Abstracts of Literature
Time-Course of Blood-Brain Barrier Permeability Changes After Experimental Subarachnoid Haemorrhage—Germanò A (Neurosurgical Clinic, Polclinico Universitario, Via Consolare Valeria, 1, 98125 Messina, Italy), d’Avella D, Imperatore C, Caruso G, Tomasello F—Acta Neurochir (Wien). 2000;142:575–581. Copyright © Springer-Verlag 2000.
An increase in blood-brain barrier (BBB) permeability after subarachnoid haemorrhage (SAH) has been described in humans and has been correlated with delayed cerebral ischemia and poor clinical outcome. Few studies examined in the laboratory the relationship between SAH and BBB, with contrasting results due to limitations in experimental probes adopted and in timing of observation. The aim of this study was to quantify the time-course of BBB changes after experimental SAH. Groups of eight rats received injections of 400 μl of autologous arterial blood into the cisterna magna. BBB was assessed 6, 12, 24, 36, 48, 60, and 72 hours after SAH and in sham-operated animals separately for cerebral cortex, i.e. frontal, temporal, parietal, occipital, subcortical gray matter (Caudate-Putamen-Thalamus), cerebellar cortex and nuclei, and brain stem by a spectrophotofluorimetric evaluation of Evans Blue dye extravasation. As compared to sham-operated controls, SAH determined a significant BBB permeability change beginning 36 hours after SAH, peaking at 48 hours, and normalizing on day 3. This study provides a quantitative description of the temporal progression and recovery of BBB dysfunction after SAH. These results have implications for the management of aneurysm patients and for assessing the rationale and the therapeutic window of new pharmacological approaches.
Key Words: subarachnoid hemorrhage, blood-brain barrier
Prospective Analysis of Aneurysm Treatment in a Series of 103 Consecutive Patients When Endovascular Embolization Is Considered the First Option—Raftopoulos C (Dept of Neurosurgery, Saint-Luc Hospital, Ave Hippocrate, 1200 Brussels, Belgium), Mathurin P, Boscherini D, Billa RF, Van Boven M, Hantson P—J Neurosurg. 2000;93:175–182.
Object. The aim of this study was to evaluate prospectively the results of treating cerebral aneurysms with coil embolization (CE) or with surgical clipping when CE was considered the first option.
Methods. Whenever an aneurysm was to be treated, CE was first considered by our neurovascular team. Surgical clipping was reserved for cases excluded from CE or cases in which CE failed. The study consisted of 103 consecutive patients with 132 aneurysms, of which 127 were treated. Coil embolization was performed using Guglielmi detachable coils, and surgery was performed using Zeppelin clips. Three groups were defined: Group A consisted of 64 aneurysms that were treated by CE (neck/sac ratio <1:3); Group B, 63 aneurysms that were surgically clipped; and Group C, 12 aneurysms that failed to be satisfactorily (≥95%) embolized and were subsequently clipped. The percentages of residual aneurysm were 31.2% in Group A, 1.6% in Group B and 0% in Group C. The percentages of patients with poor Glasgow Outcome Scale (GOS) scores (GOS Scores 1–3) were 13.3% in Group A, 6.1% in Group B, and 8.3% in Group C. The percentages of poor outcome (GOS Scores 1–3) in patients with good clinical status before treatment were 10.7% in Group A, 0% in Group B, and 8.3% in Group C.
Conclusions. Even with preselection, CE remains associated with a significant number of treatment failures and poor outcomes, even in patients with good preoperative clinical status. Surgical clipping can offer better results than CE, even for more complex aneurysms of the anterior circulation, especially for those involving the middle cerebral artery cases. However, because CE can be effective and causes less stress and invasiveness for the patient, it should be considered first in aneurysms strictly selected by a neurovascular team.
Key Words: aneurysm, endovascular therapy
Improvement in Cerebral Blood Flow and Metabolism Following Subarachnoid Hemorrhage in Response to Prophylactic Administration of the Hydroxyl Radical Scavenger, AVS, (±)-N,N′-Propylenedinicotinamide: A Positron Emission Tomography Study in Rats—Yamamoto S (Dept of Neurosurgery, Hamamatsu Univ School of Medicine, 3600 Hand-cho, Hamamatsu 431-3192, Japan), Teng W, Nishizawa S, Kakiuchi T, Tsukada H—J Neurosurg. 2000;92:1009–1015.
Object. The hydroxyl radical scavenger (±)-N,N′-propylenedinicotinamide (AVS) has been shown to ameliorate the occurrence of vasospasm following experimental subarachnoid hemorrhage (SAH) and to reduce the incidence of delayed ischemic neurological deficits (DINDs) in patients with SAH. The authors investigated whether prophylactic administration of AVS could improve cerebral blood flow (CBF) and cerebral glucose utilization (CGU) following SAH in rats.
Methods. Anesthetized rats were subjected to intracisternal injection of blood (SAH group) or saline (control group). Either AVS (1 mg/kg/min) or saline (vehicle group) was continuously injected into the rat femoral vein. Forty-eight hours later, positron emission tomography scanning was used with the tracers 15O-H2O and 18F-2-fluoro-d-glucose to analyze quantitatively CBF and CGU, respectively, in the frontoparietal and occipital regions (12 regions of interest/group). In SAH rats receiving only vehicle, CBF decreased significantly (p<0.05, Tukey’s test) and CGU tended to decrease, compared with values obtained in control (non-SAH) rats receiving vehicle. In rats that were subjected to SAH, administration of AVS significantly (p<0.05, Tukey’s test) improved CBF and CGU in both the frontoparietal and occipital regions compared with administration of vehicle alone.
Conclusions. Prophylactic administration of AVS improves CBF and CGU in the rat brain subjected to SAH, and can be a good pharmacological treatment for the prevention of DINDs following SAH.
Key Words: subarachnoid hemorrhage, free radicals
Reduction in the Need for Hospitalization for Recurrent Ischemic Events and Bleeding With Clopidogrel Instead of Aspirin—Bhatt DL, Hirsch AT, Ringleb PA, Hacke W, Topol EJ (Dept of Cardiology, F25, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195), on behalf of the CAPRIE investigators—Am Heart J. 2000;140:67–73. Copyright ©2000 by Mosby, Inc.
Background Repeat hospitalizations of patients with atherosclerosis represent a considerable burden on the health care system. We sought to determine whether clopidogrel compared with aspirin decreases the need for rehospitalization for ischemia and bleeding.
Methods and Results The Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events (CAPRIE) trial was a randomized, blinded, multicenter, trial of 19,185 patients with atherosclerotic disease manifested as recent ischemic stroke or myocardial infarction or symptomatic peripheral arterial disease. Without any double-counting of events, the number of rehospitalizations for ischemic events (defined as angina, transient ischemic attack, or limb ischemia) or bleeding events was determined for the entire cohort. There was a significant reduction in the total number of rehospitalizations for ischemic events or bleeding with clopidogrel use compared with aspirin (1502 vs 1673; P=.010) over an average of 1.6 years of treatment. This reduction in rehospitalization was consistent across individual outcomes of angina, transient ischemic attack, limb ischemia, and bleeding. Compared with aspirin, clopidogrel also resulted in a 7.9% relative risk reduction in a combined end point of vascular death, stroke, myocardial infarction, or rehospitalization for ischemic events or bleeding (15.1% to 13.7% at 1 year; P=.011). Adjusting for baseline prognostic variables, clopidogrel therapy was an independent predictor for reduction of vascular death, stroke, myocardial infarction, or rehospitalization for ischemic events or bleeding (P=.009).
Conclusions Treatment with clopidogrel results in a significant decrease in the need for rehospitalization for ischemic events or bleeding compared with aspirin. This meaningful end point tracks well with other, more traditional measures of outcome and has incremental value beyond such end points.
Key Words: antiplatelet agents, stroke prevention
Coexisting Causes of Ischemic Stroke—Moncayo J, Devuyst G, Van Melle G, Bogousslavsky J (Dept of Neurology, Centre Hospitalier Universitaire Vaudois, CH 10-11 Lausanne, Switzerland)—Arch Neurol. 2000;57:1139–1144.
Background: Coexistence of multiple potential causes of cerebral infarct (MPCI) has been poorly studied.
Objective: To determine the risk factors, clinical findings, and topographical patterns of patients with at least 2 potential causes of cerebral infarct.
Design: Data analysis from a prospective acute stroke registry (the Lausanne Stroke Registry, Lausanne, Switzerland) in a community-based primary care center.
Results: Among 3525 patients with first-ever ischemic stroke consecutively admitted to a primary care stroke center, 250 patients (7%) had at least 2 MPCIs, with the following subgroups: large artery disease and a cardiac source of embolism (LAD+CSE) (43%), small artery disease and CSE (SAD+CSE) (34%), LAD+SAD (18%), and LAD+SAD+CSE (5%). Hypertension, cardiac ischemia, and a history of atrial fibrillation predominated in the LAD+SAD+CSE subgroup (P<.001), while cigarette smoking was more prevalent in the LAD+SAD subgroup (P<.05). A decreased level of consciousness and speech disorders were more common in the LAD+CSE subgroup (P<.001). Lacunar syndromes predominated in the LAD+SAD subgroup. Pure motor stroke was the most frequent lacunar syndrome in all subgroups, but sensory motor stroke predominated in the LAD+CSE subgroup (P<.05). The outcome at 1 month was worse in the LAD+CSE and SAD+CSE subgroups (P<.001). Other stroke characteristics and clinical features did not differ significantly between the 4 subgroups of patients with MPCI.
Conclusions: Our findings suggest that MPCIs are uncommon. The most frequent association is LAD+CSE. Topographical patterns of stroke and clinical characteristics in patients with MPCI only rarely allow emphasis of a preeminent cause.
Key Words: stroke classification, stroke, ischemic
How Complex Interactions of Ischemic Brain Infarcts, White Matter Lesions, and Atrophy Relate to Poststroke Dementia—Pohjasvaara T, Mäntylä R, Salonen O, Aronen HJ, Ylikoski R, Hietanen M, Kaste M, Erkinjuntti T (Dept of Clinical Neurosciences, Helsinki Univ Central Hospital, PO Box 300, FIN-00029 HYKS, Helsinki, Finland)—Arch Neurol. 2000;57:1295–1300.
Background: Cerebrovascular disease is a major factor related to cognitive impairment. However, behavioral correlates of ischemic brain lesions are insufficiently characterized.
Objective: To examine magnetic resonance imaging correlates of dementia in a large, well-defined series of patients with ischemic stroke.
Methods: Detailed medical, neurological, and neuropsychological examinations were conducted 3 months after ischemic stroke for 337 of 486 consecutive patients aged 55 to 85 years. Infarcts (type, site, side, number, and volume), extent of white matter lesions (WMLs), and degree of atrophy were categorized according to magnetic resonance images of the head. The definition for dementia of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) was used.
Results: Dementia was diagnosed in 107 (31.8%) of the patients and stroke-related dementia in 87 (25.8%). Volumes, numbers, distinct sites of infarcts, extent of WMLs, and degree of atrophy were different for the demented and nondemented subjects. Particularly, volumes of infarcts in any (right- or left-sided) superior middle cerebral artery territory (27.3 vs 13.7 cm3, P=.002) and left thalamocortical connection (14.8 vs 4.0 cm3, P=.002) differentiated the 2 groups. Logistic regression analysis showed that the correlates of any dementia included the combination of infarct features (volume of infarcts in any superior middle cerebral artery: odds ratio [OR], 1.11; frequency of left-sided infarcts: OR, 1.21), extent of WMLs (OR, 1.3), medial temporal lobe atrophy (OR, 2.1), and host factors (education; OR, 0.91). In the patients with stroke-related dementia, the main correlate was volume of infarcts in the left anterior corona radiata (OR, 1.68).
Conclusion: Correlates of poststroke dementia do not include merely 1 feature but a combination of infarct features, extent of WMLs, medial temporal lobe atrophy, and host features.
Key Words: leukoaraiosis, dementia
Extent of Cerebral White Matter Lesions Is Related to Changes of Circadian Blood Pressure Rhythmicity—Sander D (Dept of Neurology, Technical Univ of Munich, Möhlstrasse 28, 81675 München, Germany), Winbeck K, Klingelhöfer J, Conrad B—Arch Neurol. 2000;57:1302–1307.
Objective: To evaluate the relationship between circadian blood pressure patterns and the extent of cerebral white matter lesions (WML).
Design: Case-control study.
Participants: A total of 227 healthy subjects older than 55 years were investigated. Extent and occurrence of WML were evaluated using a computer-supported image analysis system. Circadian blood pressure variation was defined as the average percentage change of nighttime blood pressure compared with the daily blood pressure values.
Results: Subjects with WML were significantly older and showed more often a history of hypertension, elevated average systolic daily blood pressure, a reduced systolic circadian blood pressure variation, and an increased incidence of pathological nighttime blood pressure increases. A significant correlation was found between systolic circadian blood pressure variation and the extent of WML. A multiple regression analysis revealed that this parameter was best correlated with the extent of WML.
Conclusion: In addition to the absolute level of blood pressure, systolic circadian blood pressure variation and in particular a systolic nighttime blood pressure increase may play an important role in the pathogenesis of WML.
Key Words: leukoaraiosis, blood pressure
Efficacy of Anticoagulation in Resolving Left Atrial and Left Atrial Appendage Thrombi: A Transesophageal Echocardiographic Study—Jaber WA, Prior DL, Thamilarasan M, Grimm RA, Thomas JD, Klein AL, Asher CR (Dept of Cardiology/Desk F-15, The Cleveland Clinic Foundation, Cleveland, OH 44195)—Am Heart J. 2000;140:150–156. Copyright ©2000 by Mosby, Inc.
Background Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined.
Methods and Results We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P<.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47±18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit.
Conclusions LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.
Key Words: anticoagulants , atrial thrombi
Age Specific Prevalence of Impairment and Disability Relating to Hemiplegic Stroke in the Hai District of Northern Tanzania—Walker RW (Dept of Medicine, North Tyneside General Hospital, Rake Lane, North Shields, Tyne and Wear, NE29 8NH UK), McLarty DG, Masuki G, Kitange HM, Whiting D, Moshi AF, Massawe JG, Amaro R, Mhina A, Alberti KGMM, on behalf of the Adult Morbidity and Mortality Project—J Neurol Neurosurg Psychiatry. 2000;68:744–749.
Objectives—To determine the age specific prevalence of impairment and disability relating to hemiplegic stroke in one rural area of Tanzania.
Methods—During the yearly house to house census of the study population of 148 135 (85 152 aged 15 and over) in August 1994, specific questions were asked to identify those who might be disabled from stroke. People thus identified were subsequently interviewed and examined by one investigator. In those in whom the clinical diagnosis of stroke was confirmed a more detailed interview and examination relating to risk factors and recovery was carried out.
Results—One hundred and eight patients, 61 men and 47 women, were identified with a median age of 70 (range 18–100). Median age at first stroke was 65 years. The age specific rates in this study were lower than previous studies in developed countries. All were cared for at home although 23 (21%) were bedbound.
Conclusions—Although prevalence of impairment and disability related to stroke in this population as a whole was low this is mainly explained by the age structure, with less than 6% being aged 65 and over. Age standardized rates for stroke with residual disability were about half those found in previous studies in developed countries. Death from stroke in Africa may be higher but data are limited. With the demographic transition stroke is likely to become a more important cause of disability in sub-Saharan Africa.
Key Words: stroke outcome, epidemiology
Differences in Risk Factors, Atherosclerosis, and Cardiovascular Disease Between Ethnic Groups in Canada: The Study of Health Assessment and Risk in Ethnic Groups (SHARE)—Anand SS (Preventive Cardiology and Therapeutics Research Program, McMaster Univ, HGH-McMaster Clinic, Hamilton, ON, Canada L8L 2X2), Yusuf S, Vuksan V, Devanesen S, Teo KK, Montague PA, Kelemen L, Yi C, Lonn E, Gerstein H, Hegele RA, McQueen M, for the SHARE Investigators—Lancet. 2000;356:279–284.
Background Cardiovascular disease rates vary greatly between ethnic groups in Canada. To establish whether this variation can be explained by differences in disease risk factors and subclinical atherosclerosis, we undertook a population-based study of three ethnic groups in Canada: South Asians, Chinese, and Europeans.
Methods 985 participants were recruited from three cities (Hamilton, Toronto, and Edmonton) by stratified random sampling. Clinical cardiovascular disease was defined by history or electrocardiographic findings. Carotid atherosclerosis was measured with B-mode ultrasonography. Conventional (smoking, hypertension, diabetes, raised cholesterol) and novel risk factors (markers of a prothrombotic state) were measured.
Findings Within each ethnic group and overall, the degree of carotid atherosclerosis was associated with a higher prevalence of cardiovascular disease. South Asians had the highest prevalence of this condition compared with Europeans and Chinese (11%, 5%, and 2%, respectively, p=0.0004). Despite this finding, Europeans had more atherosclerosis (mean of the maximum intimal medial thickness 0.75 [0.16] mm) than South Asians (0.72 [0.15] mm), and Chinese (0.69 [0.16] mm). South Asians had an increased prevalence of glucose intolerance, higher total and LDL cholesterol, higher triglycerides, and lower HDL cholesterol, and much greater abnormalities in novel risk factors including higher concentrations of fibrinogen, homocysteine, lipoprotein (a), and plasminogen activator inhibitor-1.
Interpretation Although there are differences in conventional and novel risk factors between ethnic groups, this variation and the degree of atherosclerosis only partly explains the higher rates of cardiovascular disease among South Asians compared with Europeans and Chinese. The increased risk of cardiovascular events could be due to factors affecting plaque rupture, the interaction between prothrombotic factors and atherosclerosis, or as yet undiscovered risk factors.
Key Words: ethnic groups, atherosclerosis
Optic Disk and Retinal Nerve Fiber Layer Damage After Transient Central Retinal Artery Occlusion: An Experimental Study in Rhesus Monkeys—Hayreh SS (Dept of Ophthalmology and Visual Sciences, Univ Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242-1091), Jonas JB—Am J Ophthalmol. 2000;129:786–795. Copyright ©2000 by Elsevier Science Inc. Copyright ©2000 by Elsevier Science.
purpose: To evaluate the retinal tolerance time to acute ischemic insult in middle-aged or elderly rhesus monkeys with pre-existing atherosclerosis and arterial hypertension.
methods: In 39 eyes of 39 middle-aged and elderly rhesus monkeys with a mean age of 19.5±2.8 years, occlusion of the central retinal artery was produced by temporary clamping of the central retinal artery at its site of entry into the dural sheath of the optic nerve for 97 to 300 minutes. Stereoscopic color fundus photography and fluorescein fundus angiography were performed before central retinal artery occlusion and serially thereafter. Retinal nerve fiber layer damage and optic disk changes were assessed by comparing morphometric evaluation of the color fundus photographs taken before central retinal artery occlusion and color fundus photographs taken at the end of the study.
results: There was a significant correlation between duration of central retinal artery occlusion and decreased visibility of retinal nerve fiber layer (P=.018) and increasing optic disk pallor (P=.014), and a trend between residual retinal circulation and decreased visibility of retinal nerve fiber layer (P=.085) and optic disk pallor (P=.162). However, there was a marked interindividual variation between the length of central retinal artery occlusion and degree of increased optic disk pallor and decreased visibility of the retinal nerve fiber layer, even among eyes with similar duration of central retinal artery occlusion. Complete or almost total optic nerve atrophy and nerve fiber damage were present in all eyes in which the duration of central retinal artery occlusion was 240 minutes or more.
conclusions: The findings of this study, compared with our previous study in young healthy rhesus monkeys, indicate that in middle-aged or elderly atherosclerotic and arterial hypertensive rhesus monkeys, central retinal artery occlusion for less than 100 minutes produced no apparent morphometric evidence of optic nerve damage; however, central retinal artery occlusion of 105 minutes but less than 240 minutes produced a variable degree of damage; central retinal artery occlusion for 240 minutes or more produced total or almost total optic nerve atrophy and nerve fiber damage.
Key Words: retinal artery occlusion, retina
Secondary Decline in Apparent Diffusion Coefficient and Neurological Outcomes After a Short Period of Focal Brain Ischemia in Rats—Li F (Dept of Neurology, U Mass Memorial Health Care, 119 Belmont St, Memorial Campus, Worcester, MA 01605), Silva MD, Liu K-F, Helmer KG, Omae T, Fenstermacher JD, Sotak CH, Fisher M—Ann Neurol. 2000;48:236–244. Copyright ©2000 by the American Neurological Association.
This study was designed to characterize the initial and secondary changes of the apparent diffusion coefficient (ADC) of water with high temporal resolution measurements of ADC values and to correlate ADC changes with functional outcomes. Fourteen rats underwent 30 minutes of temporary middle cerebral artery occlusion (MCAO). Diffusion-, perfusion-, and T2-weighted imaging was performed during MCAO and every 30 minutes for a total of 12 hours after reperfusion (n=6). Neurological outcomes were evaluated during MCAO, every 30 minutes for a total of 6 hours and at 24 hours after reperfusion (n=8). The decreased cerebral blood flow during MCAO returned to normal after reperfusion and remained unchanged thereafter. The decreased ADC values during occlusion completely recovered at 1 hour after reperfusion. The renormalized ADC values started to decrease secondarily at 2.5 hours, accompanied by a delayed increase in T2 values. The ADC-defined secondary lesion grew over time and was 52% of the ADC-defined initial lesion at 12 hours. Histological evaluation demonstrated neuronal damage in the regions of secondary ADC decline. Complete resolution of neurological deficits was seen in 1 rat at 1 hour and in 6 rats between 2.5 and 6 hours after reperfusion; no secondary neurological deficits were observed at 24 hours. These data suggest that (1) a secondary ADC reduction occurs as early as 2.5 hours after reperfusion, evolves in a slow fashion, and is associated with neuronal injury; and (2) renormalization and secondary decline in ADC are not associated with neurological recovery and worsening, respectively.
Key Words: stroke outcome, magnetic resonance imaging
Smoking Increases Tissue Factor Expression in Atherosclerotic Plaques: Implications for Plaque Thrombogenicity—Matetzky S, Tani S, Kangavari S, Dimayuga P, Yano J, Xu H, Chyu K-Y, Fishbein MC, Shah PK, Cercek B (Div of Cardiology, Cedars-Sinai Medical Center, Rm 5314, 8700 Beverly Blvd, Los Angeles, CA 90048)—Circulation. 2000;102:602–604. Copyright ©2000 American Heart Association, Inc.
Background—Smoking increases the risk of atherothrombotic events. To determine whether smoking influences plaque thrombogenicity, we examined the effect of cigarette smoking and aspirin use on tissue factor (TF) expression in atherosclerotic plaques.
Methods and Results—A total of 23 apoE−/− mice were exposed to cigarette smoke with (n=9) or without (n=14) aspirin treatment. Eleven mice who were exposed to filtered room air served as controls. Aortic root plaques of mice exposed to smoke had higher immunoreactivity for TF (14±4% versus 6.4±3%; P=0.0005), vascular cell adhesion molecule-1 (15±4% versus 5±2%; P=0.002), and macrophages (16±5% versus 6±2%; P=0.002) compared with nonsmoking controls. Aspirin treatment attenuated smoking-induced changes in plaque composition. In human plaques obtained by carotid endarterectomy, TF immunoreactivity (8±5% versus 2±2%; P=0.0002) and activity (P=0.03) were higher in the plaques from smokers (n=28) than those from nonsmokers (n=28). Aspirin use was associated with reduced TF expression in smokers (9±8% versus 3±4%; P=0.0017).
Conclusions—Our results suggest increased plaque TF expression and thrombogenicity as a novel mechanism for the increased risk of atherothrombotic events in smokers. Treatment with aspirin may reduce TF expression.
Key Words: atherosclerosis, cigarette smoking
Coupling of Cerebral Blood Flow and Oxygen Metabolism in Infant Pigs During Selective Brain Hypothermia—Walter B (Institute of Pathophysiology, Friedrich Schiller Univ, 07740 Jena, Germany), Bauer R, Kuhnen G, Fritz H, Zwiener U—J Cereb Blood Flow Metab. 2000;20:1215–1224. Copyright © The International Society for Cerebral Blood Flow and Metabolism.
Studies documenting the cerebral hemodynamic consequences of selective brain hypothermia (SBH) have yielded conflicting data. Therefore, the authors have studied the effect of SBH on the relation of cerebral blood flow (CBF) and CMRO2 in the forebrain of pigs. Selective brain hypothermia was induced in seven juvenile pigs by bicarotid perfusion of the head with extracorporally cooled blood. Cooling and stepwise rewarming of the brain to a Tbrain of 38°C, 25°C, 30°C, and 38°C at normothermic Ttrunk (38°C) decreased CBF from 71±12 mL 100 g−1 min−1 at normothermia to 26±3 mL 100 g−1 min−1 and 40±12 mL 100 g−1 min−1 at a Tbrain of 25°C and 30°C, respectively. The decrease of CMRO2 during cooling of the brain to a Tbrain of 25°C resulted in a mean Q10 of 2.8. The ratio between CBF and CMRO2 was increased at a Tbrain of 25°C indicating a change in coupling of flow and metabolism. Despite this change, regional perfusion remained coupled to regional temperatures during deep cerebral hypothermia. The data demonstrate that SBH decreases CBF and oxygen metabolism to a degree comparable with the cerebrovascular and metabolic effects of systemic hypothermia. The authors conclude that, irrespective of a change in coupling of blood flow and metabolism during deep cerebral hypothermia, cerebral metabolism is a main determinant of CBF during SBH.
Key Words: cerebral blood flow, hypothermia
Advantages of Adding Diffusion-Weighted Magnetic Resonance Imaging to Conventional Magnetic Resonance Imaging for Evaluating Acute Stroke—Lansberg MG, Norbash AM, Marks MP, Tong DC, Moseley ME, Albers GW (Stanford Stroke Center, 701 Welch Rd, Bldg B, Suite 325, Palo Alto, CA 94304-1705)—Arch Neurol. 2000;57:1311–1316.
Background: Accurate localization of acute ischemic lesions in patients with an acute stroke may aid in understanding the etiology of their stroke and may improve the management of these patients.
Objective: To determine the yield of adding diffusion-weighted magnetic resonance imaging (DWI) to a conventional magnetic resonance imaging (MRI) protocol for acute stroke.
Design: A prospective cohort study.
Setting: A referral center.
Patients and Methods: Fifty-two patients with a clinical diagnosis of acute stroke who presented within 48 hours after symptom onset were included. An MRI scan was obtained within 48 hours after symptom onset. A neuroradiologist (A.M.N.) and a stroke neurologist (G.W.A.) independently identified suspected acute ischemic lesions on MRI sequences in the following order: (1) T2-weighted and proton density–weighted images, (2) fluid-attenuated inversion recovery images, and (3) diffusion-weighted images and apparent diffusion coefficient maps.
Main Outcome Measures: Diagnostic yield and interrater reliability for the identification of acute lesions, and confidence and conspicuity ratings of acute lesions for different MRI sequences.
Results: Conventional MRI correctly identified at least one acute lesion in 71% (34/48) to 80% (39/49) of patients who had an acute stroke; with the addition of DWI, this percentage increased to 94% (46/49) (P<.001). Conventional MRI showed only moderate sensitivity (50%–60%) and specificity (49%–69%) compared with a “criterion standard.” Based on the diffusion-weighted sequence, interrater reliability for identifying acute lesions was moderate for conventional MRI (κ=0.5–0.6) and good for DWI (κ=0.8). The observers’ confidence with which lesions were rated as acute and the lesion conspicuity was significantly (P<.01) higher for DWI than for conventional MRI.
Conclusion: During the first 48 hours after symptom onset, the addition of DWI to conventional MRI improves the accuracy of identifying acute ischemic brain lesions in patients who experienced a stroke.
Key Words: magnetic resonance imaging, stroke assessment
Hemodynamic Assessment of Acute Stroke Using Dynamic Single-Slice Computed Tomographic Perfusion Imaging—Röther J (Univ Hospital, Hamburg Eppendorf, Dept of Neurology, Martinistr. 52, 20246 Hamburg, Germany), Jonetz-Mentzel L, Fiala A, Reichenbach JR, Herzau M, Kaiser WA, Weiller C—Arch Neurol. 2000;57:1161–1166.
Background: Stroke management would benefit from a broadly available imaging tool that detects perfusion deficits in patients with acute stroke.
Objective: To determine the role of dynamic, single-slice computed tomographic (CT) perfusion imaging (CTP) in the assessment of acute middle cerebral artery stroke.
Design and Patients: Imaging with CTP and CT within the first 6 hours of symptom onset and before the start of treatment in a consecutive clinical series of 22 patients (mean age, 68.3 years; 14 women; studied within 143±96 minutes of stroke onset).
Setting: A stroke unit in a university hospital.
Main Outcome Measures: Area of the perfusion deficit (nAP0) from time-to-peak maps, hemispheric lesion area from follow-up CT (HLAF), final infarct volume, and stroke recovery (National Institutes of Health Stroke Scale scores).
Results: Eighteen patients had perfusion deficits in the middle cerebral artery territory and corresponding hypoattenuation in follow-up CT. Three patients with normal CTP findings showed lacunar infarctions or normal findings on follow-up CT. In 1 patient, CTP did not reveal a territorial deficit above the imaging slice. The overall sensitivity and specificity of CTP for the detection of perfusion deficits in patients with proven territorial infarction (n=18) on follow-up CT were 95% and 100%, respectively. The nAP0 was significantly correlated with the National Institutes of Health Stroke Scale score at admission (P<.003) and the HLAF (P<.001). Different stroke patterns were identified in patients with follow-up CTP (n=10): (1) initial perfusion deficit and partial nutritional reperfusion (nAP0>HLAF; n=6), (2) initial perfusion deficit and nonnutritional reperfusion (nAP0≥HLAF; n=2), and (3) initial perfusion deficit without reperfusion (nAP0≥HLAF; n=2).
Conclusions: Computed tomographic perfusion imaging detects major perfusion deficits in the middle cerebral artery territory. Because CTP is broadly available, it may play a role in acute stroke management.
Key Words: stroke assessment, tomography, x-ray computed
MRI of Acute Experimental Intracerebral Hematoma—Hartmann M (Dept of Neuroradiology, Univ of Heidelberg Medical School, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany), Jansen O, Deinsberger W, Vogel J, Sartor K—Neurol Res. 2000;22:512–516. Copyright ©2000 Forefront Publishing Group.
The purpose of the study was to evaluate the ability of different MR-sequences to detect and delineate experimentally produced hyperacute intracerebral hematomas in rats. Twenty male Sprague–Dawley rats received a unilateral hematoma of various volumes by stereotactic injection of fresh autologous arterial blood into the right caudatoputamen. MRI was performed up to 30 min after generation of each hematoma. We obtained coronal T2- and T1-weighted spin–echo images. Furthermore we acquired RF-spoiled 2D- and 3D-FLASH images. MR-images were evaluated for signal behavior, location, configuration, size, and volume of each hematoma on a dedicated work station. MR volumetry was correlated to volumetric data obtained from the serial stained histological sections. All hematomas produced signal abnormalities on all sequences in each case. In the majority of cases the hematomas were hypointense. RF-spoiled FLASH 2D- and 3D-sequences showed the best detection of the hematoma owing to their high sensitivity to susceptibility effects. The best correlation between MR- and histological volumetry was found on RF-spoiled FLASH 2D- (corr. 0.81), SE T2- (corr. 0.79), and T1- (corr. 0.74) weighted images. The lowest correlation index was found on the RF-spoiled FLASH 3D-images (corr. 0.51). Signal loss of hematomas on gradient-echo images and—to a lesser extent—spin–echo T2-weighted images due to susceptibility effects can reliably delineate an acute state, whereas conventional MR scans of ischemic stroke may be normal. MRI may thus be the imaging modality of choice in patients with acute brain attack, especially when it is planned to perform diffusion and perfusion MRI before thrombolytic therapy.
Key Words: magnetic resonance imaging , intracerebral hemorrhage
Common Carotid Artery Intima-Media Thickness and Brain Infarction: The Étude du Profil Génétique de I’Infarctus Cérébral (GÉNIC) Case-Control Study—Touboul P-J (Neurology Dept, Lariboisière Hospital, 2 rue Ambroise Paré, 75010 Paris, France), Elbaz A, Koller C, Lucas C, Adraï V, Chédru F, Amarenco P, for the GÉNIC Investigators—Circulation. 2000;102:313–318. Copyright ©2000 American Heart Association, Inc.
Background—The use of intima-media thickness (IMT) as an outcome measure in observational studies and intervention trials relies on the view that it reflects early stages of atherosclerosis and cardiovascular risk. There is little knowledge concerning the relation between IMT and brain infarction (BI).
Methods and Results—We investigated the relation of IMT with BI and its subtypes in 470 cases and 463 controls. Cases with BI proven by MRI were consecutively recruited and classified into subtypes by cause of BI. Controls were recruited among individuals hospitalized at the same institutions and matched for age, sex, and center. IMT was measured at the far wall of both common carotid arteries (CCA) using an automatic detection system. Adventitia-to-adventitia diameters and CCA-IMT were measured on transverse views; lumen diameter was computed using these measures. Mean (±SEM) CCA-IMT was higher in cases (0.797±0.006 mm) than in controls (0.735±0.006 mm; P<0.0001). This difference remained after adjustment for lumen diameter and when analyses were restricted to subjects free of previous cardiovascular or cerebrovascular history. The difference in CCA-IMT between cases and controls was significant in the main subtypes. The risk of BI increased continuously with increasing CCA-IMT. The odds ratio per SD increase (0.150 mm) was 1.82 (95% confidence interval, 1.54 to 2.15); adjustment for cardiovascular risk factors slightly attenuated this relation (odds ratio, 1.73; 95% confidence interval, 1.45 to 2.07).
Conclusions—An increased CCA-IMT was associated with BI, both overall and in the main subtypes. An increased IMT may help select patients at high risk for BI.
Key Words: ultrasonography , carotid artery diseases
Conventional Physiotherapy and Treadmill Re-Training for Higher-Level Gait Disorders in Cerebrovascular Disease—Liston R, Mickelborough J, Harris B, Hann AW, Tallis RC (Dept of Geriatric Medicine, Clinical Sciences Bldg, Hope Hospital, Eccles Old Rd, Salford M6 8HD, UK)—Age Ageing. 2000;29:311–318. Copyright ©2000 British Geriatrics Society.
Objectives: to compare the therapeutic effects of two approaches to gait re-training—a schedule of conventional physiotherapy and treadmill re-training—in patients with higher-level gait disorders associated with cerebral multi-infarct states.
Design: single-blind crossover study involving a 4-week baseline period, 4 weeks of treadmill re-training and 4 weeks of conventional physiotherapy.
Setting: a large teaching hospital.
Subjects: patients with cerebral multi-infarct states who met the criteria for higher-level gait disorders. Computed tomographic brain scans showed at least one large vessel infarct, basal ganglia and white matter lacunes or extensive leukoaraiosis.
Interventions: a schedule of treadmill re-training and a specific schedule of physiotherapy containing 31 interventions in three treatment modules: (i) for gait ignition failure and turning; (ii) to improve postural alignment and enhance balance reactions; and (iii) for other components of cerebral multi-infarct state disordered gait.
Main outcome measures: spatial and temporal gait measures and activity of daily living assessments.
Results: we recruited 18 patients, mean (SD) age 79.1 (6.8) years. Patients walked an average of 7.9 (5.5) km on the treadmill and had an average of 6.7 (3.2) h of physiotherapy. There were clinically moderate but highly statistically significant (P<0.001) improvements in the following indices: time taken to complete the sit-to-stand test; time taken to walk 10 m; number of steps over 10 m; walking velocity; right and left step lengths; and time taken to complete the ‘S’ test. There were no differences in the results obtained in each limb of the study.
Conclusion: there is no difference between the effects of conventional physiotherapy and treadmill re-training on the gait of patients with higher-level gait disorders associated with cerebral multi-infarct states. However, the improvements seen during the treatment period suggest that there is scope to improve the gait of this group of frail, elderly patients.
Key Words: aging, gait
Patients Satisfaction After Carotid Endarterectomy Using a Selective Policy of Local Anesthesia—Quigley TM (Section of General, Thoracic, and Vascular Surgery, Virginia Mason Medical Center, 1100 Ninth Ave (C6-GSUR), Seattle, WA 98111), Ryan WR, Morgan S—Am J Surg. 2000;179:382–385. Copyright ©2000 by Excerpta Medica, Inc.
background: Patient satisfaction after carotid endarterectomy has not been specifically studied or reported. Results of carotid endarterectomy using either local or general anesthesia have been widely reported, and outcomes are not significantly different for either technique. Patient satisfaction data were obtained in order to determine whether patients preferred one method of anesthesia over another. Data regarding outcome may be added to the surgical literature as benchmark data when comparing operative carotid endarterectomy to newer techniques.
methods: During a 30-month period, 186 consecutive carotid endarterectomies were performed on 169 patients by a single surgeon with assistance from senior surgical residents. All patients were offered local anesthesia using a cervical block technique with intraoperative supplementation. Patients for whom local anesthesia was inappropriate or who declined were operated on using general endotracheal anesthesia. Results of operation were tabulated including indication for operation, method of anesthesia, intraoperative and postoperative complications, and mortality, and completion of a patient satisfaction survey form either on postoperative visit or by telephone questionnaire.
results: Of 169 patients who underwent carotid endarterectomy, 151 (89%) completed the satisfaction survey form. One hundred fourteen (62%) had local anesthesia and 71 patients (38%) had general anesthesia. There was 1 stroke (0.5%) and 1 death (0.5%) in the series. Perioperative complications including temporary cranial nerve injury, neck hematoma, myocardial infarction, and restenosis were noted and not significantly different in either the general anesthesia or local anesthesia group. Patient satisfaction data including intraoperative discomfort, postoperative pain, attentiveness of the operating room staff, and length of stay were all tabulated. There was no statistically significant difference in satisfaction between the general anesthesia group and the local anesthesia group (chi-square and Fisher’s exact test). Additionally, satisfaction with the procedure was extremely high.
conclusions: Patient outcome and perception of pain and recovery were not statistically significantly different in patients undergoing carotid endarterectomy using local anesthesia compared with general anesthesia. Overall patient satisfaction was extremely high. Patients should be offered carotid endarterectomy using an anesthesia technique with which the surgeon and patients are both comfortable, having confidence that the outcome is not related to anesthesia technique and that patients will be highly satisfied.
Key Words: carotid endarterectomy, anesthesia
Items of Interest
A Clustering of Unfavourable Common Genetic Mutations in Stroke Cases—Szolnoki Z (H-5600 Békéscsaba, Pipacs köz 9, Hungary), Somogyvári F, Szabó M, Fodor L—Acta Neurol Scand. 2000;102:124–128. Copyright © Munksgaard 2000.
Functional Differentiation of Multiple Perilesional Zones After Focal Cerebral Ischemia—Witte OW (Dept of Neurology, Heinrich Heine Univ, Moorenstr. 5, D-40225 Düsseldorf, Germany), Bidmon H-J, Schiene K, Redecker C, Hagemann G—J Cereb Blood Flow Metab. 2000;20:1149–1165. Copyright ©2000 The International Society for Cerebral Blood Flow and Metabolism.
Can Diffusion Weighted Magnetic Resonance Imaging Help Differentiate Stroke From Stroke-Like Events in MELAS?—Oppenheim C (Dept of Neuroradiology, Groupe Hospitalier Pitié-Salpêtrière, Paris VI Univ, 47 Boulevard de l’Hôpital, 75651 Paris, Cedex 13, France), Galanaud D, Samson Y, Sahel M, Dormont D, Wechsler B, Marsault C—J Neurol Neurosurg Psychiatry. 2000;69:248–250.
Transplantation of Cultured Human Neuronal Cells for Patients With Stroke—Kondziolka D (Suite B-400, UPMC, 200 Lothrop St, Pittsburgh, PA 15213), Wechsler L, Goldstein S, Meltzer C, Thulborn KR, Gebel J, Jannetta P, DeCesare S, Elder EM, McGrogan M, Reitman MA, Bynum L—Neurology. 2000;55:565–569. Copyright ©2000 by AAN Enterprises, Inc.
Cerebral Blood Flow and Glucose Metabolism in Mitochondrial Disorders—Molnár MJ (National Institute of Psychiatry and Neurology, Budapest, Hungary, H-1021 Budapest Hüvösvölgyi u. 116), Valikovics A, Molnár S, Trón L, Diószeghy P, Mechler F, Gulyás B—Neurology. 2000;55:544–548. Copyright ©2000 by AAN Enterprises, Inc.
The abstracts in this section have been typeset for consistency with journal format but otherwise appear as in the original articles.
- Copyright © 2000 by American Heart Association