MRI of the pharynx in ischemic stroke patients with and without obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) is common after stroke and associated with poor stroke outcomes. Whether OSA after acute stroke is caused by anatomic, physiologic, or both etiologies has not been studied. We therefore used brain magnetic resonance imaging (MRI) scans to assess oropharyngeal anatomy in stroke patients with and without OSA.

METHODS

Patients within 7 days of ischemic stroke underwent nocturnal polysomnography. Sagittal T1-weighted MRI performed for clinical purposes was used to measure retropalatal distance, soft palatal length, soft palatal thickness, retroglossal space, and tongue length. Nasopharyngeal area and high retropharyngeal area were measured from axial T2-weighted images, and lateral pharyngeal wall thickness from coronal T1-weighted images.

RESULTS

Among 27 subjects, 18 (67%) had OSA (apnea/hypopnea index (AHI)5). Demographics, vascular risk factors, and stroke severity were similar in the two groups. Median retropalatal distance was shorter in subjects with OSA (Wilcoxon rank-sum test, p=0.03). Shorter retropalatal distance was associated with higher AHI (linear regression, p=0.04). None of the other morphological characteristics differed.

CONCLUSIONS

Anatomic difference between awake acute stroke patients with and without OSA shows that the sleep disorder cannot be attributed solely to sleep, sleeping position, or changes in neuromuscular control that are specific to the sleep state.

Congenital hepatic fibrosis in 5 dogs

Congenital hepatic fibrosis is a disorder of biliary system development histologically characterized by diffuse periportal to bridging fibrosis with numerous small often-irregular bile ducts and reduction in the number of portal vein branches. The condition results from abnormal development of the ductal plate, the embryonic precursor to the interlobular bile ducts. It has rarely been reported in veterinary species, and it has never been reported in dogs. This article describes 5 cases of a ductal plate malformation in dogs consistent with congenital hepatic fibrosis. On light microscopy, all 5 livers had severe bridging fibrosis with a marked increase in the number of small bile ducts, which often had irregular, dilated profiles reminiscent of the developing ductal plate. In addition, 80% (4 of 5) of cases lacked typical portal vein profiles. Cytokeratin 7 and proliferating cell nuclear antigen immunohistochemistry was performed on the 3 cases for which paraffin-embedded tissue was available. The bile duct profiles were strongly positive for cytokeratin 7 in all 3 cases, and they were negative for proliferating cell nuclear antigen or only had rare positive cells. All 5 dogs presented with clinical signs of portal hypertension. Congenital hepatic fibrosis should be considered in the differential diagnosis in young dogs that present with portal hypertension and lesions that may have been interpreted as bridging biliary hyperplasia or extrahepatic biliary obstruction.

Phase IIB/III trial of tenecteplase in acute ischemic stroke: results of a prematurely terminated randomized clinical trial

BACKGROUND AND PURPOSE

Intravenous alteplase (rtPA) remains the only approved treatment for acute ischemic stroke, but its use remains limited. In a previous pilot dose-escalation study, intravenous tenecteplase showed promise as a potentially safer alternative. Therefore, a Phase IIB clinical trial was begun to (1) choose a best dose of tenecteplase to carry forward; and (2) to provide evidence for either promise or futility of further testing of tenecteplase versus rtPA. If promise was established, then the trial would continue as a Phase III efficacy trial comparing the selected tenecteplase dose to standard rtPA.

METHODS

The trial began as a small, multicenter, randomized, double-blind, controlled clinical trial comparing 0.1, 0.25, and 0.4 mg/kg tenecteplase with standard 0.9 mg/kg rtPA in patients with acute stroke within 3 hours of onset. An adaptive sequential design used an early (24-hour) assessment of major neurological improvement balanced against occurrence of symptomatic intracranial hemorrhage to choose a "best" dose of tenecteplase to carry forward. Once a "best" dose was established, the trial was to continue until at least 100 pairs of the selected tenecteplase dose versus standard rtPA could be compared by 3-month outcome using the modified Rankin Scale in an interim analysis. Decision rules were devised to yield a clear recommendation to either stop for futility or to continue into Phase III.

RESULTS

The trial was prematurely terminated for slow enrollment after only 112 patients had been randomized at 8 clinical centers between 2006 and 2008. The 0.4-mg/kg dose was discarded as inferior after only 73 patients were randomized, but the selection procedure was still unable to distinguish between 0.1 mg/kg and 0.25 mg/kg as a propitious dose at the time the trial was stopped. There were no statistically persuasive differences in 3-month outcomes between the remaining tenecteplase groups and rtPA. Symptomatic intracranial hemorrhage rates were highest in the discarded 0.4-mg/kg tenecteplase group and lowest (0 of 31) in the 0.1-mg/kg tenecteplase group. Neither promise nor futility could be established.

CONCLUSION

This prematurely terminated trial has demonstrated the potential efficiency of a novel design in selecting a propitious dose for future study of a new thrombolytic agent for acute stroke. Given the truncation of the trial, no convincing conclusions can be made about the promise of future study of tenecteplase in acute stroke.

The food environment in an urban Mexican American community

The objective was to determine whether ethnic composition of neighborhoods is associated with number and type of food stores in an urban, Mexican American US community. Data were from a commercial food store data source and the US Census. Multivariate count models were used to test associations with adjustment for neighborhood demographics, income, and commercialization. Neighborhoods at the 75th percentile of percent Mexican American (76%) had nearly four times the number of convenience stores (RR=3.9, 95% CI: 2.2-7.0) compared with neighborhoods at the 25th percentile (36%). Percent Mexican American in the neighborhood was not associated with the availability of other food store types (supermarkets, grocery stores, specialty stores, convenience stores with gas stations) in the adjusted model. The impact of greater access to convenience stores on Mexican American residents' diets requires exploration.

Validity of proxies and correction for proxy use when evaluating social determinants of health in stroke patients

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate stroke patient-proxy agreement with respect to social determinants of health, including depression, optimism, and spirituality, and to explore approaches to minimize proxy-introduced bias.

METHODS

Stroke patient-proxy pairs from the Brain Attack Surveillance in Corpus Christi Project were interviewed (n=34). Evaluation of agreement between patient-proxy pairs included calculation of intraclass correlation coefficients, linear regression models (ProxyResponse=alpha(0)+alpha(1)PatientResponse+delta, where alpha(0)=0 and alpha(1)=1 denotes no bias) and kappa statistics. Bias introduced by proxies was quantified with simulation studies. In the simulated data, we applied 4 approaches to estimate regression coefficients of stroke outcome social determinants of health associations when only proxy data were available for some patients: (1) substituting proxy responses in place of patient responses; (2) including an indicator variable for proxy use; (3) using regression calibration with external validation; and (4) internal validation.

RESULTS

Agreement was fair for depression (intraclass correlation coefficient, 0.41) and optimism (intraclass correlation coefficient, 0.48) and moderate for spirituality (kappa, 0.48 to 0.53). Responses of proxies were a biased measure of the patients' responses for depression, with alpha(0)=4.88 (CI, 2.24 to 7.52) and alpha(1)=0.39 (CI, 0.09 to 0.69), and for optimism, with alpha(0)=3.82 (CI, -1.04 to 8.69) and alpha(1)=0.81 (CI, 0.41 to 1.22). Regression calibration with internal validation was the most accurate method to correct for proxy-induced bias.

CONCLUSIONS

Fair/moderate patient-proxy agreement was observed for social determinants of health. Stroke researchers who plan to study social determinants of health may consider performing validation studies so corrections for proxy use can be made.

Evaluation of sham non‐invasive ventilation for randomized, controlled trials in ALS

Non-invasive positive pressure ventilation (NIV) treatment of advanced respiratory insufficiency prolongs survival in ALS. To investigate the critical question of whether earlier initiation of NIV might provide additional benefit, a randomized trial with an appropriate placebo is needed. This study evaluated sub-therapeutic (sham) continuous positive airway pressure as a potential placebo. In a single-blind design, 40 ALS patients with forced vital capacity>50% were randomized to receive 30 seconds (s) of either active NIV, with 8 cm H2O inspiratory and 4 cm H2O expiratory pressure, or sham NIV with<1 cm of H2O continuous positive airway pressure at the mask. A questionnaire was then used to assess whether subjects thought that they had received a "real" or "pretend" treatment trial. The subjects' median age was 60.5 years, and 38% were female. Twelve of 20 subjects (60%) who received active NIV and 7 (35%) of the 20 subjects who received sham thought that they had tried the active treatment (p = 0.11). Only 8 (20%) of all subjects were confident about their determination that they had received "real" or "pretend" NIV. Thus, sub-therapeutic (sham) continuous positive airway pressure is a promising placebo control for NIV trials in ALS.

Rotating night shift work and the risk of ischemic stroke

Rotating night shift work disrupts circadian rhythms and is associated with coronary heart disease. The relation between rotating night shift work and ischemic stroke is unclear. The Nurses' Health Study, an ongoing cohort study of registered female nurses, assessed in 1988 the total number of years the nurses had worked rotating night shifts. The majority (69%) of stroke outcomes from 1988 to 2004 were confirmed by physician chart review. The authors used Cox proportional hazards models to assess the relation between years of rotating night shift work and ischemic stroke, adjusting for multiple vascular risk factors. Of 80,108 subjects available for analysis, 60% reported at least 1 year of rotating night shift work. There were 1,660 ischemic strokes. Rotating night shift work was associated with a 4% increased risk of ischemic stroke for every 5 years (hazard ratio = 1.04, 95% confidence interval: 1.01, 1.07; P(trend) = 0.01). This increase in risk was similar when limited to the 1,152 confirmed ischemic strokes (hazard ratio = 1.03, 95% confidence interval: 0.99, 1.07; P(trend) = 0.10) and may be confined to women with a history of 15 or more years of rotating shift work. Women appear to have a modestly increased risk of stroke after extended periods of rotating night shift work.

Predicting ischaemic stroke subtype from presenting systolic blood pressure: the BASIC Project

OBJECTIVE

We hypothesized that low presenting systolic blood pressure (SBP) predicted cardioembolic stroke aetiology.

DESIGN

Active and passive surveillance were used to identify all ischaemic strokes as part of the Brain Attack Surveillance in Corpus Christi (BASIC) population-based study. Multinomial logistic regression was used to examine the association between stroke subtype and first documented SBP in the medical record.

SETTING

Nueces County, TX, USA (313,645 residents in 2000). The community is urban with the majority of the population residing in the city of Corpus Christi. The area is served by seven adult acute care hospitals.

PATIENTS

Three hundred and eight cases with completed ischaemic stroke and determined subtype aetiology between January 2000 and December 2002.

RESULTS

Lower presenting SBP was associated with stroke subtype (P = 0.001). This association remained significant in the final model adjusted for age and history of coronary artery disease. The odds of cardioembolic versus small vessel occlusion increased by 20% (OR = 1.20, 95% CI: 1.07-1.35) for every 10 mmHg decrease in presenting SBP. Other covariates including race/ethnicity, gender, history of hypertension, and diabetes were neither significant predictors of stroke subtype, nor did they confound the association of SBP and stroke subtype. A 5 year increase in age increased the odds of cardioembolic subtype by 25% (OR = 1.25, 95% CI: 1.07-1.47).

CONCLUSIONS

Lower initial SBP and older age at ischaemic stroke presentation were associated with cardioembolic stroke. Suspicion of cardioembolic stroke should be increased in those presenting with low SBP.

Age at natural menopause and risk of ischemic stroke: the Framingham heart study

BACKGROUND AND PURPOSE

Women have increased lifetime stroke risk and more disabling strokes compared with men. Insights into the association between menopause and stroke could lead to new prevention strategies for women. The objective of this study was to examine the association of age at natural menopause with ischemic stroke risk in the Framingham Heart Study.

METHODS

Participants included women who survived stroke-free until age 60, experienced natural menopause, did not use estrogen before menopause, and who had complete data (n=1430). Participants were followed until first ischemic stroke, death, or end of follow-up (2006). Age at natural menopause was self-reported. Cox proportional hazards models were used to examine the association between age at natural menopause (<42, 42 to 54, >or=55) and ischemic stroke risk adjusted for age, systolic blood pressure, atrial fibrillation, diabetes, current smoking, cardiovascular disease and estrogen use.

RESULTS

There were 234 ischemic strokes identified. Average age at menopause was 49 years (SD=4). Women with menopause at ages 42 to 54 (hazard ratio=0.50; 95% CI: 0.29 to 0.89) and at ages >or=55 (hazard ratio=0.31; 95% CI: 0.13 to 0.76) had lower stroke risk compared with those with menopause <42 years adjusted for covariates. Women with menopause before age 42 had twice the stroke risk compared to all other women (hazard ratio=2.03; 95% CI: 1.16 to 3.56).

CONCLUSIONS

In this prospective study, age at natural menopause before age 42 was associated with increased ischemic stroke risk. Future stroke studies with measures of endogenous hormones are needed to inform the underlying mechanisms so that novel prevention strategies for midlife women can be considered.

Acute stroke symptoms: comparing women and men

BACKGROUND AND PURPOSE

In a recent meta-analysis, women with stroke had 30% lower odds of receiving tissue plasminogen activator than did men, and some studies have reported greater in-hospital delays in women with stroke. Causes of these disparities are unclear but could result from a different symptom presentation in women. Our objective was to prospectively investigate gender differences in acute stroke symptoms.

METHODS

Ischemic stroke/TIA cases presenting to the University of Michigan Hospital (January 2005 to December 2007) were identified. Stroke/TIA symptoms, ascertained by patient interview, were classified as traditional or nontraditional (pain, mental status change, lightheadedness, headache, other neurological, nonneurological). Prevalence of any nontraditional symptom and of each symptom were calculated by gender. Logistic regression was used to compare nontraditional symptoms by gender adjusted for stroke vs TIA, proxy use, age, and discharge disposition (home vs other).

RESULTS

Included were 461 cases (48.6% women; median age, 67). Among women, 51.8% reported >or=1 nontraditional stroke/TIA symptom compared to 43.9% of men (P=0.09). The most prevalent nontraditional symptom was mental status change (women, 23.2%; men, 15.2%; P=0.03). The odds of reporting at least 1 nontraditional stroke/TIA symptom were 1.42 times (95% CI, 0.97-2.06) greater in women than in men.

CONCLUSIONS

A high prevalence of nontraditional symptoms among both genders was found, with women more likely to report nontraditional symptoms and, in particular, altered mental status, compared with men. Larger-scale studies focusing on stroke in women are warranted and could confirm gender differences in symptoms in a larger, more representative stroke population and address the clinical consequences.

Performance of automated slidemakers and stainers in a working laboratory environment - routine operation and quality control

The automated slidemaker/stainers of the four Beckman Coulter LH755 hematology systems in our laboratory are operated as analyzers, with similar requirements for setup, maintenance and quality control. A study was performed to confirm that these slide maker/stainers in routine use produce peripheral blood films that are completely satisfactory for microscopy and without cells, particularly abnormal cells, being pulled to the edges or sides of the film outside the usual working area. One hundred and thirty-nine automated blood films that had been produced during routine operation were compared with well-prepared manual films from the same patients. None of the films was unacceptable for microscopy. The distributions of normal white cell types within the counting areas of automated films compared with manual films, for all 139 samples for WBC from 1.0 to 352.8 × 10⁹/l; for blasts and promyelocytes in the 65 samples in which they occurred and for nucleated red blood cells in the 58 samples in which they occurred all fell within the expected limits of 200 cell differential counts of CLSI H20-A. Red cell morphology and the occurrence of WBC clumps, platelet clumps and smudge cells were comparable between the automated and manual films of all samples. We conclude that automated slidemaker/stainers, as typified by those of the Beckman Coulter LH755 system, are capable of producing blood films comparable with well-prepared manual films in routine laboratory use; and that the maintenance and quality control procedures used in our laboratory ensure consistent high quality performance from these systems.

Comparison of two headgear systems for sleep apnea treatment of stroke patients

BACKGROUND

Obstructive sleep apnea is a very common condition after stroke, and it predicts poor outcomes. Unfortunately, stroke patients often do not tolerate continuous positive airway pressure. We hypothesized that a 1-piece head frame headgear would be easier and quicker to use than a traditional strap headgear.

METHODS

A convenience sample of ischemic stroke patients was taught to use 2 different headgear systems, a head frame and straps. Subjects were timed while putting on and taking off the 2 headgears, and they were queried about their ease of use.

RESULTS

All the 30 enrolled subjects found the head frame to be easier to apply and to remove than the straps. The patients took longer to put on (p < 0.01) and to remove (p < 0.01) the straps than the head frame.

CONCLUSIONS

Headgear selection should be considered when fitting a stroke patient with a continuous positive airway pressure mask.

Ambient air pollution and risk for ischemic stroke and transient ischemic attack

OBJECTIVE

Data on the association between air pollution and cerebrovascular disease in the United States are limited. The objective of this study was to investigate the association between short-term exposure to ambient air pollution and risk for ischemic cerebrovascular events in a US community.

METHODS

Daily counts of ischemic strokes/transient ischemic attacks (TIAs) (2001-2005) were obtained from the population-based Brain Attack Surveillance in Corpus Christi (BASIC) Project. Daily particulate matter less than 2.5microm in diameter (PM(2.5)), ozone (O(3)), and meteorological data were obtained from Texas Commission on Environmental Quality. To examine the association between PM(2.5) and stroke/TIA risk, we used Poisson regression. Separate models included same-day PM(2.5), PM(2.5) lagged 1 to 5 days, and an averaged lag effect. All models were adjusted for temperature, day of week, and temporal trends in stroke/TIA. The effects of O(3) were also investigated.

RESULTS

Median PM(2.5) was 7.0microg/m(3) (interquartile range, 4.8-10.0microg/m(3)). There were borderline significant associations between same-day (relative risk [RR], 1.03; 95% confidence interval [CI], 0.99-1.07 for an interquartile range increase in PM(2.5)) and previous-day (RR, 1.03; 95% CI, 1.00-1.07) PM(2.5) and stroke/TIA risk. These associations were independent of O(3), which demonstrated similar associations with stroke/TIA risk (same-day RR, 1.02; 95% CI, 0.97-1.08; previous-day RR, 1.04; 95% CI, 0.99-1.09).

INTERPRETATION

We observed associations between recent PM(2.5) and O(3) exposure and ischemic stroke/TIA risk even in this community with relatively low pollutant levels. This study provides data on environmental exposures and stroke risk in the United States, and suggests future research on ambient air pollution and stroke is warranted.

High prevalence of supine sleep in ischemic stroke patients

BACKGROUND AND PURPOSE

Sleep apnea is very common after stroke and is associated with poor outcome. Supine sleep is known to exacerbate apneas in the general sleep apnea population. We therefore investigated the pattern of sleep positions in the acute stroke period.

METHODS

Inpatients with acute ischemic stroke underwent full polysomnography that included continuous monitoring of sleep positions. Sleep apnea severity was measured using the apnea-hypopnea index (AHI). Stroke severity was measured by the NIH Stroke Scale (NIHSS) at the time of study enrollment by certified study personnel. Percent total sleep time spent in the supine position was calculated and compared by stroke severity based on a median split of NIHSS using a Wilcoxon rank-sum test.

RESULTS

Of the 30 patients, the median age was 67. The median AHI was 23 (IQR: 6, 47). Twenty-two patients (73%) had sleep apnea with an AHI >/=5. The vast majority of sleep time among the stroke cases was spent supine, with a median percent sleep time spent supine of 100 (IQR: 62, 100). The majority (63%) of subjects spent no time asleep in any of the nonsupine positions (prone, left, right). Median percent sleep time supine was 100 (IQR: 100, 100) in those with a higher NIHSS and 63 (IQR: 51, 100) in those with a lower NIHSS (P<0.01).

CONCLUSIONS

Given the high prevalence of supine sleep identified, research into positional therapy for stroke patients with sleep apnea seems warranted.

Gender and ethnic differences in subarachnoid hemorrhage

BACKGROUND

Mexican Americans (MAs) comprise the largest component of the largest minority group within the United States. The purpose of this study was to examine ethnic and gender differences in the epidemiology, presentation, and outcomes after subarachnoid hemorrhage (SAH) in a representative United States community. Targeted public health interventions are dependent on accurate assessments of groups at highest disease risk.

METHODS

All patients with nontraumatic SAH older than 44 years were prospectively identified from January 1, 2000, to December 31, 2006, as part of the Brain Attack Surveillance In Corpus Christi project, an urban population-based study in southeast Texas. Risk ratios for cumulative SAH incidence comparing MAs with non Hispanic whites (NHWs) and women with men were calculated. Descriptive statistics for other clinical and demographic variables were computed overall, by gender, and by ethnicity.

RESULTS

A total of 107 patients had a SAH during the time period (7-year cumulative incidence: 11/10,000); of these, 43 were NHW (40% of cases vs 53% of the population) and 64 were MA (60% of cases vs 48% of the population). The overall age-adjusted risk ratio for SAH in MAs compared with NHWs was 1.67 (95% CI: 1.13, 2.47), and in women compared to men was 1.74 (95% CI 1.16, 2.62). Overall in-hospital mortality was 32.2%. No ethnic difference was observed for discharge disability or in-hospital mortality.

CONCLUSIONS

Subarachnoid hemorrhage disproportionately affects Mexican Americans and women. Public health interventions should target these groups to reduce the impact of this severe disease.

Kids Identifying and Defeating Stroke (KIDS): development and implementation of a multiethnic health education intervention to increase stroke awareness among middle school students and their parents

The Kids Identifying and Defeating Stroke (KIDS) project is a 3-year prospective, randomized, controlled, multiethnic school-based intervention study. Project goals include increasing knowledge of stroke signs and treatment and intention to immediately call 911 among Mexican American (MA) and non-Hispanic White (NHW) middle school students and their parents. This article describes the design, implementation, and interim evaluation of this theory-based intervention. Intervention students received a culturally appropriate stroke education program divided into four 50-minute classes each year during the sixth, seventh, and eighth grades. Each class session also included a homework assignment that involved the students' parents or other adult partners. Interim-test results indicate that this educational intervention was successful in improving students' stroke symptom and treatment knowledge and intent to call 911 upon witnessing a stroke compared with controls. The authors conclude that this school-based educational intervention to reduce delay time to hospital arrival for stroke shows early promise.

Stroke health and risk education (SHARE) pilot project: feasibility and need for church-based stroke health promotion in a bi-ethnic community

BACKGROUND AND PURPOSE

We performed a pilot project to assess the need for and feasibility of a church-based stroke risk reduction intervention in a predominantly Mexican American community.

METHODS

Participants were recruited after each mass on a single weekend from 2 Catholic churches in Corpus Christi, Texas. Questionnaires about personal stroke risk factors and interest in program participation were completed, and blood pressure screening was performed.

RESULTS

A total of 150 individuals participated (63% Mexican American, median age 62). A substantial majority (84%) were interested in being part of a long-term church-based health education project. Blood pressure was >139/89 mm Hg in 50 of 78 (64%) of individuals with a self-reported history of hypertension, and in 17 of 69 (25%) of individuals without known hypertension, with no ethnic differences in blood pressure. Mexican Americans were younger, had a higher BMI, and were more likely to have diabetes than non-Hispanic whites.

CONCLUSIONS

There is substantial burden of stroke risk factors in these predominantly Mexican American church communities. Church-based health interventions may be a way to reduce stroke in this at-risk population.

CT angiography is cost-effective for confirmation of internal carotid artery occlusions

BACKGROUND AND PURPOSE

While sensitive to internal carotid artery (ICA) occlusion, carotid ultrasound can produce false-positive results. CT angiography (CTA) has a high specificity for ICA occlusion and is safer and cheaper than catheter angiography, although less accurate. We determined the cost-effectiveness of CTA versus catheter angiography for confirming an ICA occlusion first suggested by carotid ultrasound.

METHODS

A Markov decision-analytic model was constructed to estimate the cost-effectiveness of CTA compared with catheter angiography in a hypothetical cohort of symptomatic patients with a screening examination consistent with an ICA occlusion. Costs in 2004 dollars were estimated from Medicare reimbursement. Effectiveness was measured in quality-adjusted life years.

RESULTS

The 2-year cost in the CTA scenario was $9,178, and for catheter angiography, $11,531, consistent with a $2,353 cost-savings per person for CTA. CTA resulted in accrual of 1.83 quality-adjusted life years while catheter angiography resulted in 1.82 quality-adjusted life years. CTA was less costly and marginally more effective than catheter angiography. In sensitivity analyses, when CTA sensitivity and specificity were allowed to vary across a plausible range, CTA remained cost-effective.

CONCLUSIONS

After screening examination has suggested an ICA occlusion, confirmatory testing with CTA provides similar effectiveness to catheter angiography and is less costly.

Determining intravenous rt-PA eligibility in the Emergency Department

INTRODUCTION

The purpose of this study was to assess the agreement of Emergency Department (ED) attendings, ED residents, and neurology residents compared with stroke neurologists in the assessment of intravenous rt-PA eligibility.

METHODS

A convenience sample of patients presenting with possible stroke symptoms to the University of Michigan Hospital ED from June 2003 to July 2004 was identified. A physician from each of four groups: ED attending, ED resident, neurology resident, and stroke neurology attending independently evaluated each patient for eligibility for intravenous (i.v.) rt-PA. Accuracy, sensitivity, and positive predictive value (PPV) with 95% confidence intervals (CI) were calculated by physician type, compared with the stroke neurologist, for eligibility for i.v. rt-PA.

RESULTS

Exactly 36 (49%) out of the 73 evaluated patients were diagnosed with acute ischemic stroke and 11 were deemed eligible for treatment with i.v. tPA by the stroke neurologist. Agreement with the stroke neurologist for rt-PA eligibility was 93% [95% CI: 84%, 98%] (sensitivity = 82% [48%, 98%], PPV = 82% [48%, 99%]) for the ED attendings, 79% [65%, 90%] (sensitivity = 75% [35%, 97%], PPV = 43% [18% 71%]) for the ED residents, and 84% [73%, 92%] (sensitivity = 100% [74%, 100%], PPV = 52% [31%, 73%]) for the neurology residents. There were two false positive cases identified by ED attendings, eight, by ED residents, and 11 by neurology residents.

CONCLUSIONS

This study suggests that the agreement between ED attendings and stroke neurologists for determination of rt-PA eligibility is good. There is room for improvement, however, in the determination of acute stroke therapy eligibility in the ED setting especially among trainees.

Risk of fractures after stroke

BACKGROUND

The aim of this study was to determine the risk of fractures after stroke/transient ischemic attack (TIA) in relatively young patients.

METHODS

Administrative claims data were identified for patients aged 18 years and older hospitalized for stroke/TIA from 1997 to 2005 using ICD-9 codes. Fractures after stroke/TIA were identified for the same time period.

RESULTS

The median age was 56 years. Females represented 47%. There were 411 ischemic strokes, 195 TIAs and 36 intracerebral hemorrhages, as well as 46 fractures in 41 individuals. The risk of fracture after stroke/TIA was 1.2% at 30 days and 3.1% at 1 year. There was no significant difference in survival free from fracture between ischemic stroke and TIA cases (p = 0.8489).

CONCLUSIONS

Patients with stroke/TIA, including men and younger patients, appear to be at risk for bone fractures.

Screening for myocardial infarction and ischemic stroke: a population-based study

Studies that accurately identify myocardial infarction (MI) and stroke within populations would provide valuable epidemiological information as well as data on vascular disease prevention. We performed a pilot study to assess the feasibility of adding MI surveillance to an ongoing population-based stroke surveillance study, the Brain Attack Surveillance in Corpus Christi (BASIC) Project. We also tested two screening methods for MI ascertainment: discharge International Classification of Diseases, Ninth Revision (ICD-9) codes and cardiac biomarker screening. This pilot study suggests that the addition of MI surveillance to community-based stroke surveillance studies is feasible. Screening for abnormal cardiac biomarkers to identify potential MI cases may be more accurate and efficient than using ICD-9 codes.

A randomized, controlled trial to teach middle school children to recognize stroke and call 911: the kids identifying and defeating stroke project

BACKGROUND AND PURPOSE

Underutilization of acute stroke therapy is driven by delay to hospital arrival. We present the primary results of a pilot, randomized, controlled trial to encourage calling 911 for witnessed stroke among middle school children and their parents.

METHODS

This project occurred in Corpus Christi, an urban Texas community of 325,000. Three intervention and 3 control schools were randomly selected. The intervention contained 12 hours of classroom instruction divided among sixth, seventh, and eighth grades. Parents were educated indirectly through homework assignments. Two-sample t tests were used to compare pretest and posttest responses.

RESULTS

Domain 1 test questions involved stroke pathophysiology. Intervention students improved from 29% to 34% correct; control students changed from 28% to 25%. Domain 2 test questions involved stroke symptom knowledge. Intervention school students changed from 28% correct to 43%; control school students answered 25% correctly on the pretest and 29% on the posttest. Domain 3 test questions involved what to do for witnessed stroke. Intervention school students answered 36% of questions correctly on the pretest and 54% correctly on the posttest, whereas control students changed from 32% correct to 34%. A comparison of change in the mean proportion correct over time between intervention and control students was P<0.001 for each of the 3 individual domains. A poor parental response rate impaired the ability to assess parental improvement.

CONCLUSIONS

A scientific, theory-based, educational intervention can potentially improve intent to call 911 for stroke among middle school children. A different mechanism is needed to effectively diffuse the curriculum to parents.

Impact of Drug‐Exposure Intensity and Duration of Therapy on the Emergence ofStaphylococcus aureusResistance to a Quinolone Antimicrobial

We have shown previously in animal model and in vitro systems that antimicrobial therapy intensity has a profound influence on subpopulations of resistant organisms. Little attention has been paid to the effect of therapy duration on resistant subpopulations. We examined the influence of therapy intensity (area under the concentration/time curve for 24 h:minimum inhibitory concentration [AUC24:MIC] ratio) and therapy duration on resistance emergence using an in vitro model of Staphylococcus aureus infection. AUC24:MIC ratios of>or=100 were necessary to kill a substantial portion of the total population. Importantly, we demonstrated that therapy duration is a critical parameter. As the duration increased beyond 5 days, the intensity needed to suppress the antibiotic-resistant subpopulations increased, even when the initial bacterial kill was>4 log10 (cfu/mL). These findings were prospectively validated in an independent experiment in which exposures were calculated from the results of fitting a large mathematical model to all data simultaneously. All of the prospectively determined predictions were fulfilled in this validation experiment.

Veterinary aspects and perspectives of nutrigenomics: a critical review

Nutrigenomics examines nutrient-gene interactions on a genome-wide scale. Increased dietary fat or higher non-esterified fatty acids (NEFA) from starvation-induced mobilisation may enhance hepatic oxidation and decrease esterification of fatty acids by reducing the expression of the fatty acid synthase gene. The key factors are the peroxisome proliferator-activated receptors (PPARs). Dietary carbohydrates--both independently and through insulin effect--influence the transcription of the fatty acid synthase gene. Oleic acid or n-3 fatty acids downregulate the expression of leptin, fatty acid synthase and lipoprotein lipase in retroperitoneal adipose tissue. Protein-rich diets entail a shortage of mRNA necessary for expression of the fatty acid synthase gene in the adipocytes. Conjugated linoleic acids (CLAs) are activators of PPAR and also induce apoptosis in adipocytes. Altered rumen microflora produces CLAs that are efficient inhibitors of milk fat synthesis in the mammary gland ('biohydrogenation theory'). Oral zinc or cadmium application enhances transcription rate in the metallothionein gene. Supplemental CLA in pig diets was found to decrease feed intake and body fat by activating PPARgamma-responsive genes in the adipose tissue. To prevent obesity and type II diabetes, the direct modulation of gene expression by nutrients is also possible. Nutrigenomics may help in the early diagnosis of genetically determined metabolic disorders and in designing individualised diets for companion animals.

Early care limitations independently predict mortality after intracerebral hemorrhage

OBJECTIVE

Intracerebral hemorrhage (ICH) is associated with a high early mortality rate. We examined the impact of early do not resuscitate (DNR) orders and other limitations in aggressive care on mortality after ICH in a community-based study.

METHODS

Cases of spontaneous ICH from 2000 to 2003 were identified from the Brain Attack Surveillance in Corpus Christi (BASIC) project, with deaths ascertained through 2005. Charts were reviewed for early (<24 hours from presentation) DNR orders, withdrawal of care, or deferral of other life sustaining interventions, analyzed together as combined DNR (C-DNR). Multivariable Cox-proportional hazards models were used to examine the association between short- and long-term all-cause mortality and early C-DNR, adjusted for demographics and established predictors of mortality after ICH.

RESULTS

Of 18,393 subjects screened for cerebrovascular disease, 270 non-traumatic ICH cases were included. Cumulative mortality risk was 0.43 at 30 days and 0.55 over the study course. Early C-DNR was noted in 34% of cases and was associated with a doubling in the hazard of death both at 30 days (hazard ratio [HR] 2.17, 95% CI 1.38, 3.41) and at end of follow-up (HR 1.92, 95% CI 1.29, 2.87) despite adjustment for age, gender, ethnicity, Glasgow Coma Scale, ICH volume, intraventricular hemorrhage, and infratentorial hemorrhage.

CONCLUSIONS

Early care limitations are independently associated with both short- and long-term all-cause mortality after intracerebral hemorrhage (ICH) despite adjustment for expected predictors of ICH mortality. Physicians should carefully consider the effect of early limitations in aggressive care to avoid limiting care for patients who may survive their acute illness.

Large calcifications in ovaries otherwise normal on ultrasound

OBJECTIVE

To evaluate calcifications >or= 5 mm in length in ovaries that are otherwise normal on ultrasound, and to determine whether such large ovarian calcifications are an indicator of ovarian neoplasm.

METHODS

This was a retrospective study reviewing pelvic ultrasound results at our unit between October 1994 and April 2002 to identify patients with ovarian calcifications that were >or= 5 mm in maximum length in otherwise normal ovaries, and who also had follow-up imaging studies. Patient medical histories were reviewed, calcification characteristics, including number, size, shape and laterality of calcifications, were recorded and follow-up imaging studies were reviewed to assess change in size of the calcification and to see if a neoplasm had developed.

RESULTS

The study group consisted of 28 patients. The mean length of imaging follow-up was 35.2 +/- 30.7 months. The mean size of the calcifications was 7.4 +/- 2.3 (range, 5-13) mm. The calcification remained stable in all 28 patients and no ovarian neoplasms developed in any of the patients. Histological confirmation was available in one patient and this revealed dystrophic calcification in a corpus albicans.

CONCLUSION

Calcifications ranging from 5 to 13 mm in length in otherwise normal ovaries remain stable on follow-up imaging and are not an indicator of current or future ovarian neoplasm. Published by John Wiley & Sons, Ltd.

Defining cause of death in stroke patients: The Brain Attack Surveillance in Corpus Christi Project

Stroke mortality is an important national health statistic and represents a frequent endpoint for epidemiologic studies. Several methods have been used to determine cause of death after stroke, but their agreement and reliability are unknown. Two hundred consecutive deaths of transient ischemic attack or ischemic stroke patients were identified (January 2000-September 2001) from an ongoing population-based stroke surveillance study in Texas, The Brain Attack Surveillance in Corpus Christi Project. Two neurologists independently recorded the cause of death based on two methods: 1) determining the underlying cause of death as defined by the World Health Organization, and 2) determining whether the death was stroke related. Kappa statistics with 95% confidence intervals were calculated by comparing agreement between methods within reviewers and between reviewers within methods. Agreement between the two cause-of-death-determination methods for each neurologist was 0.41 (95% confidence interval (CI): 0.31, 0.51) and 0.47 (95% CI: 0.38, 0.58), respectively. Agreement between neurologists for the underlying-cause-of-death method was 0.46 (95% CI: 0.32, 0.60); for the stroke-related method, it was 0.63 (95% CI: 0.52, 0.75). Accurate, reliable determinations of cause of death after stroke/transient ischemic attack are not currently feasible. More research is needed to identify a reliable process for coding cause of death from stroke.

Kids Identifying and Defeating Stroke (KIDS): design of a school-based intervention to improve stroke awareness

BACKGROUND

We describe the design and baseline data of an educational intervention targeting predominantly Mexican American middle school students and their parents in an effort to improve stroke awareness. Increasing awareness in this group may increase the number of patients eligible for acute stroke treatment by encouraging emergency medical services (EMS) activation.

METHODS

This is a prospective, randomized study in which six middle schools were randomly assigned to receive a stroke education program or the standard health class. Primary outcome measures are the percentage of students and parents who recognize stroke symptoms and express the intent to activate EMS upon recognition of these findings.

RESULTS

A total of 547 students (271 control, 276 intervention) and 484 parents (231 control, 253 intervention) have been enrolled. Pretests were administered. The intervention has been successfully carried out in the parent and student cohorts over a three-year period. Posttests and persistence test results are pending.

CONCLUSION

Implementing a school-based stroke education initiative is feasible. Followup testing will demonstrate whether this educational initiative translates into a measurable and persistent improvement in stroke knowledge and behavioral intent to activate EMS upon recognition of stroke symptoms.

Ethnic differences in stroke recurrence

OBJECTIVE

To determine whether stroke recurrence and the effect of recurrence on mortality differ by ethnicity.

METHODS

Using methods from the Brain Attack Surveillance in Corpus Christi project, we prospectively identified first-ever ischemic strokes from emergency department logs and hospital admissions (January 2000 to December 2004). Recurrent strokes and deaths were identified for the same period. Cumulative probability of stroke recurrence was estimated. Cox proportional hazards models were used to examine ethnic differences in recurrence and to examine the relation among ethnicity, recurrence, and mortality.

RESULTS

During the time interval, 1,345 first-ever ischemic strokes were validated. Median age of patients was 72 years; 53% were Mexican American (MA). There were 126 recurrent strokes. Cumulative risk for recurrence at 30 days and 1 year was 2.6 and 7.5%, respectively. MAs had higher risk for stroke recurrence (risk ratio, 1.57; 95% confidence interval, 1.05-2.34) compared with non-Hispanic white patients, adjusted for demographics, stroke risk factors, and stroke severity. Stroke recurrence was related to mortality to a similar extent across ethnic groups (non-Hispanic white patients: risk ratio, 3.32; 95% confidence interval, 2.07-5.32; MAs: risk ratio, 2.35; 95% confidence interval, 1.42-3.88).

INTERPRETATION

MAs had higher stroke recurrence risk compared with non-Hispanic white patients. Stroke recurrence had an important impact on mortality. Efforts to reduce stroke recurrence in MAs are needed.

Increased risk of death in community-dwelling older people with white matter hyperintensities on MRI

BACKGROUND

Previous studies in subjects with a history of stroke have shown that white matter hyperintensities (WMH) on MRI are associated with increased risk of death. However, it has not been determined whether WMH are independently related to death in community-dwelling older people without stroke.

METHODS

In a sample of community-dwelling people over 75 years with no history of stroke or other neurological diseases, WMH on brain MRI T2-weighted sequences were classified as grade 0, grade 1, or grade 2. Grade 2 WMH were identified in 36 subjects. Age- and sex-matched grade 0 and grade 1 WMH groups were selected for comparison to the grade 2 WMH group. All subjects underwent an initial clinical evaluation and were followed for a median of 11.8 years (interquartile range=10.7 to 12.2 years). Cox proportional-hazards analysis was used to determine the independent association between WMH and time to death from any cause.

RESULTS

In an unadjusted analysis, grade 2 WMH was associated with death from any cause (hazard ratio=1.98; 95% confidence interval=1.06, 3.70). After adjustment for hypertension, high cholesterol, diabetes, and coronary artery disease, grade 2 WMH remained significantly associated with death (hazard ratio=2.31; 95% confidence interval=1.21, 4.40) in these age- and sex-matched groups.

CONCLUSIONS

Severe WMH increase the risk of death, even in community-dwelling elderly without stroke or other neurological disease, independent of other covariates including hypertension, age, and coronary artery disease.

Barriers to intravenous tissue plasminogen activator for acute stroke therapy in women

BACKGROUND

Given the increased lifetime risk of stroke and worse stroke outcomes in women, it is imperative to improve access to acute stroke therapy in the female population.

OBJECTIVE

The goals of this review were to analyze data comparing IV tissue plasminogen activator (tPA) use by sex, examine the literature regarding barriers to acute stroke therapy in women, and suggest areas for future research to improve understanding of these barriers as well as access in this population.

METHODS

The authors reviewed the MEDLINE literature (using the terms: stroke, women, gender, sex, tissue plasminogen activator, barriers, knowledge, risk factors, recognition, awareness, delay, presentation, access, and symptoms in various combinations) from January 1, 1996, through February 28, 2006, identified by various search strategies and the reference lists of retrieved articles.

RESULTS

Some evidence suggests that there may be less utilization of IV tPA in women compared with men. Stroke knowledge remains low for both sexes, but little is known about the recognition and translation of stroke symptoms in women. Although sex differences in out-of-hospital delays are not widespread, there is some evidence to suggest that, due to in-hospital delays during acute stroke, access to care may be more problematic for women. Overall, barriers to acute stroke therapy in women are not well understood.

CONCLUSION

tPA utilization is poor overall and may be poorer still in women than in men. Future research is needed to understand women's response to specific stroke symptoms, to elucidate sex differences in acute stroke symptom presentation, to determine reasons for in-hospital delays in women with stroke, and to understand sex-specific differences in response to acute stroke therapy. These research results may then aid in the development of intervention strategies that target women and affect physicians' decisions regarding the use of tPA in this population.

Projected costs of ischemic stroke in the United States

BACKGROUND

There are barriers to acute stroke care in minority groups as well as a higher incidence of ischemic stroke when compared with non-Hispanic whites.

OBJECTIVE

To estimate the future economic burden of stroke in non-Hispanic whites, Hispanics, and African Americans in the United States from 2005 to 2050.

METHODS

We used U.S. Census estimates of the race-ethnic group populations age 45 years and older. We obtained stroke epidemiology and service utilization data from the Northern Manhattan Stroke Study and the Brain Attack Surveillance in Corpus Christi project and other published data. We estimated costs directly from Medicare reimbursement or from studies that used Medicare reimbursement. Direct and indirect costs considered included ambulance services, initial hospitalization, rehabilitation, nursing home costs, outpatient clinic visits, drugs, informal caregiving, and potential lost earnings.

RESULTS

The total cost of stroke from 2005 to 2050, in 2005 dollars, is projected to be 1.52 trillion dollars for non-Hispanic whites, 313 billion dollars for Hispanics, and 379 billion dollars for African Americans. The per capita cost of stroke estimates are highest in African Americans (25,782 dollars), followed by Hispanics (17,201 dollars), and non-Hispanic whites (15,597 dollars). Loss of earnings is expected to be the highest cost contributor in each race-ethnic group.

CONCLUSIONS

The economic burden of stroke in African Americans and Hispanics will be enormous over the next several decades. Further efforts to improve stroke prevention and treatment in these high stroke risk groups are necessary.

Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study

BACKGROUND AND PURPOSE

Dizziness, vertigo, and imbalance are common presenting symptoms in the emergency department. Stroke is a leading concern even when these symptoms occur in isolation. The objective of the present study was to determine the "real-world" proportion of stroke among patients presenting to the emergency department with these dizziness symptoms (DS).

METHODS

From a population-based study, patients >44 years of age presenting with DS to the emergency department, or directly admitted to the hospital, were identified. Demographics, the frequency of new cerebrovascular events, and the frequency of isolated DS (ie DS with no other stroke screening term or accompanying neurologic signs or symptoms) were assessed. Multivariable logistic regression was used to evaluate the association of age, gender, ethnicity, and isolated DS with stroke/transient ischemic attack (TIA). The association of the presenting symptoms with stroke/TIA was also assessed.

RESULTS

Stroke/TIA was diagnosed in 3.2% (53 of 1666) of all patients with DS. Only 0.7% (9 of 1297) of those with isolated DS had a stroke/TIA. Patients with stroke/TIA were slightly older than those without stroke/TIA (69.3+/-11.7 vs 65.3+/-12.9, P=0.02). Male gender was associated with stroke/TIA, whereas isolated DS was negatively associated with stroke/TIA. Patients with imbalance (dizziness as referent) were more likely to have stroke/TIA.

CONCLUSIONS

The proportion of cerebrovascular events in patients presenting with dizziness, vertigo, or imbalance is very low. Isolated dizziness, vertigo, or imbalance strongly predicts a noncerebrovascular cause. The symptom of imbalance is a predictor of stroke/TIA.

Longitudinal assessment of noninvasive positive pressure ventilation adjustments in ALS patients

The absence of data guiding optimal titration of noninvasive positive pressure ventilation (NIPPV) over time in ALS patients may contribute to the under-prescribing of NIPPV. We conducted a retrospective, single-center, chart review assessment of NIPPV pressure settings used for symptomatic treatment of ALS patients to determine NIPPV adjustments, and to compare survival between those who were tolerant and intolerant to NIPPV. All subjects were started on nocturnal NIPPV at 8 and 3 cm H2O inspiratory and expiratory pressure, respectively. Of the 18 tolerant subjects identified, 4 (22%) had no NIPPV pressure changes before death; 8 (44%), 1 change; 4 (22%), 2 changes; 1 (6%), 3 changes; and 1 (6%), 5 changes. Most pressure changes occurred during the first year of NIPPV initiation. The maximum pressure needed for comfort by any patient in this study was 19/5 cm H2O, while 4 (22%) found the original 8/3 cm H2O settings to be sufficient until death. Subjects in the tolerant group had better survival, when adjusting for age and site of symptom onset (bulbar versus limb), with a hazard ratio of 0.23 [95% confidence interval: 0.10, 0.54]. The current data suggest that ALS patients who are tolerant to NIPPV typically need at least one upward change in pressure settings. Tolerance to relatively low NIPPV inspiratory pressures is associated with improved survival.

Stroke Information Reported on Local Television News

Background and Purpose— Local television news commonly reports on health. This study aimed to characterize local TV news stroke reporting in America.

Methods— Content analysis of stroke stories reported on 122 US local television stations. All stroke stories were coded for main focus and discussion of risk factors, stroke signs and symptoms, recombinant tissue plasminogen activator, treatment within 3 hours, or recommendation to call 911.

Results— Of the 1799 health stories, only 13 stroke stories aired, and the median story length was 24 seconds (interquartile range 21 to 48). Stroke was the 22nd most common health topic. Few stroke stories discussed useful information about prevention or treatment of stroke.

Conclusion— Stroke stories were nearly nonexistent in our sample, and those reported failed to discuss important messages needed to improve stroke prevention and treatment.

Differences in intracerebral hemorrhage between Mexican Americans and non-Hispanic whites

BACKGROUND

Mexican Americans (MAs) have higher incidence rates of intracerebral hemorrhage (ICH) than non-Hispanic whites (NHWs). The authors present clinical and imaging characteristics of ICH in MAs and NHWs in a population-based study.

METHODS

This work is part of the Brain Attack Surveillance in Corpus Christi (BASIC) project. Cases of nontraumatic ICH were identified from 2000 to 2003. Multivariable logistic regression was used to assess the independent associations between ethnicity and ICH location (lobar vs nonlobar) and volume (> or = 30 vs < 30 mL), adjusting for demographics and baseline clinical characteristics. Logistic regression was also used to determine the association between ethnicity and in-hospital mortality, adjusting for confounders.

RESULTS

A total of 149 MAs and 111 NHWs with ICH were identified. MAs were younger (70 vs 77, p < 0.001), more often male (55% vs 42%, p = 0.04), had a lower prevalence of atrial fibrillation (2.0% vs 13%, p < 0.001), and a higher prevalence of diabetes (39% vs 19%, p < 0.001). MA ethnicity was independently associated with nonlobar hemorrhage (OR 2.08, 95% CI: 1.15, 3.70). MAs had over two times the odds of having small (< 30 mL) hemorrhages compared with NHWs (OR = 2.41, 95% CI: 1.31, 4.46). NHWs had higher in-hospital mortality, though this association was no longer significant after adjustment for ICH volume, location, age, and sex.

CONCLUSIONS

There are significant differences in the characteristics of ICH in MAs and NHWs, with MA patients more likely to have smaller, nonlobar hemorrhages. These differences may be used to examine the underlying pathophysiology of ICH.

Sleep disorders and stroke

Obstructive sleep apnea (OSA) is a very common condition in patients with stroke and is found in over half of stroke patients. There is a complex relationship between OSA and stroke, attributable to shared risk factors. There are numerous mechanisms by which OSA may contribute to increased stroke risk, including promotion of atherosclerosis, hypercoagulability, and adverse effects on cerebral hemodynamics. Obstructive sleep apnea is also a risk factor for hypertension, and likely for atrial fibrillation and diabetes, conditions that in turn are risk factors for stroke. OSA is also associated with poor outcomes following stroke. Further epidemiological studies are needed to assess the relationship between OSA and stroke better. Clinical trials using continuous positive airway pressure as a treatment for OSA in stroke patients are needed to determine whether treatment of this condition alters outcome following stroke.

Gender comparisons of diagnostic evaluation for ischemic stroke patients

BACKGROUND

Sixty-two percent of all stroke deaths in the United States occur in women. We compared diagnostic evaluations by gender in ischemic stroke patients in a biethnic, population-based study.

METHODS

A random sample of patients with ischemic stroke identified between 2000 and 2002 by BASIC (Brain Attack Surveillance in Corpus Christi Project) were selected for this study (n = 381). Gender differences in the use of stroke diagnostic tests were assessed. Separate multivariable logistic regression models predicting diagnostic test use were constructed, adjusted for age, ethnicity, hypertension, atrial fibrillation, diabetes, history of stroke, coronary artery disease, having a primary care provider, discharge disposition, modified Rankin Scale score at discharge, and insurance status.

RESULTS

The study population consisted of 161 men and 220 women. Median age was 74.3 years. The respective proportions of males and females receiving any carotid artery evaluation were 71% and 62%; brain MRI, 43% and 41%; echocardiography, 57% and 48%; and EKG, 90% and 86%. Multivariable logistic models found that women were less likely to undergo echocardiography (odds ratio [OR] 0.64, CI: 0.42 to 0.98) and carotid evaluation (OR 0.57, CI: 0.36 to 0.91). There was no association of ischemic stroke subtype and gender to explain these results (p = 0.76).

CONCLUSIONS

Despite controlling for explanatory variables, women with stroke were less likely to receive standard diagnostic tests vs men. Intervention is needed to increase access to quality stroke care for women.

Presentation of intracerebral haemorrhage in a community

BACKGROUND

Studies on intracerebral haemorrhage (ICH) from tertiary care centres may not be an accurate representation of the true spectrum of disease presentation.

OBJECTIVE

To describe the clinical and imaging presentation of ICH in a community devoid of the referral bias of an academic medical centre; and to investigate factors associated with lower Glasgow coma scale (GCS) score at presentation, as GCS is crucial to early clinical decision making.

METHODS

The study formed part of the BASIC project (Brain Attack Surveillance in Corpus Christi), a population based stroke surveillance study in a bi-ethnic Texas community. Cases of first non-traumatic ICH were identified from years 2000 to 2003, using active and passive surveillance. Clinical data were collected from medical records by trained abstractors, and all computed tomography (CT) scans were reviewed by a study physician. Multivariable linear regression was used to identify clinical and CT predictors of a lower GCS score.

RESULTS

260 cases of non-traumatic ICH were identified. Median ICH volume was 11 ml (interquartile range 3 to 36) with hydrocephalus noted in 45%. Median initial GCS score was 12.5 (7 to 15). Hydrocephalus score (p = 0.0014), ambient cistern effacement (p = 0.0002), ICH volume (p = 0.014), and female sex (p = 0.024) were independently associated with lower GCS score at presentation, adjusting for other variables.

CONCLUSIONS

ICH has a wide range of severity at presentation. Hydrocephalus is a potentially reversible cause of a lower GCS score. Since early withdrawal of care decisions are often based on initial GCS, recognition of the important influence of hydrocephalus on GCS is warranted before withdrawal of care decisions are made.

Vascularized tissue‐engineered chambers promote survival and function of transplanted islets and improve glycemic control

We have developed a chamber model of islet engraftment that optimizes islet survival by rapidly restoring islet-extracellular matrix relationships and vascularization. Our aim was to assess the ability of syngeneic adult islets seeded into blood vessel-containing chambers to correct streptozotocin-induced diabetes in mice. Approximately 350 syngeneic islets suspended in Matrigel extracellular matrix were inserted into chambers based on either the splenic or groin (epigastric) vascular beds, or, in the standard approach, injected under the renal capsule. Blood glucose was monitored weekly for 7 weeks, and an intraperitoneal glucose tolerance test performed at 6 weeks in the presence of the islet grafts. Relative to untreated diabetic animals, glycemic control significantly improved in all islet transplant groups, strongly correlating with islet counts in the graft (P<0.01), and with best results in the splenic chamber group. Glycemic control deteriorated after chambers were surgically removed at week 8. Immunohistochemistry revealed islets with abundant insulin content in grafts from all groups, but with significantly more islets in splenic chamber grafts than the other treatment groups (P<0.05). It is concluded that hyperglycemia in experimental type 1 diabetes can be effectively treated by islets seeded into a vascularized chamber functioning as a "pancreatic organoid."

Family history and stroke outcome in a bi-ethnic, population-based stroke surveillance study

Background

The genetic epidemiology of ischemic stroke remains relatively unstudied, and information about the genetic epidemiology of ischemic stroke in populations with significant minority representation is currently unavailable.

Methods

The Brain Attack Surveillance in Corpus Christi project (BASIC) is a population-based stroke surveillance study conducted in the bi-ethnic community of Nueces County, Texas, USA. Completed ischemic strokes were identified among patients 45 years or older seen at hospitals in the county between January 1, 2000 – December 31, 2002. A random sample of ischemic stroke patients underwent an in-person interview and detailed medical record abstraction (n = 400). Outcomes, including initial stroke severity (NIH stroke scale), age at stroke onset, 90-day mortality and functional outcome (modified Rankin scale ≥2), were studied for their association with family history of stroke among a first degree relative using multivariable logistic and linear regression. A chi-square test was used to test the association between family history of stroke and ischemic stroke subtype.

Results

The study population was 53.0% Mexican American and 58.4% female. Median age was 73.2 years. Forty percent reported a family history of stroke among a first degree relative. Family history of stroke was borderline significantly associated with stroke subtype (p = 0.0563). Family history was associated with poor functional outcome in the multivariable model (OR = 1.87; 95% CI: 1.14–3.09). Family history was not significantly related to initial stroke severity, age at stroke onset, or 90-day mortality.

Conclusion

Family history of stroke was related to ischemic stroke subtype and to functional status at discharge. More research is needed to understand whether stroke subtype would be a useful selection criterion for genetic association studies and to hypothesize about a possible genetic link to recovery following ischemic stroke.

Is It Time for a Large, Collaborative Study of Pediatric Stroke?

Background and Purpose— A 2002 report from the National Institute of Neurological Disorders and Stroke cited the critical importance of more childhood stroke studies. We present the incidence rate of pediatric stroke from a biethnic community-based project and calculate the population size required for future prospective studies of pediatric stroke.

Methods— This work is part of the Brain Attack Surveillance in Corpus Christi (BASIC) project. The community of 325 000 is located in southeast Texas and is composed of approximately equal numbers of Mexican Americans (MAs) and non-Hispanic whites (NHWs). Discharge diagnosis codes from all hospitals in the county were used to identify cases of childhood stroke (age >1 month and <20 years) in 2002 and 2003, and stroke cases were validated by source document review. On the basis of the incidence rates, the population size required to complete a case-control study to examine risk factors for pediatric stroke was calculated.

Results— Eight cases of pediatric stroke were identified, yielding an annual incidence rate of 4.3 per 100 000 (95% CI, 1.9 to 8.5). There were 5 cases of intracerebral hemorrhage, 1 subarachnoid hemorrhage, 1 ischemic stroke, and 1 transient ischemic attack. All of the events occurred in MAs. Depending on the prevalence of the risk factors of interest, future studies of pediatric stroke would have to draw from a population of up to 59 million children to complete a case-control study within 4 years.

Conclusions— Given the rarity of pediatric stroke, future studies will require multicenter efforts and possibly a national surveillance system.

The cost-effectiveness of early noninvasive ventilation for ALS patients

Background

Optimal timing of noninvasive positive pressure ventilation (NIPPV) initiation in patients with amyotrophic lateral sclerosis (ALS) is unknown, but NIPPV appears to benefit ALS patients who are symptomatic from pulmonary insufficiency. This has prompted research proposals of earlier NIPPV initiation in the ALS disease course in an attempt to further improve ALS patient quality of life and perhaps survival. We therefore used a cost-utility analysis to determine a priori what magnitude of health-related quality of life (HRQL) improvement early NIPPV initiation would need to achieve to be cost-effective in a future clinical trial.

Methods

Using a Markov decision analytic model we calculated the benefit in health-state utility that NIPPV initiated at ALS diagnosis must achieve to be cost-effective. The primary outcome was the percent utility gained through NIPPV in relation to two common willingness-to-pay thresholds: $50,000 and $100,000 per quality-adjusted life year (QALY).

Results

Our results indicate that if NIPPV begun at the time of diagnosis improves ALS patient HRQL as little as 13.5%, it would be a cost-effective treatment. Tolerance of NIPPV (assuming a 20% improvement in HRQL) would only need to exceed 18% in our model for treatment to remain cost-effective using a conservative willingness-to-pay threshold of $50,000 per QALY.

Conclusion

If early use of NIPPV in ALS patients is shown to improve HRQL in future studies, it is likely to be a cost-effective treatment. Clinical trials of NIPPV begun at the time of ALS diagnosis are therefore warranted from a cost-effectiveness standpoint.

Emergency department evaluation of ischemic stroke and TIA: the BASIC Project

OBJECTIVE

To identify demographic and clinical variables of emergency department (ED) practices in a community-based acute stroke study.

METHODS

By both active and passive surveillance, the authors identified cerebrovascular disease cases in Nueces County, TX, as part of the Brain Attack Surveillance in Corpus Christi (BASIC) Project, a population-based stroke surveillance study, between January 1, 2000, and December 31, 2002. With use of multivariable logistic regression, variables independently associated with three separate outcomes were sought: hospital admission, brain imaging in the ED, and neurologist consultation in the ED. Prespecified variables included age, sex, ethnicity, insurance status, NIH Stroke Scale score, type of stroke (ischemic stroke or TIA), vascular risk factors, and symptom presentation variables. Percentage use of recombinant tissue plasminogen activator (rt-PA) was calculated.

RESULTS

A total of 941 Mexican Americans (MAs) and 855 non-Hispanic whites (NHWs) were seen for ischemic stroke (66%) or TIA (34%). Only 8% of patients received an in-person neurology consultation in the ED, and 12% did not receive any head imaging. TIA was negatively associated with neurology consultations compared with completed stroke (odds ratio [OR] 0.35 [95% CI 0.21 to 0.57]). TIA (OR 0.14 [0.10 to 0.19]) and sensory symptoms (OR 0.59 [0.44 to 0.81]) were also negatively associated with hospital admission. MAs (OR 0.58 [0.35 to 0.98]) were less likely to have neurology consultations in the ED than NHWs. Only 1.7% of patients were treated with rt-PA.

CONCLUSIONS

Neurologists are seldom involved with acute cerebrovascular care in the emergency department (ED), especially in patients with TIA. Greater neurologist involvement may improve acute stroke diagnosis and treatment efforts in the ED.

Stroke burden in Mexican Americans: the impact of mortality following stroke

PURPOSE

To estimate ethnic-specific all-cause mortality risk following ischemic stroke and to compare mortality risk by ethnicity.

METHODS

DATA from the Brain Attack Surveillance in Corpus Christi Project, a population-based stroke surveillance study, were used. Stroke cases between January 1, 2000 and December 31, 2002 were identified from emergency department (ED) and hospital sources (n = 1,234). Deaths for the same period were identified from the surveillance of stroke cases, the Texas Department of Health, the coroner, and the Social Security Death Index. Ethnic-specific all-cause cumulative mortality risk was estimated at 28 days and 36 months using Kaplan Meier analysis. Cox proportional hazards regression was used to compare mortality risk by ethnicity.

RESULTS

Cumulative 28-day all-cause mortality risk for Mexican Americans (MAs) was 7.8% and for non-Hispanic whites (NHWs) was 13.5%. Cumulative 36-month all-cause mortality risk was 31.3% in MAs and 47.2% in NHWs. MAs had lower 28-day (RR = 0.58; 95% CI: 0.41, 0.84) and 36-month all-cause mortality risk (RR = 0.79, 95% CI: 0.64, 0.98) compared with NHWs, adjusted for confounders.

CONCLUSIONS

Better survival after stroke in MAs is surprising considering their similar stroke subtype and severity compared with NHWs. Social or psychological factors, which may explain this difference, should be explored.

Survey of Emergency Physicians About Recombinant Tissue Plasminogen Activator for Acute Ischemic Stroke

STUDY OBJECTIVE

The use of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke is controversial among emergency physicians. We survey emergency physicians to determine (1) the proportion of emergency physicians resistant to using rt-PA in the ideal setting because of the risk of symptomatic intracerebral hemorrhage; (2) the proportion of emergency physicians resistant to using rt-PA in the ideal setting because of the perceived lack of benefit; (3) the highest acceptable symptomatic intracerebral hemorrhage risk; and (4) the lowest acceptable accompanying relative improvement in neurologic outcome.

METHODS

The American College of Emergency Physicians randomly selected 2,600 of its active members for anonymous Web-based or paper survey. The proportion of ED physicians resistant to rt-PA use because of symptomatic intracerebral hemorrhage risk and perceived lack of benefit, in addition to the mean acceptable symptomatic intracerebral hemorrhage risk and associated benefit, was calculated with 95% confidence intervals (CIs). Multivariable logistic regression was used to identify factors independently associated with willingness to use rt-PA in the ideal setting.

RESULTS

The median age of the 1,105 (43%) respondents was 44 years. Overall, the mean upper limit of symptomatic intracerebral hemorrhage tolerable was 3.4% (95% CI 3.2% to 3.5%), with associated lowest acceptable mean relative improvement of 40% (95% CI 39% to 41%). Forty percent (95% CI 37% to 44%) of physicians reported that they were not likely to use rt-PA. Of these, 65% (95% CI 61% to 69%) of physicians reported this was because of the risk of symptomatic intracerebral hemorrhage, 23% (95% CI 19% to 27%) reported the cause was the perceived lack of benefit, and 12% (95% CI 9% to 15%) reported both reasons were the cause. Independently associated with willingness to use rt-PA were female sex (odds ratio 2.30 [1.57, 3.36]) and previous use of rt-PA for stroke (3.13 [2.33, 4.17]).

CONCLUSION

Symptomatic intracerebral hemorrhage risk is the factor most likely to preclude rt-PA use by emergency physicians. Of the 40% of physicians who would not use rt-PA, about two thirds reported this was due to symptomatic intracerebral hemorrhage risk, and about a quarter of physicians cited the relative lack of benefit. Treatment trials that aim to reduce symptomatic intracerebral hemorrhage risk to 2% to 3% are likely to stimulate the interest of emergency physicians in the use of thrombolytics for acute ischemic stroke.

Screening for Obstructive Sleep Apnea in Stroke Patients

Background and Purpose— Obstructive sleep apnea (OSA) is common after acute ischemic stroke and predicts poor stroke recovery, but whether screening for OSA and treatment by continuous positive airway pressure (CPAP) improves neurological outcome is unknown. We used a cost-effectiveness model to estimate the magnitude of benefit that would be necessary to make polysomnography (PSG) and OSA treatment cost-effective in stroke patients.

Methods— A decision tree modeled 2 alternative strategies: PSG followed by 3 months of CPAP for those found to have OSA versus no screening. The primary outcome was the utility gained through OSA screening and treatment in relation to 2 common willingness-to-pay thresholds of $50 000 and $100 000 per quality-adjusted life year (QALY).

Results— Screening resulted in an incremental cost-effectiveness ratio of $49 421 per QALY. Screening is cost-effective as long as the treatment of stroke patients with OSA by CPAP improves patient utilities by >0.2 for a willingness-to-pay of $50 000 per QALY and 0.1 for a willingness-to-pay of $100 000 per QALY.

Conclusions— A clinical trial assessing the effectiveness of CPAP in improving stroke outcome is warranted from a cost-effectiveness standpoint.