bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reperfusion after thrombolytic therapy in ischemic stroke measured by single-photon emission computed tomography.
Authors: Baird A E , Donnan G A , Austin M C , Fitt G J , Davis S M , McKay W J 
Published: June 2011

We used 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography (SPECT) to study cerebral perfusion in patients treated with streptokinase for acute ischemic stroke in an open and prospective study. Our primary aims were (1) to compare the extent of reperfusion between patients who had received thrombolytic therapy and a control group studied during the same period who were ineligible to receive such therapy and (2) to determine if, among all patients, reperfusion led to improved outcome.
Fifty-seven patients (22 treated with streptokinase) had two SPECT studies performed, the first before streptokinase administration and the second 24 hours later.
On the first SPECT study hyperfusion was present in the middle cerebral artery or anterior cerebral artery territories in 40 patients (17 treated with streptokinase). Patients in the treatment and control groups with initial hypoperfusion on SPECT were well matched for the volume of the perfusion defect and the severity of neurological deficit. A greater number of patients who received streptokinase developed at least partial reperfusion (streptokinase, 65%; control, 52%) on the second study but not significantly so (P = .43). Similarly, the proportion of each hypoperfused region that reperfused (P = .74) and the reduction in the size of the perfusion defect (P = .06) were higher in the streptokinase group but did not reach statistical significance. When all patients were considered, those who did not reperfuse had higher mortality rates (P = .008), less neurological improvement (P = .016), and more functional disability (P < .001) than patients who had reperfusion or normal perfusion initially.
These findings suggest that at least some reperfusion during the first 48 hours of ischemic stroke is a common natural occurrence and is of prognostic significance. The observed trend toward better reperfusion indexes among patients treated with streptokinase is encouraging, but larger controlled trials are required to answer this definitively.
Effect of carotid endarterectomy on patterns of cerebrovascular reactivity in patients with unilateral carotid artery stenosis.
Authors: Hartl W H , Janssen I , Fürst H 
Published: June 2011

Patients with unilateral significant carotid artery stenosis present with a variable intracranial hemodynamic status. In the majority of patients, hemodynamics are normal because of sufficient collateral flow. One subgroup shows poor ipsilateral hemodynamics because of a severely reduced blood supply, whereas in another subgroup of patients a steal phenomenon from the contralateral to the ipsilateral hemisphere can be observed during pharmacological provocation. The present study examined the effect of carotid endarterectomy (CEA) on these patterns of cerebrovascular hemodynamics in patients with carotid artery stenosis.
The CO2 reactivity of the cerebral resistance index (CRi) was determined with transcranial Doppler sonography in 63 patients with unilateral high-grade to threadlike carotid artery stenosis before and 3 months after CEA and in 37 control subjects. The interhemispheric asymmetry of CRi reactivity of the control group was used to differentiate between normal and abnormal findings.
In patients with normal CRi asymmetry (comparable CRi reactivities at both hemispheres, n = 41), CEA did not change hemispheric CRi reactivity. In patients in whom CRi reactivity was absent at the contralateral hemisphere (intracerebral steal during hypercapnia, n = 12), CEA abolished the steal phenomenon by significantly increasing CRi reactivity at the contralateral hemisphere (preoperative, -1.0 +/- 2.1 %CRi/vol%CO2; postoperative, 5.2 +/- 0.7 %CRi/vol%CO2; P < .01). Patients who showed severely diminished ipsilateral CRi reactivity, compatible with a significantly reduced perfusion pressure at the poststenotic hemisphere (n = 10), demonstrated an improvement of ipsilateral CRi reactivity after surgery (preoperative, 0.6 +/- 0.8 %CRi/vol%CO2; postoperative, 3.7 +/- 1.1 %CRi/vol%CO2; P < .01).
Most patients do not respond significantly to CEA. One small subgroup of patients who presented with severely disturbed ipsilateral hemodynamics demonstrated postoperative improvement at the poststenotic hemisphere, whereas in another small subgroup, who showed a steal phenomenon at the contralateral hemisphere, CEA improved contralateral hemodynamics. Determination of preoperative CRi reactivity allowed precise prediction of the effect of CEA on intracerebral hemodynamics.
Atherosclerosis of the ascending aorta. Prevalence and role as an independent predictor of cerebrovascular events in cardiac patients.
Authors: Dávila-Román V G , Barzilai B , Wareing T H , Murphy S F , Schechtman K B , Kouchoukos N T 
Published: June 2011

The cause of cerebral and peripheral embolism remains undetermined in a significant number of patients. An atherosclerotic thoracic aorta has thus far been considered to be an uncommon one.
To define the potential role of the ascending thoracic aorta as an embolic source, intraoperative ultrasonic aortic imaging was performed in 1200 of 1334 consecutive patients aged 50 years and older who were undergoing cardiac surgery. Patients were divided into two groups according to the results of the ultrasound study in terms of presence or absence of atherosclerotic disease. The prevalence of previous neurological events in the two groups was characterized and compared.
Ascending aortic atherosclerosis was present in 231 (19.3%) of the patients studied. Patients in this category were older (P < .0001). A higher percentage of them were smokers (P < .0001) compared with patients with less severe disease. Coronary artery disease was more extensive (P = .012), and a higher percentage of these patients had a history of peripheral vascular disease (P < .0001). Univariate analysis of the subjects with (n = 158) and without (n = 1042) previous neurological events indicated that age, body mass index, atrial fibrillation, hypertension, and atherosclerosis of the ascending aorta were associated significantly with previous occurrence of a cerebrovascular accident. For the group as a whole, multiple logistic regression analysis demonstrated that hypertension (odds ratio, 1.81; P = .002), atherosclerosis of the ascending aorta (odds ratio, 1.65; P = .013), and atrial fibrillation (odds ratio, 1.54; P = .060) were significantly and independently associated with the occurrence of previous neurological events.
Atherosclerosis of the ascending aorta is an independent risk factor for cerebrovascular events. An atherosclerotic ascending aorta may represent a potential source of emboli or may be a marker of generalized atherosclerosis.
Twenty-four-hour beta-endorphin secretory pattern in stroke patients.
Authors: Franceschini R , Gandolfo C , Cataldi A , Del Sette M , Cianciosi P , Finocchi C , Rolandi E , Barreca T 
Published: June 2011

Abnormalities of hypothalamo-pituitary-adrenocortical axis function have been observed frequently in stroke patients. The aim of this study was to investigate plasma beta-endorphin and cortisol 24-hour secretory patterns in patients early after stroke and in the convalescent period to evaluate a possible influence of brain damage on hormonal circadian pattern.
Patients (n = 15; age, 46 to 75 years) were evaluated in the first 24 hours and 10 days after hospital admission for ischemic cerebral stroke and compared with 15 age- and sex-matched normal subjects. Blood samples for beta-endorphin and cortisol determination were drawn every 4 hours from 8 AM to 8 PM and every 2 hours from midnight to 6 AM.
Mean 24-hour beta-endorphin and cortisol levels, recorded in the acute phase, were significantly (P < .05) higher than those recorded in normal subjects; circadian rhythm was not demonstrable for either hormone. In the convalescent period, plasma cortisol 24-hour mean values and circadian rhythm returned to the normal range, whereas the plasma beta-endorphin 24-hour mean values and circadian rhythm did not.
Cerebral stroke induces abnormalities of beta-endorphin and cortisol circadian secretion. Whereas cortisol abnormalities are transient, those of beta-endorphin last longer. The dissociation between beta-endorphin and cortisol 24-hour secretory patterns might potentially serve as a marker of psychoneurological abnormalities occurring after stroke.
EEG recordings in the course of recovery from stroke.
Authors: Giaquinto S , Cobianchi A , Macera F , Nolfe G 
Published: June 2011

This study was designed to assess the value of quantified electroencephalography (EEG) in the follow-up of stroke and its possible correlation with other measures of recovery.
EEGs were recorded over a period of 6 months in 34 patients with ischemic stroke in the middle cerebral artery territory who underwent spectral analysis. Two groups were formed: (1) 28 patients with a Barthel Index score of less than 60 at admission and (2) 6 patients with a Barthel score of over 60 and therefore with a much better prognosis. Ten recordings were made in each patient in the first group and at least three in the second group. Motor functions and activities of daily living (ADL) were assessed three times, on admission to the study and after 3 and 6 months.
Quantified EEG was significantly abnormal in the affected hemisphere of the first group. Side and site were not relevant. Longitudinal recordings showed a significant improvement of the power spectrum in the first 3 months. Alpha mean weighted frequency of the injured hemisphere was always slower than that of the contralateral side. All patients improved in motor performance and ADL, with the greatest gain in the first 3 months. However, no correlation between quantified EEG and clinical testing was found. By looking at individual profiles, a frequent and unpredictable instability was seen in the "unaffected" hemisphere. In those who made the best recovery, the EEG spectrum became more symmetrical over the left and right hemispheres, an aspect that continued beyond the point of a good motor and ADL recovery.
Quantified EEG undergoes early and subtle changes in the follow-up of stroke that can outlast clinical recovery. Routine evaluation for prognosis is not recommended because motor and ADL scales provide earlier and more accurate indicators. In contrast, quantified EEG can be useful for individual patients undergoing rehabilitation to monitor mechanisms of local repair and also to detect changes in the so-called normal hemisphere. It may reveal focal abnormalities that are undetected by coarse clinical evaluation and that call for appropriate neuropsychological testing.
Improved reliability of the NIH Stroke Scale using video training. NINDS TPA Stroke Study Group.
Authors: Lyden P , Brott T , Tilley B , Welch K M , Mascha E J , Levine S , Haley E C , Grotta J , Marler J 
Published: June 2011

Despite the frequent use of clinical rating scales in multicenter therapeutic stroke trials, no generally acceptable method exists to train and certify investigators to use the instrument consistently. We desired to train investigators to use the National Institutes of Health Stroke Scale in a study of acute stroke therapy so that all examiners rated patients comparably.
We devised a two-camera videotape method that optimizes the visual presentation of examination findings. We then measured the effectiveness of the training by asking each investigator to evaluate a set of 11 patients, also on videotape. We tabulated the evaluations, devised a scoring system, and calculated measures of interobserver agreement among the participants in this study.
We trained and certified 162 investigators. We found moderate to excellent agreement on most Stroke Scale items (unweighted kappa > 0.60). Two items, facial paresis and ataxia, exhibited poor agreement (unweighted kappa < 0.40) and should be revised in future editions of the scale. Performance improved with video training compared with previous studies. Inclusion of the motor rating of the unaffected limbs in the total score did not affect reliability.
Video training and certification is a practical and effective method to standardize the use of examination scales. Two cameras must be used during the taping of patients to accurately present the clinical findings. This method is easily adapted to any study in which a large number of investigators will be enrolling patients at multiple clinical centers.
Diaspirin cross-linked hemoglobin improves neurological outcome following reversible but not irreversible CNS ischemia in rabbits.
Authors: Bowes M P , Burhop K E , Zivin J A 
Published: June 2011

Hemodilution using modified hemoglobin solutions may reduce ischemic central nervous system injury. Purified diaspirin cross-linked hemoglobin (DCLHb) is a cell-free hemoglobin that is intramolecularly cross-linked between the two alpha subunits, resulting in enhanced oxygen offloading to tissues and increased half-life. In the present experiments, we evaluated the ability of DCLHb to reduce neurological damage in two rabbit stroke models.
In a reversible spinal cord ischemia model, ischemia of the caudal lumbar spinal cord was produced by temporary occlusion of the abdominal aorta. In an irreversible model of cerebral ischemia, plastic microspheres (50 microns) were injected into the internal carotid artery and lodged in the cerebral microvasculature. DCLHb was administered 5 minutes after initiation of ischemia as either a 10-mL/kg infusion, 10-mL/kg exchange transfusion, or a 20-mL/kg infusion. Control animals received human serum albumin that was oncotically matched to the DCLHb.
In the spinal cord model, DCLHb significantly increased the duration of ischemia required to produce permanent paralysis from 27.33 +/- 8.71 minutes (mean +/- SD) in controls to 42.59 +/- 10.10 minutes in the 10-mL/kg exchange transfusion group and to 40.82 +/- 18.16 minutes in the 20-mL/kg infusion condition (P < .05). DCLHb did not significantly reduce neurological damage in the microsphere embolization model.
These data suggest that cross-linked hemoglobin reduces neurological damage after reversible central nervous system ischemia and that this is not attributable to hemodilution or hypervolemia only.
Aneurysm of the left middle cerebral artery caused by myxoid degeneration of the vessel wall.
Authors: O'Boynick P , Green K D , Batnitzky S , Kepes J J , Pietak R 
Published: June 2011

Myxoid degeneration of arterial walls may result in dissection and dissecting aneurysms in extracranial and intracranial portions of cerebral arteries. Rarely, saccular aneurysms may also develop on that basis, but thus far these have only been reported in the cervical portions of the carotid arteries. We describe a case of a nondissecting aneurysm of the left middle cerebral artery caused by myxoid degeneration of the media.
A 39-year-old man had acute onset of frontal headache and neck stiffness. Computed tomographic scan and lumbar puncture established the presence of subarachnoid hemorrhage. Angiography demonstrated a left middle cerebral artery aneurysm. This was clipped and the wall biopsied. Microscopically the entire thickness of the vascular wall showed marked myxoid alterations. No dissection was present. The patient had an uneventful recovery.
This observation confirms that myxoid degeneration of arterial walls may cause aneurysms with eventual rupture even in the absence of dissection. Rare cases of this type of aneurysm have been reported to occur in the cervical portions of the carotid arteries, but this is the first reported observation of such changes involving an intracerebral artery.
Development of aspirin resistance in persons with previous ischemic stroke.
Authors: Helgason C M , Bolin K M , Hoff J A , Winkler S R , Mangat A , Tortorice K L , Brace L D 
Published: June 2011

The ex vivo effect of aspirin (ASA) on platelet aggregation, the platelet component of thrombosis, was studied at repeated intervals in a cohort of patients taking aspirin for recurrent ischemic stroke prevention to define the maintenance of efficacy over time.
We administered increasing doses of aspirin (from 325 to 1300 mg/d) to patients with previous ischemic stroke and determined the extent of inhibition of platelet aggregation after 2 weeks and thereafter at approximately 6-month intervals.
Over 33 months, 306 patients had platelet aggregation studies performed to define their initial response to ASA therapy. Of these, 228 had complete and 78 had partial inhibition of platelet aggregation at initial testing. To date, 119 of those who had complete inhibition and 52 who had partial inhibition have undergone repeat testing at least once. At repeat testing 39 of the 119 (32.7%) with complete inhibition at initial testing had lost part of the antiplatelet effect of ASA and converted from complete to partial inhibition without change in ASA dosage. Of the 52 with partial inhibition at initial testing, 35 achieved complete inhibition either by ASA dosage escalation (in 325 mg/d increments) or fluctuation of response at the same dosage, but 8 of those 35 (22.8%) had reverted to partial inhibition when tested again. Overall, 8.2% of patients ultimately exhibited ASA resistance to 1300 mg/d-8 of 52 (15.4%) with partial inhibition and 6 of 119 (5.0%) with complete inhibition at initial testing.
The antiplatelet (and presumably the antithrombotic) effect of a fixed dose of ASA is not constant over time in all individuals. The mechanisms by which increased dosage requirement or ASA resistance develops and the clinical significance of this development are currently undefined.
Compliance with antiplatelet therapy in patients with ischemic cerebrovascular disease. Assessment by platelet aggregation testing.
Authors: Komiya T , Kudo M , Urabe T , Mizuno Y 
Published: June 2011

Antiplatelet therapy is currently one of the methods for preventing transient ischemic attacks and cerebral thrombosis. Because antiplatelet agents are generally administered on a long-term basis, patient compliance is an important factor. The purpose of this study was to determine the compliance of patients during antiplatelet therapy by testing platelet aggregation.
To establish the conditions for measuring platelet aggregation, the platelet aggregation test was performed in patients taking 81 mg/d aspirin or 200 mg/d ticlopidine at the following final concentrations of aggregation-inducing agents: 0.5, 1, 2, and 4 mumol/L ADP and 0.5 and 2 micrograms/mL collagen. The optimum measurement conditions for assessing patient compliance were determined. Under the conditions determined in the first study, platelet aggregation was assessed, and the effects of treatment were studied in 159 outpatients and 79 inpatients undergoing antiplatelet therapy. If the antiplatelet effect was insufficient, compliance was checked by interview.
The agents used and the final concentrations found to be optimum for assessing platelet aggregation were 2 micrograms/mL collagen for patients taking aspirin 81 mg/day and 2 mumol/L ADP for patients taking ticlopidine 200 mg/d. In 17 (10%) of the 159 outpatients, platelet aggregation was not adequately reduced because of noncompliance with their antiplatelet therapy.
This study indicated that monitoring of compliance is important for outpatients on antiplatelet therapy. It is best if platelet aggregation can be checked, but when this is impossible it is necessary to assess compliance periodically and provide patient guidance.
Costs of stroke in Sweden. A national perspective.
Authors: Terént A , Marké L A , Asplund K , Norrving B , Jonsson E , Wester P O 
Published: June 2011

Cost-effectiveness analyses of stroke management are hampered by paucity of economic data. We made an update of the direct and indirect costs of stroke in Sweden (population, 8.5 million).
Direct costs (ie, the costs for hospital and outpatient care and social services) were estimated on the basis of two prospective population-based studies of stroke and of two nationwide cross-sectional inventories of bed-days and diagnoses. Indirect costs (ie, the costs for loss of productivity and early retirement) were based on official statistics.
The direct annual costs of care for stroke patients in 1991 equaled 7836 million Swedish krona (SKr) ($1306 million in US dollars), and the indirect costs, 2430 million SKr ($405 million). The cost of stroke care was 1208 SKr ($201) per inhabitant in Sweden. The expected direct costs per patient from first stroke to death were 440,000 SKr ($73,333). When prestroke costs for other diseases and advanced age were subtracted, the sum was reduced to 180,000 SKr ($30,000).
Costs for hospital and outpatient care and social services accounted for 76% of Swedish stroke costs and for 24% of costs for loss of production and early retirement. Only 41% of direct costs were stroke-related.
Determining functional/health status and its relation to disability in stroke survivors.
Authors: Segal M E , Schall R R 
Published: June 2011

Determining the functional/health status of stroke survivors poses special difficulties because of cognitive impairments that frequently result from stroke. A possible means of assessing the status of stroke survivors who are cognitively impaired is getting proxy responses from a family member or other caregiver. Proxy agreement was evaluated for two measures of functional/health status, the Frenchay Activities Index (FAI) and the Health Status Questionnaire (HSQ), and a measure of disability, the Functional Independence Measure (FIM).
Thirty-eight stroke survivors were administered the measures at follow-up (median time since the stroke, 6 months). Caregivers were instructed to answer as proxies for the stroke survivors in their care. Demographics on age, sex, race, marital status, educational level, side of lesion, and relation of stroke survivor to caregiver were collected.
Proxy agreement was excellent for the FAI (intraclass correlation, .85) and the FIM (.87), but poor for the HSQ scales (average proxy agreement, .32). Patients' scores were low and positively skewed for the FAI but high and negatively skewed for the FIM. Although Spearman rho coefficients between the measures were fairly high for both stroke survivors and proxy respondents, the correlation of scores was substantially weaker when the group of less severely impaired survivors (as established by FIM ratings) was considered separately.
The FAI and the FIM are useful for assessing the functional/health status of stroke survivors because answers can be obtained by proxy. Future studies should examine the relations between disability and functional/health status, with explicit attention paid to variations in the level of disability in the stroke survivors.