Risk factors and outcome of patients with carotid artery stenosis presenting with lacunar stroke. North American Symptomatic Carotid Endarterectomy Trial Group

Intracranial carotid artery calcification morphology differs in patients with lacunar and nonlacunar acute ischemic strokes

BACKGROUND AND PURPOSE

Intracranial carotid artery calcifications (ICACs) are a common finding on noncontrast computed tomography (NCCT) and have been associated with an increased risk of ischemic stroke. However, no data are available about the association between ICAC patterns and stroke etiology. We investigated the association between ICAC patterns and etiological subtypes of ischemic stroke.

METHODS

We retrospectively analyzed a single center cohort of patients admitted for ischemic stroke with known etiology. Each carotid artery was evaluated separately on NCCT scans to define the ICAC pattern (intimal, medial, mixed). The association between ICAC patterns and stroke etiology was investigated using logistic regression models adjusting for relevant confounders.

RESULTS

A total of 485 patients were included (median age = 78 [interquartile range (IQR) = 70-85] years, 243 [50%] female, median National Institutes of Health Stroke Scale = 6 [IQR = 3-12]). Frequencies of ICAC patterns were: intimal, n = 96 (20%); medial, n = 273 (56%); mixed, n = 51 (11%), indistinct/absent, n = 65 (13%) patients. Intimal pattern was more frequent in lacunar compared with nonlacunar (33% vs. 16%, p < 0.001) stroke etiology, whereas medial pattern was less frequent in lacunar compared with nonlacunar stroke (36% vs. 62%, p < 0.001). After adjustment for confounders, intimal ICAC predominant pattern remained associated with lacunar stroke etiology in two multivariate models (Model 1: adjusted odds ratio [aOR] = 2.08, 95% confidence interval [CI] = 1.20-3.56; Model 2: aOR = 2.01, 95% CI = 1.16-3.46).

CONCLUSIONS

Our study suggests that intimal ICAC pattern is associated with lacunar stroke and may serve as a marker for lacunar stroke etiology, possibly strengthening the relation between endothelial dysfunction and lacunar stroke.

Prevention of Neurologic Disease with Fasting

Fasting has been widely studied in both prevention and treatment of many neurologic disorders. Some conditions may be prevented with any type of fasting, while some may require a stricter regimen. Fasting reduces weight, fasting blood glucose, and insulin resistance, and favorably alters the gut biome and the immune system. This article discusses various versions of fasting that have been studied as well as the known and theoretical mechanisms of how fasting effects the body and the brain. This article will then review evidence supporting the potential preventive and treatment effects of fasting in specific neurologic disorders including ameliorating the symptoms of Parkinson's disease, improving cognition in Alzheimer's disease, reducing migraine frequency and intensity, and reducing seizure frequency in epilepsy.

Elevated Neutrophil to Lymphocyte Ratio is Associated with Worse Outcomes after Carotid Endarterectomy in Asymptomatic Patients

OBJECTIVE

Management of carotid artery stenosis (CAS) remains controversial and proper patient selection critical. Elevated neutrophil to lymphocyte ratio (NLR) has been associated with poor outcomes after vascular procedures. The effect of NLR on outcomes after carotid endarterectomy (CEA) in asymptomatic and symptomatic patients is assessed.

MATERIALS AND METHODS

A retrospective review was conducted of all patients between 2010 and 2018 with carotid stenosis >70% as defined by CREST 2 criteria. A total of 922 patients were identified, of whom 806 were treated with CEA and 116 non-operatively with best medical therapy (BMT). Of patients undergoing CEA, 401 patients (290 asymptomatic [aCEA], 111 symptomatic [sCEA]) also had an available NLR calculated from a complete blood count with differential. All patients treated with BMT were asymptomatic and had a baseline NLR available. Kaplan-Meier analysis assessed composite ipsilateral stroke or death over 3 years.

RESULTS

In sCEA group, the 3-year composite stroke/death rates did not differ between NLR < 3.0 (22.9%) vs NLR > 3.0 (38.1%) (P=.10). In aCEA group, patients with a baseline NLR >3.0 had an increased risk of 3-year stroke/death (42.6%) compared to both those with NLR <3.0 (9.3%, P<.0001) and those treated with BMT (23.6%, P=.003). In patients with NLR <3.0, aCEA showed a superior benefit over BMT with regard to stroke or death (9.3% vs. 26.2%, P=.02). However, in patients with NLR >3.0, there was no longer a benefit to prophylactic CEA compared to BMT (42.6% vs. 22.2%, P=.05). Multivariable analysis identified NLR >3.0 (HR, 3.23; 95% CI, 1.93-5.42; P<.001) and congestive heart failure (HR, 2.18; 95% CI, 1.33-3.58; P=.002) as independent risk factors for stroke/death in patients with asymptomatic carotid artery stenosis.

CONCLUSIONS

NLR >3.0 is associated with an increased risk of late stroke/death after prophylactic CEA for asymptomatic carotid artery stenosis, with benefits not superior to BMT. NLR may be used to help with selecting asymptomatic patients for CEA. The effect of NLR and outcomes in symptomatic patients requires further study. Better understanding of the mechanism(s) for NLR elevation and medical intervention strategies are needed to modulate outcome risk in these patients.

Carotid revascularization and cognitive impairment: the neglected role of cerebral small vessel disease

Carotid atherosclerosis is a pathological process that leads to narrowing of the vessel lumen and a consequent risk of stroke. Revascularization procedures such as carotid endarterectomy (CEA) and carotid stenting aim to reduce occurrence of stroke in selected patients. Due to the proven benefit and low intraoperative risk, CEA is currently the preferred choice in candidates for carotid revascularization. However, the risk of cognitive impairment subsequent to CEA has not been fully elucidated and is unclear whether certain conditions, such as frailty, may increase this risk. There is consistent evidence that shows that frail patients have higher risk of cognitive impairment after surgical procedure. Moreover, brain pre-existing conditions may play a role in cognitive impairment after CEA. Cerebral small vessel disease (SVD) is a pathology that involves microcirculation and is detectable with computed tomography or magnetic resonance. SVD shares common vascular risk factors with carotid atherosclerosis, is a major contributor to vascular cognitive impairment and vascular dementia, and has been proposed as a marker of brain frailty. In this review, we discuss the current evidence about the link between carotid revascularization and cognitive impairment and advance the hypothesis that SVD may play a relevant role in development of cognitive impairment after carotid revascularization.

Lacunar stroke: mechanisms and therapeutic implications

Lacunar stroke is a marker of cerebral small vessel disease and accounts for up to 25% of ischaemic stroke. In this narrative review, we provide an overview of potential lacunar stroke mechanisms and discuss therapeutic implications based on the underlying mechanism. For this paper, we reviewed the literature from important studies (randomised trials, exploratory comparative studies and case series) on lacunar stroke patients with a focus on more recent studies highlighting mechanisms and stroke prevention strategies in patients with lacunar stroke. These studies suggest that lacunar stroke is a heterogeneous disease with various mechanisms, including most commonly lipohyalinosis and less commonly atheromatous disease and cardioembolism, highlighting the importance of a careful review of brain and neurovascular imaging, a cardiac and systemic evaluation. A better understanding of pathomechanisms of neurological deterioration may lead to investigating the utility of novel treatment strategies and optimisation of short-term antithrombotic treatment strategies to reduce the risk of neurological deterioration and prevent long-term disability in patients with lacunar stroke.

Total small vessel disease burden and functional outcome in patients with ischemic stroke

Background

Cerebral small vessel disease (SVD) is comprised of lacunes, cerebral microbleeds (CMBs), white matter hyperintensities (WMHs), and enlarged perivascular space (EPVS). We investigated the cumulative effect of SVD on 3-month functional outcome following ischemic stroke using the total SVD score.

Methods

The total SVD score of 477 acute ischemic stroke patients with adequate brain MRI was analyzed. We used multivariable ordinal logistic regression analysis to investigate the independent impact of total SVD score on ordinal modified Rankin Scale (mRS) score at 3-month after ischemic stroke.

Results

Mean age was 66±14 years, and 61% were men. The distribution of the total SVD score from 0 to 4 was 27%, 24%, 26%, 16%, and 7%, respectively. The proportion of mRS scores 2 or greater was 16% and 47% in total SVD score 0 and 4, respectively. Multivariable ordinal logistic regression analysis results showed that compared with the total SVD score of 0, total SVD scores of 2, 3, and 4 were independently associated with higher mRS scores with adjusted odds ratios (95% confidence intervals) of 1.68 (1.02–2.76), 2.24 (1.25–4.00), and 2.00 (1.02–4.29). Lacunes, CMBs, WMHs but not EPVS were associated with mRS scores at 3 months. However, the impact of each SVD marker on stroke outcome was smaller than that of the total SVD score.

Conclusion

We found an independent association between total SVD scores and functional outcome at 3 months following ischemic stroke. The total SVD score may be useful for stratification of patients who are at a high-risk of unfavorable outcomes.

CIMT as a risk factor for stroke subtype: A systematic review

INTRODUCTION

An increase in the common carotid artery intima-media thickness (CCA-IMT) is generally considered an early marker of atherosclerosis and is a well-established predictor of cardiovascular disease (CVD). An association between changes in CCA-IMT and risk of stroke has been reported but has conflicting findings.

OBJECTIVE

The present meta-analysis was aimed to clarify the association between CCA-IMT with the risk of stroke and its subtype by estimating pooled analysis of published literature.

METHODS

Comprehensive search for all published articles was performed in electronic databases including PubMed, Embase, Cochrane Library, Trip Databases, Worldwide Science, CINAHL and Google Scholar from 01 January 1950 to 30 April 2020.

RESULTS

In our meta-analysis, a total of 19 studies, of which sixteen studies involving 3475 ischaemic stroke (IS) cases and 11 826 controls; six studies with 902 large vessel disease (LVD) and 548 small vessel disease (SVD) of IS subtypes; five studies with 228 intracerebral haemorrhage (ICH) and 1032 IS cases, were included. Our findings suggest a strong association between increased CCA-IMT with risk of IS as compared to control subjects [SMD = 1.46, 95% CI = 0.90-2.02]. However, there is an increased risk of LVD as compared to the SVD subtype of IS [SMD = 0.36, 95% CI = 0.19-0.52] and more chance of occurrence of IS rather than ICH [SMD = 0.71, 95% CI = 0.28-1.41].

CONCLUSIONS

Carotid intima thickness measurements are found to be associated with the risk of stroke along with its subtypes and may be used as a diagnostic marker for predicting the risk of stroke events.

Rapid progression of carotid stenosis was rare in a large integrated healthcare system during an eight-year period

OBJECTIVE

Few studies have evaluated the rapid progression of carotid stenosis on a large scale. We created a custom software algorithm to analyze an electronic medical record database to examine the natural progression of carotid stenosis, identify a subset of patients with rapid progression, and evaluate the specific patient risk factors associated with this rapid progression.

METHODS

Patients in a large integrated healthcare system who had undergone two or more carotid ultrasound scans from August 2010 to August 2018 were identified. We did not distinguish between those with an established carotid stenosis diagnosis and those with a screening ultrasound scan. We used our novel algorithm to extract data from their carotid ultrasound reports. The degrees of carotid stenosis were categorized as follows: level 1, 0% to 39%; level 2, 40% to 59%; level 3, 60% to 79%; level 4, 80% to 99%; and level 5, complete occlusion. The primary endpoint was rapid vs slow progression of carotid stenosis, with rapid progression defined as an increase of two or more levels within any 18-month period of the study, regardless of the date of the initial ultrasound scan. The association of the demographic and clinical characteristics with rapid progression was assessed by univariable and multivariable logistic regression.

RESULTS

From a cohort of 4.4 million patients, we identified 4982 patients with two or more carotid ultrasound scans and a median follow-up period of 13.1 months (range, 0.1-93.7 months). Of the 4982 patients, 879 (17.6%) had shown progression of carotid stenosis. Only 116 patients (2.3%) had had progression to level 4 (80%-99% stenosis) from any starting level during a median of 11.5 months. A total of 180 patients (3.6%) were identified as experiencing rapid progression during a median follow-up of 9.9 months. The final multivariable analysis showed that younger age (P < .01), white race (P = .02), lower body mass index (P = .01), a diagnosis of peripheral arterial disease (P = .03), and a diagnosis of transient ischemic attack (P < .01) were associated with rapid progression.

CONCLUSIONS

Using a novel algorithm to extract data from >4 million patient records, we found that rapid progression of carotid stenosis appears to be rare. Although 17.6% of patients showed any degree of progression, only 3.6% had experienced rapid progression. Among those with any disease progression, 20.5% had experienced rapid progression. Although the overall incidence of rapid progression was low, patients with any progression might warrant close follow-up, especially if they have the associated risk factors for rapid progression. The custom software algorithm might be a powerful tool for creating and evaluating large datasets.

Intra-carotid arterial transfusion of circulatory-derived autologous endothelial progenitor cells in rodent after ischemic stroke-evaluating the impact of therapeutic time points on prognostic outcomes

Background

This study tested the optimal time point for left intra-carotid arterial (LICA) administration of circulatory-derived autologous endothelial progenitor cells (EPCs) for improving the outcome in rat after acute ischemic stroke (IS).

Methods and results

Adult male SD rats (n = 70) were equally categorized into group 1 (sham-operated control), group 2 (IS), group 3 (IS+EPCs/1.2 × 10⁶ cells/by LICA administration 3 h after IS), group 4 (IS+EPCs/LICA administration post-day-3 IS), group 5 (IS+EPCs/LICA administration post-day-7 IS), group 6 (IS+EPCs/LICA administration post-day-14 IS), and group 7 (IS+EPCs/LICA administration post-day-28 IS). The brain infarct volume (BIV) (at day 60/MRI) was lowest in group 1, highest in group 2, and significantly progressively increased from groups 3 to 7, whereas among the IS animals, the neurological function was significantly preserved in groups 3 to 6 than in groups 2 and 7 post-day-60 IS (all P < 0.0001). By day 60, the endothelial cell markers at protein and cellular levels and number of small vessels exhibited an opposite pattern of BIV among the groups (all P < 0.0001). The protein and cellular levels of inflammation, and protein levels of oxidative stress, autophagy, and apoptosis were highest in group 2, lowest in group 1, and progressively increased from groups 3 to 7 (all P < 0.0001). The angiogenesis biomarkers at protein and cellular levels were significantly progressively increased from groups 1 to 3, then significantly progressively decreased from groups 4 to 7 (all P < 0.0001).

Conclusion

Early EPC administration provided better benefits on improving functional/image/molecular-cellular outcomes after acute IS in rat.

Are morphologic features of recent small subcortical infarcts related to specific etiologic aspects?

Background:

Recent small subcortical infarcts (RSSIs) mostly result from the occlusion of a single, small, brain artery due to intrinsic cerebral small-vessel disease (CSVD). Some RSSIs may be attributable to other causes such as cardiac embolism or large-artery disease, and their association with coexisting CSVD and vascular risk factors may vary with morphological magnetic resonance imaging (MRI) features.

Methods:

We retrospectively identified all inpatients with a single symptomatic MRI-confirmed RSSI between 2008 and 2013. RSSIs were rated for size, shape, location (i.e. anterior: basal ganglia and centrum semiovale posterior cerebral circulation: thalamus and pons) and MRI signs of concomitant CSVD. In a further step, clinical data, including detailed diagnostic workup and vascular risk factors, were analyzed with regard to RSSI features.

Results:

Among 335 RSSI patients (mean age 71.1 ± 12.1 years), 131 (39%) RSSIs were >15 mm in axial diameter and 66 (20%) were tubular shaped. Atrial fibrillation (AF) was present in 44 (13.1%) and an ipsilateral vessel stenosis > 50% in 30 (9%) patients. Arterial hypertension and CSVD MRI markers were more frequent in patients with anterior-circulation RSSIs, whereas diabetes was more prevalent in posterior-circulation RSSIs. Larger RSSIs occurred more frequently in the basal ganglia and pons, and the latter were associated with signs of large-artery atherosclerosis. Patients with concomitant AF had no specific MRI profile.

Conclusion:

Our findings suggest the contribution of different pathophysiological mechanisms to the occurrence of RSSIs in the anterior and posterior cerebral circulation. While there appears to be some general association of larger infarcts in the pons with large-artery disease, we found no pattern suggestive of AF in RSSIs.

Abnormal P-Wave Axis and Ischemic Stroke: The ARIC Study (Atherosclerosis Risk In Communities)

BACKGROUND AND PURPOSE

Abnormal P-wave axis (aPWA) has been linked to incident atrial fibrillation and mortality; however, the relationship between aPWA and stroke has not been reported. We hypothesized that aPWA is associated with ischemic stroke independent of atrial fibrillation and other stroke risk factors and tested our hypothesis in the ARIC study (Atherosclerosis Risk In Communities), a community-based prospective cohort study.

METHODS

We included 15 102 participants (aged 54.2±5.7 years; 55.2% women; 26.5% blacks) who attended the baseline examination (1987-1989) and without prevalent stroke. We defined aPWA as any value outside 0 to 75° using 12-lead ECGs obtained during study visits. Each case of incident ischemic stroke was classified in accordance with criteria from the National Survey of Stroke by a computer algorithm and adjudicated by physician review. Multivariable Cox regression was used to estimate hazard ratios and 95% confidence intervals for the association of aPWA with stroke.

RESULTS

During a mean follow-up of 20.2 years, there were 657 incident ischemic stroke cases. aPWA was independently associated with a 1.50-fold (95% confidence interval, 1.22-1.85) increased risk of ischemic stroke in the multivariable model that included atrial fibrillation. When subtyped, aPWA was associated with a 2.04-fold (95% confidence interval, 1.42-2.95) increased risk of cardioembolic stroke and a 1.32-fold (95% confidence interval, 1.03-1.71) increased risk of thrombotic stroke.

CONCLUSIONS

aPWA is independently associated with ischemic stroke. This association seems to be stronger for cardioembolic strokes. Collectively, our findings suggest that alterations in atrial electric activation may predispose to cardiac thromboembolism independent of atrial fibrillation.

Xueshuantong improves cerebral blood perfusion in elderly patients with lacunar infarction

A total of 64 patients with acute lacunar infarction were enrolled within 24 hours of onset. The patients received conventional therapy (antiplatelet drugs and hypolipidemic drugs) alone or conventional therapy plus 450 mg Xueshuantong once a day. The main ingredient of the Xueshuantong lyophilized powder used for injection was Panax notoginseng saponins. Assessments were made at admission and at discharge using the National Institutes of Health Stroke Scale, the Activity of Daily Living and the Mini-Mental State Examination. Additionally, the relative cerebral blood flow, relative cerebral blood volume and relative mean transit time in the region of interest were calculated within 24 hours after the onset of lacunar infarction, using dynamic susceptibility contrast magnetic resonance perfusion imaging technology. Patients underwent a follow-up MRI scan after 4 weeks of treatment. There was an improvement in the Activity of Daily Living scores and a greater reduction in the scores on the National Institutes of Health Stroke Scale in the treatment group than in the control group. However, the Mini-Mental State Examination scores showed no significant differences after 4 weeks of treatment. Compared with the control group, the relative cerebral blood flow at discharge had increased and showed a greater improvement in the treatment group. Furthermore, there was a reduction in the relative mean transit time at discharge and the value was lower in the treatment group than in the control group. The experimental findings indicate that Xueshuantong treatment improves neurological deficits in elderly patients with lacunar infarction, and the mechanism may be related to increased cerebral perfusion.

Advancements in understanding the mechanisms of symptomatic lacunar ischemic stroke: translation of knowledge to prevention strategies

Symptomatic lacunar ischemic stroke (25% of all brain infarctions) results from occlusion of a single penetrating artery by microatheromas or lipohyalinosis and rarely from an intracranial atheromatous branch disease. Recurrent lacunar stroke may be associated with more severe clinical features and has been involved in producing lacunar state and vascular subcortical dementia. In the first multicenter randomized clinical trial (SPS3) focused on stroke prevention among patients with recent lacunar stroke, the addition of clopidogrel to aspirin not only did not reduced significantly the risk of recurrent stroke, but also increased significantly the likelihood of hemorrhage and fatal outcome. If lacunar stroke is primarily non-atherothromboembolic, secondary prevention aimed at preventing atheroma progression may not be very effective. The efficacy of drugs that improve endothelial function in lacunar stroke patients remains to be studied in the future.

Asymptomatic carotid stenosis: immediate revascularization or watchful waiting?

Based on several randomized clinical trials, carotid revascularization has been shown to reduce future stroke risk among individuals with severe asymptomatic carotid stenosis. However, a well-recognized problem with such prophylactic intervention is the risk of periprocedural stroke, death, or myocardial infarction. If actual stroke risk with asymptomatic carotid stenosis can be reduced significantly by aggressive medical management, carotid revascularization may yield marginal benefit or even cause harm especially in those with limited life expectancy. Based on recent observational data, it is becoming apparent that the stroke risk in this population has been declining with better medical management alone. This has prompted a few to avoid carotid revascularization for asymptomatic carotid stenosis altogether. Others feel such conclusions cannot be made with observational data alone. In the midst of this controversy, it is important that clinicians perform carotid revascularization on a case by case basis while ensuring optimal medical management in all patients. An algorithmic approach to decision making based on available evidence will enable clinicians to personalize patient management with efficiency.

Risk modeling to identify patients with symptomatic carotid stenosis most at risk of stroke

We have reliable data on the degree of stenosis above which endarterectomy for symptomatic carotid stenosis is beneficial, but benefit is also influenced by other factors, particularly age, sex, the timing of surgery, plaque surface morphology and the nature of the presenting symptomatic event(s). This review will consider the selection of patients for carotid surgery based on the factors that influence the likely risk of stroke on medical treatment. In order to take into account all of the relevant factors, a risk prediction model is considered.

[Secondary prophylaxis of stroke from a neurological perspective]

Patients who have suffered ischemic stroke or transient ischemic attack (TIA) are at high risk of recurrent stroke, myocardial infarction or vascular death. Early pathophysiological based diagnostics and resulting secondary prevention are critical for reduction of stroke risk. Optimization of lifestyle factors, treatment of hypertension, cholesterol reduction with statins and use of antiplatelet agents in non-cardiogenic or anticoagulation in cardiogenic ischemia as well as internal carotid revascularization, in cases of more than 50% diameter stenosis of the internal carotid artery, are proven strategies for reduction of ischemic stroke risk.

Do Lacunar Strokes Benefit from Thrombolysis? Evidence from the Registry of the Canadian Stroke Network

Background

Lacunar infarcts constitute up to 25% of all ischaemic strokes. As acute intracranial vascular imaging has become widely available with computed tomographic angiography, thrombolysis of lacunar strokes has become contentious because an intracranial vascular lesion cannot be visualized. We studied the effect of thrombolysis on lacunar strokes compared to other clinical ischaemic stroke sub-types.

Methods

Ischaemic stroke patients from phase 3 of the Registry of the Canadian Stroke Network data (July 2003–March 2008) were included. Lacunar stroke was defined as a lacunar syndrome supported by computed tomography brain showing a subcortical hypodense lesion with a diameter <20 mm. Clinical syndromes were used to define other stroke sub-types. The outcomes were mortality at 90 days, modified Rankin Scale score 0–2 at discharge, occurrence of intracranial haemorrhage as a complication of stroke in-hospital, and discharge disposition to home.

Results

A total of 11 503 patients of ischaemic stroke were included from the Registry of the Canadian Stroke Network 3 between July 2003 and March 2008. Lacunar strokes formed 19·1% of the total strokes. The total number of patients who received tissue plasminogen activator was 1630 (14·2%). A significant association was found between tissue plasminogen activator treatment and outcomes after controlling Oxfordshire Community Stroke Project types – for modified Rankin Scale at discharge and discharge to home, but not for mortality. A thrombolysis-by-Oxfordshire Community Stroke Project stroke sub-type interaction was observed due to lack of benefit among the posterior circulation stroke sub-types. Patients with lacunar strokes, partial anterior circulation stroke, and total anterior circulation strokes all benefited approximately equally from thrombolysis.

Conclusions

Thrombolysis is associated with clinically improved outcome among patients with lacunar stroke syndromes.

Carotid artery stenosis as a cause of stroke

BACKGROUND

Population-based studies have estimated that about 15% of ischemic strokes are caused by large-vessel cerebrovascular disease. We determined the types of large-vessel atherosclerosis responsible for ischemic strokes in a population-based stroke study.

METHODS

Patients with first-ever or recurrent ischemic stroke in the Greater Cincinnati area were identified during 2005 at all local hospitals. Study physicians assigned ischemic stroke subtypes. Overall event rates and incidence rates for first-ever events were calculated, and age-, race- and sex-adjusted to the 2000 US population.

RESULTS

There were 2,204 ischemic strokes, including 365 strokes of large-vessel subtype (16.6% of all ischemic strokes). Extracranial internal carotid artery (ICA) stenosis was associated with 8.0% of all ischemic strokes, while extracranial ICA occlusion and intracranial atherosclerosis were each associated with 3.5% of strokes. The annual rate of first-ever and recurrent stroke attributed to extracranial ICA was 13.4 (11.4-15.4) per 100,000 persons. We conservatively estimate that about 41,000 strokes may be attributed to extracranial ICA stenosis annually in the United States.

CONCLUSIONS

Large-vessel atherosclerosis is an important cause of stroke, with extracranial ICA stenosis being significantly more common than extracranial ICA occlusion or intracranial atherosclerotic disease.

Risk factors and outcome of patients with symptomatic intracranial stenosis presenting with lacunar stroke

BACKGROUND AND PURPOSE

We hypothesized that patients with intracranial stenosis with lacunar stroke presentations would face lower risks of recurrent stroke than those with index nonlacunar strokes, and that their recurrent strokes would predominantly be lacunar.

METHODS

We analyzed subjects enrolled with an index stroke into the Warfarin Aspirin Symptomatic Intracranial Disease (WASID) trial. The index stroke was classified as lacunar or nonlacunar. The primary end point was recurrent ischemic stroke. Cox proportional hazard models were generated with stratification for severity of stenosis.

RESULTS

Three hundred forty-seven subjects were enrolled after an index stroke; 38 were lacunar and 309 were nonlacunar. Over a mean follow-up of 1.8 years, there was no significant difference in stroke recurrence between patients whose index stroke was lacunar (7 of 38 [18%]) versus nonlacunar (69 of 309 [22%]; hazard ratio, 0.79; 95% CI, 0.36-1.71). Furthermore, no significant differences were found when groups were stratified by 50% to 69% stenosis (hazard ratio, 0.50; 95% CI, 0.12-2.1) and ≥ 70% stenosis (hazard ratio, 0.87; 95% CI, 0.34-2.2). Of the 7 recurrent strokes in patients whose index stroke was lacunar, all 7 were nonlacunar and 3 were in the territory of the stenotic artery.

CONCLUSIONS

In patients with symptomatic intracranial stenosis, the risk of recurrent stroke was similar in patients who presented with lacunar and nonlacunar strokes, and recurrent strokes in patients presenting with lacunar stroke were typically nonlacunar. These findings suggest that the pathophysiology of these strokes is related to the stenosis rather than small vessel disease. Patients presenting with lacunar strokes should be included in trials investigating secondary prevention for symptomatic intracranial stenosis.

Small vessel cerebrovascular disease: the past, present, and future

Brain infarction due to small vessel cerebrovascular disease (SVCD)-also known as small vessel infarct (SVI) or "lacunar" stroke-accounts for 20% to 25% of all ischemic strokes. Historically, SVIs have been associated with a favorable short-term prognosis. However, studies over the years have demonstrated that SVCD/SVI is perhaps a more complex and less benign phenomenon than generally presumed. The currently employed diagnostic and therapeutic strategies are based upon historical and contemporary perceptions of SVCD/SVI. What is discovered in the future will unmask the true countenance of SVCD/SVI and help furnish more accurate prognostication schemes and effective treatments for this condition. This paper is an overview of SVCD/SVI with respect to the discoveries of the past, what is known now, and what will the ongoing investigations evince in the future.

Is investigating for carotid artery disease warranted in non-cortical lacunar infarction?

Carotid intervention in severe carotid stenosis after an anterior circulation ischemic event reduces the risk of further infarcts if the surgery is performed soon after the incident event. At present, there is no recommendation to differentiate among subtypes of anterior circulation infarcts or transient ischemic events. However, evidence is mounting that demonstrates a difference in pathophysiology of lacunar and nonlacunar (large artery) infarcts. The natural history of lacunar strokes is different from large artery infarcts for recurrence and mortality. Stroke is a heterogenous disease and consideration needs to be directed to manage different stroke subtypes differently. Lacunar infarcts mostly do not arise from large artery atheromatous disease or by cardioembolic phenomena, and there is a negative predictive value for severe carotid stenosis in lacunar strokes. Thus, current evidence suggests that lacunar strokes may not warrant investigation for carotid stenosis.

Lacunar stroke

Lacunar infarcts or small subcortical infarcts result from occlusion of a single penetrating artery and account for one quarter of cerebral infarctions. Patients with a lacunar infarct usually present with a classical lacunar syndrome (pure motor hemiparesis, pure sensory syndrome, sensorimotor stroke, ataxic hemiparesis or dysarthria-clumsy hand) and, less frequently, an atypical lacunar syndrome. Hypertension and diabetes mellitus are major risk factors for lacunar stroke. Lacunar infarcts show a paradoxical clinical course with a favorable prognosis in the short term, characterized by a low early mortality and reduced functional disability on hospital discharge, but with an increased risk of death, stroke recurrence and dementia in the mid- and long term. Asymptomatic progression of small-vessel disease is a typical feature of the lacunar infarcts. For this reason, lacunar infarction should be regarded as a potentially severe condition rather than a relatively benign disorder and, therefore, lacunar stroke patients require adequate and rigorous management and follow-up. Antiplatelet drugs, careful blood pressure control, the use of statins and modification of lifestyle risk factors are key elements in secondary prevention after lacunar stroke.

Atherosclerotic carotid vulnerable plaque and subsequent stroke: a high-resolution MRI study

BACKGROUND

High-resolution contrast-enhanced magnetic resonance imaging (CEMRI) has been proven to be an effective tool for the identification of carotid atherosclerotic vulnerable plaque, such as a large lipid core and thin fibrous cap. The aim of this study was to evaluate the relationship between carotid plaque characteristics and the types of stroke in patients who had carotid artery (CA) stenosis > or =50%.

METHODS

102 consecutive subjects (mean age 67.2 +/- 10.2 years; 73 males) who initially had ischemic stroke or asymptomatic CA stenosis from 50 to 100% diagnosed by ultrasound were included in this study. Carotid CEMRI, brain MRI and magnetic resonance angiography were performed to understand the infarct patterns and to exclude intracranial artery stenosis. The modified American Heart Association (AHA) plaque classification was used in our study.

RESULTS

Our study demonstrated that 45 patients had CA stroke, and 55 patients had lacunar and asymptomatic lesions. The majority of patients had AHA classification type IV-V and VI which presented as vulnerable plaques. Of 63 patients with mild to moderate stenosis (< or =70%), 44 (69.8%) had type IV-V vulnerable plaques, which was significantly higher than those of patients with severe stenosis (>70%; p < 0.001). In CA stroke, the number of patients with a thin or ruptured fibrous cap was twice that of those with a thick and intact fibrous cap.

CONCLUSIONS

CEMRI may have important applications in clinical risk evaluations in CA atherosclerosis. Physicians ought to recognize that different types of stroke should be identified by brain MRI detection before invasive therapies.

Prevalence of CT-detected cerebral abnormalities in an elderly Swedish population sample

OBJECTIVE

To measure the prevalence of computed tomography (CT)-detected cerebral lesions in a population-based sample of elderly persons living in Göteborg, Sweden.

METHODS

Cerebral CT-scans were performed in the case of 466 women (mean age 74.3 +/- 5.1 years) and 191 70-year-old men. A single rater assessed white matter lesions (WML) using four different scales, lacunar lesions, large infarcts, cortical atrophy, and basal ganglia calcifications.

RESULTS

White matter lesions frequency assessed by different scales ranged between 54.5% and 68.5%. Lacunar lesions were detected in 46.7% (30.1% had lacunes >5 mm) and cerebral infarcts in 3.0% of participants. Overall, 72.8% of participants evidenced cerebral vascular abnormalities. Severe cortical atrophy was more common in temporal (6.4%) and frontal (6.7%) lobes, than in parietal (1.7%) and occipital (1.1%) lobes. Basal ganglia calcifications were found in 38.7% of participants. WML, lacunar lesions, large infarcts, and degree of cortical atrophy correlated positively with age. More lacunes, basal ganglia calcifications, and occipital lobe atrophy were associated with male gender.

CONCLUSIONS

Vascular and other brain lesions are very common on CT-scan in an elderly population, but large vascular lesions are rare. This study provides the first reference for the prevalence of CT-detected abnormalities in an elderly Swedish population.

An experimental model of lacunar infarction: embolization of microthrombi

OBJECTIVES

Microthrombi are undoubtedly the most common embolic material in the cerebral circulation, originating from even minor irregularities of the arterial wall, fibrillating atria, cardiac valves, and patent foramen ovale. Thrombus fragments are globular and likely to completely obstruct terminal vessels. In contrast, previous work with "atheroemboli" of needle-like cholesterol crystals rarely cause occlusions or infarctions instead creating small foci of inflammation. In this work, we asked if microthrombi would occlude terminal vessels and create lacunar type infarctions in the subcortical tissues of the rat brain where, as in human brain, collateral flow is limited relative to the cortex.

METHODS

Three treatment groups of adult male Sprague-Dawley rats were studied. All groups underwent general anesthesia with monitoring of temperature and blood pressure during cannulation of the right internal carotid artery. In the group embolized with thrombus fragments (n = 12), animals had injections of 300 fragments of thrombus size 60 to 100 microns, the cholesterol group (n = 6) had injections of 300 cholesterol crystals of similar size, and the control group (n = 4) had injections of saline. Brains were harvested at 4 days with perfusion fixation and were examined by immunohistochemical staining for breaks in the blood brain barrier (BBB) (albumin), microglial activation (CD11b), astrocyte activation (GFAP), and infarction (loss of NeuN staining). Size and location of the areas of injury and infarction were recorded.

RESULTS

Clot fragments caused discreet infarcts in 10/12 animals that were 0.1-1.7 mm in diameter and coincided with activation of microglia and astrocytes. In some areas, necrosis was already underway at this early time point. Consistent with our previous work, the infarcts caused by cholesterol crystals were smaller (P = .014). Foci of BBB disruption and microglial activation were distributed throughout the brain whereas areas of infarction were found almost exclusively in subcortical tissues (P = .029).

CONCLUSIONS

Injecting microthrombi reproducibly caused areas of necrosis resembling lacunar type infarctions. These were primarily located in the striatum and thalamus presumably because these areas lack the branching, collateral network seen in the cortex. In addition, these data give further evidence that the extent of brain injury from emboli depends upon composition and shape as well as size.

A Computerized Algorithm for Etiologic Classification of Ischemic Stroke

Background and Purpose— The SSS-TOAST is an evidence-based classification algorithm for acute ischemic stroke designed to determine the most likely etiology in the presence of multiple competing mechanisms. In this article, we present an automated version of the SSS-TOAST, the Causative Classification System (CCS), to facilitate its utility in multicenter settings.

Methods— The CCS is a web-based system that consists of questionnaire-style classification scheme for ischemic stroke (http://ccs.martinos.org). Data entry is provided via checkboxes indicating results of clinical and diagnostic evaluations. The automated algorithm reports the stroke subtype and a description of the classification rationale. We evaluated the reliability of the system via assessment of 50 consecutive patients with ischemic stroke by 5 neurologists from 4 academic stroke centers.

Results— The kappa value for inter-examiner agreement was 0.86 (95% CI, 0.81 to 0.91) for the 5-item CCS (large artery atherosclerosis, cardio-aortic embolism, small artery occlusion, other causes, and undetermined causes), 0.85 (95% CI, 0.80 to 0.89) with the undetermined group broken into cryptogenic embolism, other cryptogenic, incomplete evaluation, and unclassified groups (8-item CCS), and 0.80 (95% CI, 0.76 to 0.83) for a 16-item breakdown in which diagnoses were stratified by the level of confidence. The intra-examiner reliability was 0.90 (0.75–1.00) for 5-item, 0.87 (0.73–1.00) for 8-item, and 0.86 (0.75–0.97) for 16-item CCS subtypes.

Conclusions— The web-based CCS allows rapid analysis of patient data with excellent intra- and inter-examiner reliability, suggesting a potential utility in improving the fidelity of stroke classification in multicenter trials or research databases in which accurate subtyping is critical.

Cognitive dysfunction in 16 patients with carotid stenosis: detailed neuropsychological findings

Background

Impairment of cognitive function is often present in patients with carotid artery stenosis but the details of this dysfunction have rarely been reported. Our purpose was to elucidate the cognitive dysfunction in patients with unilateral severe carotid stenosis using comprehensive neuropsychological testing, and also to identify the specific underlying clinical and radiological factors.

Methods

We analyzed the results of neuropsychological testing, the clinical history, and MR findings in 16 consecutive patients with angiographically proven severe (70-99%) stenosis of the extra cranial internal carotid artery (ICA). Cognitive functions were examined using the Seoul Neuropsychological Screening Battery and the Neglect Battery. We excluded patients with cortical infarction and those with contra lateral ICA occlusion or severe stenosis.

Results

Our comprehensive neuropsychological testing revealed obvious cognitive deficits in all patients with unilateral severe ICA stenosis, the most common being frontal executive impairment. The mean cognitive score on the memory test was also significantly lower in patients with symptomatic ICA stenosis than in asymptomatic patients (29.33±10.98, mean±SD, p < 0.05). The total score on the global cognitive test was significantly lower in patients with an ischemic lesion on MRI than in no lesion patients (113.23±34.78, p < 0.05). The presence of symptoms related to the ICA stenosis was related to cognitive dysfunction even when there were no ischemic lesions on MRI. SPECT revealed ipsilateral cortical hypoperfusion in 9 of 12 patients (75%).

Conclusions

Cognitive deficits are common in patients with unilateral severe ICA stenosis. Our findings suggest that an additional mechanism beyond the structural lesion such as chronic hypoperfusion may affect cognitive function in patients with high-grade ICA stenosis.

Carotid intima-media thickness is different in large- and small-vessel ischemic stroke: the SMART study

BACKGROUND AND PURPOSE

The role of athersclerosis in the difference between the pathogenesis of large-vessel disease (LVD) and small-vessel disease (SVD) is a matter of debate. Common carotid artery intima-media thickness (CCA IMT) is a marker of atherosclerosis. Our aim was to compare CCA IMT between SVD and LVD patients.

METHODS

Two independent observers classified ischemic stroke or transient ischemic attack as caused by SVD or LVD, primarily based on imaging and in addition on clinical features. Mean CCA IMT was calculated based on 6 measurements for each patient.

RESULTS

Four hundred and seventeen patients were classified LVD and 115 SVD. Mean CCA IMT was higher in patients with LVD (1.08 mm) than in patients with SVD (0.92 mm). The crude mean difference was 0.16 mm (95% CI, 0.09 to 0.23). After adjustment for age, sex and hypertension, the mean difference was 0.11 mm (95% CI, 0.05 to 0.18).

CONCLUSIONS

CCA IMT is higher in LVD patients than in SVD patients supporting the hypothesis that LVD and SVD have a different pathogenesis.

A New Subtype Classification of Ischemic Stroke Based on Treatment and Etiologic Mechanism

A new subtype classification of ischemic stroke was developed to reflect recent therapeutic strategies as well as evolving concepts of stroke definitions and mechanisms. In 200 consecutive patients with acute ischemic stroke, the inter-rater reliability and proportion of subtypes of the new classification system were assessed and compared with those of the Trial of ORG 10172 in the Acute Stroke Treatment (TOAST) classification. The most frequent subtype of the new classification was atherothrombosis (n = 80, 40%), followed by stroke of undetermined etiology (n = 54, 27%), small artery disease (n = 33, 16.5%), cardioembolism (n = 26, 13%), and stroke of other determined etiology (n = 7, 3.5%). Three raters agreed to the stroke subtype diagnosis in 165 out of 200 cases and the overall kappa value was excellent (kappa = 0.82). The new classification system for brain infarction was easy to use and had high inter-rater reliability.

Intracranial carotid artery calcification on head CT and its association with ischemic changes on brain MRI in patients presenting with stroke-like symptoms: retrospective analysis

INTRODUCTION

Our purpose was to study the association between the intracranial arterial calcifications observed on head CT and brain infarcts demonstrated by MRI in patients presenting with acute stroke symptoms.

METHODS

Institutional review board approval was obtained for this retrospective study which included 65 consecutive patients presenting acutely who had both head CT and MRI. Arterial calcifications of the vertebrobasilar system and the intracranial cavernous carotid arteries (intracranial carotid artery calcification, ICAC) were assigned a number (1 to 4) in the bone window images from CT scans. These four groups were then combined into high calcium (grades 3 and 4) and low calcium (grades 1 and 2) subgroups. Brain MRI was independently evaluated to identify acute and chronic large-vessel infarcts (LVI) and small-vessel infarcts (SVI). The relationship between ICAC and infarcts was evaluated before and after adjusting for demographics and cardiovascular risk factors.

RESULTS

Statistical analysis could not be performed for the vertebrobasilar system due to an insufficient number of patients in the high calcium group. Of the 65 patients, 46 (71%) had a high ICAC grade on head CT. They were older and had a higher prevalence of cardiovascular risk factors. Acute SVI (P = 0.006), chronic SVI (P = 0.006) and acute LVI (P = 0.04) were associated with a high ICAC grade. After adjustment for age and other risk factors, only acute SVI was associated with a high ICAC grade (P = 0.002).

CONCLUSION

Although age emerged as the most important determinant of ischemic cerebral changes, there were rather complex interactions among multiple risk factors with different infarct types. A high ICAC grade demonstrated a correlation with acute SVI in our patients independent of these risk factors.

Symptomatic and asymptomatic carotid stenosis: just when we thought we had all the answers

The management of symptomatic and asymptomatic carotid stenosis has been a hotly debated topic for decades. The publication of four randomized controlled trials of carotid endarterectomy has clarified many of the issues. Patients with symptomatic carotid stenosis >70% benefit most with an absolute risk reduction of 17% over 2 years with numbers needed to treat of 3-6, whereas in patients with asymptomatic carotid stenosis >60%, the absolute risk reduction is 1% per annum (numbers needed to treat = 14-17). There is doubt about the benefit in women >70 years of age with asymptomatic stenosis. Carotid angioplasty and stenting is in its infancy and may one day supplant carotid endarterectomy as the treatment of choice; however, currently indications for this procedure include participation in randomized controlled trials, surgically inaccessible stenosis, in patients with combined symptomatic carotid and symptomatic coronary artery disease or in patients with severe co-morbidities that preclude formal carotid endarterectomy.

Midlife Respiratory Function Related to White Matter Lesions and Lacunar Infarcts in Late Life

BACKGROUND AND PURPOSE

Increased evidence suggests that poor respiratory function increases risk of ischemic damage to the brain. Longitudinal studies on respiratory function and cerebral small-vessel disease are lacking. We examined midlife and late-life respiratory function in relation to small-vessel disease on computed tomography (CT) in women followed for 26 years.

METHODS

White matter lesions (WMLs) and lacunar infarcts were rated on brain CT scans in 2000 in 379 women 70 to 92 years of age from a longitudinal population study in Göteborg, Sweden. Respiratory function was measured by peak expiratory flow (PEF) in 1974 and 2000 and by forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) in 1980 and 2000.

RESULTS

Lower FVC and FEV1 in 1980 and 2000 were associated with presence and severity of WMLs and lacunar infarcts in 2000. Per 1-SD decrease of FVC in 1980, odds ratios (95% CIs) were 1.49 (1.11 to 2.02) for presence of WMLs and 1.95 (1.34 to 2.84) for lacunar infarcts after adjustment for potential confounders. Per 1-SD decrease of FEV1 in 1980, adjusted odds ratios were 1.46 (1.06 to 2.00) for presence of WMLs and 1.42 (1.02 to 1.97) for lacunar infarcts. PEF in 1974 and 2000 was not associated with WMLs or lacunar infarcts.

CONCLUSIONS

WMLs and lacunar infarcts in elderly women were related to lower midlife respiratory function. Although our data may not establish causation between lower respiratory function and small-vessel disease, they imply the importance of good respiratory function in midlife.

Lipids and stroke: the opportunity of lipid-lowering treatment

Dyslipemia is a clear risk factor (RF) for ischemic heart disease and peripheral artery disease, but its relation with ischemic stroke (IS) is not so clear. HMG-CoA reductase inhibitor drugs or statins (simvastatin, atorvastatin, pravastatin) reduce the relative risk of IS by between 18 and 51% in patients with IHD, in patients with high vascular disease risk and in hypertensive patients with other RFs, acute coronary syndrome, and type 2 diabetes mellitus. According to the guidelines for use, statins are indicated in the majority of patients with IS since the risk is equivalent to that of IHD or high vascular disease risk. In view of the existing clinical evidence of benefit, it would not seem unreasonable to proceed with treatment of patients using statins while awaiting specific studies justifying their use. The non-lipid-lowering mechanisms of the statins and results of studies, such as the Heart Protection Study, provide evidence for widening the indications of statins beyond the prevention of dyslipemia, as a new therapeutic approach in the prevention of IS in patients with plasma levels of total cholesterol or low density lipoproteins currently considered within the normal distribution. The neuroprotective role, which these drugs may play in the acute phase of cerebral ischemia, remains to be clarified, but very recent evidence suggests that such patients may also benefit.