Silent stroke in patients with transient ischemic attack or minor ischemic stroke. The Dutch TIA Trial Study Group

Phenotypes of Chronic Covert Brain Infarction in Patients With First-Ever Ischemic Stroke: A Cohort Study

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Background and Purpose:

The aim of this study was to assess the rate of chronic covert brain infarctions (CBIs) in patients with acute ischemic stroke (AIS) and to describe their phenotypes and diagnostic value.

Methods:

This is a single-center cohort study including 1546 consecutive patients with first-ever AIS on magnetic resonance imaging imaging from January 2015 to December 2017. The main study outcomes were CBI phenotypes, their relative frequencies, location, and association with vascular risk factors.

Results:

Any CBI was present in 574/1546 (37% [95% CI, 35%–40%]) of patients with a total of 950 CBI lesions. The most frequent locations of CBI were cerebellar in 295/950 (31%), subcortical supratentorial in 292/950 (31%), and cortical in 213/950 (24%). CBI phenotypes included lacunes (49%), combined gray and white matter lesions (30%), gray matter lesions (13%), and large subcortical infarcts (7%). Vascular risk profile and white matter hyperintensities severity (19% if no white matter hyperintensity, 63% in severe white matter hyperintensity, P<0.001) were associated with presence of any CBI. Atrial fibrillation was associated with cortical lesions (adjusted odds ratio, 2.032 [95% CI, 1.041–3.967]). Median National Institutes of Health Stroke Scale scores on admission were higher in patients with an embolic CBI phenotype (median National Institutes of Health Stroke Scale, 5 [2–10], P=0.025).

Conclusions:

CBIs were present in more than a third of patients with first AIS. Their location and phenotypes as determined by MRI were different from previous studies using computed tomography imaging. Among patients suffering from AIS, those with additional CBI represent a vascular high-risk subgroup and the association of different phenotypes of CBIs with differing risk factor profiles potentially points toward discriminative AIS etiologies.

Teneligliptin protects against ischemia/reperfusion-induced endothelial permeability in vivo and in vitro

Ischemic stroke is a leading cause of disability and mortality worldwide, especially among the elderly population. Ischemia and reperfusion cause damage to cells and initiate an acute inflammatory response, which leads to cerebral endothelial dysfunction, increased endothelial permeability, and potentially permanent disability. Teneligliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor that has been used almost exclusively in the treatment of type 2 diabetes mellitus. However, it is still unknown whether teneligliptin possesses a protective effect in brain endothelial dysfunction in the context of ischemic stroke. In the present work, we demonstrate the potential of teneligliptin treatment to protect against ischemia/reperfusion-induced damage using a series of both in vivo and in vitro experiments. Our key findings are that administration of teneligliptin could reduce brain infarct volume, ameliorate neurological damage, and improve brain permeability by increasing the expression of the tight junction protein occludin in middle cerebral artery occlusion (MCAO) mice models. Importantly, teneligliptin displayed a robust protective effect against oxygen–glucose deprivation/reperfusion (OGD/R)-induced cell death of primary human brain microvascular endothelial cells (HBMVECs) in vitro. Notably, teneligliptin prevented OGD/R-induced increased endothelial monolayer permeability in HBMVECs by increasing the expression of occludin, which was mediated by the ERK5/KLF2 signaling pathway. These findings suggest that teneligliptin might serve as a potential therapeutic agent for the treatment of stroke

Ischemic stroke is a leading cause of disability and mortality worldwide, especially among the elderly population.

Why Are Only Some Subcortical Ischemic Lesions on Diffusion Magnetic Resonance Imaging Associated With Stroke Symptoms in Small Vessel Disease?

Background and Purpose- In cerebral small vessel diseases, small subcortical ischemic lesions (SSIL) on diffusion imaging are responsible for stroke manifestations but can also be occasionally observed in the absence of overt neurological symptoms. We aimed to determine, in a large cohort of young patients with CADASIL (Cerebral Autosomal-Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy), a severe monogenic condition leading to SSIL in young patients, the characteristics of SSIL and of surrounding cerebral tissue associated with the presence of stroke symptoms. Methods- Among a cohort of 323 genetically confirmed CADASIL patients who were systematically evaluated every 18 months clinically and with magnetic resonance imaging, we studied all visible SSIL and documented ischemic stroke events with available magnetic resonance imaging data. We used mixed-effect logistic regression models to determine whether the presence of stroke symptoms was associated with age, sex, the volume of SSIL, their location with respect to preexisting white matter hyperintensities and with the load of the different magnetic resonance imaging markers of small vessel disease. Results- We identified 73 SSIL (30 with stroke symptoms and 43 without) in 55 patients. In multivariable models, stroke symptoms were more frequent in male patients (estimate=1.94; SE=0.82; P=0.03) and less frequent when SSIL appeared in contact to preexisting white matter hyperintensities (estimate=-2.12; SE=0.83; P=0.01). Within pyramidal tracts, stroke symptoms were more frequent in patients with extensive white matter hyperintensities (estimate=3.8×10^-5; SE=9.3×10^-6; P<10^-4). Conclusions- Altogether, our results suggest that when SSIL occur, the presence of stroke symptoms may depend on sex and alterations of the surrounding brain tissue rather than on the characteristics of the SSIL itself.

Binge ethanol effects on prefrontal cortex neurons, spatial working memory and task-induced neuronal activation in male and female rats

Excessive alcohol intake is associated with a multitude of health risks, especially for women. Recent studies in animal models indicate that the female brain is more negatively affected by alcohol, compared to the male brain. Among other regions, excessive alcohol consumption damages the frontal cortex, an area important for many functions and decision making of daily life. The objective of the present study was to determine whether the medial prefrontal cortex (mPFC) in female rats is selectively vulnerable to alcohol-induced damage. In humans, loss of prefrontal grey matter resulting from heavy alcohol consumption has been documented, however this volume loss is not necessarily due to a decrease in the number of neurons. We therefore quantified both number and nuclear volume of mPFC neurons following binge alcohol, as well as performance and neuronal activation during a prefrontal-dependent behavioral task. Adult male and female Long-Evans rats were assigned to binge or control groups and exposed to ethanol using a well-established 4-day model of alcohol-induced neurodegeneration. Both males and females had significantly smaller average neuronal nuclei volumes than their respective control groups immediately following alcohol binge, but neither sex showed a decrease in neuron number. Binged rats of both sexes initially showed spatial working memory deficits. Although they eventually achieved control performance, binged rats of both sexes showed increased c-Fos labeling in the mPFC during rewarded alternation, suggesting decreased neural efficiency. Overall, our results substantiate prior evidence indicating that the frontal cortex is vulnerable to alcohol, but also indicate that sex-specific vulnerability to alcohol may be brain region-dependent.

Topographical disorientation after ischemic mini infarct in the dorsal hippocampus: whispers in silence

Silent focal ischemic mini infarcts in the brain are thought to cause no clinically overt symptoms. Some populations of hippocampal cells are particularly sensitive to ischemic events, however, rendering hippocampal functions especially vulnerable to ischemia-induced deficits. The present study investigated whether an otherwise silent ischemic mini infarct in the hippocampus (HPC) can produce impairments in spatial performance in rats. Spatial performance was assessed in the ziggurat task (ZT) using a 10-trial spatial learning protocol for 4 days prior to undergoing hippocampal ischemic lesion or sham surgery. Hippocampal silent ischemia was induced by infusion of endothelin-1 (ET-1), a potent vasoconstrictor, into either the dorsal or the ventral hippocampus (dHPC and vHPC). When tested postoperatively in the ZT using a standard testing protocol for 8 days, rats with hippocampal lesions exhibited no spatial deficit. Although spatial learning and memory in the ZT were not affected by the ET-1-induced silent ischemia, rats with dHPC stroke showed more returns when navigating the ZT as opposed to the vHPC rats. Comparison of region-specific HPC lesions in the present study indicated that dorsal hippocampal function is critically required for topographic orientation in a complex environment. Topographic disorientation as reflected by enhanced return behaviors may represent one of the earliest predictors of cognitive decline after silent ischemic insult that may be potentially traced with sensitive clinical examination in humans.

[Central nervous system embolism in the course of infective endocarditis]

Despite the progress made in diagnosis and treatment of heart valve diseases, the incidence of infective endocarditis (IE) remains constant. It is still associated with high mortality and high rate of embolic complications, including most dangerous one, i.e. stroke. It has a significant impact on further treatment and qualifications for cardiac surgery. In this paper, the authors discuss the epidemiology, mechanisms of stroke and its impact on the qualifications for cardiac surgery. The authors discuss the problem of clinically silent central nervous system embolism in the course of IE and the usefulness of neuroimaging and markers of central nervous system damage in diagnosis of cerebral embolism.

Bilateral internal carotid arteries ligation temporary impairs brain vasculaturev in young rats

Bilateral internal carotid artery ligation (BICL) rat model is one of the chronic cerebral hypoperfusion animal models used for investigating brain dysfunction related diseases. Cerebral blood flow decreases in different cerebral regions in a time-dependent manner after the BICL. However little is known about the cerebral vasculature change in the brain after the BICL. In the current study, the bilateral internal carotid arteries of the juvenile rats were permanently ligated and the change of the cerebral vasculature was studied 7, 14 and 21 days after the BICL. In the juvenile rats, 7 days after the BICL, the functional vascular area was decreased significantly in the anterior half of the cerebral cortex, but it had only little decrease in the posterior half of the cerebral cortex and hippocampus. However, at the time points of 14 and 21 days after the surgery, the functional vascular area throughout the whole cerebral cortex and hippocampus was almost similar to those in the sham control rats. In conclusion, the results from our current study showed that in the BICL hypoperfusion model in young rats, the brain functional vascular area was impaired initially in certain brain regions after the artery ligation, but likely to be quickly self-recovered late after. The results suggest that the brain vasculature in young rats has plasticity to external insult caused by cerebral hypoperfusion.

Silent brain infarction in the presence of systemic vascular disease

Objective

To determine the prevalence of asymptomatic brain ischaemic in the presence of vascular disease in other arterial territories.

Design

Studies up to January 2011 were identified through comprehensive search strategies. Arcsine transformation for meta-analysis was used to calculate the standardized mean difference (SMD) and 95% confidence intervals (CI).

Setting

A systematic review and meta-analysis were performed.

Participants

For each study, the proportion of patients positive for SBI in the presence of other systemic vascular disease was extracted and analyzed.

Main outcome measures

Using a random-effects model, a pooled effect estimate interpreted as a percentage prevalence of disease was calculated.

Results

SBI in the presence of acute ischaemic stroke was found in 23% (SMD 0.99; P < 0.001; 95% CI 0.88–1.10); a 35% prevalence was found in patients with coronary artery disease (SMD 1.26; P < 0.001; 95% CI 0.95–1.58); and a 14% prevalence in patients with peripheral artery disease (SMD 0.48; P < 0.002; 95% CI 0.42–0.54), although the data-set in the latter is smaller.

Conclusions

Patients with systemic vascular disease are at an increased risk of silent brain infarction.

Incidental acute infarcts identified on diffusion-weighted images: a university hospital-based study

BACKGROUND AND PURPOSE

Pathogenesis of leukoaraiosis is incompletely understood and accumulation of small infarctions may be one of the possible sources of such white matter lesions. Thus, the purpose of this study was to identify the rate of incident infarction as depicted on diffusion-weighted images (DWIs) obtained from a general patient population.

MATERIALS AND METHODS

During the 4-year study period, a total of 60 patients (36 men and 24 women) had an incidental DWI-defined infarction without overt clinical symptoms suggestive of a stroke or a transient ischemic attack. All of the MR images were obtained by using a similar protocol on 2 identical 1.5T whole-body scanners. The patient's vascular risk factors, as well as the presence of white matter lesions (WMLs) on MR imaging and atheromatous changes on MR angiography, were assessed retrospectively. The incidental DWI-defined infarcts were also characterized in terms of their lateralization, lobe, and specific location.

RESULTS

A total of 16,206 consecutive brain MR images were done during the study period; the overall incidence of incidental infarcts was 0.37%. Most of these patients with an incidental infarct had vascular risk factors and WMLs on MR images. Most of these patients (80%) had a single lesion on DWI. A total of 88 lesions were identified; most were located in the white matter of the supratentorial brain, primarily in the frontoparietal lobes. There were also lesions involving the brain stem (n = 2). The lesions involving cerebrum were more commonly located in the right side (right to left = 52:34).

CONCLUSION

Small, DWI-defined acute brain infarctions can be found incidentally in an asymptomatic population; this finding may account, at least in part, for the pathogenesis of WMLs identified on MR imaging.

Silent cerebral infarction in patients with dilated cardiomyopathy: Echocardiographic correlates

BACKGROUND

Patients with dilated cardiomyopathy (DCM) have an increased risk of thromboembolic events. Incidence of silent cerebral infarction (SCI) has not been investigated in these patients. The aim of this study was to investigate the incidence of SCI in patients with DCM and to determine its associations with echocardiographic parameters.

METHODS AND RESULTS

Seventy-two patients (mean age 62+/-12 years) with DCM underwent cranial magnetic resonance imaging in addition to transthoracic and transesophageal echocardiographic examination. A total of 56 age-matched healthy volunteers served as a control group for comparison SCI prevalence. Prevalence of SCI was significantly higher in patients with DCM (35% vs. 3.6%; p<0.001). In DCM group, patients with SCI had significantly impaired left ventricular systolic function, higher frequency of restrictive diastolic filling, moderate to severe left atrial spontaneous echo contrast (SEC), aortic SEC, and complex atherosclerosis or calcified plaques in the aorta. In logistic regression analysis, type of diastolic filling emerged as the only independent risk factor for SCI (p<0.001). When the type of diastolic filling was removed from the analysis, ejection fraction, marked left atrial SEC, complex-calcified aortic atheroma and age appeared as the other independent risk factors (p = 0.003, p = 0.009, p = 0.013 and p = 0.018, respectively).

CONCLUSION

SCI is a frequent finding in DCM patients. Impaired systolic function, restrictive filling pattern, presence of moderate to severe left atrial SEC, and complex atherosclerosis in the aorta are the factors contributing to the development of SCI.

Late-onset seizures as a predictor of subsequent stroke

BACKGROUND Cerebrovascular disease is thought to be a major cause of epilepsy in late life. We investigated the hypothesis that the onset of seizures after the age of 60 years in people with no history of overt stroke might be associated with an increased risk of subsequent stroke.

METHODS

Data were obtained from the UK General Practice Research Database on 4709 individuals who had seizures beginning at or after the age of 60 years, and on 4709 randomly selected controls with no history of seizures, matched for age, sex, and general practice. Individuals with a history of cerebrovascular disease, other acquired brain injury, brain tumour, drug or alcohol misuse, or dementia were not eligible for inclusion. Computerised patients' records were searched for subsequent diagnoses of stroke.

FINDINGS

Log-rank testing, adjusted for matching, showed a highly significant difference in stroke-free survival between the two groups (p<0.0001). With a Cox's model, we estimated that the relative hazard of stroke at any point for people with seizures compared with the control group was 2.89 (95% CI 2.45-3.41).

INTERPRETATION

Our findings show that the onset of seizures in late life is associated with a striking increase in the risk of stroke. Further research is warranted to assess the benefit of specific interventions to prevent stroke in patients with seizures.

Smoking is Associated with Silent Cerebrovascular Disease in a High-Risk Japanese Community-Dwelling Population

We aimed to investigate the relationships between smoking and silent cerebrovascular damage. We performed brain MRI to evaluate silent cerebral infarct (SCI) and periventricular hyperintensity (PVH), and carotid-ultrasonography to investigate carotid atherosclerotic plaque in 170 high-risk community-dwelling subjects (mean age: 67.2 years; men: 28.7%) who met more than 3 of the following 9 criteria: 1) high blood pressure (BP); 2) hypercholesterolemia; 3) left ventricular hypertrophy; 4) high hemoglobin A1c; 5) proteinuria; 6) high waist-to-hip ratio; 7) smoking > or =30 cigarettes/day; 8) heavy alcohol intake; 9) family history of stroke. The subjects with SCI (SCI group) were older (70 years vs. 66 years, p=0.004) and had higher systolic BP (SBP) (160 vs. 148 mmHg, p <0.001) and higher carotid plaque score (2.3 vs. 1.5/person, p <0.05) than those without SCI. Among the variables, smoking status (r =0.34, p <0.001), SBP (r =0.28, p <0.001), male gender (r =0.29, p <0.001), left ventricular mass index (r =0.25, p =0.001), and serum creatinine (r =0.20, p =0.006) were significantly correlated with the number of SCIs. Among smokers, the number of SCIs was significantly higher in current smokers than in past smokers (1.9+/-2.2 vs. 0.5+/-0.8, p <0.01). In multiple regression analysis, smoking status (beta =0.183, p =0.045) and SBP (beta =0.196, p =0.011) were independent determinants of the increased number of SCIs. In conclusion, smoking status was an independent determinant of multiple SCIs in a high-risk Japanese community-dwelling population.

Frequency of white matter lesions and silent lacunar infarcts

White matter lesions and silent lacunar infarcts are related to and may result from cerebral small vessel disease. Reported frequencies of these lesions vary largely among studies. Differences in imaging techniques, rating scales, cut-off points in lesion severity grading and study populations contribute to the variation, in addition to differences in risk factor profiles across studies. In this paper, we will firstly discuss general methodological issues that may influence reported frequencies of white matter lesions and silent lacunar infarctions, and then review published data. We will focus on the results from population-based studies and only briefly comment on patient series of stroke and dementia.

Brain CT-scan in acute stroke patients: silent infarcts and relation to outcome

Silent infarcts (SIs) are common findings in stroke patients, but their clinical significance remains controversial. Aim of this study was to evaluate the prevalence of SI in consecutive stroke patients, characteristics, associated factors, and influence on in-hospital mortality. The population consisted of 191 patients, consecutively admitted for an acute stroke. Of 191 patients, 74 had SI on CT-scan. Silent infarcts were often multiple, right sided, lacunar. We found SI more frequently in older patients, smokers, with an ischemic stroke having small vessel disease as presumed cause. In our study SI were associated with ageing, smoke habit and lacunar stroke. Silent infarcts size influenced the rate of in-hospital mortality.

Silent brain infarction in patients with rheumatic mitral stenosis

Silent brain infarction (SBI) is defined as asymptomatic infarction areas detected in computerized tomography (CT) scans in patients without a history of stroke. The incidence of SBI is increased in CT or magnetic resonance imaging in patients with carotid stenosis and with atrial fibrillation (AF), but its relation with rheumatic mitral stenosis (MS), another major source of emboli, is uncertain. The aim of this study was to investigate the incidence of SBI in patients with MS. Fifty-three patients with MS (44 females and 9 males; range 25-52 years; mean age 38 +/- 7 years) diagnosed by transthoracic echocardiography (TTE) were enrolled in the study. Mitral valve calcification, left atrium (LA) dimension, and the presence of associating mitral regurgitation on TTE were recorded. Electrocardiographic evaluation was done for rhythm analysis and neurologic examination was performed prior to cerebral CT. Carotid artery Doppler examination was carried out in patients with SBI to exclude carotid artery lesions. Patients with a history of hypertension, diabetes mellitus, anticoagulant drug usage, presence of thrombus in LA, left ventricular segmental or systolic dysfunction, or other valve diseases were excluded from the study. The incidence of SBI was found to be 24.5% in patients with MS (47% cortical, 53% lacunar). SBI was observed to be significantly high in patients with LA dimension > 4 cm or in patients with AF (p < 0.05). The SBI incidence was markedly higher if AF was found with enlarged LA when compared with patients having sinus rhythm and small LA (p < 0.01). When moderate to severe mitral regurgitation was associated with MS, the SBI incidence was found to be lower (p < 0.05). Although SBI was higher in patients with MVA < 1.5 cm2, it was not statistically significant (p > 0.05). No significant correlation was found between calcific and noncalcific valves for SBI (p > 0.05). Our data suggest that SBI may be expected in about 1/4 of patients with MS. The presence of LA enlargement and AF increase the incidence of SBI in patients with MS, whereas the presence of moderate to severe mitral regurgitation decreases the incidence of SBI.

Cigarette smoking in men and vascular responsiveness

AIMS

Smoking is a major risk factor for developing atherosclerosis. In order to understand the vascular abnormalities observed in smokers, we investigated vascular responsiveness in cigarette smokers.

METHODS

We performed two consecutive matched group comparative studies to investigate vascular responsiveness using venous occlusion plethysmography. The mean effects of three incremental doses of each vasoactive agent are presented. Both studies compared smokers with nonsmokers.

RESULTS

The first investigated 68 subjects (smokers = 29; mean +/- s.d. ages; 24 +/- 6 vs 25 +/- 5 years; P = NS) and found smoking was associated with a significant blunting of the flow ratio between treated and untreated arms to endothelium-dependent vasodilatation to acetylcholine (mean +/- s.d., nonsmokers vs smokers) 4.07 +/- 2.18 vs 3.42 +/- 1.79 (P = 0.04, 95% CI 0.02, 1.12). By contrast, there was no significant difference in the responses to the endothelium-independent vasodilators sodium nitroprusside and verapamil. Smoking was also associated with a significant impairment in endothelium-dependent vasoconstriction induced by monomethyl-L-arginine (L-NMMA) 0.78 +/- 0.22 vs 0.87 +/- 0.21 (P = 0.006, 95% CI -0.14, -0.02) and a trend to blunted endothelium-independent vasoconstrictor responses to noradrenaline. In the second study we investigated the response to angiotensin I and II in 23 subjects (smokers = 12; mean +/- s.d. ages; 34 +/- 10 vs 32 +/- 11 years). There was significant impairment in smokers of the mean vasoconstrictor response to angiotensin I 0.51 +/- 0.15 vs 0.59 +/- 0.16 (nonsmokers vs smokers; P = 0.003, 95% CI -0.13, -0.03) and a nonsignificant trend towards impairment of the response to angiotensin II.

CONCLUSIONS

Cigarette smoking in male volunteers is associated with blunted basal and stimulated nitric oxide bioactivity. Endothelial independent vasodilator responses (to nitroprusside and verapamil) were unaltered in smokers. A defect in the vasoconstrictor response to angiotensin I was also seen.

Atrial fibrillation and cognitive disorders in older people

OBJECTIVES

To find a correlation between chronic nonrheumatic atrial fibrillation (CNRAF) and cognitive impairment in a group of older, nondemented patients.

SETTING

Acute Care Unit for the Elderly, Poliambulanza Hospital, Brescia (Italy).

METHODS

Two hundred fifty-five hospital in-patients older than 70 years (42 with CNRAF and 213 controls with normal sinus rhythm) were assessed by complete clinical history, physical examination, ECG, serum albumin levels, APACHE II score, mental status (Mini-Mental State Exam [MMSE] and Geriatric Depression Score [GDS]), functional status (Barthel Index and instrumental activities of daily living [IADL]), number of prescribed drugs, and comorbidity (Charlson Index).

RESULTS

The group of patients with CNRAF had MMSE scores significantly lower than that of the reference group with normal sinus rhythm. Chronic nonrheumatic atrial fibrillation retained an independent relation to cognitive impairment also after adjusting for those variables associated with mental decline in univariate models (GDS, IADL, and APACHE II scores).

CONCLUSIONS

The results of this study support the relationship between nonrheumatic atrial fibrillation and impaired cognitive function. Independent of etiopathogenetic mechanisms (thromboembolic or hemodynamic hypotheses), prevention of cognitive impairment in older persons should take into account the treatment of atrial fibrillation and its consequences.

Cerebral tomographic findings in patients undergoing carotid endarterectomy for asymptomatic carotid stenosis: short-term and long-term implications

PURPOSE

Preoperative cerebral imaging has been considered not to be cost-effective in carotid endarterectomy (CEA) for asymptomatic carotid stenosis. Yet, silent brain infarction (SBI) has been associated with the embolization potential of a severe carotid stenosis. Thus the presence of SBI may represent an additional indication for CEA in asymptomatic patients. We examined the predictive value of preoperatively detected silent cerebral lesions on early and late outcomes in patients undergoing CEA for asymptomatic carotid stenosis.

METHODS

Preoperative cerebral tomographic (CT) scans performed on 301 asymptomatic patients undergoing 346 CEAs from 1986 to 1995 were reviewed by a single neuroradiologist blinded to patients' records. Mean follow-up was 67. 3 months (range, 24-130 months). The degree of internal carotid lumen reduction was measured bilaterally in all patients (602 carotid arteries); carotid stenosis of 60% or more was found in 399 carotid arteries.

RESULTS

Of the 103 (34%) CT scans positive for cerebral lesions, 58% were lacunar. No significant association was observed between the side of the cerebral lesion on CT scan and the severity of the corresponding carotid stenosis; 38 silent lesions were detected in the 203 hemispheres ipsilateral to carotid stenoses that were less than 60% versus 95 SBIs in the 399 hemispheres ipsilateral to carotid stenoses that were 60% or more (19% vs 24%; P =.2). There were no significant differences in the perioperative stroke/death rate in patients with or without cerebral CT lesions (2% vs 1%; odds ratio, 1.94; P =.6). Mortality rate during follow-up was 22% in patients with preoperative SBI and 15% in patients without SBI (P =.1). However, actuarial survival at 10 years was shorter (P =.02) in patients with SBI. Late stroke occurred in 11% of patients with preoperative SBI and in 3% of patients without preoperative SBI (P =.006). Cox regression analysis showed that both preoperative lacunar and nonlacunar infarctions were independent predictors of late stroke (hazard ratio, 3.6; P =.04; and hazard ratio, 7.1; P =.001; respectively).

CONCLUSION

In our experience, preoperative SBI did not occur more frequently in the hemisphere ipsilateral to asymptomatic severe carotid stenosis. Although our study lacks a medically treated control group, our data show that SBI is predictive of poor neurologic outcome in asymptomatic patients undergoing CEA. We conclude that CT before CEA, selectively applied, provides information on long-term neurologic prognosis and that a less aggressive attitude towards CEA in asymptomatic patients with SBI may be justified.

Cerebral blood flow and metabolism in patients with silent brain infarction: occult misery perfusion in the cerebral cortex

OBJECTIVES

Silent brain infarction (SBI) is of growing interest as a possible risk factor for symptomatic stroke. Although morphological characteristics of SBI have been well defined, their characteristic patterns of cerebral blood flow (CBF) and metabolism are in dispute. The purpose of this study was to elucidate CBF and metabolism in patients with SBI in relation to symptomatic stroke.

METHODS

The patients underwent PET and were separated into three groups; control group (C group), with no lesions on CT (n=9, mean age 57), SBI group, with no neurological signs or history of stroke, but with ischaemic lesions on CT (n=9, mean age 63), and brain infarction group (BI group), with neurological deficits and compatible CT lesions in the area supplied by perforating arteries (n=19, mean age 56). Regional CBF, oxygen extraction fraction (OEF), cerebral metabolic rate for oxygen (CMRO2), and cerebral blood volume (CBV) were measured by PET.

RESULTS

Mean values for CBF to the cerebral cortex and deep grey matter were lower in the SBI group (31.6 (SD 5.8) and 34.3 (SD 6.9) ml/100 g/min, respectively) and in the BI group (30.8 (SD 5.2), 33.9 (SD 5.9), respectively) than in the C group (36.0 (SD 6.6) and 43.5 (SD 9.5), respectively). Although mean CMRO2 of deep grey matter (2.36 (SD 0.52) ml/100 g/min) was significantly decreased in the SBI group compared with the C group (2.76 (SD 0.480), p<0.01), CMRO2 of the cortical area was as well preserved in the SBI patients (2.36 (SD 0.39)) as in the controls (2.48 (SD 0.32)) with a compensatory increase of mean OEF (0.45 (SD 0.06) and 0.41 (SD 0.05), respectively).

CONCLUSIONS

Patients with SBI showed decreased CBF and CMRO2 in deep grey matter. On the other hand, decreased CBF with milder increased OEF, resulting in preserved CMRO2 in the cerebral cortex indicates the presence of occult misery perfusion, suggesting that patients with SBI have reduced cerebral perfusional reserves.

Cigarette smoking is associated with increased human monocyte adhesion to endothelial cells: reversibility with oral L-arginine but not vitamin C

OBJECTIVES

This study sought to assess the effect of cigarette smoking on adhesion of human monocytes to human endothelial cells and to measure the effect of L-arginine and vitamin C supplementation on this interaction.

BACKGROUND

Cigarette smoking has been associated with abnormal endothelial function and increased leukocyte adhesion to endothelium, both key early events in atherogenesis. Supplementation with both oral L-arginine (the physiologic substrate for nitric oxide) and vitamin C (an aqueous phase antioxidant) may improve endothelial function; however, their benefit in cigarette smokers is not known.

METHODS

Serum was collected from eight smokers (mean [+/-SD] age 33 +/- 5 years) with no other coronary risk factors and eight age- and gender-matched lifelong nonsmokers. The serum was added to confluent monolayers of human umbilical vein endothelial cells and incubated for 24 h. Human monocytes obtained by counterflow centrifugation elutriation were then added to these monolayers for 1 h, and adhesion then was measured by light microscopy. To assess reversibility, monocyte/ endothelial cell adhesion was then measured for each subject 2 h after 2 g of oral vitamin C and 2 h after 7 g of oral L-arginine.

RESULTS

In smokers compared with control subjects, monocyte/ endothelial cell adhesion was increased (46.4 +/- 4.5% vs. 27.0 +/- 5.2%, p < 0.001), endothelial expression of intercellular adhesion molecule (ICAM)-1 was increased (0.31 +/- 0.02 vs. 0.22 +/- 0.03, p = 0.004), and vitamin C levels were reduced (33.7 +/- 24.1 vs. 53.4 +/- 11.5 mumol/liter, p = 0.028). After oral L-arginine, monocyte/ endothelial cell adhesion was reduced in smokers (from 46.4 +/- 4.5% to 35.1 +/- 4.0%, p = 0.002), as was endothelial cell expression of ICAM-1 (from 0.31 +/- 0.02 to 0.27 +/- 0.01, p = 0.001). After vitamin C, there was no significant change in monocyte/ endothelial cell adhesion or ICAM-1 expression from baseline in the smokers despite an increase in vitamin C levels (to 115 +/- 7 mumol/liter).

CONCLUSIONS

Cigarette smoking is associated with increased monocyte-endothelial cell adhesion when endothelial cells are exposed to serum from healthy young adults. This abnormality is acutely reversible by oral L-arginine but not by vitamin C.

The Copenhagen Stroke Study experience

The Copenhagen Stroke (COST) Study was a prospective, consecutive, community-based study of 1,197 patients with acute stroke who underwent acute stroke care and rehabilitation in a stroke unit setting. This article reviews the results of this study with respect to (1) the effect of organized stroke care and rehabilitation, (2) neurological outcome and functional outcome of stroke in relation to initial stroke severity and functional disability, (3) recovery of upper-extremity function and walking, (4) time course of neurological and functional recovery relative to initial stroke severity, (5) mechanisms of stroke recovery, and (6) the effect on stroke recovery of various demographic, medical, and pathophysiological factors, such as stroke in progression, spontaneous reperfusion age, diabetes, blood glucose on admission, stroke type (hemorrhage/infarction), silent infarction, and leuco-araiosis.

Computerised tomography findings as a risk factor in carotid endarterectomy: early and late results

OBJECTIVES

To evaluate whether preoperative CT evidence of brain infarction is associated with an increased risk of early and late stroke and death in patients undergoing CEA.

DESIGN

Retrospective clinical study.

MATERIALS AND METHODS

We evaluated 844 CT scanning records from 893 patients undergoing CEA from 1986-1994: 43% (367) CT positive for cerebral infarction and 57% (477) negative. Univariate and multivariate analysis was performed for risk factors and preoperative symptoms in patients with positive and negative CT scans, and Kaplan Meier survival curves for late events.

RESULTS

A positive CT was significantly more frequent in males vs. females (p < 0.0001; O.R. 2.52; C.I. 1.73-3.73), diabetics vs. non-diabetics (p = 0.03; O.R. 1.52; C.I. 1.03-2.26), symptomatics vs. asymptomatics (p < 0.001; O.R. 2; C.I. 1.93-3.53) and contralateral occlusion vs. patency (p < 0.001; O.R. 2; C.I. 1.30-3.10). The perioperative disabling stroke/ death rate was higher in patients with a positive CT (p = 0.002; O.R. 6.27; C.I. 1.73-34.20); in asymptomatic patients this difference was striking (5 patients vs. O, p = 0.0002). Multiple logistic regression analysis for risk factors, CT findings, symptoms preceding surgery, and congruity of brain infarction confirmed a significantly higher incidence of perioperative stroke/death rate (p = 0.003; O.R. 6.37; C.I. 5.12-7.63) and early and late stroke (p = 0.02; O.R. 1.95; C.I. 1.38-2.53) and death (p = 0.0005; O.R. 2.38; C.I. 1.89-2.88) in patients with brain lesions. After 7 years, the survival rate (p = 0.0009) and stroke-free interval (p = 0.003) were lower in patients with a positive CT. After 5 years, in asymptomatic patients the survival rate (p = 0.003) and stroke-free interval (p = 0.01) were lower in the positive CT group.

CONCLUSIONS

A positive CT finding, regardless of congruity of the lesion, should be regarded as an indicator of an increased risk of stroke and death in patients scheduled for carotid surgery, especially in those with asymptomatic stenosis.

Silent brain infarcts in 755 consecutive patients with a first-ever supratentorial ischemic stroke. Relationship with index-stroke subtype, vascular risk factors, and mortality

BACKGROUND AND PURPOSE

We wanted to establish independent associations of various clinical variables, computed tomographic (CT) scan features, presenting stroke subtypes, and outcome with the presence of silent infarcts on CT.

METHODS

We studied 755 consecutive patients in a prospective registration of patients with first-ever supratentorial atherothrombotic, cardioembolic, or lacunar stroke or stroke of undetermined cause by multiple logistic regression analysis.

RESULTS

Two hundred six patients (27%) with a first symptomatic territorial or small deep ischemic stroke had one or more silent infarcts on CT. Of all silent lesions, 169 (82%) were small and deep. Silent infarcts were significantly more strongly associated with a lacunar than atherothrombotic (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.02 to 2.47; P = .039) or cardioembolic (OR, 1.89; 95% CI, 1.2 to 2.99; P = .005) index stroke. Silent territorial lesions were more strongly associated with cardioembolic than with lacunar stroke but not with atherothrombotic stroke. In this respect, no differences were found between the atherothrombotic and undetermined-cause group. Advanced age and hypertension were the only risk factors that were significantly associated with silent infarcts (OR, 1.76; 95% CI, 1.14 to 2.71; P = .011; and OR, 1.58; 95% CI, 1.13 to 2.21; P = .007; respectively), mainly because of a strong independent association of these risk factors with silent small deep infarcts (OR, 1.75; 95% CI, 1.10 to 2.79; P = .018; and OR, 1.57; 95% CI, 1.09 to 2.24; P = .014; respectively). A cardioembolic source or atrial fibrillation in specific was not independently associated with any type or number of silent infarcts. Significant carotid stenosis (diameter reduction > 50%) was not significantly associated with any type of silent lesion. Initial severe handicap (Rankin Scale score > 3), 30-day case fatality rate, and 1-year mortality were not affected by the presence of silent infarcts.

CONCLUSIONS

The strong association of silent small deep lesions with first symptomatic small deep infarcts suggests a common underlying mechanism (presumably small-vessel vasculopathy), whereas cardiogenic embolism and large-vessel thromboembolism are the most likely causes in both silent and first symptomatic territorial infarcts. Single or multiple silent infarcts do not predict a cardioembolic stroke mechanism in first symptomatic supratentorial brain infarcts. As silent infarcts do not predict the cause of carotid embolic stroke in first symptomatic brain infarcts, their presence should not influence the decision on carotid surgery. Silent infarcts do not affect the degree of initial handicap, 30-day case fatality, or 1-year mortality. The significance of silent infarcts for predicting possible future cognitive decline and risk of recurrent stroke deserves further study.

Stroke in patients with diabetes. The Copenhagen Stroke Study

BACKGROUND AND PURPOSE

Although diabetes is a strong risk factor for stroke, it is still unsettled whether stroke is different in patients with and without diabetes. This is true for stroke type, stroke severity, the prognosis, and the relation between admission glucose levels and stroke severity/mortality.

METHODS

This community-based study included 1135 acute stroke patients (233 [20%] had diabetes). All patients were evaluated until the end of rehabilitation by weekly assessment of neurological deficits (Scandinavian Stroke Scale) and functional disabilities (Barthel Index). A computed tomographic scan was performed in 83%.

RESULTS

The diabetic stroke patient was 3.2 years younger than the nondiabetic stroke patient (P < .001) and had hypertension more frequently (48% versus 30%, P < .0001). Intracerebral hemorrhages were six times less frequent in diabetic patients (P = .002). Initial stroke severity, lesion size, and site were comparable between the two groups. However, mortality was higher in diabetic patients (24% versus 17%, P = .03), and diabetes independently increased the relative death risk by 1.8 (95% confidence interval [CI], 1.04 to 3.19). Outcome was comparable in surviving patients with and without diabetes, but patients with diabetes recovered more slowly. Mortality increased with increasing glucose levels on admission in nondiabetic patients independent of stroke severity (odds ratio, 1.2 per 1 mmol/L; CI, 1.01 to 1.42; P = .04). This was not the case in diabetic patients.

CONCLUSIONS

Diabetes influences stroke in several aspects: in age, in subtype, in speed of recovery, and in mortality. Increased glucose levels on admission independently increase mortality from stroke in nondiabetic but not in diabetic patients. The effect of reducing high admission glucose levels in nondiabetic stroke patients should be examined in future trials.

Silent infarction on a second CT scan in 91 patients without manifest stroke in the Dutch TIA trial

The frequency of silent infarction is an important issue because it is a marker of vascular disease. We studied the occurrence of silent infarction in a sample of patients from the Dutch TIA trial, in which patients were randomized between 30 and 283 mg of aspirin. A total of 91 patients with TIA or non-disabling ischemic stroke and who did not suffer a stroke during a period of one to four years (mean 32 months) underwent CT scanning both on entry and at the end of the study. A cardiac source of embolism was an exclusion criterion for the trial. We found only one patient with a possibly silent infarction; in four patients a previously detected symptomatic infarct on CT was no longer visible. The rarity of silent infarction in this study may have several explanations; (1) the relatively short period of follow-up, (2) the selection of patients (no cardiac source of embolism), (3) the clinical monitoring at four monthly intervals aimed at detection of focal ischemia, (4) the use of aspirin. Given these circumstances, silent infarction is an infrequent problem.

Comparison of clinical and neuroradiological findings in first-ever stroke. A population-based study

BACKGROUND AND PURPOSE

To determine how a recently proposed clinical stroke subclassification corresponds to specific findings on computed tomography (CT) and magnetic resonance imaging (MRI) of the brain.

METHODS

Two hundred twenty-eight patients with first-ever stroke were divided into four clinical subgroups: (1) total anterior circulation syndrome: both cortical and subcortical symptoms from anterior and middle cerebral artery territory; (2) partial anterior circulation syndrome: more restricted and predominantly cortical symptoms from the same arterial territories; (3) lacunar syndrome; and (4) posterior circulation syndrome: vertebrobasilar or posterior cerebral artery symptoms. The imaging protocol included CT of the brain on day 0 through 15 and a second CT and an MRI of the brain on day 16 through 180 after acute stroke onset.

RESULTS

There were 200 patients with cerebral infarction and 28 patients with intracerebral hemorrhage. Intracerebral hemorrhage was found in 19% of patients with total anterior circulation syndrome and in no patients with lacunar syndrome (chi 2 test; P < .01 for the difference between the four clinical subgroups). Of the 200 patients with cerebral infarction, 27% had total anterior circulation, 30% partial anterior circulation, 26% lacunar, and 16% posterior circulation syndromes. CT within 2 days revealed a visible lesion in about two thirds of patients with infarctions of total or partial anterior circulation syndrome type, compared with only 22% of patients with lacunar infarction (chi 2 test; P = .02 for the difference between the four subgroups). The mean volume of the symptomatic infarction on CT within 15 days was 95 mL for total anterior circulation, 20 mL for partial anterior circulation, and 2.5 mL for lacunar syndrome (one-factor ANOVA; P = .0001). A cortical involvement of the infarction on CT day 16 through 180 was seen in 81% of patients with total anterior circulation syndrome and 58% of those with partial anterior circulation syndrome, compared with only 8% of patients with lacunar syndrome (chi 2 test; P = .0001). MRI more often than CT showed a cortical involvement of lacunar infarctions and also revealed more silent lesions.

CONCLUSIONS

The described clinical subgroups significantly differed in frequencies of intracerebral hemorrhage, cortical involvement, and lesion volume on CT and MRI.

Baseline silent cerebral infarction in the Asymptomatic Carotid Atherosclerosis Study

BACKGROUND AND PURPOSE

In a group of patients with high-grade asymptomatic carotid artery stenosis, we prospectively determined the prevalence and radiological characteristics of clinically asymptomatic brain infarction evident on computed tomography. Risk factors and extent of carotid disease were also determined.

METHODS

Patients randomized into the Asymptomatic Carotid Atherosclerosis Study (ACAS) underwent a neurological history, a detailed stroke/transient ischemic attack questionnaire, and a detailed neurological examination. Computed tomography scans were examined by standardized criteria developed as part of a quality-control program supervised by a neuroradiologist. The presence, location, and size of all cerebral infarctions evident by computed tomography were determined.

RESULTS

Among 1132 patients, 848 had no history of stroke or transient ischemic attack. One hundred twenty-six patients (15%) had a silent infarct; 95 (11%) had one, 24 (3%) had two, and 7 (1%) had three or more infarcts. The infarct size was small and deep for 117 patients (72%), less than one-half lobe for 45 (28%), and one-half to less than one lobe for 1 (0.5%). The silent infarcts were evenly distributed ipsilaterally and contralaterally to the study artery but were significantly more frequent in the right hemisphere (P < .05). Factors associated with silent infarction were abnormal gait (P < .001), abnormal deep tendon reflexes or plantar responses (P = .038), but not degree of carotid stenosis. Silent infarction was less frequent among this totally asymptomatic cohort (15%) compared with those with transient ischemic attacks (34/139, 25%; P < .001).

CONCLUSIONS

Silent infarction in the setting of asymptomatic carotid stenosis is not uncommon, but silent infarctions are rarely sizable. The clinical significance of silent cerebral infarction in patients with asymptomatic carotid artery stenosis has yet to be established.

Background factors and clinical symptoms of major depression with silent cerebral infarction

BACKGROUND AND PURPOSE

We previously reported that major depression developing during or after the presenile period is frequently combined with silent cerebral infarction and that these patients have a high risk of stroke. Therefore, we investigated whether the background factors and clinical symptoms of patients with major depression with silent cerebral infarction [SCI(+)] different from those in patients with major depression without silent cerebral infarction [SCI(-)] before medical treatment.

METHODS

Patients with major depression with onset after 50 years of age were classified based on magnetic resonance imaging findings into the SCI(+) (n = 37) or SCI(-) (n = 20) group. The diagnostic criteria for major depression were those of the American Psychiatry Association (DSM-III-R). Patients with stroke or focal neurological symptoms were excluded. The SCI(+) group was subclassified according to whether the infarction area was perforating, cortical, or mixed artery. Family history of affective disorder, risk factors for stroke, and Zung's Self-rated Depression Scale (SDS) score before medical treatment of the group were compared.

RESULTS

The SCI(+) group had a significantly lower (P < .05) frequency of family history of affective disorder but a significantly higher (P < .01) frequency of hypertension than did the SCI(-) group. The mean SDS score in the SCI(+) group was significantly higher than that in the SCI(-) group (P < .01). The mean SDS score of the mixed artery infarction group was higher than that of the perforating artery infarction group (P < .05).

CONCLUSIONS

Patients with major depression with silent cerebral infarction present more marked neurological factors and more severe depressive symptoms than do those without silent cerebral infarction. Because these features were more prominent in the patients with mixed artery infarction with broad obstructions, we consider that the area of brain damage caused by cerebral infarction is positively related to the severity of depressive symptoms.

Transient ischemic attacks, risk factors, and precerebral color doppler angiosonography

The aim of this study was to ascertain the importance of color-coded Doppler sonography (CCDS), a noninvasive examination technique, in early detection of atherosclerotic lesions in precerebral arteries. CCDS was utilized in a group of patients with one or several transient ischemic attacks (TIA) and in a group of non-TIA (NTIA) cases, so that the degree of atherosclerotic lesions of precerebral vessies in TIA and NTIA patients might be compared. The presence of risk factors for cerebrovascular disease (CVD) was compared in both groups as well. We examined 87 patients with TIA (38 women and 49 men), aged 19-86 years (mean, 60.97 ± 11.97 years) and 48 NTIA patients (22 women and 26 men), aged 35-85 years (mean,60.04 ± 9.37years). No statistically significant differences in age and gender were found between the groups. A significant difference was found between the common carotid artery intimal-medial thickness (CCA IMT) in TIA patients (CCA IMT right + left = 1.12 ± 0.44 mm) and NTIA patients (CCA IMT right + left = 0.91 ± 0.32 mm) (p < 0.0001). A positive significant association was found between both groups in the number of different plaques (p < 0.0001) and the number of stenoses (p < 0.0001). When risk factors were compared, the difference between TIA and NTIA groups was statistically significant in regard to high-density lipoproteins (p < 0.002), total cholesterol (p < 0.004), and blood glucose concentrations (p < 0.013), as well as systolic blood pressure (p < 0.011). In conclusion, Doppler sonographic changes in precerebral arteries were present in the TIA group in spite of the fact that both groups had identical risk factors for CVD. CCDS is a valuable aid for early detection of TIA patients who have a significant risk of developing brain infarction.

Silent infarction in acute stroke patients. Prevalence, localization, risk factors, and clinical significance: the Copenhagen Stroke Study

BACKGROUND AND PURPOSE

Our objective was to study age-specific prevalence, computed tomographic (CT) characteristics, risk factors, and the prognostic influence on stroke outcome of silent infarction in acute stroke patients.

METHODS

The study was prospective and community-based and included 801 acute stroke patients, of whom 587 had first-ever stroke. A CT scan was performed in 500 (85%) of the 587 patients with first-ever stroke. CT was reviewed blindly, and infarcts were classified according to patient history as silent or symptomatic. Patients were evaluated initially with the Mini-Mental State Examination (MMSE) and weekly with both the Scandinavian Stroke Scale (SSS) and the Barthel Index (BI) from the onset of stroke to completion of rehabilitation. CT characteristics, risk factors, and stroke outcome were compared in stroke patients with and without silent infarction.

RESULTS

The prevalence of silent infarction in patients with first-ever stroke and recurrent strokes was similar, at 29% (group aged 0 to 54 years, 16%; 55 to 64 years, 22%; 65 to 74 years, 30%; 75 years or older, 33%). Silent infarcts were small and subcortical. Independent risk factors were increasing age (odds ratio [OR], 1.95 per 25 years; confidence interval [CI], 1.19 to 3.15), hypertension (OR, 1.75; CI, 1.13 to 2.70), claudication (OR, 1.74; CI, 1.01 to 3.00), and male sex (OR, 1.72; CI, 1.12 to 2.64); other stroke risk factors such as atrial fibrillation and former transient ischemic attack were not independent risk factors. Patients with and without silent infarction did not differ in frequency of prestroke home care (P = .2). MMSE (P = .56), initial BI (P = .62) and SSS score (P = .08), BI (P = .85) and SSS score (P = .75) after completion of rehabilitation, or in the speed of recovery (P = .85). Length of hospital stay, mortality rate, and discharge rate to nursing home also did not differ between the two groups.

CONCLUSIONS

This community-based study shows that silent infarction in stroke patients is more related to certain stroke risk factors than others and that silent infarction does not seem to influence the prognosis of stroke.

Silent infarcts in patients with ischemic stroke are related to age and size of the left atrium

BACKGROUND AND PURPOSE

Possible specific risk factors for silent infarcts remain unknown. The aim of this study was to investigate whether risk factors for silent infarcts differ from those for symptomatic infarcts in stroke patients.

METHODS

Silent infarcts were defined as asymptomatic infarcts detected on computed tomographic scan in patients free of history of stroke and unrelated to the symptoms and signs of the index stroke. Of 595 consecutive patients with stroke or transient ischemic attacks, 116 (19%) had at least one silent infarct on the first computed tomographic scan performed within 24 hours after onset. They were compared with the 479 remaining patients for cerebrovascular risk factors and for presumed mechanism of stroke by means of the odds ratio method. A discriminant analysis was then performed in the subgroup of 216 patients with ischemic stroke who underwent an exhaustive cardiac and vascular workup.

RESULTS

One hundred forty-one silent infarcts (99% confidence interval [CI], 29% to 41%) and 265 symptomatic infarcts (99% CI, 59% to 71%) were subcortical infarcts smaller than 15 mm. Univariate analysis showed that patients with silent infarcts were more likely to be older than 65 years (odds ratio [99% CI], 1.11 to 3.49) and to have left atrial enlargement on echocardiogram (odds ratio [99% CI], 1.02 to 26.70) and leukoaraiosis (odds ratio [99% CI], 1.39 to 4.21). Discriminant analysis found only two independent risk factors for silent infarcts: left atrial enlargement (P = .007) and age older than 65 years (P = .03); leukoaraiosis was not found to be an independent risk factor (P = .86).

CONCLUSIONS

Age and left atrial enlargement are the main risk factors for silent infarcts in patients with ischemic stroke or transient ischemic attacks.

Association between low bone density and stroke in elderly women. The study of osteoporotic fractures

BACKGROUND AND PURPOSE

To determine whether women with low bone mineral density are at increased risk of stroke, the present study was conducted.

METHODS

We studied 4024 ambulatory women aged 65 years or older participating in the prospective Study of Osteoporotic Fractures. Bone mineral density was measured at baseline using single photon absorptiometry; strokes were ascertained using a computerized Medicare data base and death certificates.

RESULTS

During a mean of 1.98 years of follow-up, 83 women suffered first strokes (five fatal). Osteopenia was associated with an increased stroke risk: Each SD decrease in bone mineral density at the calcaneus (0.09 g/cm2) was associated with a 1.31-fold increase in stroke (95% confidence interval, 1.03-1.65), adjusted for age, follow-up time, and several potential confounders, including diabetes, systolic blood pressure, use of alcohol, cigarettes or postmenopausal estrogens, cognitive ability, grip strength, and functional ability. The observed relation between bone density and stroke was strongest for intracerebral hemorrhages and occlusions.

CONCLUSIONS

Most likely, low bone density does not cause stroke; some other process probably results in both osteopenia and cerebrovascular disease.