultures were pretreated with 100 to 300 U/mL PEG-SOD.

Results
Increasing degrees of deformation produced increased cell injury in astrocytes, neuronal plus glial cultures, and aortic endothelial cells. By 24 hours after injury, all cultures showed evidence of repair as demonstrated by cells regaining their capacity to exclude propidium iodide. Compared with astrocytes or neuronal plus glial cultures, endothelial cells were much more resistant to stretch-induced injury and more quickly regained their capacity to exclude propidium iodide. PEG-SOD had no effect on the neuronal or glial response to injury but reduced immediate posttraumatic endothelial cell dye uptake by 51%.

Conclusions
These studies further document the utility of the model for studying cell injury and repair and further support the vascular endothelial cell as a site of free radical generation and radical-mediated injury. On the assumption that, like aortic endothelial cells, stretch-injured cerebral endothelial cells also produce oxygen radicals, our results further suggest the endothelial cell as a site of therapeutic action of free radical scavengers after traumatic brain injury.
Neurological Manifestations of Acute Posterior Multifocal Placoid Pigment Epitheliopathy
Authors: Çomu Sinan , Verstraeten Thierry , Rinkoff Jeffrey S. , Busis Neil A.
Published: June 2011

Background
Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is a chorioretinal disease that causes acute visual symptoms with characteristic fundus findings. Although this entity has been associated with a variety of neurological complications, it has received little attention in the neurological literature. We wanted to emphasize the spectrum of neurological involvement, in particular the occurrence and management of strokes in patients with APMPPE.

Case Descriptions
We report three patients with APMPPE and neurological disease. All three presented with marked visual disturbances and headaches. One patient developed recurrent strokes involving different vascular territories of the brain and required immunosuppressive treatment for presumed cerebral vasculitis. The other two patients had cerebrospinal fluid pleocytosis and persistent headaches but recovered spontaneously. The review of the literature demonstrates a particular pattern of neurological complications in a subgroup of patients with APMPPE.

Conclusions
APMPPE should be considered among the causes of stroke and aseptic meningitis in young adults. The diagnosis is critically dependent on a thorough ophthalmologic examination. Severe neurological complications are difficult to predict at the onset of the ophthalmologic disease. The patients should be monitored closely. If investigations suggest cerebral vasculitis, immunosuppressive treatment may be helpful to prevent recurrences.
Weekend and Holiday Increase in the Onset of Ischemic Stroke in Young Women
Authors: Haapaniemi Helena , Hillbom Matti , Juvela Seppo
Published: June 2011

Background and Purpose
Chronobiological analyses of stroke onset may throw some light on the mechanisms that trigger stroke. Observations may generate new hypotheses for identifying significant causal relationships.

Methods
In the present study, both the circadian and the weekend and holiday versus workday times of the onset of ischemic cerebral infarction were determined for 723 consecutive subjects, aged 16 to 60 years, who were admitted for hospital treatment in the acute phase without any selection.

Results
Among young adults (16 to 40 years) and women, more infarctions occurred during weekends and holidays than were expected. Young women in particular had an increased risk for brain infarction during weekends and holidays (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.26 to 3.63). In a multivariate analysis, age of 16 to 30 years (OR, 3.13; 95% CI, 1.57 to 6.50), female sex (OR 1.71; 95% CI, 1.12 to 2.63), and recent drinking of alcohol (
P
<.01) were associated with the onset of brain infarction during weekends and holidays, whereas current cigarette smoking was associated with the onset of brain infarction during workdays (
P
<.001). A morning increase in the onset of brain infarction was observed among middle-aged people during both weekends/holidays and workdays. Among young adults, however, an evening increase was also seen during weekends/holidays and workdays.

Conclusions
We found that young adults and women are frequently stricken by brain infarction during weekends and holidays and that the circadian distribution of the onset of brain infarction among young adults is different from that of middle-aged people. These observations suggest that there may be stroke-triggering activities that are associated with lifestyle.
Variability of Magnetic Resonance Angiography and Computed Tomography Angiography in Grading Middle Cerebral Artery Stenosis
Authors: Wong K.S. , Lam Wynnie W.M. , Liang Eisen , Huang Y.N. , Chan Y.L. , Kay Richard
Published: June 2011

Background and Purpose
Magnetic resonance angiography and computed tomography angiography are new, noninvasive methods to provide images of the cerebral vasculature. The reliability of magnetic resonance angiography and computed tomography angiography when used to grade middle cerebral artery stenosis remains to be established. We sought to study the interobserver and intraobserver variabilities of magnetic resonance angiography and computed tomography angiography in grading middle cerebral artery stenosis.

Methods
A total of 50 middle cerebral arteries in 25 patients were studied with magnetic resonance angiography and computed tomography angiography. All patients had a history of ischemic stroke. The films were read independently by two observers on separate occasions. Films were shown again to the same observer 4 weeks after the first reading. The degree of middle cerebral artery stenosis was categorized into four grades: normal/mild, moderate, severe, and occluded. The interobserver and intraobserver variabilities were calculated by the κ statistic method.

Results
Interobserver variability for grading middle cerebral artery stenosis was good (κ=0.78) for magnetic resonance angiography and moderate (κ=0.51) for computed tomography angiography. There was perfect agreement between two observers in 86% of the vessels shown in magnetic resonance angiography and in 76% of the vessels shown in computed tomography angiography. Intraobserver variability for both imaging methods was good, with the κ value in the range of 0.70 to 0.76.

Conclusions
Our results suggest that according to our protocol, magnetic resonance angiography is more reliable than computed tomography angiography in grading middle cerebral artery stenosis.
Performance of Carotid Ultrasound in Evaluating Candidates for Carotid Endarterectomy Is Optimized by an Approach Based on Clinical Outcome Rather Than Accuracy
Authors: Wilterdink Janet L. , Feldmann Edward , Easton J. Donald , Ward Richard
Published: June 2011

Background and Purpose
The best method of selecting endarterectomy candidates for cerebral angiography is controversial. Carotid duplex ultrasound (CDUS) is widely used, but its performance varies across institutions. The clinical utility of CDUS could be improved with test criteria based on patient outcome rather than test accuracy.

Methods
In 155 carotid bifurcations studied by CDUS and cerebral angiography, the degree of angiographic stenosis was measured by a reader, blinded to CDUS, using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. We calculated accuracy, sensitivity, and specificity for predicting ≥70% angiographic carotid stenosis of different peak systolic frequencies (PSF) measured by CDUS and generated a receiver operator characteristic (ROC) curve. We used NASCET outcome data and published data on angiographic complications to define relative “costs” of false-positive and false-negative CDUS, and we determined the point on the ROC curve representing the CDUS criterion with the highest clinical utility. We compared projected morbidity and mortality rates for 1000 hypothetical endarterectomy candidates resulting from the use of the most accurate CDUS criterion versus the CDUS criterion with the highest clinical utility by ROC analysis.

Results
While PSF ≥8 kHz had the highest CDUS accuracy (93%), its projected stroke and death rate due to CDUS error was 10.4/1000. On the other hand, PSF ≥7 kHz, defined by ROC analysis to have the highest clinical utility, had a lower morbidity and mortality rate of 6.8/1000.

Conclusions
The use of ROC analysis and available outcome data can improve the performance of CDUS in selecting endarterectomy candidates for cerebral angiography.
Electrophysiological Transcortical Diaschisis After Cortical Photothrombosis in Rat Brain
Authors: Buchkremer-Ratzmann Irmgard , August Matthias , Hagemann Georg , Witte Otto W.
Published: June 2011

Background and Purpose
The severity of functional deficits after a cortical infarction often does not correlate with lesion size. The stroke may affect pathways connecting to distant brain regions and therefore may also alter the function of remote parts of the cortex. Remote changes in electric activity, blood flow, and metabolism are called diaschisis. In the present study we addressed the question of whether in brain areas contralateral to a photochemically induced cortical infarction alteration of excitability can be observed as an indication of the effects of diaschisis.

Methods
We induced focal lesions in the sensory area at the border of the motor and occipital cortices by injecting the photosensitizing dye rose bengal and illuminating the skull stereotaxically. Seven days after induction of photothrombosis, electrophysiological recordings were obtained with standard methods from 400-μm-thick neocortical coronal slices. As an indication of inhibition we used a paired-pulse stimulus protocol and calculated a ratio of the amplitudes of the second versus the first excitatory postsynaptic potential.

Results
In lesioned animals we found a significant increase of the ratio over a wide zone of the neocortex, both ipsilateral and contralateral, compared with unlesioned animals.

Conclusions
Our results suggest that a neocortical infarction leads to hyperexcitability not only in its direct vicinity but also in the contralateral hemisphere. Such hyperexcitability may contribute to increased activation of contralateral brain areas and to functional reorganization after stroke.
Fluid-Attenuated Inversion Recovery (FLAIR) for Assessment of Cerebral Infarction
Authors: Brant-Zawadzki Michael , Atkinson Dennis , Detrick Mark , Bradley William G. , Scidmore Gerald
Published: June 2011

Background and Purpose
Our aim was to evaluate fluid-attenuated inversion recovery (FLAIR) sequence in the diagnosis of cerebral infarction with MRI.

Methods
A retrospective review was undertaken of 50 consecutive MRI studies ordered for suspected cerebrovascular accident. All studies included FLAIR and rapid acquisition with relaxation enhancement (RARE) T
2
-weighted spin-echo sequences. The two sequences were compared independently by four observers at two different institutions. Detectability of lesions and image quality were scored.

Results
Overall, FLAIR sequences proved superior in 10 patients, detecting acute cortical infarcts missed with RARE spin-echo technique in five patients. In five additional patients, improved characterization of chronic infarction and improved detection of microangiopathic deep hemispheric changes were observed. One brain stem infarct was missed with the FLAIR sequence.

Conclusions
FLAIR offers advantages in detection of acute infarcts affecting the cortical ribbon, is a useful, rapid adjunct to conventional T
2
-weighted spin-echo sequences, and has the potential to replace these in the future.
Complications and Outcome After Acute Stroke
Authors: Smithard D.G. , O'Neill P.A. , Park C. , Morris J. , Wyatt R. , England R. , Martin D.F.
Published: June 2011

Background and Purpose
The published data on the relationship between dysphagia and both outcome and complications after acute stroke have been inconclusive. We examined the relationship between these, using bedside assessment and videofluoroscopic examination.

Methods
We prospectively studied 121 consecutive patients admitted with acute stroke. A standardized bedside assessment was performed by a physician. We performed videofluoroscopy blinded to this assessment within 3 days of stroke onset and within a median time of 24 hours of the bedside evaluations. The presence of aspiration was recorded. Mortality, functional outcome, length of stay, place of discharge, occurrence of chest infection, nutritional status, and hydration were the main outcome measures.

Results
Patients with an abnormal swallow (dysphagia) on bedside assessment had a higher risk of chest infection (
P
=.05) and a poor nutritional state (
P
<.001). The presence of dysphagia was associated with an increased risk of death (
P
=.001), disability (
P
=.02), length of hospital stay (
P
<.001), and institutional care (
P
<.05). When other factors were taken into account, dysphagia remained as an independent predictor of outcome only with regard to mortality. The use of videofluoroscopy in detecting aspiration did not add to the value of bedside assessment.

Conclusions
Bedside assessment of swallowing is of use in identifying patients at risk of developing complications. The value of routine screening with videofluoroscopy to detect aspiration is questioned.
Cerebral Oxygenation During Cardiopulmonary Resuscitation With Epinephrine and Vasopressin in Pigs
Authors: Prengel Andreas W. , Lindner Karl H. , Keller Andreas
Published: June 2011

Background and Purpose
Administration of vasopressin during cardiopulmonary resuscitation (CPR) improves vital organ blood flow compared with epinephrine, but the effect of vasopressin on cerebral oxygenation and cerebral venous hypercarbia during CPR has not previously been studied.

Methods
Fourteen pigs were allocated to receive either epinephrine (0.2 mg/kg) or vasopressin (0.4 U/kg) after 4 minutes of ventricular fibrillation and 3 minutes of CPR. Cerebral blood flow was determined by radiolabeled microspheres, and arterial and cerebral venous blood gases were measured.

Results
Cerebral blood flow, measured before and 90 seconds and 5 minutes after drug administration, was 9 (3; 12), 25 (19; 27), and 18 (10; 23) mL/min per 100 g (median and 25th and 75th percentiles, respectively) in the epinephrine group and 12 (5; 16), 51 (48; 70), and 53 (45; 63) mL/min per 100 g in the vasopressin group (
P
<.05 at 90 seconds,
P
<.01 at 5 minutes between groups). Five minutes after drug administration, cerebral venous P
co
2
was 63 (59; 68) mm Hg in the epinephrine group and 47 (43; 55) mm Hg in the vasopressin group (
P
<.01); at the same time cerebral venous pH was 7.18 (7.17; 7.20) and 7.26 (7.22; 7.36) (
P
<.01) in the epinephrine and vasopressin groups, respectively. Cerebral oxygen extraction ratio, calculated before and 90 seconds and 5 minutes after drug administration, was 0.42 (0.32; 0.57), 0.47 (0.41; 0.57), and 0.56 (0.56; 0.64) in the epinephrine group and 0.43 (0.38; 0.45), 0.38 (0.25; 0.44), and 0.35 (0.33; 0.49) in the vasopressin group (
P
<.05 at 90 seconds and 5 minutes).

Conclusions
Compared with epinephrine, vasopressin not only increases cerebral blood flow but also improves cerebral oxygenation and decreases cerebral venous hypercarbia when administered during CPR in pigs.
Hemostatic Markers in Acute Ischemic Stroke
Authors: Feinberg William M. , Erickson Laurie P. , Bruck Denise , Kittelson John
Published: June 2011

Background and Purpose
Hemostatic markers can identify activation of the coagulation system in stroke patients. We evaluated whether the levels of these markers at the time of stroke are correlated with stroke severity, type, or mortality.

Methods
We measured fibrinopeptide A, cross-linked
d
-dimer, and β-thromboglobulin in 70 patients within 1 week of stroke. We examined the association between the level of each of these markers and survival. We adjusted for the possible confounding effect of age, stroke type, or stroke severity using a multivariate Cox proportional hazards model.

Results
The median follow-up was 1.22 years. Fourteen patients died during follow-up. Univariate survival analysis identified age (hazard ratio, 1.06; 95% confidence interval [CI], 1.00 to 1.12), stroke type (hazard ratio, 4.44; 95% CI, 1.29 to 15.23), initial Toronto Stroke Scale score (hazard ratio, 5.05; 95% CI, 2.08 to 12.27), cross-linked
d
-dimer (hazard ratio, 6.43; 95% CI, 2.83 to 14.62), fibrinopeptide A (hazard ratio, 2.14; 95% CI, 1.26 to 3.63), and β-thromboglobulin (hazard ratio, 7.63; 95% CI, 2.22 to 26.28) as significantly associated with mortality. In a multivariate model, initial stroke severity and each of the hemostatic markers were independently associated with subsequent mortality.

Conclusions
Elevated hemostatic markers after acute ischemic stroke identify patients with increased risk for mortality. This association appears to be independent of stroke severity or stroke type.
Outcome in Patients With Acute Basilar Artery Occlusion Requiring Mechanical Ventilation
Authors: Wijdicks Eelco F.M. , Scott John P.
Published: June 2011

Background and Purpose
Many patients with acute basilar artery occlusion may require endotracheal intubation and mechanical ventilation. The circumstances and predictive value for outcome in these patients are not well documented.

Methods
We reviewed the medical records of 25 patients admitted into the intensive care unit with a clinical diagnosis of acute basilar artery occlusion and need for mechanical ventilation. The medical records were reviewed for clinical features, breathing patterns, mode of mechanical ventilation, ability to wean from the ventilator, and neurological outcome.

Results
Apneic episodes resulted in endotracheal intubation in 8 patients. In the remaining 17 patients, intubation was needed for airway protection. Seven of 8 patients presenting with apneic episodes lost all brain stem reflexes. All 17 patients intubated for airway protection could be successfully weaned to a T-tube circuit. Outcome was generally poor and 22 patients died, of whom 7 died of early systemic complications. Only 3 of 25 patients, all with locked-in syndrome, survived.

Conclusions
Mortality is high in patients who require mechanical ventilation after acute basilar artery occlusion. No neurological improvement beyond a locked-in syndrome occurred in survivors. Recurrent apnea appears to predict further progression to brain stem death.
Autonomic Neuropathy Predicts the Development of Stroke in Patients With Non-Insulin-Dependent Diabetes Mellitus
Authors: Töyry Jari P. , Niskanen Leo K. , Länsimies Esko A. , Partanen Kaarina P.L. , Uusitupa Matti I.J.
Published: June 2011

Background and Purpose
Our aim was to determine the predictive factors for stroke in patients with non–insulin-dependent diabetes mellitus (NIDDM).

Methods
We studied 133 patients with NIDDM at the time of diagnosis and 5 and 10 years later.

Results
The number of new fatal or nonfatal strokes was 19 (14.7%; 14 after 5-year examination). High initial fasting blood glucose (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.04 to 1.4) and the use of β-blocking agents (OR, 6.7; 95% CI, 2.1 to 21.5) at baseline and the presence of parasympathetic neuropathy (OR, 6.7; 95% CI, 1.5 to 29.9), or sympathetic autonomic nervous dysfunction (OR, 1.1; 95% CI, 1.01 to 1.2), hypertriglyceridemia (OR, 5.7; 95% CI, 1.1 to 31.0), or use of β-blocking agents (OR, 6.4; 95% CI, 1.3 to 31.2), and high fasting plasma glucose (OR, 1.2; 95% CI, 1.0 to 1.5) determined at 5-year examination predicted the development of stroke.

Conclusions
Autonomic neuropathy is an independent risk factor for stroke in NIDDM.
Nocturnal Blood Pressure and Silent Cerebrovascular Lesions in Elderly Japanese
Authors: Watanabe Noriko , Imai Yutaka , Nagai Kenichi , Tsuji Ichiro , Satoh Hiroshi , Sakuma Mariko , Sakuma Hiromichi , Kato Junko , Onodera-Kikuchi Noriko , Yamada Masaaki , Abe Fumiaki , Hisamichi Shigeru , Abe Keishi
Published: June 2011

Background and Purpose
We conducted a cross-sectional epidemiological survey using ambulatory blood pressure monitoring and brain MRI in a cohort from northern Japan to determine whether an inappropriately low nocturnal blood pressure, or an excess fall in nocturnal blood pressure, might be responsible for silent cerebrovascular lesions in the elderly.

Methods
Untreated subjects over 55 years and under 64 years of age (late middle age; 24 men and 46 women, 60% of eligible people) and over 65 years and under 75 years of age (elderly; 29 men and 52 women, 91% of eligible people) participated in the study. We evaluated the relationship between the amplitude (Daytime Average−Nighttime Average) or the rate ([Daytime Average−Nighttime Average]/Daytime Average) of the fall in nocturnal blood pressure and the incidence of silent cerebrovascular lesions on MRI (number of lacunar infarctions or extent of periventricular hyperintensity).

Results
The amplitude or the rate of the fall in nocturnal blood pressure in elderly women with one or two lacunar infarctions was significantly higher than that in those without such infarctions. There was a significant positive correlation between the amplitude or the rate of the fall in nocturnal blood pressure and the extent of periventricular hyperintensity in the elderly women. This relationship was observed in women, but not in men, of late middle age; this was not seen in elderly men.

Conclusions
Results indicate that an inappropriately low nocturnal blood pressure, or an excessive fall in nocturnal blood pressure, is associated with ischemic silent cerebrovascular lesions, at least in elderly women. Treatment of hypertension in such women should be administered with care and with regard to nocturnal blood pressure.
Prevalence of Stroke in Kinmen
Authors: Fuh J.L. , Wang S.J. , Larson E.B. , Liu H.C.
Published: June 2011

Background and Purpose
Stroke is the second most common cause of death in Taiwan. We studied its prevalence, risk factors, and mortality in a rural Chinese population.

Methods
A door-to-door survey of stroke was conducted in two Kinmen Island townships with a total population of 26 105 people. Our target population (n=5061) consisted of all the registered residents in these townships who were aged ≥50 years on August 1, 1993. All participants were given a standardized neurological examination and a questionnaire.

Results
The participation rate was 77.4% (n=3915). Ninety-six cases of completed stroke were identified. Eighty-nine patients had one, 6 patients had two, and 1 patient had three episodes of stroke. The prevalence of stroke in persons aged ≥50 years was 24.5 per 1000 (95% confidence interval, 19.7 to 29.3 per 1000). Prevalence increased with age. Statistically significant risk factors associated with stroke included hypertension, diabetes mellitus, and irregular heartbeats. Of the stroke survivors, 59% were independent in activities of daily living and 71% could walk independently.

Conclusions
Compared with other countries, Taiwan has a moderately high prevalence of stroke. The risk factors for stroke in this rural region of a developing country are similar to those in developed countries. Most stroke survivors here perform their daily activities independently without outside assistance.
Transvenous Hemodynamic Assessment of Arteriovenous Malformations and Fistulas
Authors: Murayama Yuichi , Usami Shino , Hata Yuichi , Ganaha Fumikiyo , Hasegawa Yuzuru , Terao Tohru , Abe Satoshi , Furuhata Hiroshi , Abe Toshiaki
Published: June 2011

Background and Purpose
Transvenous monitoring of blood flow through intracranial vascular malformations was performed with an intravascular Doppler guidewire to assess hemodynamic changes during endovascular embolotherapy.

Methods
Flow velocity was assessed in the intracranial venous sinuses of two patients with arteriovenous malformations and seven patients with dural arteriovenous fistulas. In all cases, the Doppler guidewire was positioned in the dural sinuses coaxially through a 2.1F microcatheter. The Doppler guidewire was then advanced to the site of arteriovenous shunting for sampling of venous average peak velocity (APV) and pulsatility index. In two cases, simultaneous feeding artery flow velocity was monitored by transcranial color-coded duplex sonography.

Results
Before embolotherapy, the flow pattern in the venous sinuses was pulsatile, with a mean (±SD) APV of 39.0±22.5 cm/s. Total or near-total embolization was achieved in six of the nine cases. After embolization, the flow pattern became less pulsatile and the APV was reduced to a mean of 21.2±14.6 cm/s (
P
=.0123, one-tailed paired
t
test). The pulsatility index was used to calculate the maximum minus the minimum peak velocity (MxPV−MnPV). This was reduced from an average of 27.0±8.7 cm/s to 13.5±8.3 cm/s after treatment (
P
=.0456). A parallel reduction in APV of the feeding arteries was observed with embolization.

Conclusions
Preliminary clinical experience indicates that transvenous assessment of two parameters, APV and MxPV−MnPV, is useful in the hemodynamic evaluation of intracranial arteriovenous shunts. This valuable hemodynamic information may be used for objective and quantitative monitoring during embolotherapy of intracranial vascular malformations.
Leukoencephalopathy-Related Cerebral Amyloid Angiopathy With Cystatin C Deposition
Authors: Shimode Koichi , Kobayashi Shotai , Imaoka Kaoru , Umegae Nobuyuki , Nagai Atsushi
Published: June 2011

Background
We have described sporadic cases of cerebral amyloid angiopathy with cerebral hemorrhage showing a low cystatin C level in the cerebrospinal fluid detected by enzyme-linked immunosorbent assay. Recently, several cases of leukoencephalopathy in patients with cerebral amyloid angiopathy have been reported. We describe a sporadic case of leukoencephalopathy with cystatin C-type cerebral amyloid angiopathy diagnosed during life by enzyme-linked immunosorbent assay.

Case Description
A 74-year-old man who had suffered from progressive dementia for 3 years was admitted with right hemiparesis, dysarthria, and ataxia. MRI revealed pontine infarction and multiple lacunar state with leukoaraiosis. We suspected cystatin C-type cerebral amyloid angiopathy because of the low level of cystatin C in the cerebrospinal fluid. The patient died of sepsis 3 months later, and the presence of leukoencephalopathy with cerebral amyloid angiopathy was confirmed by autopsy. Immunohistological examination disclosed cystatin C and β-protein deposition in amyloid structures of the cortical cerebral arteries.

Conclusions
Measurement of cystatin C in the cerebrospinal fluid by enzyme-linked immunosorbent assay is a useful method of diagnosing leukoencephalopathy related to sporadic cystatin C-type cerebral amyloid angiopathy.
Late Outcome of Patients With Premature Carotid Atherosclerosis After Carotid Endarterectomy
Authors: Valentine R. James , Myers Stuart I. , Hagino Ryan T. , Clagett G. Patrick
Published: June 2011

Background and Purpose
The durability of carotid endarterectomy (CEA) in young adults with premature carotid atherosclerosis has not been adequately assessed. This study examined the late recurrence and mortality rates in young adults undergoing CEA.

Methods
We studied 42 young patients (mean age, 45.5±0.5 years) who underwent CEA and compared them with 110 older control subjects (mean age, 65.8±0.4 years) undergoing CEA during the same period. Data were collected regarding demographics, operative indications, follow-up carotid duplex studies, recurrent symptoms, and deaths.

Results
Demographics and atherosclerotic risk factors were similar between the two groups. During a mean follow-up of 57.9±6.0 months, 10 (24%) young patients and 3 (3%) control subjects developed significant, recurrent ipsilateral stenoses (≥50% diameter loss) (
P
<.001). Six (14%) young patients and 1 control subject had recurrent ipsilateral symptoms (
P
=.002). Nine (21%) young patients and 26 (24%) older control subjects required contralateral CEA; 8 (18%) young patients and 18 (16%) older control subjects underwent lower extremity revascularization procedures. Cumulative 5-year survival by life-table analysis was 0.83 (95% confidence interval [CI], 0.71 to 0.95) for study patients and was 0.67 (95% CI, 0.58 to 0.77) for control subjects (
P
=.06).

Conclusions
These data demonstrate a trend toward more favorable survival in young versus older patients after CEA; however, survival differences did not achieve statistical significance. Young patients are far more likely to develop recurrent symptoms and recurrent carotid stenoses than older counterparts. Close follow-up with serial duplex ultrasound may be important in young patients after CEA.
Streptokinase Increases Luxury Perfusion After Stroke
Authors: Infeld Bernard , Davis Stephen M. , Donnan Geoffrey A. , Lichtenstein Meir , Baird Alison E. , Binns David , Mitchell Peter J. , Hopper John L.
Published: June 2011

Background and Purpose
Recent acute stroke trials have reported that intravenous streptokinase is associated with an increased risk of adverse outcomes. We aimed to study the effect of streptokinase on the nature of reperfusion and the relation between reperfusion and clinical outcome.

Methods
We studied 24 patients in the Australian Streptokinase Trial with acute middle cerebral cortical infarction using
99m
Tc–hexamethylpropyleneamine oxime single-photon emission CT. Eleven of the 24 patients were scanned before therapy and again 24 hours later. The remaining 13 were scanned once either before therapy (1 patient) or after therapy (12 patients). All patients had outcome scans after 3 months. Infarct hypoperfusion was measured with a validated volumetric technique. Neurological impairment and functional outcome were assessed with the Canadian Neurological Scale and the Barthel Index, respectively.

Results
Fifteen patients received streptokinase and 9 received placebo. There was no difference in early reperfusion between streptokinase and placebo. However, streptokinase was associated with a greater amount of nonnutritional reperfusion than was placebo (
P
=.04). This luxury perfusion was associated with poor functional outcome (
P
=.02).

Conclusions
This study suggests that streptokinase augments luxury perfusion after stroke. Luxury perfusion is associated with a worse outcome, which might be due in part to reperfusion injury.
Infarction of Superior Cerebellar Artery Presenting as Cerebellar Symptoms
Authors: Terao Shin-ichi , Sobue Gen , Izumi Masayuki , Miura Naofumi , Takeda Akio , Mitsuma Terunori
Published: June 2011

Background
MRI of the brain has facilitated the diagnosis of cerebellar infarction in the territory of the superior cerebellar artery (SCA). We analyzed the data on patients with SCA infarction who presented with only cerebellar symptoms in an attempt to define its underlying pathophysiology.

Summary of Report
Ten patients with SCA infarction who presented with cerebellar symptoms were studied by brain MRI, angiography, and underlying pathology. Brain MRI demonstrated an infarct in the SCA territory in the anterior rostral cerebellum of all patients. None had abnormalities in the brain stem. In four patients, a hemorrhagic infarct was present in the same region. Cerebral angiography revealed no obvious SCA occlusion or atherosclerotic vascular disease in any patient. Eight of the 10 patients had heart disease, such as atrial fibrillation or old myocardial infarction. The presumed diagnosis was occlusion of the SCA in its periphery due to cardiogenic embolism.

Conclusions
When a patient presents with only cerebellar symptoms and has cerebellar infarction demonstrated by brain MRI, the SCA branch is probably occluded by cardiogenic embolism.
Length of Hospital Stay and Discharge Delays in Stroke Patients
Authors: van Straten A. , van der Meulen J.H.P. , van den Bos G.A.M. , Limburg M.
Published: June 2011

Background and Purpose
In The Netherlands, many stroke patients stay in the hospital for some time merely waiting for discharge placement. This indicates an inefficient use of hospital resources, as well as a possible deficiency in the quality of care, because hospitals are not adequately equipped to care for these patients. In this study, we tried to quantify this “waiting problem.”

Methods
Six hospitals and 29 neurologists participated in this prospective study. The neurologists were asked during weekly interviews to specify for 154 patients the rea son for retention in the hospital on a day-to-day basis. The reasons were noted on a list specified by the authors in advance.

Results
The mean length of hospital stay was 28 days. On average, there were “hard” medical reasons for 15 days (54%) and “soft” medical reasons for 3 days (10%), whereas the remaining 10 days (36%) were explained by nonmedical reasons (most frequently, waiting for placement in a nursing home).

Conclusions
The length of hospital stay for stroke patients in The Netherlands can be reduced considerably without compromising the quality of care. This might be realized by increasing the capacity of long-term care facilities, improving the efficiency of the discharge procedures, or creating “stroke services.”