Neuropsychiatric symptoms and brain morphology in patients with mild cognitive impairment, cerebrovascular disease and Parkinson disease: A cross sectional and longitudinal study

OBJECTIVES

Neuropsychiatric symptoms (NPS) increase risk of developing dementia and are linked to various neurodegenerative conditions, including mild cognitive impairment (MCI due to Alzheimer's disease [AD]), cerebrovascular disease (CVD), and Parkinson's disease (PD). We explored the structural neural correlates of NPS cross-sectionally and longitudinally across various neurodegenerative diagnoses.

METHODS

The study included individuals with MCI due to AD, (n = 74), CVD (n = 143), and PD (n = 137) at baseline, and at 2-years follow-up (MCI due to AD, n = 37, CVD n = 103, and PD n = 84). We assessed the severity of NPS using the Neuropsychiatric Inventory Questionnaire. For brain structure we included cortical thickness and subcortical volume of predefined regions of interest associated with corticolimbic and frontal-executive circuits.

RESULTS

Cross-sectional analysis revealed significant negative correlations between appetite with both circuits in the MCI and CVD groups, while apathy was associated with these circuits in both the MCI and PD groups. Longitudinally, changes in apathy scores in the MCI group were negatively linked to the changes of the frontal-executive circuit. In the CVD group, changes in agitation and nighttime behavior were negatively associated with the corticolimbic and frontal-executive circuits, respectively. In the PD group, changes in disinhibition and apathy were positively associated with the corticolimbic and frontal-executive circuits, respectively.

CONCLUSIONS

The observed correlations suggest that underlying pathological changes in the brain may contribute to alterations in neural activity associated with MBI. Notably, the difference between cross-sectional and longitudinal results indicates the necessity of conducting longitudinal studies for reproducible findings and drawing robust inferences.

Men Are at Higher Risk of Screening Positive for Vascular Cognitive Impairment Compared to Women after Stroke and Transient Ischemic Attack

While women have greater incidence of dementia, men have higher prevalence of vascular risk factors. This study examined sex differences in risk of screening positive for cognitive impairment after stroke. Ischemic stroke/TIA patients (N = 5969) participated in this prospective, multi-centered study, which screened for cognitive impairment using a validated brief screen. Men showed a higher risk of screening positive for cognitive impairment after adjusting for age, education, stroke severity, and vascular risk factors, suggesting that other factors may be contributing to increased risk among men (OR = 1.34, CI 95% [1.16, 1.55], p < 0.001). The effect of sex on cognitive impairment after stroke warrants further attention.

Characteristics of the Ontario Neurodegenerative Disease Research Initiative cohort

INTRODUCTION

Understanding synergies between neurodegenerative and cerebrovascular pathologies that modify dementia presentation represents an important knowledge gap.

METHODS

This multi-site, longitudinal, observational cohort study recruited participants across prevalent neurodegenerative diseases and cerebrovascular disease and assessed participants comprehensively across modalities. We describe univariate and multivariate baseline features of the cohort and summarize recruitment, data collection, and curation processes.

RESULTS

We enrolled 520 participants across five neurodegenerative and cerebrovascular diseases. Median age was 69 years, median Montreal Cognitive Assessment score was 25, median independence in activities of daily living was 100% for basic and 93% for instrumental activities. Spousal study partners predominated; participants were often male, White, and more educated. Milder disease stages predominated, yet cohorts reflect clinical presentation.

DISCUSSION

Data will be shared with the global scientific community. Within-disease and disease-agnostic approaches are expected to identify markers of severity, progression, and therapy targets. Sampling characteristics also provide guidance for future study design.

Language discordance as a marker of disparities in cerebrovascular risk and stroke outcomes: A multi-center Canadian study

Background

Differences in ischemic stroke outcomes occur in those with limited English proficiency. These health disparities might arise when a patient's spoken language is discordant from the primary language utilized by the health system. Language concordance is an understudied concept. We examined whether language concordance is associated with differences in vascular risk or post-stroke functional outcomes, depression, obstructive sleep apnea and cognitive impairment.

Methods

This was a multi-center observational cross-sectional cohort study. Patients with ischemic stroke/transient ischemic attack (TIA) were consecutively recruited across eight regional stroke centers in Ontario, Canada (2012 - 2018). Participants were language concordant (LC) if they spoke English as their native language, ESL if they used English as a second language, or language discordant (LD) if non-English speaking and requiring translation.

Results

8156 screened patients. 6,556 met inclusion criteria: 5067 LC, 1207 ESL and 282 LD. Compared to LC patients: (i) ESL had increased odds of diabetes (OR = 1.28, p = 0.002), dyslipidemia (OR = 1.20, p = 0.007), and hypertension (OR = 1.37, p<0.001) (ii) LD speaking patients had an increased odds of having dyslipidemia (OR = 1.35, p = 0.034), hypertension (OR = 1.37, p<0.001), and worse functional outcome (OR = 1.66, p<0.0001). ESL (OR = 1.88, p<0.0001) and LD (OR = 1.71, p<0.0001) patients were more likely to have lower cognitive scores. No associations were noted with obstructive sleep apnea (OSA) or depression.

Conclusions

Measuring language concordance in stroke/TIA reveals differences in neurovascular risk and functional outcome among patients with limited proficiency in the primary language of their health system. Lower cognitive scores must be interpreted with caution as they may be influenced by translation and/or greater vascular risk. Language concordance is a simple, readily available marker to identify those at risk of worse functional outcome. Stroke systems and practitioners must now study why these differences exist and devise adaptive care models, treatments and education strategies to mitigate barriers influenced by language discordance.

Abstract WMP54: Stroke Secondary Prevention Care In Persons With Schizophrenia

Introduction: Schizophrenia is associated with stroke incidence and case-fatality but the causes of this are not well-understood. We evaluated the association between comorbid schizophrenia and the quality of secondary prevention care after ischemic stroke.

Methods: We used linked health administrative data to identify adults discharged alive from acute care hospitals in Ontario, Canada between 2004 and 2017 following an incident ischemic stroke and identified those with a history of schizophrenia using a validated algorithm. Outcomes were screening, treatment among those with the risk factor, control of vascular risk factors, and receipt of outpatient physician services. We used modified Poisson regression to model the relative risk of each indicator outcome among persons with and without schizophrenia who were alive one year after discharge, adjusting for age, sex, income, comorbidity and rural residence.

Results: Among 85,046 persons with ischemic stroke, 886 (1.04%) had a diagnosis of schizophrenia. Those with schizophrenia were younger (median age 64 vs 72), more likely to be female (50.1% vs 44.6%), live in the lowest neighbourhood income quintile (41.1% vs 23.0%) and have diabetes (42.8% vs 32.3%). Of those alive 1 year after stroke, those with schizophrenia were less likely to be screened for hyperlipidemia (adjusted relative risk (aRR) 0.89; 95% confidence interval (CI) 0.84 to 0.94) or diabetes (aRR 0.93; 95% CI 0.89 to 0.97), be prescribed antihypertensive agents (aRR 0.96; 95% CI 0.93 to 0.99), or achieve target lipid levels (LDL < 2 mml/L) (aRR 0.87; 95% CI 0.78 to 0.96). There were no differences in prescription of antilipemic (aRR 0.96; 95% CI 0.91 to 1.01) or antiglycemic (aRR 0.95; 95% CI 0.87 to 1.03) agents or in achievement of target HbA1c ≤ 7% (aRR 0.89; 95% CI 0.78 to 1.02). Outpatient stroke specialist care in the 3 months after discharge was less likely among those with schizophrenia (aRR 0.72; 95% CI 0.65 to 0.78) as were visits to primary care physicians (aRR 0.93; 95% CI 0.91 to 0.96).

Conclusions: People with schizophrenia and stroke are less likely to receive secondary preventive care across many indicators measured. This information may be useful for targeted interventions to improve post-stroke care in those with schizophrenia.

Contribution of rare variant associations to neurodegenerative disease presentation

Genetic factors contribute to neurodegenerative diseases, with high heritability estimates across diagnoses; however, a large portion of the genetic influence remains poorly understood. Many previous studies have attempted to fill the gaps by performing linkage analyses and association studies in individual disease cohorts, but have failed to consider the clinical and pathological overlap observed across neurodegenerative diseases and the potential for genetic overlap between the phenotypes. Here, we leveraged rare variant association analyses (RVAAs) to elucidate the genetic overlap among multiple neurodegenerative diagnoses, including Alzheimer's disease, amyotrophic lateral sclerosis, frontotemporal dementia (FTD), mild cognitive impairment, and Parkinson's disease (PD), as well as cerebrovascular disease, using the data generated with a custom-designed neurodegenerative disease gene panel in the Ontario Neurodegenerative Disease Research Initiative (ONDRI). As expected, only ~3% of ONDRI participants harboured a monogenic variant likely driving their disease presentation. Yet, when genes were binned based on previous disease associations, we observed an enrichment of putative loss of function variants in PD genes across all ONDRI cohorts. Further, individual gene-based RVAA identified significant enrichment of rare, nonsynonymous variants in PARK2 in the FTD cohort, and in NOTCH3 in the PD cohort. The results indicate that there may be greater heterogeneity in the genetic factors contributing to neurodegeneration than previously appreciated. Although the mechanisms by which these genes contribute to disease presentation must be further explored, we hypothesize they may be a result of rare variants of moderate phenotypic effect contributing to overlapping pathology and clinical features observed across neurodegenerative diagnoses.

Stroke care and case fatality in people with and without schizophrenia: a retrospective cohort study

BACKGROUND

Schizophrenia is associated with an increased risk of death following stroke; however, the magnitude and underlying reasons for this are not well understood.

OBJECTIVE

To determine the association between schizophrenia and stroke case fatality, adjusting for baseline characteristics, stroke severity and processes of care.

DESIGN

Retrospective cohort study used linked clinical and administrative databases.

SETTING

All acute care institutions (N=152) in the province of Ontario, Canada.

PARTICIPANTS

All patients (N=52 473) hospitalised with stroke between 1 April 2002 and 31 March 2013 and included in the Ontario Stroke Registry. Those with schizophrenia (n=612) were identified using validated algorithms.

MAIN OUTCOMES AND MEASURES

We compared acute stroke care in those with and without schizophrenia and used Cox proportional hazards models to examine the association between schizophrenia and mortality, adjusting for demographics, comorbidity, stroke severity and processes of care.

RESULTS

Compared with those without schizophrenia, people with schizophrenia were less likely to undergo thrombolysis (10.1% vs 13.4%), carotid imaging (66.3% vs 74.0%), rehabilitation (36.6% vs 46.6% among those with disability at discharge) or be treated with antihypertensive, lipid-lowering or anticoagulant therapies. After adjustment for age and other factors, schizophrenia was associated with death from any cause at 1 year (adjusted HR (aHR) 1.33, 95% CI 1.14 to 1.54). This was mainly attributable to early deaths from stroke (aHR 1.47, 95% CI 1.20 to 1.80, with survival curves separating in the first 30 days), and the survival disadvantage was particularly marked in those aged over 70 years (1-year mortality 46.9% vs 35.0%).

CONCLUSIONS

Schizophrenia is associated with increased stroke case fatality, which is not fully explained by stroke severity, measurable comorbid conditions or processes of care. Future work should focus on understanding this mortality gap and on improving acute stroke and secondary preventive care in people with schizophrenia.

Endovascular Treatment Versus Best Medical Therapy in Acute Ischemic Stroke Patients with Mild Symptoms

BACKGROUND

The benefit of endovascular treatment (EVT) for acute ischemic stroke patients with mild deficits is unknown. We sought to evaluate the natural history of patients with a low National Institute of Health Stroke Score (NIHSS) and an intracranial occlusion.

METHODS

We included patients with a computed tomography angiogram-proven intracranial arterial occlusion who presented within 24 hours of symptom onset with an NIHSS of ≤6. We compared outcomes of patients who were treated with EVT and those who were not by performing propensity score-matched analysis. Primary outcome was modified Rankin score (mRS) at 90 days.

RESULTS

A total of 66 patients were included: 38 were men (57.6%) with a median age of 69 (interquartile range [IQR], 57-79.5) years. Median NIHSS was 3 (IQR, 2-5). Median time from symptom onset to presentation was 2.87 hours (IQR, 1.3-5.9). Forty of the total cohort underwent best medical therapy alone (60.6%), whereas 26 underwent EVT (39.4%). Nineteen of the 26 patients who underwent EVT had a good clinical outcome (mRS ≤2) (73.1%), compared with 29 of 40 best medical therapy patients (72.5%) (odds ratio, 0.833 with 95% confidence interval, 0.263-2.631; P = 0.755). Following propensity score adjustment there was a tendency toward lower mRS following EVT (P = 0.051).

CONCLUSIONS

Despite the higher number of proximal occlusions in the EVT group, overall outcomes were similar, with >70% of patients in each cohort having a good outcome at 90 days.

Discrepancy between post-treatment infarct volume and 90-day outcome in the ESCAPE randomized controlled trial

BACKGROUND

Some patients with ischemic stroke have poor outcomes despite small infarcts after endovascular thrombectomy, while others with large infarcts sometimes fare better.

AIMS

We explored factors associated with such discrepancies between post-treatment infarct volume (PIV) and functional outcome.

METHODS

We identified patients with small PIV (volume ≤ 25th percentile) and large PIV (volume ≥ 75th percentile) on 24-48-h CT/MRI in the ESCAPE randomized-controlled trial. Demographics, comorbidities, baseline, and 24-48-h stroke severity (NIHSS), stroke location, treatment type, post-stroke complications, and other outcome scales like Barthel Index, and EQ-5D were compared between "discrepant cases" - those with 90-day modified Rankin Scale(mRS) ≤ 2 despite large PIV or mRS ≥ 3 despite small PIV - and "non-discrepant cases". Multi-variable logistic regression was used to identify pre-treatment and post-treatment factors associated with small-PIV/mRS ≥ 3 and large-PIV/mRS ≤ 2. Sensitivity analyses used different definitions of small/large PIV and good/poor outcome.

RESULTS

Among 315 patients, median PIV was 21 mL; 27/79 (34.2%) patients with PIV ≤ 7 mL (25th percentile) had mRS ≥ 3; 12/80 (15.0%) with PIV ≥ 72 mL (75th percentile) had mRS ≤ 2. Discrepant cases did not differ by CT versus MRI-based PIV ascertainment, or right versus left-hemisphere involvement (p = 0.39, p = 0.81, respectively, for PIV ≤ 7 mL/mRS ≥ 3). Pre-treatment factors independently associated with small-PIV/mRS ≥ 3 included older age (p = 0.010), cancer, and vascular risk-factors; post-treatment factors included 48-h NIHSS (p = 0.007) and post-stroke complications (p = 0.026). Absence of vascular risk-factors (p = 0.004), CT-based lentiform nucleus sparing (p = 0.002), lower 24-hour NIHSS (p = 0.001), and absence of complications (p = 0.013) were associated with large-PIV/mRS ≤ 2. Sensitivity analyses yielded similar results.

CONCLUSIONS

Discrepancies between functional ability and PIV are likely explained by differences in age, comorbidities, and post-stroke complications, emphasizing the need for high-quality post-thrombectomy stroke care.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT01778335.

A Feasibility Study Involving Recruitment and Screening for Aphasia in Acute Stroke: Emerging Viability of the English Adaptation of the Language Screening Test (LASTen)

Objectives

We describe recruitment feasibility for language screening in acute stroke using the English adaptation the Language Screening Test (LASTen), originally developed in French. We also elucidate preliminary measurement properties of LASTen in patients with and without aphasia.

Design

Prospective eligibility tracking, recruitment, and screening for aphasia using the 2 parallel forms, LASTen-A and LASTen-B.

Setting

The Neurovascular Unit and the Transient Ischemic Attack and Minor Stroke Unit of a tertiary care hospital.

Participants

Stroke patients (N=12) with hyperacute to subacute stroke.

Interventions

Not applicable

Main Outcome Measures

Numbers of eligible patients and recruitment viability, individual performance indicators for both LASTen versions (15 points each) in 12 patients grouped by aphasia status, and reliability of the 2 parallel forms.

Results

There were 25 eligible stroke patients over 1 month. All 12 recruited patients consented to testing. The patients ranged in age from 29 to 85 years, and 5 were women. Three patients had intracerebral hemorrhage, and 6 had aphasia (mild to severe). The median LASTen scores in patients with and without aphasia were 10 (interquartile range, 8) and 15 (interquartile range, 0), respectively. Five patients had discrepant scores across versions involving a 1-point difference. One patient with aphasia had a 5-point difference, demonstrating improvement on the second version. The Pearson correlation coefficient was 0.95 for parallel form reliability.

Conclusions

Our study confirmed that LASTen appears to function as designed. There was score heterogeneity for patients with aphasia and desired ceiling effects for those without aphasia, alongside excellent parallel form reliability. The findings provide the impetus for a large-scale diagnostic accuracy trial in acute stroke patients.

Canadian Stroke Best Practice Recommendations: Rehabilitation, Recovery, and Community Participation following Stroke. Part Two: Transitions and Community Participation Following Stroke

The sixth update of the Canadian Stroke Best Practice Recommendations for Transitions and Community Participation following Stroke is a comprehensive set of evidence-based guidelines addressing issues faced by people following an acute stroke event. Establishing a coordinated and seamless system of care that supports progress achieved during the initial recovery stages throughout the transition to the community is more essential than ever as the medical complexity of people with stroke is also on the rise. All members of the health-care team engaged with people with stroke, their families, and caregivers are responsible for partnerships and collaborations to ensure successful transitions and return to the community following stroke. These guidelines reinforce the growing and changing body of research evidence available to guide ongoing screening, assessment, and management of individuals following stroke as they move from one phase and stage of care to the next without “falling through the cracks.” It also recognizes the growing role of family and informal caregivers in providing significant hours of support that disrupt their own lives and responsibilities and addresses their support and educational needs. According to Statistics Canada, in 2012, eight million Canadians provided care to family members or friends with a long-term health condition, disability, or problems associated with aging. These recommendations incorporate aspects that were previously in the rehabilitation module for the purposes of streamlining, and both modules should be reviewed in order to provide comprehensive care addressing recovery and community reintegration and participation. These recommendations cover topics related to support and education of people with stroke, families, and caregivers during transitions and community reintegration. They include interprofessional planning and communication, return to driving, vocational roles, leisure activities and relationships and sexuality, and transition to long-term care.

Canadian Stroke Best Practice Recommendations: Rehabilitation, Recovery, and Community Participation following Stroke. Part One: Rehabilitation and Recovery Following Stroke; 6th Edition Update 2019

The sixth update of the Canadian Stroke Best Practice Recommendations: Rehabilitation, Recovery, and Reintegration following Stroke. Part one: Rehabilitation and Recovery Following Stroke is a comprehensive set of evidence-based guidelines addressing issues surrounding impairments, activity limitations, and participation restrictions following stroke. Rehabilitation is a critical component of recovery, essential for helping patients to regain lost skills, relearn tasks, and regain independence. Following a stroke, many people typically require rehabilitation for persisting deficits related to hemiparesis, upper-limb dysfunction, pain, impaired balance, swallowing, and vision, neglect, and limitations with mobility, activities of daily living, and communication. This module addresses interventions related to these issues as well as the structure in which they are provided, since rehabilitation can be provided on an inpatient, outpatient, or community basis. These guidelines also recognize that rehabilitation needs of people with stroke may change over time and therefore intermittent reassessment is important. Recommendations are appropriate for use by all healthcare providers and system planners who organize and provide care to patients following stroke across a broad range of settings. Unlike the previous set of recommendations, in which pediatric stroke was included, this set of recommendations includes primarily adult rehabilitation, recognizing many of these therapies may be applicable in children. Recommendations related to community reintegration, which were previously included within this rehabilitation module, can now be found in the companion module, Rehabilitation, Recovery, and Community Participation following Stroke. Part Two: Transitions and Community Participation Following Stroke.

Derivation and External Validation of a Scoring System for Predicting Fracture Risk After Ischemic Stroke in a Canadian Cohort

Importance

The risk for low-trauma fracture is increased by more than 30% after ischemic stroke, but existing fracture risk scores do not account for history of stroke as a high-risk condition.

Objective

To derive a risk score to predict the probability of fracture within 1 year after ischemic stroke and validate it in a separate cohort.

Design, Setting, and Participants

Prognostic study of a cohort from the Ontario Stroke Registry, a population-based sample of adults in Ontario, Canada, who were hospitalized with ischemic stroke from July 1, 2003, to March 31, 2012, with 1 year of follow-up. A population-based validation cohort consisted of a sample of 13 698 consecutive stroke admissions captured across 5 years: April 2002 to March 2003, April 2004 to March 2005, April 2008 to March 2009, April 2010 to March 2011, and April 2012 to March 2013.

Exposures

Predictor variables were selected based on biological plausibility and association with fracture risk. Age, sex, and modified Rankin score were abstracted from the medical records part of the Ontario Stroke Audit, and other characteristics were abstracted from administrative health data.

Main Outcomes and Measures

Incidence of low-trauma fracture within 1 year of discharge, based on administrative health data.

Results

The Fracture Risk after Ischemic Stroke (FRAC-Stroke) Score was derived in 20 435 patients hospitalized for ischemic stroke (mean [SD] age, 71.6 [14.0] years; 9564 [46.8%] women) from the Ontario Stroke Registry discharged from July 1, 2003, to March 31, 2012, using Fine-Gray competing risk regression. Low-trauma fracture occurred within 1 year of discharge in 741 of the 20 435 patients (3.6%) in the derivation cohort. Age, discharge modified Rankin score (mRS), and history of rheumatoid arthritis, osteoporosis, falls, and previous fracture were associated with the cumulative incidence of low trauma fracture in the derivation cohort. Model discrimination in the validation cohort (n = 13 698) was good (C statistic, 0.70). Discharge mRS was an important discriminator of risk (relative integrated discrimination improvement, 8.7%), with highest risk in patients with mRS 3 and 4 but lowest in bedbound patients (mRS 5). From the lowest to the highest FRAC-Stroke quintile, the cumulative incidence of 1-year low-trauma fracture increased from 1.3% to 9.0% in the validation cohort. Predicted and observed rates of fracture were similar in the external validation cohort. Analysis was conducted from July 2016 to January 2019.

Conclusions and Relevance

The FRAC-Stroke score allows the clinician to identify ischemic stroke survivors at higher risk of low-trauma fracture within 1 year of hospital discharge. This information might be used to select patients for interventions to prevent fractures.

Canadian Stroke Best Practice Recommendations: Mood, Cognition and Fatigue following Stroke, 6th edition update 2019

The 2019 update of the Canadian Stroke Best Practice Recommendations (CSBPR) for Mood, Cognition and Fatigue following Stroke is a comprehensive set of evidence-based guidelines addressing three important issues that can negatively impact the lives of people who have had a stroke. These include post-stroke depression and anxiety, vascular cognitive impairment, and post-stroke fatigue. Following stroke, approximately 20% to 50% of all persons may be affected by at least one of these conditions. There may also be overlap between conditions, particularly fatigue and depression. If not recognized and treated in a timely matter, these conditions can lead to worse long-term outcomes. The theme of this edition of the CSBPR is Partnerships and Collaborations, which stresses the importance of integration and coordination across the healthcare system to ensure timely and seamless care to optimize recovery and outcomes. Accordingly, these recommendations place strong emphasis on the importance of timely screening and assessments, and timely and adequate initiation of treatment across care settings. Ideally, when screening is suggestive of a mood or cognition issue, patients and families should be referred for in-depth assessment by healthcare providers with expertise in these areas. As the complexity of patients treated for stroke increases, continuity of care and strong communication among healthcare professionals, and between members of the healthcare team and the patient and their family is an even bigger imperative, as stressed throughout the recommendations, as they are critical elements to ensure smooth transitions from acute care to active rehabilitation and reintegration into their community.

Abstract TP160: Predicting Bone Fracture After Stroke—The Fracture Risk After Ischemic Stroke (FRAC-Stroke) Score

Background: Risk for low trauma fracture is increased by >30% after ischemic stroke. Additionally, in the IRIS trial pioglitazone therapy prevented ischemic stroke but increased fracture risk. We derived a risk score to predict risk of fracture one year after ischemic stroke.

Methods: The Fracture Risk after Ischemic Stroke (FRAC-Stroke) Score was derived in 20,435 ischemic stroke patients from the Ontario Stroke Registry discharged from 2003-2012, using Fine-Gray competing risk regression. Candidate variables were medical conditions included in the validated World Health Organization FRAX risk score complemented by variables related to stroke severity. Registry patients were linked to population-based Ontario health administrative data to identify low trauma fractures (defined as any fracture of the femur, forearm, humerus, pelvis or vertebrae, excluding fractures resulting from trauma, motor vehicle accidents, falls from a height or in people with active cancer). The score was externally validated in 13,698 other ischemic stroke patients in the population-based Ontario stroke audit (2002-2012).

Results: Mean age was 72; 42% were women. Low trauma fracture occurred within 1 year of discharge in 741/20435 (3.6%); cumulative incidence increased linearly throughout follow-up. Age, discharge modified Rankin score (mRS), and history of arthritis, osteoporosis, falls and previous fracture contributed significantly to the model. Model discrimination was good (c statistic 0.72). Including discharge mRS significantly improved discrimination (relative integrated discrimination index 8.7%). Fracture risk was highest in patients with mRS 3 and 4 but lowest in bedbound patients (mRS 5). From the lowest to the highest FRAC-Stroke quintile the cumulative incidence of 1-year low trauma fracture increased from 1% to 9%. Predicted and observed rates of fracture were similar in the external validation cohort.

Conclusion: The FRAC-Stroke score allows the clinician to identify ischemic stroke patients at higher risk of low trauma fracture within one year. This information might be used to target patients for early bone densitometry screening to diagnose and manage osteoporosis, and to estimate baseline risk prior to starting pioglitazone therapy.

Early Trajectory of Stroke Severity Predicts Long-Term Functional Outcomes in Ischemic Stroke Subjects

Background and Purpose—

The trajectory of neurological improvement after stroke treatment is clinically likely to be an important prognostic signal. We compared the accuracy of early longitudinal National Institutes of Health Stroke Scale (NIHSS) measurement versus other early markers of stroke severity post treatment in predicting subjects’ 90-day stroke outcome.

Methods—

Data are from the Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with ESCAPE trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times). Stroke severity was assessed at baseline, 1, 2, 5, 30, and 90 days. Subjects’ functional outcome was assessed using the modified Rankin Scale at baseline, 30 days, and 90 days. Group-based trajectory model was used to identify distinct subgroups of longitudinal trajectories of NIHSS measured over the first 2, 5, and 30 days. The accuracy of baseline NIHSS, infarct volume, 24-hour change in NIHSS, infarct volume, and disease severity trajectory subgroups in predicting 90-day stroke outcome were assessed using logistic regression analysis.

Results—

Group-based trajectory model of the 2-day longitudinal NIHSS data revealed 3 distinct subgroups of NIHSS trajectories—large improvement (41.6%), minimal improvement (31.1%), and no improvement (27.3%) subgroups. Individuals in the large improvement group were more likely were more likely to exhibit good outcomes after 90 days than those in the minimal improvement or no improvement subgroup. Among candidate predictors, the 2-day trajectory subgroup variable was the most accurate in predicting 90-day modified Rankin Scale at 84.5%.

Conclusions—

Early trajectory of neurological improvement defined by 2-day longitudinal NIHSS data predicts functional outcomes with greater accuracy than other common variables.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01778335.

Infarct in a New Territory After Treatment Administration in the ESCAPE Randomized Controlled Trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times)

Background and Purpose—

Infarct in a new previously unaffected territory (INT) is a potential complication of endovascular treatment. We applied a recently proposed methodology to identify and classify INTs in the ESCAPE randomized controlled trial (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times).

Methods—

The core laboratory identified INTs on 24-hour follow-up imaging, blinded to treatment allocation, after assessing all baseline imaging. INTs were classified into 3 types (I–III) and 2 subtypes (A/B) based on size and if catheter manipulation was likely performed across the vessel territory ostium. Logistic regression was used to understand the effect of multiple a priori identified variables on INT occurrence. Ordinal logistic regression was used to analyze the effect of INTs on modified Rankin Scale shift at 90 days.

Results—

From 308 patients included, 14 INTs (4.5% overall; 2.8% on follow-up noncontrast computed tomography, 11.7% on follow-up magnetic resonance imaging) were identified (5.0% in endovascular treatment arm versus 4.0% in control arm [ P =0.7]). The use of intravenous alteplase was associated with a 68% reduction in the odds of INT occurrence (3.0% with versus 9.1% without; odds ratio, 0.32; 95% confidence interval, 0.11–0.96; adjusted for age, sex, and treatment type). No other variables were associated with INTs. INT occurrence was associated with reduced probability of good clinical outcome (common odds ratio, 0.25; 95% confidence interval, 0.09–0.74; adjusted for age, type of treatment, and follow-up scan).

Conclusions—

INTs are uncommon, detected more frequently on follow-up magnetic resonance imaging, and affect clinical outcome. In experienced centers, endovascular treatment is likely not causal, whereas intravenous alteplase may be therapeutic.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01778335.

Improving reperfusion time within the ESCAPE Endovascular Clinical Trial

Introduction

Endovascular treatment of acute ischemic stroke is more effective when performed quickly. In this report, we describe quality interventions to ensure fast endovascular treatment times in the ESCAPE (Endovascular Treatment for Small Core and Anterior circulation Proximal Occlusion with Emphasis on Minimizing CT to Recanalization Times) trial.

Methods

An "audit and feedback" intervention using webinar and letter was used to improve treatment time over the course of the trial. The time metrics were computed tomography-to-groin-puncture (target < 60 min) and computed tomography-to-first-reperfusion (target < 90 min). Each site was provided with their data for computed tomography-to-groin-puncture and computed tomography-to-first-reperfusion for all their patients that were randomized to the treatment arm, and their median time was compared to the overall median times of all sites in the trial. We assessed for changes in treatment time over the course of the trial.

Results

There were 165 patients enrolled into the endovascular arm from 22 sites. The computed tomography-to-groin-puncture time dropped from 57 to 47 min (p = 0.14) while computed tomography-to-reperfusion time dropped from 89 to 81 min (p = 0.48). Over the course of the trial, the absolute treatment benefit increased by 7.8% (p < 0.001).

Conclusions

An "audit and feedback" intervention throughout the conduct of the ESCAPE trial was a feasible way to ensure fast treatment times. Quality improvement processes should continue as standard practice beyond the trial to encourage good patient selection and the best clinical outcomes.

Risk of fractures after stroke: Results from the Ontario Stroke Registry

OBJECTIVE

To determine the risk of fractures after stroke.

METHODS

Using the Ontario Stroke Registry, we identified a population-based sample of consecutive patients seen in the emergency department or hospitalized with stroke (n = 23,751) or TIA (n = 11,240) at any of 11 stroke centers in Ontario, Canada, and discharged alive between July 1, 2003, and March 31, 2012. We compared the risk of low-trauma fractures in patients with stroke vs those with TIA using propensity score methods to adjust for differences in baseline factors. Secondary analyses compared fracture risk poststroke with that in age-/sex-matched controls without stroke or TIA (n = 23,751) identified from the Ontario Registered Persons Database.

RESULTS

The 2-year rate of fracture was 5.7% in those with stroke compared to 4.8% in those with TIA (adjusted cause-specific hazard ratio [aHR] for those with stroke vs TIA 1.32; 95% confidence interval [CI] 1.19-1.46) and 4.1% in age-/sex-matched controls (aHR for those with stroke vs controls 1.47; 95% CI 1.35-1.60). In the cohort with stroke, factors associated with fractures were older age, female sex, moderate stroke severity, prior fractures or falls, and preexisting osteoporosis, rheumatoid arthritis, hyperparathyroidism, and atrial fibrillation.

CONCLUSIONS

Stroke is associated with an increased risk of low-trauma fractures. Individuals with stroke and additional risk factors for fractures may benefit from targeted screening for low bone mineral density and initiation of treatment for fracture prevention.

Carotid artery web and ischemic stroke: A case-control study

OBJECTIVE

To determine whether there is an association between carotid artery web and ischemic stroke.

METHODS

This was a single-center, age- and sex-matched, case-control study. Cases were consecutive patients with anterior circulation ischemic stroke of undetermined etiology (Trial of Org 10172 in Acute Stroke Treatment [TOAST] classification). Controls were consecutive patients with cerebral aneurysms, arteriovenous malformations, or primary intracerebral hemorrhages. Additional inclusion criteria were age <60 years and CT angiography of the neck. Two neuroradiologists diagnosed webs according to previously published criteria. One neuroradiologist also assessed for nonstenotic atherosclerotic plaque (carotid wall thickness ≥3 mm or intramural calcification). We used conditional logistic regression to estimate the odds ratio between carotid web and ischemic stroke and its 95% confidence interval.

RESULTS

Fifty-three of 62 cases (85%) were matched by age (within 1 year) and by sex to 102 controls. There was a carotid web in 4 of 53 cases (9.4%) vs 1 of 102 controls (1.0%, odds ratio = 8.0, 95% confidence interval = 1.2-67, p = 0.032). There was no significant difference in the prevalence of nonstenotic carotid atherosclerotic plaque between the case and control groups. There was agreement on diagnosis of web for 163 of 164 patients (99%) and 7 of 8 webs (88%), and the Cohen κ for interobserver agreement was 0.93.

CONCLUSIONS

There is an association between carotid artery web and ischemic stroke in patients who lack an alternative cause of stroke. Carotid web may be an underappreciated risk factor for stroke.

Mechanical Thrombectomy in Acute Ischemic Stroke: A Systematic Review

Although intravenous thrombolysis increases the probability of a good functional outcome in carefully selected patients with acute ischemic stroke, a substantial proportion of patients who receive thrombolysis do not have a good outcome. Several recent trials of mechanical thrombectomy appear to indicate that this treatment may be superior to thrombolysis. We therefore conducted a systematic review and meta-analysis to evaluate the clinical effectiveness and safety of new-generation mechanical thrombectomy devices with intravenous thrombolysis (if eligible) compared with intravenous thrombolysis (if eligible) in patients with acute ischemic stroke caused by a proximal intracranial occlusion. We systematically searched seven databases for randomized controlled trials published between January 2005 and March 2015 comparing stent retrievers or thromboaspiration devices with best medical therapy (with or without intravenous thrombolysis) in adults with acute ischemic stroke. We assessed risk of bias and overall quality of the included trials. We combined the data using a fixed or random effects meta-analysis, where appropriate. We identified 1579 studies; of these, we evaluated 122 full-text papers and included five randomized control trials (n=1287). Compared with patients treated medically, patients who received mechanical thrombectomy were more likely to be functionally independent as measured by a modified Rankin score of 0-2 (odds ratio, 2.39; 95% confidence interval, 1.88-3.04; I2=0%). This finding was robust to subgroup analysis. Mortality and symptomatic intracerebral hemorrhage were not significantly different between the two groups. Mechanical thrombectomy significantly improves functional independence in appropriately selected patients with acute ischemic stroke.

Post-stroke depression, obstructive sleep apnea, and cognitive impairment: Rationale for, and barriers to, routine screening

Stroke can cause neurological impairment ranging from mild to severe, but the impact of stroke extends beyond the initial brain injury to include a complex interplay of devastating comorbidities including: post-stroke depression, obstructive sleep apnea, and cognitive impairment (“DOC”). We reviewed the frequency, impact, and treatment options for each DOC condition. We then used the Ottawa Model of Research Use to examine gaps in care, understand the barriers to knowledge translation, identification, and addressing these important post-stroke comorbidities. Each of the DOC conditions is common and result in poorer recovery, greater functional impairment, increased stroke recurrence and mortality, even after accounting for traditional vascular risk factors. Despite the strong relationships between DOC comorbidities and these negative outcomes as well as recommendations for screening based on best practice recommendations from several countries, they are frequently not assessed. Barriers related to the nature of the screening tools (e.g., time consuming in high-volume clinics), practice environment (e.g., lack of human resources or space), as well as potential adopters (e.g., equipoise surrounding the benefits of treatment for these conditions) pose challenges to routine screening implementation. Simple, feasible approaches to routine screening coupled with appropriate, evidence-based treatment protocols are required to better identify and manage depression, obstructive sleep apnea, and cognitive impairment symptoms in stroke prevention clinic patients to reduce the impact of these important post-stroke comorbidities. These tools may in turn facilitate large-scale randomized controlled treatment trials of interventions for DOC conditions that may help to improve cardiovascular outcomes after stroke or TIA.

Mechanical thrombectomy in patients with acute ischemic stroke: a cost-utility analysis

BACKGROUND

The beneficial effects of endovascular treatment with new-generation mechanical thrombectomy devices compared with intravenous thrombolysis alone to treat acute large-artery ischemic stroke have been shown in randomized controlled trials (RCTs). This study aimed to estimate the cost utility of mechanical thrombectomy compared with the established standard of care.

METHODS

We developed a Markov decision process analytic model to assess the cost-effectiveness of treatment with mechanical thrombectomy plus intravenous thrombolysis versus treatment with intravenous thrombolysis alone from the public payer perspective in Canada. We conducted comprehensive literature searches to populate model inputs. We estimated the efficacy of mechanical thrombectomy plus intravenous thrombolysis from a meta-analysis of 5 RCTs, and we used data from the Oxford Vascular Study to model long-term clinical outcomes. We calculated incremental cost-effectiveness ratios (ICER) using a 5-year time horizon.

RESULTS

The base case analysis showed the cost and effectiveness of treatment with mechanical thrombectomy plus intravenous thrombolysis to be $126 939 and 1.484 quality-adjusted life-years (QALYs), respectively, and the cost and effectiveness of treatment with intravenous thrombolysis alone to be $124 419 and 1.273 QALYs, respectively. The mechanical thrombectomy plus intravenous thrombolysis strategy was associated with an ICER of $11 990 per QALY gained. Probabilistic sensitivity analysis showed that the probability of treatment with mechanical thrombectomy plus intravenous thrombolysis being cost-effective was 57.5%, 89.7% and 99.6% at thresholds of $20 000, $50 000 and $100 000 per QALY gained, respectively. The main factors influencing the ICER were time horizon, extra cost of mechanical thrombectomy treatment and age of the patient.

INTERPRETATION

Mechanical thrombectomy as an adjunct therapy to intravenous thrombolysis is cost-effective compared with treatment with intravenous thrombolysis alone for patients with acute large-artery ischemic stroke.

Association between hospitalization and care after transient ischemic attack or minor stroke

OBJECTIVE

To evaluate the care and outcomes of patients with TIA or minor stroke admitted to the hospital vs discharged from the emergency department (ED).

METHODS

We used the Ontario Stroke Registry to create a cohort of patients with minor ischemic stroke/TIA who presented to the hospital April 1, 2008, to March 31, 2009, or April 1, 2010, to March 31, 2011, in the province of Ontario, Canada. We compared processes of care and outcomes (death or recurrent stroke/TIA) in patients admitted to the hospital and discharged with and without stroke prevention clinic follow-up.

RESULTS

In our sample of 8,540 patients, the use of recommended interventions was highest in admitted patients, followed by discharged patients referred to prevention clinics, followed by those discharged without clinic referral. Eight percent of nonadmitted patients returned to the hospital with recurrent stroke/TIA within 1 week of the index event. One-year stroke case-fatality was similar in admitted and discharged patients (adjusted hazard ratio 1.11; 95% confidence interval 0.92-1.34). Among patients discharged from EDs, referral to a stroke prevention clinic was associated with a markedly lower risk of mortality (adjusted hazard ratio 0.49; 95% confidence interval 0.38-0.64).

CONCLUSIONS

Patients with minor ischemic stroke or TIA discharged from the ED are less likely than admitted patients to receive timely stroke care interventions. Among discharged patients, referral to a stroke prevention clinic is associated with improved processes of care and lower mortality. Additional strategies are needed to improve access to high-quality outpatient TIA care.

Canadian Stroke Best Practice Recommendations: Hyperacute Stroke Care Guidelines, Update 2015

The 2015 update of the Canadian Stroke Best Practice Recommendations Hyperacute Stroke Care guideline highlights key elements involved in the initial assessment, stabilization, and treatment of patients with transient ischemic attack (TIA), ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, and acute venous sinus thrombosis. The most notable change in this 5th edition is the addition of new recommendations for the use of endovascular therapy for patients with acute ischemic stroke and proximal intracranial arterial occlusion. This includes an overview of the infrastructure and resources required for stroke centers that will provide endovascular therapy as well as regional structures needed to ensure that all patients with acute ischemic stroke that are eligible for endovascular therapy will be able to access this newly approved therapy; recommendations for hyperacute brain and enhanced vascular imaging using computed tomography angiography and computed tomography perfusion; patient selection criteria based on the five trials of endovascular therapy published in early 2015, and performance metric targets for important time-points involved in endovascular therapy, including computed tomography-to-groin puncture and computed tomography-to-reperfusion times. Other updates in this guideline include recommendations for improved time efficiencies for all aspects of hyperacute stroke care with a movement toward a new median target door-to-needle time of 30 min, with the 90th percentile being 60 min. A stronger emphasis is placed on increasing public awareness of stroke with the recent launch of the Heart and Stroke Foundation of Canada FAST signs of stroke campaign; reinforcing the public need to seek immediate medical attention by calling 911; further engagement of paramedics in the prehospital phase with prehospital notification to the receiving emergency department, as well as the stroke team, including neuroradiology; updates to the triage and same-day assessment of patients with transient ischemic attack; updates to blood pressure recommendations for the hyperacute phase of care for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. The goal of these recommendations and supporting materials is to improve efficiencies and minimize the absolute time lapse between stroke symptom onset and reperfusion therapy, which in turn leads to better outcomes and potentially shorter recovery times.

Discrete event simulation of patient admissions to a neurovascular unit

Evidence exists that clinical outcomes improve for stroke patients admitted to specialized Stroke Units. The Toronto Western Hospital created a Neurovascular Unit (NVU) using beds from general internal medicine, Neurology and Neurosurgery to care for patients with stroke and acute neurovascular conditions. Using patient-level data for NVU-eligible patients, a discrete event simulation was created to study changes in patient flow and length of stay pre- and post-NVU implementation. Varying patient volumes and resources were tested to determine the ideal number of beds under various conditions. In the first year of operation, the NVU admitted 507 patients, over 66% of NVU-eligible patient volumes. With the introduction of the NVU, length of stay decreased by around 8%. Scenario testing showed that the current level of 20 beds is sufficient for accommodating the current demand and would continue to be sufficient with an increase in demand of up to 20%.

Atrial fibrillation in patients with cryptogenic stroke

BACKGROUND

Atrial fibrillation is a leading preventable cause of recurrent stroke for which early detection and treatment are critical. However, paroxysmal atrial fibrillation is often asymptomatic and likely to go undetected and untreated in the routine care of patients with ischemic stroke or transient ischemic attack (TIA).

METHODS

We randomly assigned 572 patients 55 years of age or older, without known atrial fibrillation, who had had a cryptogenic ischemic stroke or TIA within the previous 6 months (cause undetermined after standard tests, including 24-hour electrocardiography [ECG]), to undergo additional noninvasive ambulatory ECG monitoring with either a 30-day event-triggered recorder (intervention group) or a conventional 24-hour monitor (control group). The primary outcome was newly detected atrial fibrillation lasting 30 seconds or longer within 90 days after randomization. Secondary outcomes included episodes of atrial fibrillation lasting 2.5 minutes or longer and anticoagulation status at 90 days.

RESULTS

Atrial fibrillation lasting 30 seconds or longer was detected in 45 of 280 patients (16.1%) in the intervention group, as compared with 9 of 277 (3.2%) in the control group (absolute difference, 12.9 percentage points; 95% confidence interval [CI], 8.0 to 17.6; P<0.001; number needed to screen, 8). Atrial fibrillation lasting 2.5 minutes or longer was present in 28 of 284 patients (9.9%) in the intervention group, as compared with 7 of 277 (2.5%) in the control group (absolute difference, 7.4 percentage points; 95% CI, 3.4 to 11.3; P<0.001). By 90 days, oral anticoagulant therapy had been prescribed for more patients in the intervention group than in the control group (52 of 280 patients [18.6%] vs. 31 of 279 [11.1%]; absolute difference, 7.5 percentage points; 95% CI, 1.6 to 13.3; P=0.01).

CONCLUSIONS

Among patients with a recent cryptogenic stroke or TIA who were 55 years of age or older, paroxysmal atrial fibrillation was common. Noninvasive ambulatory ECG monitoring for a target of 30 days significantly improved the detection of atrial fibrillation by a factor of more than five and nearly doubled the rate of anticoagulant treatment, as compared with the standard practice of short-duration ECG monitoring. (Funded by the Canadian Stroke Network and others; EMBRACE ClinicalTrials.gov number, NCT00846924.).

Abstract WP373: A Novel High-risk TIA and Minor Stroke Rapid Assessment Day-unit to Improve Quality of Care and Patient Outcomes

Background: About one in four ischemic strokes are preceded by a TIA; 43% of TIAs occur within one week before stroke. Patients with a TIA require urgent assessment, risk stratification, and preventative treatment, but often cannot access a Stroke Prevention Clinic in a timely fashion. Therefore, these patients are often admitted to hospital for evaluation but it is unclear if inpatient evaluation is optimal or specifically necessary for this patient population.

Methods: We developed a novel high-risk TIA and Minor Stroke (TAMS) day-unit to provide rapid access to patient assessment, investigations, initiation of prevention strategies, and stroke prevention education. The TAMS Unit patient assessments were based on a collaborative model led by stroke Nurse Practitioners and an attending stroke Neurologist. All patients had cerebrovascular imaging (CT angiography, MR angiography, or carotid Doppler if there were exclusions to CT or MR angiography), and as appropriate, echocardiography and Holter monitoring initiated at the TAMS Unit visit. We evaluated the feasibility of this novel care model. Outcomes including time to assessment, investigations, and treatment for high-risk TIA/stroke etiologies and stroke risk factors, as well as return emergency department visits or readmissions within 30 days were assessed.

Results: Between Sept. 6, 2011 and Aug. 8, 2012, 142 patients were seen in the TAMS Unit. Median time from emergency department visit to TAMS Unit assessment was 1 day. The final diagnosis was TIA in 41% of patients and minor stroke (NIHSS < 4) in 27.5% of patients. Atrial fibrillation was diagnosed in 8 (5.6%) patients; anticoagulation was initiated promptly upon diagnosis. High-grade carotid stenosis was diagnosed in 4 (2.8%) patients and these patients were referred for urgent endarterectomy. There were 12 (8.5%) patients that had a return visit to the emergency department within 30 days; 2 (1.4%) with stroke, 8 (5.6%) with recurrent TIA or fluctuating symptoms, and 2 (1.4%) with other diagnoses.

Conclusion: Our novel TAMS Unit is a feasible care model that provides rapid access to assessment and treatment of high-risk TIA and minor stroke patients, and is another level of care between hospital admission and the outpatient Stroke Prevention Clinic.

Salvage of the carotid artery with covered stent after perforation with dialysis sheath. A case report

We present a rare case of carotid tear caused by iatrogenic erroneous insertion of a dialysis sheath into the common carotid artery (CCA). This was treated by placement of a covered stent-graft in the CCA over the puncture site. This treatment achieved hemostasis while preserving the carotid artery with good outcome. The technical details are presented and the relevant literature regarding treatment of carotid blowout syndrome is discussed. This case suggests that placement of a covered stent-graft is a good option not only for the "usual" blowout syndrome due to head and neck tumors, but also for treatment of iatrogenic injury to the carotid artery.

A 5-item prediction rule to identify severe renal dysfunction in patients with acute stroke

BACKGROUND AND PURPOSE

Although patients with severe renal dysfunction who receive iodinated contrast are at high risk of CIN, contrast-enhanced CT scans are often obtained without prior knowledge of kidney function in patients with acute stroke. We aimed to develop a tool to identify patients with acute stroke at a high risk of CIN in the absence of a recent GFR.

MATERIALS AND METHODS

We used the RCSN (9872 patients) and OSA (2544 patients) for our derivation and validation cohort, respectively. A multivariable logistic regression model was performed to develop a predictive tool to identify severe renal dysfunction (defined as a GFR < 30 mL/min/1.73 m(2)).

RESULTS

The overall prevalence of severe renal dysfunction was 4.9% and 5.2% in the derivation and validation cohort, respectively. The prediction rule was designed as follows: (age in years) + (5 points for women) + (5 points for history of diabetes mellitus) + (15 points for preadmission insulin use) + (10 points for history of hypertension). The prevalence of severe renal dysfunction is negligible in patients with a total score of ≤70 (≤0.005%-0.7%) but increases with higher Renal Risk Scores (eg, scores 71-80: 2.1%-2.2%; scores 91-100: 6.6%-7.1%; scores 111-120: 15.9%-28.1%).

CONCLUSIONS

The Renal Risk Score is a validated tool that helps clinicians select which patients with stroke can safely proceed to contrast-enhanced brain imaging without waiting for laboratory evidence of good renal function.

The gene responsible for a severe form of peripheral neuropathy and agenesis of the corpus callosum maps to chromosome 15q

Peripheral neuropathy with or without agenesis of the corpus callosum (ACCPN) is a devastating neurodegenerative disorder that is transmitted as an autosomal recessive trait. Genealogical studies in a large number of affected French Canadian individuals suggest that ACCPN results from a single founder mutation. A genomewide search using 120 microsatellite DNA markers in 14 French Canadian families allowed the mapping of the ACCPN gene to a 5-cM region on chromosome 15q13-q15 that is flanked by markers D15S1040 and D15S118. A maximum two-point LOD score of 11.1 was obtained with the marker D15S971 at a recombination fraction of 0. Haplotype analysis and linkage disequilibrium support a founder effect. These findings are the first step in the identification of the gene responsible for ACCPN, which may shed some light on the numerous conditions associated with the progressive peripheral neuropathy or agenesis of the corpus callosum.