Computed tomographic patterns of proven embolic brain infarctions

The hypereosinophilic syndrome - an unusual cause of myocarditis and cardioembolic strokes

Hypereosinophilic syndrome is a rare disorder characterized by excessive peripheral eosinophilia and eosinophil associated end-organ damage. Clinical presentations are heterogenous and can involve skin, pulmonary, cardiac and neurologic dysfunction. Eosinophilic myocarditis is a life-threatening complication that increases the risk of cardiac microemboli, which can subsequently lead to embolic strokes. Secondary to changes in blood viscosity, impaired clearance of microemboli, impaired cerebral blood flow, and pro-thrombotic conditions in the setting of hypereosinophilia, infarcts often present in vascular border zone regions. Here we present two cases of cardioembolic strokes involving borderzone regions in the setting of hypereosinophilic syndrome.

Early recurrence in patients with symptomatic, non-cardioembolic, internal carotid artery occlusion

INTRODUCTION

There are limited data on the clinical course of patients with non-cardioembolic, mostly atherosclerotic, internal carotid artery occlusion (ICAO). The purpose of this study was to elucidate the frequency and underlying pathogenesis of early recurrent ischemic stroke in symptomatic non-cardioembolic ICAO.

MATERIALS AND METHODS

Consecutive patients with symptomatic non-cardioembolic ICAO were retrospectively reviewed. Those who had a tandem occlusion of the proximal middle cerebral artery (MCA) or underwent endovascular thrombectomy were excluded. Early recurrent stroke was defined as deterioration of the NIHSS score by ≥1 point with new lesions on magnetic resonance (MR) diffusion-weighted imaging (DWI) in the ipsilateral territory of the ICAO within 30 days of the index stroke onset. Patients were classified into two groups on carotid ultrasonography: cervical occlusion and intracranial occlusion. The presumed pathogenesis of recurrent stroke was categorized as embolic or hemodynamic according to the topographical features of subsequent lesions on DWI.

RESULTS

Of 36 consecutive medically treated patients with symptomatic non-cardioembolic ICAO without tandem MCA occlusion, 23 patients had cervical occlusion, and 13 had intracranial occlusion. Early recurrent stroke occurred in 16 patients (44.4%), which happened much more with intracranial occlusion than with cervical occlusion (69.2% vs 30.4%, p<0.02). Focusing on the presumed pathogenesis, hemodynamic was more common than embolic (68.8% vs 31.2%), especially with intracranial occlusion (77.8%).

CONCLUSIONS

Early recurrent stroke occurs at a high frequency in symptomatic non-cardioembolic ICAO, and intracranial occlusion may be a risk factor for early recurrent stroke. The pathogenesis of recurrence is more often hemodynamic than embolic.

Hospital Revisits for Post-Ischemic Stroke Epilepsy after Acute Stroke Interventions

OBJECTIVES

Improvements in acute stroke care have led to an increase in ischemic stroke survivors, who are at risk for development of post-ischemic stroke epilepsy (PISE). The impact of therapies such as thrombectomy and thrombolysis on risk of hospital revisits for PISE is unclear. We utilized administrative data to investigate the association between stroke treatment and PISE-related visits.

MATERIALS AND METHODS

Using claims data from California, New York, and Florida, we performed a retrospective analysis of adult survivors of acute ischemic strokes. Patients with history of epilepsy, trauma, infections, or tumors were excluded. Included patients were followed for a primary outcome of revisits for seizures or epilepsy. Cox proportional hazards regression was used to identify covariates associated with PISE.

RESULTS

In 595,545 included patients (median age 74 [IQR 21], 52% female), the 6-year cumulative rate of PISE-related revisit was 2.20% (95% CI 2.16-2.24). In multivariable models adjusting for demographics, comorbidities, and indicators of stroke severity, IV-tPA (HR 1.42, 95% CI 1.31-1.54, p<0.001) but not MT (HR 1.62, 95% CI 0.90-1.50, p=0.2) was associated with PISE-related revisit. Patients who underwent decompressive craniectomy experienced a 2-fold increase in odds for returning with PISE (HR 2.35, 95% CI 1.69-3.26, p<0.001). In-hospital seizures (HR 4.06, 95% CI 3.76-4.39, p<0.001) also elevated risk for PISE.

SIGNIFICANCE

We demonstrate that ischemic stroke survivors who received IV-tPA, underwent decompressive craniectomy, or experienced acute seizures were at increased risk PISE-related revisit. Close attention should be paid to these patients with increased potential for long-term development of and re-hospitalization for PISE.

Assessment of patients with a suspected cardioembolic ischemic stroke. A national consensus statement

OBJECTIVES

Several cardiovascular, structural, and functional abnormalities have been considered as potential causes of cardioembolic ischemic strokes. Beyond atrial fibrillation, other sources of embolism clearly exist and may warrant urgent action, but they are only a minor part of the many stroke mechanisms and strokes that seem to be of embolic origin remain without a determined source. The associations between stroke and findings like atrial fibrillation, valve calcification, or heart failure are confounded by co-existing risk factors for atherosclerosis and vascular disease. In addition, a patent foramen ovale which is a common abnormality in the general population is mostly an innocent bystander in patients with ischemic stroke. For these reasons, experts from the national Danish societies of cardiology, neurology, stroke, and neuroradiology sought to develop a consensus document to provide national recommendations on how to manage patients with a suspected cardioembolic stroke. Design: Comprehensive literature search and analyses were done by a panel of experts and presented at a consensus meeting. Evidence supporting each subject was vetted by open discussion and statements were adjusted thereafter. Results: The most common sources of embolic stroke were identified, and the statement provides advise on how neurologist can identify cases that need referral, and what is expected by the cardiologist. Conclusions: A primary neurological and neuroradiological assessment is mandatory and neurovascular specialists should manage the initiation of secondary prophylactic treatment. If a cardioembolic stroke is suspected, a dedicated cardiologist experienced in the management of cardioembolism should provide a tailored clinical and echocardiographic assessment.

[Pathogenetic and therapeutic aspects of cardioembolic stroke]

Cardioembolic stroke (CS) is the one of the most severe and requiring dynamic monitoring among the all subtypes of ischemic stroke. Patients with CS require joint treatment with cardiologists. CS is characterized by a greater severity of neurological deficits, a high risk of repeated acute cerebral circulatory disorders and fatal outcomes. This review considers the main causes of CS, the etiopathogenesis of thrombus formation in the heart chambers, current verification criteria and therapeutic aspects of CS, recommendations for the prescription of anticoagulant therapy for primary and secondary preventive treatment.

The role of echocardiography in the embolic stroke of undetermined source

: Echocardiography plays an important role both in the diagnosis and the treatment/prevention of embolic stroke of undetermined source and should be performed as soon as possible for preventing ischemic stroke recurrencies, which occur more frequently during the first week after the first ischemic event. Early identification of the cause of a transient ischemic attack or stroke is indeed a primary goal for the neurologist in the Stroke Unit and requires specific diagnostic strategies. Echocardiography, together with other diagnostic tools such as carotid and transcranial ultrasounds, provides this information promptly. In particular, echocardiography might be able to detect the main sources of the embolic stroke, such as atrial fibrillation, ventricular akinesia, aortic atheroma plaques and/or cardiac shunts. The present review discusses the importance and the practical role of echocardiography as a crucial diagnostic tool for detecting the main source of emboli in the setting of the acute stroke.

Factors Associated With Remote Diffusion-Weighted Imaging Lesions in Spontaneous Intracerebral Hemorrhage

Background and purpose

Remote diffusion-weighted imaging lesions (R-DWILs) have been detected in patients with spontaneous intracerebral hemorrhage (ICH) and may be correlated with clinical outcome. However, the mechanisms and characteristics of R-DWILs have not been fully elucidated. In this study, we sought to demonstrate the clinical characteristics of R-DWILs in spontaneous ICH.

Methods

We prospectively collected data with spontaneous ICH patients from November 2016 to December 2017. In these patients, cerebral magnetic resonance imaging was performed within 28 days after ICH onset. R-DWIL was defined as a hyperintensity signal in diffusion-weighted imaging with corresponding hypointensity in apparent diffusion coefficient, and at least 20 mm apart from the hematoma. We compared two groups of patients with or without R-DWIL with the demographic and clinical characteristics, laboratory parameters, and imaging characteristics, by using univariate and multivariate analysis.

Results

Of the 222 patients enrolled, a total of 75 R-DWILs were observed in 41 patients (18.5%). Among these lesions, the cortical and subcortical areas were the predominant locations with a proportion of 77.3%. The median diameter of R-DWILs was 7 mm (range 2–20 mm). Twelve patients were found having more than one lesion, with five among which showed R-DWILs in multiple cerebral arterial territories. In multivariate modeling, higher fasting glucose (OR 1.231; 95% CI 1.035–1.465; p = 0.019) and more severe white matter hyperintensity (WMH) (OR 6.589; 95% CI 2.975–14.592; p < 0.001) were independent factors related to the presence of R-DWILs.

Conclusion

In our study, approximately one-fifth of ICH patients showed coexistence of R-DWIL. Higher fasting glucose and more severe WMH were associated with R-DWIL occurrence in spontaneous ICH.

Cardioembolic Stroke

Cardiac embolism accounts for an increasing proportion of ischemic strokes and might multiply several-fold during the next decades. However, research points to several potential strategies to stem this expected rise in cardioembolic stroke. First, although one-third of strokes are of unclear cause, it is increasingly accepted that many of these cryptogenic strokes arise from a distant embolism rather than in situ cerebrovascular disease, leading to the recent formulation of embolic stroke of undetermined source as a distinct target for investigation. Second, recent clinical trials have indicated that embolic stroke of undetermined source may often stem from subclinical atrial fibrillation, which can be diagnosed with prolonged heart rhythm monitoring. Third, emerging evidence indicates that a thrombogenic atrial substrate can lead to atrial thromboembolism even in the absence of atrial fibrillation. Such an atrial cardiomyopathy may explain many cases of embolic stroke of undetermined source, and oral anticoagulant drugs may prove to reduce stroke risk from atrial cardiomyopathy given its parallels to atrial fibrillation. Non-vitamin K antagonist oral anticoagulant drugs have recently expanded therapeutic options for preventing cardioembolic stroke and are currently being tested for stroke prevention in patients with embolic stroke of undetermined source, including specifically those with atrial cardiomyopathy. Fourth, increasing appreciation of thrombogenic atrial substrate and the common coexistence of cardiac and extracardiac stroke risk factors suggest benefits from global vascular risk factor management in addition to anticoagulation. Finally, improved imaging of ventricular thrombus plus the availability of non-vitamin K antagonist oral anticoagulant drugs may lead to better prevention of stroke from acute myocardial infarction and heart failure.

Premature Atrial Contractions on the Screening Electrocardiogram and Risk of Ischemic Stroke: The Reasons for Geographic and Racial Differences in Stroke Study

BACKGROUND

It is currently unknown if premature atrial contractions (PACs) detected on the routine screening electrocardiogram are associated with an increased risk of ischemic stroke.

METHODS

We examined the association between PACs and ischemic stroke in 22,975 (mean age 64 ± 9.2; 56% women; 40% black) participants from the Reasons for Geographic and Racial Differences in Stroke study. Participants who were free of stroke at baseline were included. PACs were detected from centrally read electrocardiograms at baseline. Cox regression was used to examine the association between PACs and ischemic stroke events through March 31, 2014.

RESULTS

PACs were present in 1,687 (7.3%) participants at baseline. In a Cox regression model adjusted for stroke risk factors and potential confounders, PACs were associated with an increased risk of ischemic stroke (hazards ratio (HR) 1.34, 95% CI 1.04-1.74). The relationship was limited to non-lacunar infarcts (HR 1.42, 95% CI 1.08-1.87), and not lacunar strokes (HR 1.01, 95% CI 0.51-2.03). An interaction by sex was detected, with the association between PACs and ischemic stroke being stronger among women (HR 1.82, 95% CI 1.29-2.56) than men (HR 1.03, 95% CI 0.69-1.52; p-interaction = 0.0095).

CONCLUSION

PACs detected on the routine electrocardiogram are associated with an increased risk for non-lacunar ischemic strokes, especially in women.

The Impact of Risk Burden Differences between Men and Women on the Clinical Course of Ischemic Stroke

BACKGOUND

Our objective is to assess the impact of varying risk profiles in men and women on the clinical picture of ischemic stroke.

MATERIALS AND METHODS

The study involved 185 patients, 100 women and 85 men. We assessed the patients' neurological status upon admission, 1 and 2 weeks following stroke onset, using the Scandinavian Stroke Scale and the Barthel Index; stroke syndromes according to the Oxfordshire Classification; their etiology and pathogenesis according to the Trial of Org 10172 in Acute Stroke Treatment; and the prevalence of vascular risk factors. We used cranial magnetic resonance imaging to locate infarcts.

RESULTS

Women had more total anterior circulation infarct subtype strokes, whereas men had more posterior circulation infarct and lacunar infarct. On neuroimaging, women had more infarcts in the middle cerebral artery circulation, whereas men had more in the brain stem and/or cerebellum. Women had a higher prevalence of atrial fibrillation (AF) and coronary artery disease, whereas men were more likely to smoke and abuse alcohol. Women had more cases of cardioembolism, whereas men had more strokes caused by atherosclerosis of large vessels.

CONCLUSIONS

In the present study, heart diseases, such as coronary artery disease and AF, were more prevalent among women. It seems that AF is a risk factor with significant impact on the epidemiological differences regarding ischemic stroke in men and women.

Electrocardiographic left atrial abnormality and stroke subtype in the atherosclerosis risk in communities study

OBJECTIVE

The aim of this study was to assess the relationship between abnormally increased P-wave terminal force in lead V1 , an electrocardiographic (ECG) marker of left atrial abnormality, and incident ischemic stroke subtypes. We hypothesized that associations would be stronger with nonlacunar stroke, given that we expected left atrial abnormality to reflect the risk of thromboembolism rather than in situ cerebral small-vessel occlusion.

METHODS

Our cohort comprised 14,542 participants 45 to 64 years of age prospectively enrolled in the Atherosclerosis Risk in Communities study and free of clinically apparent atrial fibrillation (AF) at baseline. Left atrial abnormality was defined as PTFV1 >4,000μV*ms. Outcomes were adjudicated ischemic stroke, nonlacunar (including cardioembolic) ischemic stroke, and lacunar stroke.

RESULTS

During a median follow-up period of 22 years (interquartile range, 19-23 years), 904 participants (6.2%) experienced a definite or probable ischemic stroke. A higher incidence of stroke occurred in those with baseline left atrial abnormality (incidence rate per 1,000 person-years, 6.3; 95% confidence interval [CI]: 5.4-7.4) than in those without (incidence rate per 1,000 person-years, 2.9; 95% CI: 2.7-3.1; p < 0.001). In Cox regression models adjusted for potential confounders and incident AF, left atrial abnormality was associated with incident ischemic stroke (hazard ratio [HR]: 1.33; 95% CI: 1.11-1.59). This association was limited to nonlacunar stroke (HR, 1.49; 95% CI: 1.07-2.07) as opposed to lacunar stroke (HR, 0.89; 95% CI: 0.57-1.40).

INTERPRETATION

We found an association between ECG-defined left atrial abnormality and subsequent nonlacunar ischemic stroke. Our findings suggest that an underlying atrial cardiopathy may cause left atrial thromboembolism in the absence of recognized AF.

Association between left atrial abnormality on ECG and vascular brain injury on MRI in the Cardiovascular Health Study

BACKGROUND AND PURPOSE

Emerging evidence suggests that atrial disease is associated with vascular brain injury in the absence of atrial fibrillation.

METHODS

The Cardiovascular Health Study prospectively enrolled community-dwelling adults aged ≥65 years. Among participants who underwent MRI, we examined associations of ECG left atrial abnormality with brain infarcts and leukoaraiosis. P-wave terminal force in lead V1 was the primary measure of left atrial abnormality; P-wave area and duration were secondary predictors. We excluded participants with atrial fibrillation before or on their index ECG. Primary outcomes were incident infarcts and worsening leukoaraiosis from initial to follow-up scan ≈5 years later. Secondary outcomes were prevalent infarcts and degree of leukoaraiosis on initial MRI. Relative risk (RR) and linear regression models were adjusted for vascular risk factors.

RESULTS

Among 3129 participants with ≥1 scan, each SD increase in P-wave terminal force in lead V1 was associated with a 0.05-point (95% confidence interval [CI], 0.0003-0.10) higher baseline white matter grade on a 10-point scale. P-wave terminal force in lead V1 was associated with prevalent infarcts of any type (RR per SD, 1.09; 95% CI, 1.04-1.16) and more so with prevalent nonlacunar infarcts (RR per SD, 1.22; 95% CI, 1.08-1.38). Among 1839 participants with 2 scans, P-wave terminal force in lead V1 was associated with worsening leukoaraiosis (RR per SD, 1.09; 95% CI, 1.01-1.18), but not with incident infarcts (RR per SD, 1.06; 95% CI, 0.93-1.20). Sensitivity analyses adjusting for incident atrial fibrillation found similar results. P-wave area and duration were not associated with outcomes.

CONCLUSIONS

ECG left atrial abnormality is associated with vascular brain injury in the absence of documented atrial fibrillation.

Cryptogenic transient ischemic attack after nose blowing: association of huge atrial septal aneurysm with patent foramen ovale as potential cause

Association of atrial septal aneurysm (ASA) with patent foramen ovale (PFO) is considered an important risk factor for cardioembolism frequently forwarding paradoxical embolism in patients with cryptogenic or unexplained cerebral ischemic events. We herein describe the case of a 69-year-old male patient reporting uncontrolled movements of the right arm due to a muscle weakness, slurred speech, and paresthesia in the oral region some seconds after he had blown his nose. These neurological symptoms had improved dramatically within a few minutes and were completely regressive at admission to our hospital about two hours later. On transesophageal echocardiography (TEE) a huge ASA associated with PFO was detected. Diagnosis of the large-sized ASA was also confirmed by cardiac magnetic resonance imaging. Due to the early complete recovery from his neurological symptoms, the patient was diagnosed with a transient ischemic attack (TIA). After nine days he was discharged in a good clinical condition under the treatment with oral anticoagulation. It is concluded that in cryptogenic or unexplained stroke or TIA TEE should always be performed to rule out ASA and PFO as potential sources for paradoxical embolism in those inconclusive clinical situations.

Antihypertensives for combating dementia? A perspective on candidate molecular mechanisms and population-based prevention

Age-related increases in prevalent dementia over the next 30-40 years risk collapsing medical resources or radically altering the way we treat patients. Better prevention of dementia therefore needs to be one of our highest medical priorities. We propose a perspective on the pathological basis of dementia based on a cerebrovascular-Alzheimer disease spectrum that provides a more powerful explanatory framework when considering the impact of possible public health interventions. With this in mind, a synthesis of evidence from basic, clinical and epidemiological studies indeed suggests that the enhanced treatment of hypertension could be effective for the primary prevention of dementia of either Alzheimer or vascular etiology. In particular, we focus on candidate preventative mechanisms, including reduced cerebrovascular disease, disruption of hypoxia-dependent amyloidogenesis and the potential neuroprotective properties of calcium channel blockers. Following the successful translation of large, long-term and resource-intense trials in cardiology into improved vascular health outcomes in many countries, new multinational prevention trials with dementia-related primary outcomes are now urgently required.

[Magnetic resonance imaging and computed tomography findings in lacunar brain infarctions]

Lacunar brain infarctions belong to the most common causes of stroke and are typically located in basal ganglia with embolic, atheromatous or thrombotic etiology. Lipohyalinosis, often as a result of a long history of hypertension, can also be a cause of lacunar lesions. At present more than 20 different lacunar syndromes have been described. However clinical findings may be variable ranging from clinically"silent" to focal neurologic deficits to cognitive impairment. Magnetic resonance imaging (using diffusion-weighted sequences) generally allows diagnosis in most cases of acute lacunar infarcts and is superior to computed tomography especially in cases of additional leucoaraiosis.

Technology insight: brain MRI and cardiac surgery--detection of postoperative brain ischemia

Annually, an estimated 1 million patients undergo heart surgery worldwide. Unfortunately, stroke continues to be a frequent complication of cardiac surgery, with the specific cerebrovascular risk depending upon the particular surgical procedure performed. Neuroimaging has an integral role in the initial evaluation and management of patients who present with acute stroke symptoms following cardiac surgery. The aim of this paper is to review the role brain MRI has in detecting postoperative brain ischemia in these patients. Multimodal MRI--using diffusion-weighted MRI (DWI), perfusion-weighted MRI, and gradient-recalled echo imaging--has an excellent capacity to identify and delineate the size and location of acute ischemic strokes as well as intracerebral hemorrhages. This differentiation is critical in making appropriate treatment decisions in the acute setting, such as determining patient eligibility for thrombolytic or hemodynamic therapies. At present, DWI offers prognostic value in patients with strokes following cardiac surgery. Additionally, DWI could be a valuable tool for evaluating stroke preventive measures as well as therapeutic interventions in patients undergoing CABG surgery.

Diffusion weighted MRI imaging and MES detection in the assessment of stroke origin

OBJECTIVES

This study compares the additional benefit of diffusion-weighted MRI (DWI) and microembolus detection by transcranial Doppler ultrasonography (TCD) in the assessment of stroke etiology.

METHODS

Fifty-five acute anterior circulation stroke or TIA patients were investigated by both cranial DWI and bilateral TCD of the middle cerebral arteries (1 hour).

RESULTS

In one of the 13 patients without acute ischemic lesions visualized on DWI, microembolic signal (MES) detection was positive. However, in 33 out of 44 patients without MES, DWI revealed at least one lesion. In two patients with unilateral territorial infarction and otherwise normal cardiovascular work-up, bilateral MES were found thus localizing the embolic source into the aortic arch or the heart. In a further patient with a dissection, the occurrence of contralateral MES raised doubts on a dissection to be the cause of the infarct.

DISCUSSION

There is a contribution of both techniques to the understanding of stroke etiology. The impact of DWI is, however, superior to that of MES detection. Longer TCD recording times may diminish this discrepancy.

Patterns of Infarction in Hemodynamic Failure

BACKGROUND AND PURPOSE

The mechanism of stroke in patients with atherosclerotic occlusive disease and hemodynamic failure may be primarily hemodynamic or a combination of hemodynamic and embolic factors. The purpose of this study was to investigate the clinical and imaging features of stroke in these patients.

METHODS

Eleven patients with complete atherosclerotic carotid artery occlusion and increased oxygen extraction fraction measured in the hemisphere distal to the occlusion developed an ischemic stroke during the observation phase of a prospective study of cerebral hemodynamics and stroke risk. The medical and study records related to the endpoint event for these 11 patients were reviewed. Records were reviewed for evidence of associated hypotension and for specific details of the neurological deficit. Infarct location was characterized, based on review of imaging and clinical features, as: (1) middle cerebral artery (MCA) core; (2) possible cortical border zone, or (3) internal border zone.

RESULTS

One patient had a retinal infarction; the remaining 10 had MCA territory strokes. Six of the 10 infarctions occurred in the MCA core territory. Two of these 6 were fatal hemispheric events. One of the 10 infarctions occurred in the cortical border zone region. Two of the remaining 3 infarctions were localized to the internal border zone. One was indeterminate.

CONCLUSIONS

The clinical features and radiological patterns of stroke in many patients with hemodynamic impairment failure and carotid occlusion are most consistent with large artery thromboembolic stroke. These data suggest a synergistic effect between embolic and hemodynamic mechanisms for large artery thromboembolic stroke.

Effect of white matter hyperintensities on cortical cerebral blood volume using perfusion MRI

White matter hyperintensities (WMHs) are commonly seen on brain magnetic resonance imaging (MRI) scans of elderly individuals, but their functional significance remains controversial. We used perfusion-weighted MRI to determine the impact of WMHs on cortical regional cerebral blood volume (rCBV). We studied 24 elderly stroke patients and 27 control subjects with conventional MRI which included T2-weighted FLAIR coronal slices through whole brain and gadolinium-DTPA (0.2 mmol/kg)-based perfusion MRI (pMRI) with echo planar imaging. Volumes of WMHs, including deep WMHs and periventricular hyperintensities (PVHs), were computed by an automated method after excluding regions of infarction. Partial correlations between WMH and corresponding cortical rCBV were determined after correction for age and atrophy. The relative rCBV of gray matter was higher in control subjects and there was no significant hemispheric asymmetry. When both stroke and control groups were included, there were significant correlations among frontal cortical rCBV and frontal WMHs, temporal cortical rCBV with temporal WMHs, and cortical rCBV with both total deep WMHs and PVHs. Although the trends of correlation still existed when the two groups were analyzed separately, they were not significant. The correlations between cortical rCBV and WMHs in the same lobe were significant for subjects with more severe hyperintensities irrespective of the group. In conclusion, T2-weighted WMHs are associated with reduced rCBV in the cerebral cortex, particularly in individuals with extensive hyperintensities.

Isolated middle cerebral artery disease: clinical and neuroradiological features depending on the pathogenesis

BACKGROUND

Isolated atherosclerotic middle cerebral artery (MCA) disease is often difficult to differentiate from cardioembolic disease if intracranial atherosclerosis coexists with cardiac disease.

OBJECTIVES

To evaluate whether clinical and neuroradiological features of isolated MCA disease differ according to the underlying aetiology.

METHODS

Isolated MCA disease was defined as a unilateral angiographically occlusive lesion of the MCA on the symptomatic side without lesions of other intracranial or extracranial vessels. Patients with isolated MCA disease were divided into atherosclerotic and potentially cardioembolic, and the clinical, laboratory, and neuroradiological data analysed.

RESULTS

Among the 850 consecutive patients with acute ischaemic stroke or transient ischaemic attack, 107 (12.6%) met the criteria for isolated MCA disease (76 with atherosclerotic disease and 31 with a potential source of cardiac embolism). Total anterior circulation infarcts were more common and baseline NIHSS score was higher in potentially embolic occlusions than in atherosclerotic disease (each p<0.001). While cortical infarcts and territorial infarcts were more common in the potential embolism group (p = 0.028 and p<0.001, respectively), subcortical border zone infarcts were more common in the atherosclerotic group (p<0.001). Multiple regression analysis showed that border zone infarcts and mild stroke were independently associated with atherosclerotic MCA disease, while territorial and cortical infarcts were associated with potential cardiac embolic disease.

CONCLUSIONS

Clinical and neuroradiological characteristics can differentiate isolated atherosclerotic MCA disease from MCA disease associated with potential sources of cardiac embolism, and may reflect the differences in underlying pathogenesis.

Risk of stroke, transient ischemic attack, and vessel occlusion before endarterectomy in patients with symptomatic severe carotid stenosis

BACKGROUND AND PURPOSE

We aimed to identify and determine the clinical relevance of parameters predictive of stroke recurrence and vessel occlusion before carotid endarterectomy.

METHODS

One hundred forty-three consecutive patients (105 men; mean age, 66.1+/-8 years) with symptomatic severe carotid artery stenosis were prospectively followed up until carotid endarterectomy. Patients had suffered an ischemic vascular event in the ipsilateral anterior circulation 9.6 days (median; range, 0 to 92 days) before presentation and assessment of stenosis. Admission examination included medical history, neurological status, extracranial and transcranial Doppler/duplex sonography, CT/MRI, ECG, and routine laboratory examination. All patients were reevaluated in the same way the day before surgery (without CT/MRI) and at recurrence of an ischemic event (including CT/MRI).

RESULTS

The end point of follow-up after 19.0 days (median; range, 0 to 118) was carotid endarterectomy in 120 patients, ipsilateral recurrent ischemia in 15 patients (7 transient events and 8 disabling strokes, with carotid occlusion in 4), and (asymptomatic) carotid occlusion in 8 patients. An exhausted cerebrovascular reactivity as determined by a Doppler CO2 test in the middle cerebral artery ipsilateral to the stenosis was the only independent predictive parameter for disabling stroke (odds ratio [OR], 9.7; 95% confidence interval [CI], 2.1 to 44.1; P=0.003). Stroke rate in patients with exhausted reactivity was 27% per month compared with 5.2% in those with normal reactivity. Progression of stenosis toward occlusion was observed in 12 patients and correlated with decreased poststenotic peak systolic velocity (OR, 0.75; 95% CI, 0.62 to 0.90; P=0.002), poststenotic arterial narrowing (OR, 22.7; 95% CI, 3.6 to 141.6; P=0.001), and very severe stenosis (OR, 13.6; 95% CI, 2.2 to 83.7; P=0.005). In patients without hemodynamic compromise, occlusion was not associated with increased stroke risk.

CONCLUSIONS

Patients with recently symptomatic high-grade carotid artery stenosis and ipsilateral hemodynamic compromise are at high risk for early disabling stroke. Assessment of the hemodynamic status is recommended after diagnosis of severe carotid stenosis in symptomatic patients to further investigate and evaluate whether these patients may benefit from early endarterectomy.

Stroke during coronary bypass surgery: principal role of cerebral macroemboli

OBJECTIVE

The purpose of this study was to gain insight into the etiology of stroke during coronary bypass surgery.

METHODS

Retrospective review of prospectively gathered data on 6682 consecutive coronary bypass patients. Patients undergoing simultaneous procedures, including carotid endarterectomy, were excluded. We performed a systematic chart review of all patients who suffered a perioperative stroke. Predictors of stroke were determined with stepwise logistic regression analysis.

RESULTS

The prevalence of stroke was 1.5% (n=98). Stroke patients had significantly increased intensive care unit and hospital length of stays, as well as increased mortality when compared to patients without stroke (all P< 0.001). Independent predictors of stroke were (in decreasing order of magnitude): age >70 years, left ventricular ejection fraction <40%, previous stroke or transient ischemic attack, normothermic cardiopulmonary bypass, diabetes, and peripheral vascular disease. Chart review revealed that the probable cause of stroke was macroemboli, likely from ascending aorta atherosclerosis, in 37% of patients and unknown in 38% of patients. Computerized tomography (CT) scans were obtained in 79 patients (81%). Lesions detected by CT were consistent with a macroembolic etiology: nearly all lesions were ischemic in nature and located in the distribution of major cerebral arteries, particularly the middle cerebral artery.

CONCLUSIONS

Stroke is a devastating complication of coronary bypass surgery. Our multivariable risk factors for stroke, chart review, and CT findings all suggest that macroemboli, presumably from the ascending aorta, are the predominant cause of stroke during coronary bypass surgery. Future studies should be directed at minimizing the risk of embolization during cardiac surgery.

Atrial fibrillation with small subcortical infarcts

OBJECTIVES

To evaluate the characteristics of cardioembolic small (maximum lesion diameter<1.5 cm) subcortical infarcts (SSI) in patients with atrial fibrillation (AF).

METHODS

Twenty seven patients with chronic AF and an isolated SSI established by CT/MRI in the anterior circulation (SSI-AF group) were evaluated and their characteristics compared with those of 45 age matched (+/-1 year) patients with SSI, but no arterial or cardiac embolic source (SSI-control group). Using the criterion of the presence or absence of established risk factors (hypertension or diabetes mellitus) for small artery disease (SAD), the SSI-AF group we also subdivided into two groups, SSI-AF-SAD+ (n=22) and SSI-AF-SAD- (n=5) and their characteristics compared.

RESULTS

Although the lack of any significant difference in the distribution of hypertension and diabetes mellitus between the SSI-AF and SSI-control groups emphasises SAD as a common cause of infarct in SSI-AF, the presence of AF-together with the higher frequency of neuropsychological disturbances in the SSI-AF group versus the SSI-control group (15% v 2%; p=0.066)-favours cardioembolism as a potential cause of infarct in several patients. The characteristic factors seen more often in the SSI-AF-SAD- group compared with the SSI-AF-SAD+ group were secondary haemorrhagic transformation, faciobrachial pure motor weakness, subinsular involvement, and better recovery of neurological deficits.

CONCLUSIONS

The study suggests that either SAD or cardioembolism can be the cause of SSI in patients with AF. Atrial fibrillation is not always coincidental in patients with SSI and a clinical lacunar stroke. Certain clinical and radiological findings may be useful in differentiating cardioembolism from SAD in patients with SSI.

The plasminogen activator inhibitor (PAI)-1 promoter 4G/4G genotype is not associated with ischemic stroke in a population of German children. Childhood Stroke Study Group

OBJECTIVES

To investigate the relationship between an insertion/deletion (4G/5G) polymorphism of the plasminogen activator inhibitor (PAI)-1 gene and childhood patients with a past history of ischemic stroke.

METHODS

The PAI-1 4G/4G genotype and the coinheritance with lipoprotein (Lp) (a) levels, the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, and the methylene-tetrahydrofolate reductase (MTHFR) T677T genotype were studied in 198 Caucasian children with stroke and 951 controls (same age, sex and ethnical distribution). In a randomly selected subgroup of patients/controls (n=60) PAI-I activities have been investigated.

RESULTS

The distribution of the 4G/5G genotypes was no different in childhood stroke patients and controls, with a 4G allele frequency of 55.8% in patients compared with 53.8% in control subjects (P=0.49). The 4G/4G genotype compared with the remaining genotypes was present in 43 cases and 167 (17.6% vs. 21.7%; OR/CI: 1.30/0.89-1.98; P=0.3). PAI-1 activity was significantly elevated (P < 0.001) in the patient group.

CONCLUSIONS

Data presented here suggest that the 4G/4G genotype is not a major risk factor in the aetiology of childhood ischemic stroke.

Magnetic resonance assessment of acute and chronic stroke

This article describes the important role of magnetic resonance imaging (MRI) in noninvasively assessing human focal ischemic stroke. Conventional MRI, diffusion-weighted and/or perfusion-weighted imaging have been used to facilitate both the qualitative and quantitative evaluation of heterogeneity of ischemic brain tissue. Further, by combining 2 or more magnetic resonance parameters, tissue-signature models have been developed that may be used as surrogate markers of tissue histopathology to characterize ischemic tissue as salvageable, necrotic, or tissue in transition to necrosis. Magnetic resonance tissue-signature models and results are presented. Dynamic changes in the evolution of ischemic tissue to infarction are also discussed. Recovery from acute stroke was studied with blood oxygenation level-dependent functional MRI to investigate the neural mechanisms for recovery from aphasia after stroke.

Influence of diabetes mellitus on regional cerebral glucose metabolism and regional cerebral blood flow

Previous studies have shown both increased and decreased regional cerebral glucose metabolism-blood flow (rMRGlu-rCBF) values in diabetes. We sought to elucidate the influence of diabetes on rMRGlu-rCBF in 57 patients with pure cerebral microangiopathy. Sixteen of 57 patients had diabetes requiring therapy (11 NIDDM, 5 IDDM). Using a special head-holder for exact repositioning, rMRGlu (PET) and rCBF (SPET) were imaged and measured in slices, followed by MRI. White matter and cortex were defined within regions of interest taken topographically from MRI (overlay). Diabetic and non-diabetic microangiopathy patients were compared to 19 age-matched controls. The diabetic patients showed significantly lower rMRGlu-rCBF values in all regions than controls, whereas non-diabetic patients did not. There were no significant NIDDM-IDDM differences. rMRGlu-rCBF did not depend on venous blood glucose levels at the time of the PET examination. However, analysis of variance with the factors diabetes, atrophy and morphological severity of microangiopathy showed that lowered rMRGlu-rCBF in the diabetic group was due to concomitant atrophy only (P < 0.005), while neither diabetes nor microangiopathy had any influence on rMRGlu-rCBF (all P > 0.2). These results were confirmed by multivariate factor analysis. It can thus be concluded that a supposed decrease in rMRGlu-rCBF in diabetes mellitus is in fact only an artefact produced by the concomitant atrophy. All previous studies failed to correct for atrophy, and a critical reappraisal is required.

Lipoprotein (a) and Genetic Polymorphisms of Clotting Factor V, Prothrombin, and Methylenetetrahydrofolate Reductase Are Risk Factors of Spontaneous Ischemic Stroke in Childhood

Ischemic stroke is a rare event in childhood. In approximately one third of cases no obvious underlying cause or disorder can be detected. We investigated the importance of genetic risk factors of venous thromboembolism in childhood or stroke in adulthood as risk factors for spontaneous ischemic stroke in children. One hundred forty-eight Caucasian infants and children (aged 0.5 to 16 years) with stroke and 296 age-matched controls from the same geographic areas as the patients were analyzed for increased lipoprotein (a) [Lp(a)] levels >30 mg/dL; for the presence of the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, and the TT677 genotype of methylenetetrahydrofolate reductase (MTHFR); and deficiencies of protein C, protein S, and antithrombin. The following frequencies (patients v controls), odds ratios (ORs), and confidence intervals (CIs) of single risk factors were found: Lp(a) >30 mg/dL (26.4% v 4.7%; OR/CI, 7.2/3.8 to 13.8; P < .0001), FV G1691A (20.2% v 4%; OR/CI, 6/2.97 to 12.1; P < .0001), protein C deficiency (6% v 0.67%; OR/CI, 9.5/2 to 44.6; P = .001), PT G20210A (6% v 1.3%; OR/CI, 4.7/1.4 to 15.6; P = .01), and the MTHFR TT677 genotype (23.6% v 10.4%; OR/CI, 2.4/1.53 to 4.5; P < .0001). A combination of the heterozygous FV G1691A mutation with increased Lp(a) (n = 11) or the MTHFR TT677 genotype (n = 5) was found in 10.8% of cases, but only 0.3% of controls (OR/CI, 35.75/4.7 to 272;P < .0001). Increased Lp (a) levels, the FV G1691A mutation, protein C deficiency, the prothrombin G20210A variant, and the MTHFR TT677 are important risk factors for spontaneous ischemic stroke in childhood.

Lipoprotein (a) and Genetic Polymorphisms of Clotting Factor V, Prothrombin, and Methylenetetrahydrofolate Reductase Are Risk Factors of Spontaneous Ischemic Stroke in Childhood

Ischemic stroke is a rare event in childhood. In approximately one third of cases no obvious underlying cause or disorder can be detected. We investigated the importance of genetic risk factors of venous thromboembolism in childhood or stroke in adulthood as risk factors for spontaneous ischemic stroke in children. One hundred forty-eight Caucasian infants and children (aged 0.5 to 16 years) with stroke and 296 age-matched controls from the same geographic areas as the patients were analyzed for increased lipoprotein (a) [Lp(a)] levels &gt;30 mg/dL; for the presence of the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, and the TT677 genotype of methylenetetrahydrofolate reductase (MTHFR); and deficiencies of protein C, protein S, and antithrombin. The following frequencies (patients v controls), odds ratios (ORs), and confidence intervals (CIs) of single risk factors were found: Lp(a) &gt;30 mg/dL (26.4% v 4.7%; OR/CI, 7.2/3.8 to 13.8; P &lt; .0001), FV G1691A (20.2% v 4%; OR/CI, 6/2.97 to 12.1; P &lt; .0001), protein C deficiency (6% v 0.67%; OR/CI, 9.5/2 to 44.6; P = .001), PT G20210A (6% v 1.3%; OR/CI, 4.7/1.4 to 15.6; P = .01), and the MTHFR TT677 genotype (23.6% v 10.4%; OR/CI, 2.4/1.53 to 4.5; P &lt; .0001). A combination of the heterozygous FV G1691A mutation with increased Lp(a) (n = 11) or the MTHFR TT677 genotype (n = 5) was found in 10.8% of cases, but only 0.3% of controls (OR/CI, 35.75/4.7 to 272;P &lt; .0001). Increased Lp (a) levels, the FV G1691A mutation, protein C deficiency, the prothrombin G20210A variant, and the MTHFR TT677 are important risk factors for spontaneous ischemic stroke in childhood.

Assessment of brain tissue viability under clinical circumstances

The growing body of clinical and instrumental information that can be gathered from the earliest phases of stroke has radically modified the way in which neurologists tackle the treatment of stroke patients. It is now theoretically possible to tailor therapeutic choices on the basis of prognostic estimates made within a few hours of stroke onset, that is at a time when numerous options to limit the ischemic insult are still open. However, once many hours or even days have passed, all one can do is witness the effects of a natural course which by then is virtually unmodifiable. This applies not only to stroke patients being treated within the context of pharmacological trials, but also to those in daily clinical management, since some choices, such as when and how to treat brain oedema and give thrombolytics, may now be made earlier and more accurately than in the past. Emergency CT in particular discloses important indices of subsequent clinical evolution and outcome, thus adding to already well-known predictors such as age and severity of neurological status at hospital admission [20]. CT does have the aforementioned limitations regarding inter-observer agreement, which may, however, be minimised by an appropriate training of observers. Moreover it has intrinsic limitations regarding the visualisation of the actual brain tissue damage, since up to one fifth of patients with no or very limited early CT signs may present symptomatic hemorrhagic transformation after thrombolysis [23] and approximately one sixth of early deteriorating patients do not show early CT signs [52]. Other techniques, such as positron and single photon emission tomography and in particular MR imaging, which may shed light on tissue viability and perfusion as well as arterial patency simultaneously, might be able to provide more accurate information [19] Nevertheless, CT is still the most widely used tool in clinical centres which hospitalise stroke patients, and is unlikely to be routinely replaced by the other imaging devices in the foreseeable future. Consequently, there is an urgent need both for a general consensus on the identification criteria of early CT signs and for the widest possible awareness of knowledge regarding CT capabilities among neurologists [47], waiting for the wide applicability of newer technologies.

Neuropsychological impairment correlates with hypoperfusion and hypometabolism but not with severity of white matter lesions on MRI in patients with cerebral microangiopathy

BACKGROUND AND PURPOSE

Cerebral microangiopathy, indicated on MRI by lacunar infarctions (LI) and deep white matter lesions (DWML), is said to lead to vascular dementia.

METHODS

Fifty-seven patients with proven cerebral microangiopathy were assessed for changes in regional cerebral blood flow (rCBF) and glucose metabolism (rMRGlu) and compared with 19 age-matched controls. The findings were correlated with results of extensive neuropsychological testing, as well as with MRI findings. A special head holder ensured reproducibility of positioning during rCBF (single-photon emission CT [SPECT]), rMRGlu (positron emission tomography [PET]), and MR imaging. White matter and cortex were quantified with regions of interest defined on MRI and superimposed to corresponding PET/SPECT slices. LI and DWML were graded by number and extent.

RESULTS

Even with severe DWML and multiple LI, rCBF and rMRGlu values were not reduced. ANOVAs identified brain atrophy and neuropsychological deficits as the main determinants for reduced rCBF and rMRGlu values in both cortex and white matter. Neuropsychological deficits correlated well with decreased rCBF and rMRGlu, whereas MRI patterns such as LI and DWML did not. Factor analysis revealed no correlation of LI and DWML with rCBF, rMRGlu, atrophy, and neuropsychological deficits, showing instead positive correlations between rCBF, rMRGlu, and neuropsychological performance and negative correlations of the latter 3 with brain atrophy.

CONCLUSIONS

From these data, we conclude that LI and DWML are epiphenomena that may morphologically characterize cerebral microangiopathy but do not in themselves indicate cognitive impairment. Dementia or neuropsychological deficits, by contrast, are reflected exclusively by functional imaging parameters (rCBF, rMRGlu) and cerebral atrophy.

Early spontaneous improvement and deterioration of ischemic stroke patients. A serial study with transcranial Doppler ultrasonography

BACKGROUND AND PURPOSE

The purpose of our study was to investigate whether emergency transcranial Doppler (TCD) findings and their modifications over the first 48 hours are related to early neurological changes in acute ischemic stroke patients.

METHODS

Ninety-three patients underwent CT scan within 5 hours of a first-ever ischemic hemispheric stroke, and TCD serial examinations at 6, 24, and 48 hours after stroke onset. We classified TCD findings as follows: normal; middle cerebral artery (MCA) asymmetry (asymmetry index between affected and contralateral MCAs below -21%); and MCA no-flow (absence of flow signal from the affected MCA in the presence of ipsilateral anterior and posterior cerebral artery signals through the same acoustic window). We considered early deterioration and early improvement to be a decrease or an increase of 1 or more points, respectively, in the Canadian Neurological Scale score over the same period.

RESULTS

At 6-hour TCD examination, MCA asymmetry and MCA no-flow were present in 6 (22%) and 2 (7%), respectively, of 27 improving patients; in 20 (43%) and 10 (22%) of 46 stable patients, and in 9 (45%) and 8 (40%) of 20 deteriorating patients. TCD findings were normal in the remaining patients (P = 0.001). At serial TCD, we detected early (within 24 hours) recanalization (from no-flow to asymmetry or normal and from asymmetry to normal) in 2 (25%) improving patients, in 7 (23%) stable patients, and in 5 (29%) deteriorating patients and late (between 24 and 48 hours) recanalization in 4 (50%) improving patients, in 6 (20%) stable patients, and in none of the deteriorating patients (P = 0.03, chi 2 for trend, improving versus nonimproving irrespective of the timing of recanalization). One deteriorating patient (5%) developed a non-flow from an initial MCA asymmetry. Logistic regression selected normal TCD (odds ratio [OR], 0.17; 95% confidence interval [CI], 0.06 to 0.46) as an independent predictor of early improvement and abnormal TCD (asymmetry plus no-flow) (OR, 5.02; 95% CI, 1.31 to 19.3) as an independent predictor of early deterioration.

CONCLUSIONS

TCD examination within 6 hours after stroke can help to predict both early deterioration and early improvement. Serial TCD shows that propagation of arterial occlusion is rarely related to early deterioration, whereas the fact that it can detect early recanalization (within 24 hours) in deteriorating patients and both early and late recanalization (after 24 hours) in improving patients suggests the existence of individual time frames for tissue recovery.

Preliminary clinical-radiological assessment of a MR tissue signature model in human stroke

We evaluated the ability of an MR signature model (SM) of cerebral ischemic injury to stage the evolution of cellular damage in human stroke. In 19 patients with ischemic stroke of presumed embolic or non-embolic cause we carried out diffusion-weighted and T2-weighted MR imaging within 48 h of onset, and obtained apparent diffusion coefficient of water (ADCw), and T2 weighted images. We used the signatures obtained from these ADCw/T2 maps to formulate two patterns of damage signifying accelerated or non-accelerated progression of cellular death after stroke onset. Those patients with the accelerated pattern corresponded to those with the neuroradiological (NRC) and clinical diagnosis (TOAST.1 and TOAST.2) of presumed embolic stroke, with clinical diagnosis performed blinded both to NRC and to SM. Agreement between the SM and NRC was substantial (kappa=0.62), moderate (0.60<kappa<0.40) between the SM or NRC and TOAST.2, and fair (0.40<kappa<0.20) among the SM or NRC and TOAST.1. We believe these results constitute a preliminary validation of the MR tissue signature modeling in clinical stroke assessment.

Cardioembolic infarction in the Sagrat Cor-Alianza Hospital of Barcelona Stroke Registry

OBJECTIVES

To describe the clinical features of cardioembolic infarcts.

MATERIAL & METHODS

Cardioembolic infarct was diagnosed in 231 (15.4%) of 1500 consecutive stroke patients included in a prospective stroke registry over an 8-year period.

RESULTS

Cardiac sources of emboli included isolated atrial dysrhythmia (57.1%), valvular heart disease (20.3%), and coronary artery disease (18.2%). Patients with cardioembolic stroke showed a significantly higher (P < 0.00001) frequency of sudden onset of neurological deficit (79.7%) and altered consciousness (31.2%) than patients with lacunar infarct (38% and 1.9%) and atherothrombotic infarction (46% and 24%). Eleven patients had a spectacular shrinking deficit and 6 a presumed cardioembolic lacunar infarct. Early recurrent embolisms occurred in 6.5% of patients mostly (60%) within 7 days of initial embolism. In-hospital mortality was 27.3% (0.8% in lacunar infarcts, 21.7% in atherothrombotic infarction, P < 0.00001).

CONCLUSION

Cardioembolic infarction is a severe subtype of stroke with a high risk of early death. Clinical features at stroke onset may help clinicians to differentiate cerebral infarction subtypes and to establish prognosis more accurately.