Stroke: epidemiology, clinical picture, and risk factors--Part I of III

Optimal medical therapy is lacking in patients undergoing intervention for symptomatic carotid artery stenosis and protects against larger areas of cerebral infarction

OBJECTIVES

Carotid interventions are indicated for both patients with symptomatic and a subset of patients with severe asymptomatic carotid artery stenosis (CAS). Symptomatic CAS accounts for up to 12%-25% of overall carotid interventions, but predictors of symptomatic presentation remain poorly defined. The aim of this study was to identify factors associated with symptomatic CAS in our patient population.

METHODS

Between January 2015 and February 2022, an institutional retrospective cohort study of prospectively collected data on patients undergoing interventions for CAS was performed. Procedures included carotid endarterectomy (CEA), transcarotid artery revascularization (TCAR), and transfemoral carotid artery stenting (TF-CAS). Demographic data, comorbidities, procedural details, and anatomic features from various imaging modalities were collected. Comparisons were made between symptomatic (symptoms within the prior 6 months) and asymptomatic patients.

RESULTS

During the study period, 279 patients who underwent intervention for symptomatic CAS were paired with a randomly selected cohort of 300 patients who underwent intervention for asymptomatic CAS from a total patient cohort of 1143 patients undergoing interventions for asymptomatic CAS. Demographic data did not differ between groups. Patients with symptomatic CAS more frequently had prior TIA/stroke (>6 months remote to the current event), but less frequently had coronary artery disease or chronic kidney disease and were less likely to receive adequate medical management including antihypertensive agents, lipid-lowering agents, and anti-platelet therapy. On multivariate analysis, remote prior TIA/stroke and lack of anti-platelet therapy remained significant. Among symptomatic patients presenting with stroke, lack of anti-platelet therapy was associated with an overall larger area of parenchymal involvement. No difference was observed with single versus dual anti-platelet therapy. Furthermore, symptomatic patients were more likely to have ulcerated plaques (30.9% vs 18%, p < .001), and symptomatic patients with ulcerated plaques more frequently had less than 50% compared to moderate/severe CAS. Nine patients who presented with symptoms had mild CAS and underwent intervention.

CONCLUSIONS

Symptomatic CAS was associated with a history of remote prior symptoms and lack of anti-platelet therapy at time of presentation. Furthermore, symptomatic patients not on anti-platelet agents were more likely to have a greater area of parenchymal involvement when presenting with stroke and symptomatic patients with ulcerated plaques were more likely to have mild CAS, suggesting the role of plaque instability in symptomatic presentation. These findings underscore the importance of appropriate medical management and adherence in all patients with CAS and perhaps a role for more frequent surveillance in those with potentially unstable plaque morphology.

Systematic Review on Magnetic Resonance Angiography with Vessel Wall Imaging for the Characterization of Symptomatic Carotid Artery Plaque

BACKGROUND

To perform a systematic literature review to assess the usefulness of performing magnetic resonance angiography (MRA) with vessel wall imaging (VWI) sequences for the assessment of symptomatic carotid artery plaques and the identification of risky plaque features predisposing for stroke.

METHODS

We performed a systematic review of the literature pertaining to MRA with VWI techniques in patients with carotid artery disease, focusing on symptomatic patients' plaque features and morphology. Independent reviewers screened and analyzed data extracted from eligible studies, and a modified Newcastle-Ottawa Scale was used to appraise the quality of the design and content of the selected manuscripts to achieve an accurate interpretation.

RESULTS

This review included nineteen peer-reviewed manuscripts, all of them including MRA and VWI assessments of the symptomatic carotid artery plaque. We focused on patients' comorbidities and reviewed plaque features, including intraplaque hemorrhage, a lipid-rich necrotic core, a ruptured fibrous cap, and plaque ulceration.

CONCLUSIONS

MRA with VWI is a useful tool in the evaluation of carotid artery plaques. This imaging technique allows clinicians to identify plaques at risk of causing a neurovascular event. The presence of intraplaque hemorrhage, plaque ulceration, a ruptured fibrous cap, and a lipid-rich necrotic core are associated with neurovascular symptoms. The timely identification of these features could have a positive impact on neurovascular event prevention.

Patterns of Visual Task-based Functional MRI Activation in Chronic Posterior Cerebral Artery Stroke Patients

PURPOSE

Stroke is a principal cause of disability worldwide. In motor stroke, the tools for stratification and prognostication are plentiful. Conversely, in stroke causing mainly visual and cognitive problems, there is still no gold standard modality to use. The purpose of this study was to explore the fMRI recruitment pattern in chronic posterior cerebral artery (PCA) stroke patients and to investigate fMRI as a biomarker of disability in these patients.

METHODS

The study included 10 chronic PCA stroke patients and another 10 age-matched volunteer controls. The clinical presentation, cognitive state, and performance in visual perceptual skills battery (TVPS-3) were determined for both patients and control groups. Task-based fMRI scans were acquired while performing a passive visual task. Individual and group analyses of the fMRI scans as well as correlation analysis with the clinical and behavioral data were done.

RESULTS

At the level of behavioral assessment there was non-selective global impairment in all visual skills subtests. On visual task-based fMRI, patients recruited more brain areas than controls. These activations were present in the ipsilesional side distributed in the ipsilesional cerebellum, dorsolateral prefrontal cortex mainly Brodmann area (BA) 9, superior parietal lobule (somatosensory associative cortex, BA 7), superior temporal gyrus (BA 22), supramarginal gyrus (BA 40), and contralesional associative visual cortex (BA 19). Spearman's rank correlation was computed to assess the relationship between the TVPS scores and the numbers of fMRI neuronal clusters in each patient above the main control activations, there was a negative correlation between the two variables, r(10) = -0.85, p ≤ 0.001.

CONCLUSION

In chronic PCA stroke patients with residual visual impairments, the brain attempts to recruit more neighboring and distant functional areas for executing the impaired visual skill. This intense recruitment pattern in poorly recovering patients appears to be a sign of failed compensation. Consequently, fMRI has the potential for clinically relevant prognostic assessment in patients surviving PCA stroke; however, as this study included no longitudinal data, this potential should be further investigated in longitudinal imaging studies, with a larger cohort, and multiple time points.

Efficacy and safety of low dose aspirin plus clopidogrel in the treatment of elderly patients with symptomatic intracranial artery stenosis

Background

As one of the most common causes of stroke, symptomatic intracranial artery stenosis (sICAS) is a great threat to public health, and its financial burden is substantial, with annual direct high medical costs particularly in China. Currently, the long-term use of conventional dual antiplatelet therapy (DAPT) as the primary modality of treatment for sICAS decreases the risk of stroke recurrence but increases the risk of bleeding. We aimed to evaluate the efficacy and safety of low dose aspirin plus clopidogrel for the treatment of sICAS in the elderly population.

Methods

This randomized, controlled study included 181 older patients with transient ischemic attack (TIA) or ischemic stroke (IS) attributed to sICAS, who were recruited between April 2015 and November 2020. The 90 patients assigned to the low dose therapy group included aspirin, 75 mg, plus clopidogrel, 50 mg, daily for 90 and 91 patients assigned to the conventional group included aspirin, 100 mg, plus clopidogrel, 75 mg, daily for 90 days (aspirin or clopidogrel alone daily thereafter) were included in this intention-to-treat analysis. Efficacy and safety analyses were done in this trial.

Results

One hundred eighty-one eligible elderly patients with sICAS were enrolled in this trial. The median age was 70 years ranged 60-83 years. Seventy-five participants were with TIA and 106 with IS. The median time of follow-up was 30 months ranged 1-36 months. Ninety patients were assigned randomly to the low dose group and 91 patients to the conventional group. The rate of primary, secondary and composite efficacy were not significantly different between the low dose and conventional group (P > 0.05). The rate of composite safety outcome was 7.8% (7/90) in the low dose group, which was lower than 17.6% (16/91) in the conventional group (χ² = 3.921, P = 0.048). At the time of last follow-up, 17 (9.4%) of 181 patients developed GI injuries, which occurred in four (4.4%) of 90 patients in the low dose group and in 13 (14.3%) of 91 patients in the conventional group (χ² = 4.058, P = 0.044). The primary efficacy outcome occurred in six (18.2%) of 33 patients with severe sICAS and in 22 (38.6%) of 57 patients with moderate sICAS (χ² = 4.064, P = 0.044) in the low dose group.

Conclusion

In this study, the safety of low dose aspirin combined with clopidogrel proved to be equally efficient and significantly safer than those of conventional dose within 24 months in elderly patients with sICAS. However, the small size of this study limits the validity of the results. Further larger longitudinal and randomized controlled trials are necessary to evaluate the role of low dose DAPT in the patients with sICAS.

Advances in Noninvasive Carotid Wall Imaging with Ultrasound: A Narrative Review

Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

Blood miR-1275 is associated with risk of ischemic stroke and inhibits macrophage foam cell formation by targeting ApoC2 gene

Apolipoprotein C2 (ApoC2) is an important member of the apolipoprotein C family and functions as a major activator of lipoprotein lipase (LPL). In cardiovascular and cerebrovascular systems, the lipolytic activity of the LPL-ApoC2 complex is critical for the metabolism of triglyceride-rich lipoproteins and contributes to the pathogenesis of ischemic stroke (IS). However, the regulation of ApoC2 in IS development remains unclear. In this study, we first explored potential ApoC2-targeting microRNAs (miRNAs) by bioinformatics tool and compared the miRNA expression profiles in the blood cells of 25 IS patients and 25 control subjects by miRNA microarray. miR-1275 was predicted to bind with the 3' untranslated region of ApoC2, and a significant reduction of blood miR-1275 levels was observed in IS patients. Dual-luciferase reporter assay and quantitative RT-PCR confirmed the regulation of ApoC2 by miR-1275 in THP-1 derived macrophages. miR-1275 also inhibited cellular uptake of ox-LDL and suppressed formation of macrophage foam cell. Furthermore, the whole blood miR-1275 levels were validated in 279 IS patients and 279 control subjects by TaqMan assay. miR-1275 levels were significantly lower in IS cases and logistic regression analysis showed that miR-1275 level was negatively associated with the occurrence of IS (adjusted OR, 0.76; 95% CI, 0.69-0.85; p < 0.001). Addition of miR-1275 to traditional risk factors showed an additive prediction value for IS. Our study shows that blood miR-1275 levels were negatively associated with the occurrence of IS, and miR-1275 might exert an athero-protective role against the development of IS by targeting ApoC2 and blocking the formation of macrophage foam cells.

Trajectories of memory, language, and visuoperceptual problems in people with stroke during the first year and controls in Colombia

AIM

Neuropsychological normative data for Latin America have been recently published, and for Colombia, in particular, but longitudinal neuropsychological outcomes after stroke have not yet been examined in this global region. The purpose of the current study was to compare functioning of individuals with stroke in Colombia, South America during the first year post-stroke to healthy controls across neuropsychological assessments of memory, language, and visuoperceptual impairments.

METHOD

A sample of 50 individuals with stroke (mean age = 51.58) and 50 matched healthy controls (mean age = 51.54) from Colombia were included in this study. Because of a lack of access to health services, individuals with stroke did not receive any inpatient or outpatient cognitive or behavioral rehabilitation. Participants were assessed on 10 visuoperceptual, language, and memory tasks at 3, 6, and 12   months.

RESULTS

Trajectories of neuropsychological performance were significantly worse among individuals with stroke than healthy controls across every index. Further, hierarchical linear models suggested that although both individuals with stroke and controls generally improved over time on these assessments, the improvements among individuals with stroke were often of no greater magnitude than the improvements seen in controls, suggesting extremely low levels of rehabilitation gains in Colombia. Only three of the 10 neuropsychological assessments did a significant time*group interaction occur, suggesting greater gains for the stroke group than controls.

CONCLUSION

These findings suggest profound disparities in post-stroke cognitive functioning in Colombia compared to other more developed global region and underscore the importance of comprehensive cognitive rehabilitation services for individuals with stroke in Colombia and other similar global regions. Implications for rehabilitation Because this study found only negligible cognitive improvements beyond practice effects over the first year after stroke in Colombia among individuals without access to acute rehabilitation, it is imperative that comprehensive cognitive rehabilitation services be implemented immediately during the acute rehabilitation period. Memory, language, and visuoperceptual training strategies can be implemented for people with stroke in underserved global regions as part of the standard of care for stroke rehabilitation. Cognitive rehabilitation strategies should be adapted into Spanish and pilot tested in Latin America to ensure cultural equivalence. Culturally competent cognitive rehabilitation strategies should be tailored based on varied educational and literacy levels.

Are the Variants of the Circle of Willis Determined by Genetic or Environmental Factors? Results of a Twin Study and Review of the Literature

BACKGROUND

Anatomic variants of the circle of Willis (CW) are commonly observed in healthy subjects. Genetic and environmental factors influencing these variants remain unclear. Our aim was to assess the genetic and environmental background affecting variant CW phenotypes.

METHODS

A total of 122 adult healthy twins from the Hungarian Twin Registry (39 monozygotic (MZ) and 22 dizygotic (DZ) pairs, average age 49.7 ± 13.4 years) underwent Time-of-Flight magnetic resonance angiography and transcranial Doppler sonography. We investigated the anterior and posterior CW according to morphological categories. Prevalence and concordance rates of CW variants were calculated. MZ twins discordant for CW variants were analyzed for cardiovascular risk factors and altered blood flow.

RESULTS

Complete CW (45.0%) and bilaterally absent posterior communicating artery (PCoA) (22.5%) were the most prevalent variants in the anterior and posterior CW, respectively. There was no significant difference regarding the prevalence of variants across zygosity except for bilaterally hypoplastic PCoA (p = .02). DZ concordance was higher compared to MZ twins regarding morphological categories of the CW. Cardiovascular risk factors were not significantly associated with variant CW in MZ twins discordant to CW morphology. Flow parameters did not differ significantly among MZ twins discordant to CW variants.

CONCLUSION

CW variants may not be determined by substantial genetic effects and are not influenced by altered blood flow in healthy individuals. Further investigations are needed to identify potential environmental factors affecting these variants.

Characterization and Natural History of Patients with Internal Carotid Occlusion: A Comparative Study

BACKGROUND

To characterize patients with internal carotid occlusion (ICO) with respect to demographic data, associated diseases, medical management, and risk factors and to compare these patients with those with nonsignificant stenosis (NSS; less than 50% stenosis). Secondary end points were new neurologic events, progression of contralateral degree of stenosis, cardiovascular symptoms, and death during follow-up.

METHODS

Retrospective analysis was performed using data collected from clinical records and added to a prospective database. Missing data were obtained during phone interviews or requested medical appointments.

RESULTS

From 2005 to 2013, 213 patients with ICO and 172 with NSS were studied (medium follow-up 37.81 months). Among the patients with ICO, a greater proportion were men, had a history of smoking, and presented with peripheral arterial disease and a lower creatinine clearance compared with those with NSS (P < 0.05). At the time of diagnosis, 76.1% of the patients with ICO were symptomatic compared with 35.5% of those with NSS (P = 0.000001). The patients in the ICO group exhibited significant progression of contralateral stenosis compared with those in the control group with progression on any side (15.0% vs. 2.3%, P = 0.00011). In addition, 18 patients in the ICO group (8.5%) exhibited new neurological symptoms compared with 13 (7.6%) in the NSS group (P = 0.41). When the ICO and NSS groups were combined, 10.8% of the initially symptomatic patients presented with new symptoms compared with 4.3% of those who were initially asymptomatic (P = 0.0218). The number of deaths was significantly higher among the patients in the ICO group (14.1% vs. 6.4%, P = 0.0150).

CONCLUSIONS

Patients presenting with ICO have more risk factors and higher mortality by any cause. Initially, symptomatic patients will likely present with more neurological symptoms during follow-up, independent of carotid morphology, ICO, or NSS. Efforts must be made to identify those at risk before occlusion and to prevent secondary events and death.

Hemicraniectomy for Ischemic and Hemorrhagic Stroke: Facts and Controversies

Malignant large artery stroke is associated with high mortality of 70% to 80% with best medical management. Decompressive craniectomy (DC) is a highly effective tool in reducing mortality. Convincing evidence has accumulated from several randomized trials, in addition to multiple retrospective studies, that demonstrate not only survival benefit but also improved functional outcome with DC in appropriately selected patients. This article explores in detail the evidence for DC, nuances regarding patient selection, and applicability of DC for supratentorial intracerebral hemorrhage and posterior fossa ischemic and hemorrhagic stroke.

The Incidence and Risk Factors of In-Stent Restenosis for Vertebrobasilar Artery Stenting

BACKGROUND AND OBJECTIVES

In-stent restenosis (ISR) remains a challenge for vertebrobasilar artery stenting (VBAS). We aimed to investigate the incidence and risk factors of ISR.

METHODS

This was a retrospective study. From July 28, 2005, to July 30, 2015, patients who received VBAS with an angiographic follow-up time of 6 to 12 months after surgery were enrolled. The clinical and angiographic issues were recorded and analyzed.

RESULTS

In total, 283 patients with 335 stents were incorporated into the study. Vertebral ostial lesions accounted for 73.4% (246/335) of the lesions. During the follow-up period, 58 patients with 60 stents experienced ISR (>50%). Stepwise logistic regression analysis showed that the degree of residual stenosis, stent diameter, and alcohol consumption were independent predictors of ISR.

CONCLUSIONS

Our study demonstrated the incidence and risk factors of ISR after VBAS. This retrospective study with the largest cohort to date provided insight into the occurrence of ISR after VBAS.

The Value of the Score for the Targeting of Atrial Fibrillation (STAF) Screening in Acute Stroke Patients

BACKGROUND AND PURPOSE

Recently, the score for the targeting of atrial fibrillation (STAF) was introduced to identify the risk of atrial fibrillation (AF) in stroke patients. In this study, we aim to evaluate the usefulness of the STAF score for AF screening in acute stroke patients.

METHODS

Patients with acute ischemic stroke who were admitted to our stroke unit were prospectively enrolled from March 2011 to March 2013. Baseline National Institutes of Health Stroke Scale (NIHSS), left atrial dilatation, and vascular etiology were assessed to calculate the STAF score. Logistic regression analysis was used to examine the relationship between AF and STAF factors. Univariate analysis of AF and age, history of coronary heart disease and rheumatic heart disease, NIHSS, left atrial dilatation, and vascular etiology was performed.

RESULTS

A total of 472 patients were enrolled in our analysis. AF was documented in 78 (16.53%) patients, of which 50% were paroxysmal. Multivariable analysis demonstrated that age, NIHSS, left atrial dilatation, and the absence of vascular etiology can each function as independent predictors for AF. In addition, all AF patients with a STAF ≥5 show a sensitivity of 76.92% and a specificity of 78.68%. The area under the receiver operating characteristic for all AF patients was .842 versus .763 for the paroxysmal AF (pAF) patients. In addition, a sensitivity of 81% (95% CI 73-92) and a ROC of .829 were for new-AF.

CONCLUSIONS

The value of the STAF system for predicting the risk of pAF and new-AF in stroke patients is relatively limited.

Imaging of the ulcerated carotid atherosclerotic plaque: a review of the literature

Abstract

Carotid atherosclerotic disease constitutes a major modern health problem whose diagnosis primarily relies on imaging. Grading of stenosis has been long used as the main factor for risk stratification and guiding of management. Nevertheless, increasing evidence has shown that additional plaque characteristics such as plaque composition and surface morphology play an important role in the occurrence of symptoms, justifying the term “vulnerable plaque”. Carotid plaque surface characteristics either in the form of surface irregularities or ulceration represent an important factor of vulnerability and are associated with the occurrence of neurologic symptoms. The delineation of the carotid plaque surface can be performed with virtually all imaging modalities including ultrasound, contrast-enhanced ultrasound, multi-detector computed tomography angiography, magnetic resonance angiography and the traditional reference method of angiography. These techniques have shown varying levels of diagnostic accuracy for the identification of ulcerated carotid plaques or plaque surface irregularities. As a consequence and given its high clinical significance, radiologists should be familiar with the various aspects of this entity, including its definition, classification, imaging findings on different imaging modalities and associations. The purpose of this review is to present the current literature regarding carotid plaque ulcerations and present illustrative images of ulcerated carotid plaques.

Teaching Points

• Plaque surface and ulceration represent risk factors for stroke in carotid disease.

• Characterisation of the plaque surface and ulcerations can be performed with every modality.

• US is the first-line modality for carotid disease and identification of ulcerations.

• The administration of microbubbles increases US accuracy for diagnosis of carotid ulceration.

• MDCTA and MRA are valuable for diagnosing ulceration and evaluating plaque composition.

Associations among hemorheological factors and maximal oxygen consumption. Is there a role for blood viscosity in explaining athletic performance?

This study examined the relationship between hematocrit, blood viscosity, plasma viscosity, erythrocyte deformability, and fibrinogen concentration during maximal oxygen uptake in aerobically trained (AT) and resistance trained (RT) athletes. Maximal oxygen uptake was assessed using a Bruce graded exercise treadmill test to exhaustion, and blood samples were collected at rest and immediately following exercise using a venous catheter. Viscometric analyses were performed using a cone and plate viscometer at varying shear rates. Hematocrit was measured as the fraction of erythrocytes suspended in plasma following centrifugation. Erythrocyte rigidity was estimated using the Dintenfass index of red blood cell rigidity. Following maximal treadmill exercise, an increase of blood viscosity at varying shear rates (22.50, 45.00, 90.00, and 225.00 s- 1; P <  0.05) was observed in RT athletes only. Plasma viscosity @ 225.00 s- 1 (1.88 ± 0.09 vs. 1.78 ± 0.03 mPa.s; P <  0.05), erythrocyte rigidity (0.52 ± 0.08 vs. 0.40 ± 0.09; P <  0.05), and plasma fibrinogen (434 ± 7 vs. 295 ± 25 mg/dL; P <  0.01) were all significantly greater in RT than AT athletes following maximal exercise. In summary, AT, but not RT, is associated with a hemorheological profile that promotes both oxygen transport and delivery. The results indicate that hematocrit alone should not be the focus of training and ergogenic supplementation to increase aerobic performance.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

Laboratory-Based Markers as Predictors of Brain Infarction During Carotid Stenting: a Prospective Study

AIM

New ischemic lesions in the brain can be detected in approximately 50% of patients undergoing carotid artery stenting (CAS). We wished to discover the laboratory-based predictors of new infarctions in the brain after CAS.

METHODS

All consecutive patients with internal carotid artery stenosis of ≥70% with indication for CAS were enrolled in a prospective study for 16 months. All patients used dual antiplatelet therapy for ≥7 days before CAS. Neurologic examination and magnetic resonance imaging (MRI) of the brain were undertaken before and at 24 h after CAS. Samples of venous blood were collected at ＜24 h before CAS for the evaluation of hematology, reticulocytes, coagulation markers (PT, APTT, Fbg, Clauss), vWF antigen, PAI-1 activity, PAI-1 polymorphism 4G/5G, and the multiplate (aspirin and clopidogrel) resistance test. Blood samples for the assessment of anti-Xa activity were collected during CAS. Differences in the values of laboratory markers between patients with and without new ischemic lesions of the brain on control MRI were evaluated.

RESULTS

The cohort comprised 81 patients (53 males; mean age, 67.3±7.2 years). New ischemic infarctions in the brain on control MRI were found in 46 (56.8%) patients. Three of seven patients with resistance to aspirin or clopidogrel had a new ischemic infarction in the brain. No significant differences for particular markers were found between patients with and without an ischemic lesion in the brain.

CONCLUSION

A high risk of a new ischemic infarction in the brain was detected in patients undergoing CAS, but a laboratory-based predictor of such an infarction could not be identified.

The impact of anemia on the course and short-term prognosis in patients with first ever ischemic stroke

BACKGROUND

Anemia is the risk factor for cerebrovascular events. The aim of this study was to evaluate the prevalence of anemia among patients with first-ever stroke and its impact on neurological state in the acute phase of the disease and the degree of disability in short-term follow-up.

PATIENTS AND METHODS

The prospective study included 107 patients aged 72.81 ± 11.12 with the first-ever stroke. Each patient underwent CT of the head and blood tests, including Hb concentration on the first day of hospitalization. We have analyzed the neurological state on the first day of stroke by NIHSS and the functional status on the 14th day after the onset of stroke by mRankin scale in patients with and without anemia. Patients with anemia were additionally divided according to Hb level (less or over 11g/dl).

RESULTS

Patients with Hb≤ 11g/dl significantly more often achieved a score of 4-5 points on mRankin scale on the 14th day of stroke compared to patients with anemia and Hb>11g/dl. Independent predictors of a worse functional status on the 14th day of stroke in patients with anemia include the neurological state on the 1st day and the hemispheric location of stroke; an independent predictor of death was the neurological state on the 1st day of onset.

CONCLUSION

Mild anemia did not influence significantly the neurological condition in acute phase of stroke but worsened the functional status in subacute phase of stroke. The neurological state on the first day of stroke and the hemispheric location of cerebral ischemia are independent factors of poor prognosis in patients with anemia in short-term follow-up.

Endovascular treatment of carotid occlusive disease

Carotid occlusive disease is one of several etiologic factors for stroke. Of all strokes, an estimated 88% are ischemic in nature. Less than 20% of these are caused by atheroma in the carotid bifurcation. Traditionally, carotid artery stenosis has been treated with carotid endarterectomy (CEA); however, carotid artery balloon angioplasty and stent placement has enjoyed significant technological advances over the last decade and can now offer a comparable treatment alternative to CEA. In this review, the authors concentrate their discussion on the treatment of carotid atherosclerotic disease with particular attention on the endovascular treatment.

Ischemic stroke after recombinant factor VIIa treatment in acquired hemophilia A patient

Acquired hemophilia is a rare, life-threatening coagulopathy in adults caused by the development of autoantibodies against factor VIII. Bypass agents such as recombinant factor VIIa (rFVIIa) are usually preferred for bleeding control; however, thromboembolic complications may occur. We report here a case that presented with extensive cutaneous and mucosal bleedings due to factor VIII inhibitors and was treated successfully with rFVIIa and steroid therapy, but was complicated with a life-threatening thromboembolic attack during follow-up.

Potential application of hydrogen in traumatic and surgical brain injury, stroke and neonatal hypoxia-ischemia

This article summarized findings of current preclinical studies that implemented hydrogen administration, either in the gas or liquid form, as treatment application for neurological disorders including traumatic brain injury (TBI), surgically induced brain injury (SBI), stroke, and neonatal hypoxic-ischemic brain insult (HI). Most reviewed studies demonstrated neuroprotective effects of hydrogen administration. Even though anti-oxidative potentials have been reported in several studies, further neuroprotective mechanisms of hydrogen therapy remain to be elucidated. Hydrogen may serve as an adjunct treatment for neurological disorders.

Aptamer-functionalized nano-biosensors

Nanomaterials have become one of the most interesting sensing materials because of their unique size- and shape-dependent optical properties, high surface energy and surface-to-volume ratio, and tunable surface properties. Aptamers are oligonucleotides that can bind their target ligands with high affinity. The use of nanomaterials that are bioconjugated with aptamers for selective and sensitive detection of analytes such as small molecules, metal ions, proteins, and cells has been demonstrated. This review focuses on recent progress in the development of biosensors by integrating functional aptamers with different types of nanomaterials, including quantum dots, magnetic nanoparticles (NPs), metallic NPs, and carbon nanotubes. Colorimetry, fluorescence, electrochemistry, surface plasmon resonance, surface-enhanced Raman scattering, and magnetic resonance imaging are common detection modes for a broad range of analytes with high sensitivity and selectivity when using aptamer bioconjugated nanomaterials (Apt-NMs). We highlight the important roles that the size and concentration of nanomaterials, the secondary structure and density of aptamers, and the multivalent interactions play in determining the specificity and sensitivity of the nanosensors towards analytes. Advantages and disadvantages of the Apt-NMs for bioapplications are focused.

The influence of anemia on clinical presentation and outcome of patients with first-ever atherosclerosis-related ischemic stroke

There is considerable debate regarding whether anemia qualifies as a prognostic factor for stroke. The purpose of this study was twofold: first, to assess the influence of anemia on vascular risk factors and clinical presentations in patients with first-ever atherosclerosis-related ischemic stroke and, second, to evaluate whether anemia may be of prognostic importance. A total of 774 consecutive patients with first-ever atherosclerosis-related ischemic stroke were prospectively investigated. Vascular risk factors, clinical presentations and outcomes were recorded and compared between those patients with and without anemia. Stroke recurrence and mortality were recorded at the 3-year follow-up. Of the study population, 168 (21.7%) were anemic. Multivariate analysis revealed that patients with anemia were more likely to be older than 70 years (p<0.001) and have chronic renal insufficiency (p<0.001). After a mean follow-up period of 958 days, 21 (12.5%) and 24 (4.0%) of the patients in the anemic and control groups, respectively, died. Within 3 years of initial onset, the mortality rate was significantly higher in patients with anemia (p=0.021). The Kaplan-Meier analysis for patients with and without anemia showed different survival curves (Log-rank test p<0.001). Within 3 years of the onset of first-ever atherosclerosis-related ischemic stroke, patients who had anemia at the time of the initial admission had an associated higher mortality rate. The stroke risk factors of being older than 70 years and having chronic renal insufficiency were more frequently observed in those patients with anemia.

MDCT features of cardiothoracic sources of stroke

Multidetector computed tomography (MDCT) is widely used in the assessment of cardiothoracic disease and provides high-resolution images of the heart, great vessels, and lungs. A range of cardiothoracic conditions can precipitate stroke, including intracardiac thrombus, right-to-left shunts, and diseases of the thoracic aorta. Many of these conditions may be identified on non-electrocardiogram (ECG)-gated studies, but the advent of high temporal resolution ECG-gated MDCT provides superior anatomical delineation. Radiologists should be familiar with the pathogenesis and CT features of cardiothoracic conditions that can precipitate stroke as their early identification to enables appropriate management and prognostic decisions.

Lack of Observed Association between High Plasma Osteoprotegerin Concentrations and Ischemic Stroke Risk in a Healthy Population

Background: Several studies suggest that osteoprotegerin (OPG) concentrations may be associated with the risk of ischemic stroke, but no large prospective studies have been conducted. We conducted a nested case-control study within a large cohort to elucidate a possible relation.

Methods: The study was done within a follow-up study including 57 053 men and women. Baseline data included OPG concentrations, lifestyle factors, and medical history. Median length of follow-up was 3.1 years. We assessed the relationship between OPG and stroke risk using conditional logistic regression to adjust for known risk factors (smoking, blood pressure, cholesterol, diabetes, body mass index, alcohol use, polyunsaturated fatty acids, and education).

Results: We identified 254 cases with verified incident acute ischemic stroke and 254 age- and sex-matched controls. Median plasma OPG concentration among cases was 1.84 μg/L (25th–75th percentile 1.45–2.30 μg/L) compared with 1.87 μg/L (1.49–2.27 μg/L) in the control group. The adjusted odds ratio was 0.87 (95% CI 0.46–1.63) comparing participants in the highest quartile of OPG concentrations with those in the lowest quartile.

Conclusions: These findings provide no support for the hypothesis that plasma OPG concentrations are associated with an increased risk of ischemic stroke. This result could indicate a different pathogenic process in stroke development from that in ischemic heart disease, where OPG is a strong predictor.

The effects of tibolone in older postmenopausal women

BACKGROUND

Tibolone has estrogenic, progestogenic, and androgenic effects. Although tibolone prevents bone loss, its effects on fractures, breast cancer, and cardiovascular disease are uncertain.

METHODS

In this randomized study, we assigned 4538 women, who were between the ages of 60 and 85 years and had a bone mineral density T score of -2.5 or less at the hip or spine or a T score of -2.0 or less and radiologic evidence of a vertebral fracture, to receive once-daily tibolone (at a dose of 1.25 mg) or placebo. Annual spine radiographs were used to assess for vertebral fracture. Rates of cardiovascular events and breast cancer were adjudicated by expert panels.

RESULTS

During a median of 34 months of treatment, the tibolone group, as compared with the placebo group, had a decreased risk of vertebral fracture, with 70 cases versus 126 cases per 1000 person-years (relative hazard, 0.55; 95% confidence interval [CI], 0.41 to 0.74; P<0.001), and a decreased risk of nonvertebral fracture, with 122 cases versus 166 cases per 1000 person-years (relative hazard, 0.74; 95% CI, 0.58 to 0.93; P=0.01). The tibolone group also had a decreased risk of invasive breast cancer (relative hazard, 0.32; 95% CI, 0.13 to 0.80; P=0.02) and colon cancer (relative hazard, 0.31; 95% CI, 0.10 to 0.96; P=0.04). However, the tibolone group had an increased risk of stroke (relative hazard, 2.19; 95% CI, 1.14 to 4.23; P=0.02), for which the study was stopped in February 2006 at the recommendation of the data and safety monitoring board. There were no significant differences in the risk of either coronary heart disease or venous thromboembolism between the two groups.

CONCLUSIONS

Tibolone reduced the risk of fracture and breast cancer and possibly colon cancer but increased the risk of stroke in older women with osteoporosis. (ClinicalTrials.gov number, NCT00519857.)

Occurrence of diabetes mellitus in spontaneous intracerebral hemorrhage

The role of diabetes mellitus (DM) in the etiopathogenesis of spontaneous intracerebral hemorrhage (SICH) is controversial. The aim was to assess the role of DM in our SICH patients. In a hospital-based cross-section study, the occurrence of DM prior to a hemorrhagic stroke was observed in 80 SICH patients (44 males, aged 36-87 years, mean 67.1 +/- 11.9 years; 36 females, aged 56-86 years, mean 71.1 +/- 8.3 years), and in a control group (CG) of 80 age- and sex-matched patients with low back pain. All patients were treated at the Departments of Neurology and Neurosurgery, University Hospital, Olomouc, Czech Republic. Two-sample t test and Pearson's homogeneity chi(2) test were applied when assessing statistical significance. DM was found in 37.5% of SICH patients versus 22.5% of CG subjects (P < 0.05). DM occurs significantly more frequently in SICH patients in the Olomouc region of the Czech Republic when compared to the general population.

The influence of anaemia on stroke prognosis and its relation to N-terminal pro-brain natriuretic peptide

Anaemia is a negative prognostic factor for patients with heart failure and impaired renal function, but its role in stroke patients is unknown. Furthermore, anaemia has been shown to influence the level of N-terminal pro-brain natriuretic peptide (NT-proBNP), but this is only investigated in patients with heart failure, not in stroke patients. Two-hundred-and-fifty consecutive, well-defined ischemic stroke patients were investigated. Mortality was recorded at 6 months follow-up. Anaemia was diagnosed in 37 patients (15%) in whom stroke severity was worse than in the non-anaemic group, whilst the prevalence of renal affection, smoking and heart failure was lower. At 6 months follow-up, 23 patients were dead, and anaemia had an odds ratio of 4.7 when adjusted for age, Scandinavian Stroke Scale and a combined variable of heart and/or renal failure and/or elevation of troponin T using logistic regression. The median NT-proBNP level in the anaemic group was significantly higher than in the non-anaemic group, and in a multivariate linear regression model, anaemia remained an independent predictor of NT-proBNP. Conclusively, anaemia was found to be a negative prognostic factor for ischemic stroke patients. Furthermore, anaemia influenced the NT-proBNP level in ischemic stroke patients, an important aspect when interpreting NT-proBNP in these patients.

Obesity and Thrombosis

OBJECTIVES

To describe the pathophysiological mechanisms by which obesity increases the propensity to thrombosis, the leading cause of death in the Western World, with particular emphasis on the role of inflammation, oxidative stress, dyslipidaemia, insulin resistance and the coagulation cascade.

DESIGN

Review article.

MATERIALS AND METHODS

Medline (1966-2005) and Cochrane library review of literature examining the relationship between obesity and thrombosis. Search terms included obesity, overweight, body mass index, thrombosis, cardiovascular disease, venous thromboembolism, peripheral arterial disease, and coronary heart disease.

RESULTS

Obesity is an important and growing public health issue that is estimated to affect more than half of the UK adult population. Obesity, in particular central (visceral) obesity, is associated with significant, and largely preventable, morbidity and mortality including an increased incidence and prevalence of arterial and venous thrombotic events. The various mechanisms by which obesity may cause thrombosis include: the actions of so-called adipocytokines from adipose tissue, e.g. leptin and adiponectin; increased activity of the coagulation cascade and decreased activity of the fibrinolytic cascade; increased inflammation; increased oxidative stress and endothelial dysfunction; and disturbances of lipids and glucose tolerance in association with the metabolic syndrome.

CONCLUSIONS

Obesity appears to be associated with thrombosis via several mechanisms. These pro-thrombotic factors are all improved by weight loss.

Effects of continuous positive airway pressure on cerebral vascular response to hypoxia in patients with obstructive sleep apnea

RATIONALE

The mechanism leading to increased risk of stroke in patients with obstructive sleep apnea (OSA) is unknown. It may occur through alteration in the regulation of cerebral blood flow, reflected in part by the response of the cerebral vasculature to hypoxia. We hypothesized that the cerebrovascular response to hypoxia is reduced in patients with OSA.

OBJECTIVE

To determine the cerebral blood flow response to hypoxia in patients with OSA.

METHODS

The cerebral blood flow response to 20 minutes of isocapnic hypoxia was measured in eight male patients with OSA before and after 4 to 6 weeks of continuous positive airway pressure (CPAP) therapy and in 10 matched healthy control subjects.

MEASUREMENTS AND MAIN RESULTS

The cerebral blood flow response to hypoxia was significantly lower in patients with OSA compared with control subjects (0.56 +/- 0.10 vs. 0.97 +/- 0.09% [mean +/- SE] change in blood flow velocity per % desaturation; p=0.007). After CPAP therapy, the cerebral blood flow response to hypoxia was similar between patients with OSA and control subjects (1.08 +/- 0.15 vs. 0.92 +/- 0.13% change in blood flow velocity per % desaturation; p=0.4). Moderately strong correlations were found between the cerebral blood flow response to hypoxia and the apnea-hypopnea index (r=-0.57; p=0.04) and nocturnal oxyhemoglobin saturation (r=0.48; p=0.01).

CONCLUSIONS

The cerebral blood flow response to hypoxia is significantly reduced in patients with OSA. Treatment of OSA with CPAP increases the cerebral blood flow response to hypoxia to normal levels. An attenuated cerebrovascular response to hypoxia in patients with OSA may contribute to their elevated risk of stroke.

Evidence of hypercoagulability and inflammation in young patients long after acute cerebral ischaemia

INTRODUCTION

Young subjects with acute cerebral ischaemia - stroke or transient ischaemic attack - form an etiologically heterogeneous and often not clearly explained group of patients. The aim was to investigate possible disturbances in haemostasis and inflammation long after an acute cerebral ischaemic event.

MATERIALS AND METHODS

Forty-four consecutive patients referred after having suffered from acute cerebral ischaemia before the age of 45 participated 1 to 9 years (median value 5 years) after the event. At the time of blood sampling 33 (75%) patients were receiving antithrombotic treatment. Forty-six apparently healthy subjects of the same age group served as controls. In all subjects global haemostasis parameters (overall haemostasis, coagulation and fibrinolytic potential), thrombophilia, several markers of haemostasis activation and inflammation were determined.

RESULTS

Patients did not differ from controls in most of the conventional risk factors and the presence of most forms of thrombophilia, although in seven (17.5%) patients the weak presence of lupus anticoagulants was observed. Patients had significantly increased overall haemostasis and coagulation potential, increased soluble P-selectin and D-dimer, decreased overall fibrinolysis potential and increased fibrinogen and C-reactive protein compared to controls. The subgroups of patients receiving antiplatelet treatment, with thrombophilia and recurrent acute cerebral ischaemia, did not differ significantly from the other patients.

CONCLUSIONS

In young patients long after acute cerebral ischaemia an imbalance in the haemostatic system and a minor, but significant degree of inflammation was detected. The mechanisms behind haemostatic imbalance seem to be enhanced thrombin generation, platelet activation and depressed fibrinolysis.

Computer-aided diagnosis of carotid atherosclerosis based on ultrasound image statistics, laws' texture and neural networks

Quantitative characterisation of carotid atherosclerosis and classification into symptomatic or asymptomatic is crucial in planning optimal treatment of atheromatous plaque. The computer-aided diagnosis (CAD) system described in this paper can analyse ultrasound (US) images of carotid artery and classify them into symptomatic or asymptomatic based on their echogenicity characteristics. The CAD system consists of three modules: a) the feature extraction module, where first-order statistical (FOS) features and Laws' texture energy can be estimated, b) the dimensionality reduction module, where the number of features can be reduced using analysis of variance (ANOVA), and c) the classifier module consisting of a neural network (NN) trained by a novel hybrid method based on genetic algorithms (GAs) along with the back propagation algorithm. The hybrid method is able to select the most robust features, to adjust automatically the NN architecture and to optimise the classification performance. The performance is measured by the accuracy, sensitivity, specificity and the area under the receiver-operating characteristic (ROC) curve. The CAD design and development is based on images from 54 symptomatic and 54 asymptomatic plaques. This study demonstrates the ability of a CAD system based on US image analysis and a hybrid trained NN to identify atheromatous plaques at high risk of stroke.

Ischemic cerebral tissue response to subventricular zone cell transplantation measured by iterative self-organizing data analysis technique algorithm

To investigate the changes of the ischemic lesion in rat brain after subventricular zone (SVZ) cell transplantation and the influence of the grafted cells on the appearance of angiogenesis, SVZ cells, superparamagnetically labeled, were intracisternally transplanted into the rat brain 48 h after onset of embolic stroke. A complete set of magnetic resonance (MR) images was acquired for all animals with (n=8) and without (n=3) cell grafting at approximately 24 h, 72 h, and weekly for 6 weeks after stroke. Transplanted cells were tracked by high-resolution three-dimensional gradient-echo images and the interaction between the cells and ischemic lesion was detected by ISODATA (Iterative Self-Organizing Data Analysis Technique Algorithm) calculated from T(1), T(2) and T(1sat) maps. Tissue status from ISODATA was characterized by a specific signature, which represents the deviation from normal tissue in the feature space. Transplanted SVZ cells selectively migrated towards the ischemic side of the rat brain and approached the lesion boundary within 1-week after grafting. Cell treated rats exhibited a significant reduction of average lesion size compared with control rats (P<0.05). A significant reduction of tissue signature (P<0.001) induced by cell transplantation was localized to the position of grafted cells, and these sites exhibited stably restored cerebral blood flow (CBF) (approximately 85% of normal CBF). Angiogenesis was present in sites either immediately adjacent to or surrounded by the grafted cells. Our data indicate that map-ISODATA accurately and dynamically characterizes the ischemic lesion and its response to cell therapy.

The inflammation in the gut after experimental subarachnoid hemorrhage

BACKGROUND

Gastrointestinal dysfunction could be frequently observed in the patients suffering from SAH. This study test the hypothesis that experimental SAH could induce histopathological changes and inflammatory response associating with NF-kappaB activation pathway in the gut.

MATERIALS AND METHODS

A total of 17 rabbits were randomly divided into two groups: control group (n = 8) and SAH group (n = 9). In the SAH group, the animals were subjected to experimental SAH according to the "two-hemorrhage" method. The histopathological study was performed to detect the intestinal mucosal morphological changes and immunohistochemical study was used to detect the TNF-alpha and ICAM-1 expressions. NF-kappaB binding activity was measured using the electrophoretic mobility shift assay.

RESULTS

It was demonstrated that some damage changes and leukocytes infiltration occurred in the intestinal mucosa after SAH. More positive cells for TNF-alpha and ICAM-1 were observed in the SAH group. The NF-kappaB binding activity in the intestines was significantly increased in the SAH group (P < 0.01).

CONCLUSIONS

The results of the present study suggest that SAH in the rabbits could induce NF-kappaB and proinflammatory cytokines activation in the intestine, which is associated with morphological changes.

Carotid artery calcification detected on panoramic radiographs in a group of Thai population

OBJECTIVE

To determine the prevalence of carotid artery calcification (CAC) detected on panoramic radiographs in a Thai population.

STUDY DESIGN

The panoramic radiographs of the patients 50 and older (N = 1,370) visiting Mahidol University from January 1998 through September 2004 were retrospectively reviewed for CAC. The medical records of the positive subjects were then reviewed.

RESULTS

Thirty-four (2.5%) of the 1,370 patients, 16 men and 18 women, with a mean age of 69 and a range of 50 to 87 years, had 1 or more CACs. These calcifications were unilateral in 25 (73.5%) and bilateral in 9 (26.5%) subjects. Of those positive subjects, 18 reported hypertension, 10 reported diabetes mellitus, and 5 reported hyperlipidemia.

CONCLUSIONS

Although it is uncommon to find CAC in the Thai population, dentists should be aware of this calcification on the routine panoramic radiographs and promptly refer for cerebrovascular and cardiovascular evaluation.

Effect of antihypertensive treatment on plasma fibrinogen and serum HDL levels in patients with essential hypertension

The influence of hypertension, and its treatment, on circulating lipid and fibrinogen (Fib) concentrations in patients with essential hypertension was investigated. The lipid profile and Fib levels were measured in 353 patients (131 men) with essential hypertension. Their median age was 60 years (range: 18-85 years). All patients had normal results from liver, renal, and thyroid function tests. There were 162 patients (45.9%) who were not receiving antihypertensive treatment. Of the remaining patients, 117 were taking 'lipid-hostile' beta-blockers, thiazide diuretics) antihypertensives and 74 were taking 'lipid-neutral' (angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin-II receptor blockers) agents. Patients who were taking 'lipid-hostile' antihypertensive drugs had significantly higher plasma Fib concentrations when compared with those taking 'lipid-neutral' antihypertensives or those not receiving antihypertensive treatment. These differences were not attributable to established factors that influence plasma Fib levels, since when smokers and patients with diabetes mellitus and/or vascular disease were excluded, the difference remained significant. In addition, in these more homogeneous groups, patients receiving 'lipid-neutral' treatment had significantly higher serum high-density lipoprotein (HDL) cholesterol levels when compared with both those taking 'lipid-hostile' antihypertensives and untreated ones. There were no significant differences in the other lipid variables, independently of the presence/absence or the type of antihypertensives. These results suggest that antihypertensive drugs have additional effects, beyond lowering blood pressure, on other vascular risk factors, like Fib and HDL. These effects may depend on the type of drug used.

Interaction between longevity-associated mitochondrial DNA 5178 C/A polymorphism and cigarette smoking on hematological parameters in Japanese men

Mitochondrial DNA 5178 C/A (mt5178 C/A), namely NADH dehydrogenase subunit 2 237 Leu/Met, polymorphism is as reported in literature associated with longevity and susceptibility to ischemic heart disease or cerebrovascular disorders in the Japanese population. Previous reports suggested that mt5178A genotype exerts antiatherogenic effects. The aim of this study was to investigate whether mt5178 C/A polymorphism is associated with hematological parameters, such as thrombogenic risk factors for myocardial infarction and stroke, in 321 healthy Japanese men. No significant differences were observed between mt5178 C/A genotypes, but in subjects with body mass index (BMI) of < or = 23, this polymorphism influenced the effects of habitual smoking on hematological parameters. Red blood cell (RBC) counts were significantly lower and mean corpuscular hemoglobin (MCH) levels were significantly higher in smokers with mt5178A than nonsmokers with mt5178A. Platelet counts were significantly higher in smokers with mt5178C than nonsmokers with mt5178C. Cigarette consumption was strongly associated with RBC counts, mean corpuscular volume levels, and MCH levels for men with mt5178A, and was associated with platelet counts for those with mt5178C. Moreover, BMI was significantly positively associated with RBC counts and platelet counts only in men with mt5178A, age was significantly negatively associated with RBC counts only in men with mt5178C. These data suggest that mt5178 C/A polymorphism may influence the effects of cigarette smoking on hematological parameters in healthy BMI < or = 23 Japanese men.

Ethnic Disparities in Stroke

BACKGROUND AND PURPOSE

Evidence for ethnic disparities in stroke incidence, severity, and mortality has continued to mount in recent years. However, the picture for disparities in acute management and rehabilitation remains more ambiguous. The objective of this report is to summarize current evidence from stroke epidemiology and studies focusing on disparities in stroke care and disability, suggesting courses for action.

METHODS

A comprehensive search of current literature on ethnic/racial variation in stroke incidence, mortality, and severity, as well as acute and postacute patient care was performed.

RESULTS

Recent evidence unambiguously reaffirms a greater burden of disease in stroke, greater mortality, and greater severity of strokes for blacks. Evidence for disparities in acute and postacute care is less conclusive, as is the evidence for disparities among other ethnic groups. Evidence for health disparities in stroke care across settings, regions, and the continuum of care varies considerably.

CONCLUSIONS

Minority ethnic groups have higher rates or more severe stroke, but variations in prognosis for clinical outcomes other than mortality remain less certain. There is considerable need for more studies that take into account regional ethnic variations in treatment and outcomes, and for better documentation of stroke outcomes among groups in addition to blacks. Dealing with ethnic disparities in stroke will be served by sustained attention to quality improvement in high-impact areas in stroke care, complemented by initiatives that promote cultural competence.

Reduction of cerebral infarct size by non-competitive AMPA antagonists in rats subjected to permanent and transient focal ischemia

Antagonists of 2-amino-3(3-hydroxy-5-methyl-4-isoxazolyl) propionic acid (AMPA) receptors can considerably reduce brain damage after cerebral ischemia, but effectiveness of selective AMPA antagonists has been questioned recently. Therefore, we evaluated the antiischemic efficacy of [+/-]-7-acetyl-5-[4-aminophenyl]-7,8-dihydro-8-cyano-8-methyl-9H-1,3-dioxolo-[4,5-h]-2,3-benzodiazepine (EGIS-8332) and GYKI 53405, two selective, non-competitive AMPA antagonists in two rat models of focal cerebral ischemia. Permanent focal ischemia was produced by electrocoagulation of the middle cerebral artery (MCA). EGIS-8332 and GYKI 53405 were administered 30 min after MCA occlusion at doses of 1, 3 or 10 mg/kg i.p. In transient focal ischemia, MCA was occluded for 1 h and reperfused for 24 h using the intraluminal filament technique and the compounds were given at 3x10 mg/kg i.p. 60, 120 and 180 min following occlusion. In permanent focal ischemia, EGIS-8332 decreased the volume of cerebral infarction both at 10 mg/kg i.p. (36.4%, p<0.01) and at 3 mg/kg i.p. (26.4%, p<0.05) in a dose-dependent manner. GYKI 53405 produced a similar antiischemic effect at 10 mg/kg i.p. (36.4%, p<0.01), but it was ineffective at 3 mg/kg i.p. (6.5%, p=0.57). In transient focal ischemia, EGIS-8332 reduced the volume of necrotic brain tissue (38.7%, p<0.01) and GYKI 53405 was similarly effective (32.6%, p<0.05). Both compounds afforded neuroprotection in the cortical and subcortical regions of the MCA territory. Selective, non-competitive AMPA antagonists administered after the ischemic insult can produce effective neuroprotective action in experimental models of focal cerebral ischemia; therefore, these compounds may be useful as therapeutic agents for the treatment of stroke and neurodegenerative disorders.

Oxidant stress and constrictor reactivity impair cerebral artery dilation in obese Zucker rats

This study tested the hypothesis that evolution of the metabolic syndrome in obese Zucker rats (OZR) leads to impaired dilator reactivity of cerebral resistance arteries vs. responses determined in lean Zucker rats (LZR). Middle cerebral arteries (MCA) from 17-wk-old male LZR and OZR were isolated and cannulated with glass micropipettes. Vascular reactivity was assessed in response to challenge with ACh, sodium nitroprusside (SNP), reductions and elevations in Po2, 5-HT, and increased intralumenal pressure. Vessels were treated with the free radical scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (tempol) to assess the role of superoxide production in altering reactivity, and passive vascular wall mechanics was assessed in each vessel. Vascular superoxide production was assessed in isolated arteries using fluorescence microscopy. Vessel dilation to ACh and hypoxia was impaired in OZR vs. LZR, although responses to SNP were normal. Vessel constriction to 5-HT, elevated Po2, and elevated intralumenal pressure was enhanced in OZR vs. LZR. Fluorescence microscopy demonstrated an increased superoxide production in arteries of OZR vs. LZR, correctable by incubation with tempol. Although treatment of vessels from OZR with tempol improved dilation to ACh and hypoxia, constrictor responses to 5-HT, elevated Po2, and pressure were not altered by tempol treatment. Indexes of vessel wall mechanics were comparable between groups. These results suggest that vasodilator reactivity of MCA of OZR in response to endothelium-dependent dilator stimuli is impaired vs. LZR and that this may represent a reduced bioavailability of signaling molecules due to oxidant scavenging. However, oxidative stress-independent increases in myogenic tone and constrictor reactivity may contribute to blunted dilator responses of cerebral microvessels.

Incidence and characteristics of stroke during 90-day follow-up in patients stabilized after an acute coronary syndrome

BACKGROUND

Stroke is a rare but serious event that complicates the course of patients with acute coronary syndromes (ACS). The type, outcome, and risk factors of stroke occurring in stabilized patients with ACS have not been previously reported.

METHODS

We evaluated stroke incidence, subtypes, and outcomes, in addition to demographics and clinical risk characteristics associated with stroke among patients enrolled in the Sibrafiban versus Aspirin to Yield Maximum Protection from Ischemic Heart Events Post-acute Coronary Syndromes (SYMPHONY) and 2nd SYMPHONY trials.

RESULTS

Of 15,904 stabilized patients with ACS, 113 (0.71%) had a stroke over a median follow-up of 90 days. The majority of strokes occurred within 30 days of presentation, and the time course for stroke occurrence paralleled that of myocardial (re)infarction. Most strokes were ischemic (78%), and 52% resulted in moderate or severe disability or death. Patients with stroke were older and more often had hypertension, diabetes, peripheral vascular disease, and atrial fibrillation. Among patients with stroke who had cardiac catheterization, percutaneous coronary intervention, or coronary artery bypass grafting, stroke occurred predominantly after the procedure. No difference in occurrence or type of stroke was observed in the assigned treatment groups. In multivariable modeling age, heart failure, prior stroke, left bundle branch block, and systolic blood pressure predicted the occurrence of stroke.

CONCLUSIONS

In patients stabilized after presenting with a spectrum of ACS and treated with sibrafiban and/or aspirin, stroke occurred in fewer than 1% within 90 days but carried a significant mortality and morbidity risk.

Clinical and ethnic characteristics of stroke in an Israeli population: a study in a community hospital population

Background: Stroke mainly affects the older population, although it has also been reported in younger patients. In this study, we focused on patients 65 years of age or younger with stroke. Methods: The files of three patient populations were studied: 93 patients aged 65 years or younger with stroke (group A), 93 patients older than 65 with stroke (group B), and 604 patients without stroke representing the general population of patients admitted to our service during January 2000 (group C). We reviewed the patient files and compared patient characteristics, epidemiological features, clinical picture,imaging findings, and coagulation tests. Results: Overall, 318 patients were studied. The mean age of group A was 55 years compared to 77 years in group B and 71 years in group C. In both stroke groups (A and B), the male: female ratio was 2:1, in contrast with a balanced ratio in group C. Most of the patients in group A (63%) were of Sephardic origin compared to 39% in group B (P=0.002) and 30% in group C. The clinical picture in both stroke groups (A and B) was similar. The risk factor smoking was reported by 45% in group A and by only 29% in group B (P=0.034). Hypertension, diabetes mellitus, and hyperlipidemia were evenly prevalent in both stroke groups. The coagulation system was studied in the "young" patients (group A): hyperhomocysteinemia was found in 37%, high titers of anticardiolipin antibodies in 35%, low levels of antithrombin III in 13%, protein C deficiency in 5%, and activated protein C resistance (APCR) in 4%. Overall, 49% of the patients from group A were found to have coagulation abnormalities. Conclusions: We found in our study that the younger patient with stroke tends to be a Sephardic male with the classical risk factors as well as a history of smoking and coagulopathy. These findings suggest strict medical supervision and primary prophylaxis. This work also lays the basis for a prospective, interventional trial with younger patients.

Prevention and treatment of stroke in patients with hypertension

BACKGROUND

Each year, stroke occurs in 30.9 million individuals worldwide and is responsible for approximately 4 million deaths. In the United States, it is the third leading cause of death, occurring with greater frequency than myocardial infarction in patients with hypertension. The greatest burden of stroke, apart from death, is serious long-term physical and mental disability. Stroke survivors often experience physical handicap, depression, and cognitive dysfunction, which together affect their daily functioning, quality of life, and survival. The treatment of stroke is associated with extremely high costs, with stroke-related illnesses responsible for >$49 billion in the United States in 2002. Despite intensive research efforts, few effective treatments are available once stroke has occurred; thus, stroke prevention should be a primary focus for all health care providers.

OBJECTIVE

The purpose of this article was to review the epidemiology and burden of stroke in terms of disability, quality of life, and cost of care, and to summarize the evidence for treatments having therapeutic benefit, with an emphasis on antihypertensive agents.

METHODS

Relevant studies were identified through a MEDLINE search of English-language articles published between 1990 and 2004. The search terms were stroke, epidemiology, economic impact, disability, quality of life, hypertension, drug therapy, and angiotensin II-receptor antagonists. Articles describing major clinical studies, new data, or new mechanisms pertinent to the therapy of stroke were selected for review.

CONCLUSIONS

Identifying and modifying key risk factors is crucial to reducing the morbidity and mortality of stroke. Hypertension is one of the most important risk factors for stroke, and treatment with a variety of antihypertensive agents reduces the risk. Recent evidence suggests that the angiotensin II (ATII)-receptor antagonist losartan may offer advantages beyond blood pressure lowering, including attenuation of the central aortic reflected pressure wave, molecule-specific properties, and neural protective influences on brain ATII type 2 receptors.

Echogenicity of B-mode sonographic images of the carotid artery: work in progress

OBJECTIVE

The echogenicity of the carotid atheromatous plaque estimated from B-mode sonographic images may be related to plaque content and has been analyzed with a number of techniques. The purpose of this study was to compare plaque with surrounding muscle tissue echogenicity and to validate the use of first-order mathematical descriptors as determinants of tissue echogenicity.

METHODS

We estimated echogenicity descriptors for regions in the following 3 distinct areas of a typical B-mode sonographic image of a diseased carotid artery: plaque, blood, and sternocleidomastoid muscle. Two-dimensional B-mode sonographic images from 19 symptomatic and asymptomatic plaques (17 subjects) were interrogated, in which the following estimators were calculated: minimal, maximal, mean, and median gray levels, SD of gray levels, coefficient of variation, and gray level skewness, kurtosis, entropy, and energy. Plaque echogenicity was estimated at systole and diastole for studying the effect of the phase of the cardiac cycle. To assess the effect of different fascial tissue-muscle fiber composition on the first-order mathematical descriptors, we estimated echogenicity at 3 different sites within the muscle tissue.

RESULTS

Compared with the echogenicity of surrounding muscle tissue, plaque echogenicity was characterized by (1) significantly lower (Student t test, P < .05) gray level mean, median, SD, and entropy; (2) significantly higher (Student t test, P < .05) coefficient of variation, gray level skewness, and kurtosis; and (3) similar minimal and maximal gray levels and gray level energy. The phase of the cardiac cycle, systole or diastole, did not affect the estimation of plaque echogenicity. Echogenicity was found to vary within the muscle tissue. The coefficient of variation was significantly higher in the asymptomatic plaques in the small group that was investigated.

CONCLUSIONS

First-order statistical descriptors may be used to characterize atheromatous plaques and the surrounding muscle tissue.

Bioequivalence of ximelagatran, an oral direct thrombin inhibitor, as whole or crushed tablets or dissolved formulation

OBJECTIVE

To investigate whether crushed or dissolved tablets of the oral direct thrombin inhibitor ximelagatran are bioequivalent to whole tablet administration. Ximelagatran is currently under development for the prevention and treatment of thromboembolic disorders.

RESEARCH DESIGN AND METHODS

This was an open-label, randomised, three-period, three-treatment crossover study in which 40 healthy volunteers (aged 20-33 years) received a single 36-mg dose of ximelagatran administered in three different ways: I swallowed whole, II crushed, mixed with applesauce and ingested and III dissolved in water and administered via nasogastric tube.

RESULTS

The plasma concentrations of ximelagatran, its intermediates and the active form melagatran were determined. Ximelagatran was rapidly absorbed and the bioavailability of melagatran was similar after the three different administrations, fulfilling the criteria for bioequivalence. The mean area under the plasma concentration-versus-time curve (AUC) of melagatran was 1.6 micromol.h/L (ratio 1.01 for treatment II/I and 0.97 for treatment III/I), the mean peak concentration (C(max)) was 0.3 micromol/L (ratio 1.04 for treatment II/I and 1.02 for treatment III/I) and the mean half-life (t(1/2)) was 2.8 h for all treatments. The time to C(max) (t(max)) was 2.2h for the whole tablet and approximately 0.5 h earlier when the tablet was crushed or dissolved (1.7-1.8 h), due to a more rapid absorption. The study drug was well tolerated as judged from the low incidence and type of adverse events reported.

CONCLUSION

The present study showed that the pharmacokinetics (AUC and C(max)) of melagatran were not significantly altered whether ximelagatran was given orally as a crushed tablet mixed with applesauce or dissolved in water and given via nasogastric tube.

Vegetable and Fruit Intake and Stroke Mortality in the Hiroshima/Nagasaki Life Span Study

BACKGROUND AND PURPOSE

Fruits and vegetables are known for their beneficial effects on chronic diseases. The purpose of the present study was to investigate the protective effect of a diet rich in fruits and vegetables on total stroke mortality and its 2 main subtypes in men and women separately.

METHODS

A prospective cohort study of 40 349 Japanese men and women was initiated in 1980-1981 and followed until 1998. Fruit and vegetable intake was assessed at baseline on the basis of the response to a food frequency questionnaire. During the 18-year follow-up period, deaths from stroke were registered.

RESULTS

A total of 1926 stroke deaths were identified during the follow-up period. An increasing frequency of intake of green-yellow vegetables and fruit was associated with a reduced risk of death from intracerebral hemorrhage and cerebral infarction. Daily intake of green-yellow vegetables was associated with a significant 26% reduction in the risk of death from total stroke in men and women compared with an intake of once or less per week. The protective effect associated with daily fruit and vegetable intake was observed for both cerebral infarction and intracerebral hemorrhage mortality but was slightly stronger and clearer for infarction than for hemorrhage, with a 32% reduction in men and a 30% reduction in women. Daily fruit intake was associated with a significant 35% reduction in risk of total stroke in men and a 25% reduction in women and was equally strong for both intracerebral hemorrhage and cerebral infarction.

CONCLUSIONS

Daily consumption of green-yellow vegetables and fruits is associated with a lower risk of total stroke, intracerebral hemorrhage, and cerebral infarction mortality. The protective effects are similar in both men and women.