End to end stroke triage using cerebrovascular morphology and machine learning

Background

Rapid and accurate triage of acute ischemic stroke (AIS) is essential for early revascularization and improved patient outcomes. Response to acute reperfusion therapies varies significantly based on patient-specific cerebrovascular anatomy that governs cerebral blood flow. We present an end-to-end machine learning approach for automatic stroke triage.

Methods

Employing a validated convolutional neural network (CNN) segmentation model for image processing, we extract each patient's cerebrovasculature and its morphological features from baseline non-invasive angiography scans. These features are used to detect occlusion's presence and the site automatically, and for the first time, to estimate collateral circulation without manual intervention. We then use the extracted cerebrovascular features along with commonly used clinical and imaging parameters to predict the 90 days functional outcome for each patient.

Results

The CNN model achieved a segmentation accuracy of 94% based on the Dice similarity coefficient (DSC). The automatic stroke detection algorithm had a sensitivity and specificity of 92% and 94%, respectively. The models for occlusion site detection and automatic collateral grading reached 96% and 87.2% accuracy, respectively. Incorporating the automatically extracted cerebrovascular features significantly improved the 90 days outcome prediction accuracy from 0.63 to 0.83.

Conclusion

The fast, automatic, and comprehensive model presented here can improve stroke diagnosis, aid collateral assessment, and enhance prognostication for treatment decisions, using cerebrovascular morphology.

Novel imaging markers for altered cerebrovascular morphology in aging, stroke, and Alzheimer's disease

BACKGROUND AND PURPOSE

Altered brain vasculature is a key phenomenon in several neurologic disorders. This paper presents a quantitative assessment of the anatomical variations in the Circle of Willis (CoW) and vascular morphology in healthy aging, acute ischemic stroke (AIS) and Alzheimer's Disease (AD).

METHODS

We used our novel automatic method to segment and extract geometric features of the cerebral vasculature from MR angiography scans of 175 healthy subjects, which were used to create a probabilistic atlas of cerebrovasculature and to study normal aging and intersubject variations in CoW anatomy. Subsequently, we quantified and analyzed vascular alterations in 45AIS and 50 AD patients, two prominent cerebrovascular and neurodegenerative disorders.

RESULTS

In the sampled cohort, we determined that the CoW is fully formed in only 35% of healthy adults and found significantly (p < .05) increased tortuosity and fractality, with increasing age and also with disease in both AIS and AD. We also found significantly lower vessel length, volume, and number of branches in AIS patients, as expected. The AD cerebral vessels exhibited significantly smaller diameter and more complex branching patterns, compared to age-matched healthy adults. These changes were significantly heightened (p < .05) among healthy, early onset mild AD, and moderate/severe dementia groups.

CONCLUSION

Although our study does not include longitudinal data due to paucity of such datasets, the specific geometric features and quantitative comparisons demonstrate the potential for using vascular morphology as a noninvasive imaging biomarker for neurologic disorders.

Risk Factors Associated With Mortality and Neurologic Disability After Intracerebral Hemorrhage in a Racially and Ethnically Diverse Cohort

Introduction

Intracerebral hemorrhage (ICH) is the most severe subtype of stroke. Its mortality rate is high, and most survivors experience significant disability.

Objective

To assess primary patient risk factors associated with mortality and neurologic disability 3 months after ICH in a large, racially and ethnically balanced cohort.

Design, Setting, and Participants

This cohort study included participants from the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study, which prospectively recruited 1000 non-Hispanic White, 1000 non-Hispanic Black, and 1000 Hispanic patients with spontaneous ICH to study the epidemiological characteristics and genomics associated with ICH. Participants included those with uniform data collection and phenotype definitions, centralized neuroimaging review, and telephone follow-up at 3 months. Analyses were completed in November 2021.

Exposures

Patient demographic and clinical characteristics as well as hospital event and imaging variables were examined, with characteristics meeting P < .20 considered candidates for a multivariate model. Elements included in the ICH score were specifically analyzed.

Main Outcomes and Measures

Individual characteristics were screened for association with 3-month outcome of neurologic disability or mortality, as assessed by a modified Rankin Scale (mRS) score of 4 or greater vs 3 or less under a logistic regression model. A total of 25 characteristics were tested in the final model, which minimized the Akaike information criterion. Analyses were repeated removing individuals who had withdrawal of care.

Results

A total of 2568 patients (mean [SD] age, 62.4 [14.7] years; 1069 [41.6%] women and 1499 [58.4%] men) had a 3-month outcome determination available, including death. The final logistic model had a significantly higher area under the receiver operating characteristics curve (C = 0.88) compared with ICH score alone (C = 0.76; P < .001). Among characteristics associated with neurologic disability and mortality were larger log ICH volume (OR, 2.74; 95% CI, 2.36-3.19; P < .001), older age (OR per 1-year increase, 1.04; 95% CI, 1.02-1.05; P < .001), pre-ICH mRS score (OR, 1.62; 95% CI, 1.41-1.87; P < .001), lobar location (OR, 0.22; 95% CI, 0.16-0.30; P < .001), and presence of infection (OR, 1.85; 95% CI, 1.42-2.41; P < .001).

Conclusions and Relevance

The findings of this cohort study validate ICH score elements and suggest additional baseline and interim patient characteristics were associated with variation in 3-month outcome.

Midline Shift Greater than 3 mm Independently Predicts Outcome After Ischemic Stroke

BACKGROUND

Cerebral edema is associated with worse outcome after acute stroke; however, the minimum clinically relevant threshold remains unknown. This study aimed to identify the minimal degree of midline shift (MLS) that predicts outcome in a cohort encompassing a broad range of patients with acute stroke.

METHODS

Patient-level data from six acute stroke clinical trials were combined with endovascular thrombectomy registries from two academic referral centers, generating a combined cohort of 1977 patients. MLS was extracted from the original trial data or measured on computed tomography or magnetic resonance imaging that was obtained a median of 47.0 h (interquartile range 27.0-75.1 h) after stroke onset. Logistic regression was performed to identify predictors of poor outcome and the minimal clinically relevant MLS threshold.

RESULTS

The presence of MLS was a predictor of poor outcome, independent of baseline clinical and demographic factors (adjusted odds ratio 4.46, 95% confidence interval 3.56-5.59, p < 0.001). Examining the full range of MLS values identified, a value of greater than 3 mm was the critical threshold that significantly predicted poor outcome (adjusted odds ratio 3.20 [1.31-7.82], p = 0.011).

CONCLUSIONS

These results show that the presence of MLS predicts poor outcome and, specifically, MLS value greater than 3 mm is an important threshold across a variety of clinical settings. These findings may have relevance for the design and interpretation of future trials for antiedema therapies.

Deep learning-based detection and segmentation of diffusion abnormalities in acute ischemic stroke

Background

Accessible tools to efficiently detect and segment diffusion abnormalities in acute strokes are highly anticipated by the clinical and research communities.

Methods

We developed a tool with deep learning networks trained and tested on a large dataset of 2,348 clinical diffusion weighted MRIs of patients with acute and sub-acute ischemic strokes, and further tested for generalization on 280 MRIs of an external dataset (STIR).

Results

Our proposed model outperforms generic networks and DeepMedic, particularly in small lesions, with lower false positive rate, balanced precision and sensitivity, and robustness to data perturbs (e.g., artefacts, low resolution, technical heterogeneity). The agreement with human delineation rivals the inter-evaluator agreement; the automated lesion quantification of volume and contrast has virtually total agreement with human quantification.

Conclusion

Our tool is fast, public, accessible to non-experts, with minimal computational requirements, to detect and segment lesions via a single command line. Therefore, it fulfills the conditions to perform large scale, reliable and reproducible clinical and translational research.

Automatic segmentation, feature extraction and comparison of healthy and stroke cerebral vasculature

Accurate segmentation of cerebral vasculature and a quantitative assessment of its morphology is critical to various diagnostic and therapeutic purposes and is pertinent to studying brain health and disease. However, this is still a challenging task due to the complexity of the vascular imaging data. We propose an automated method for cerebral vascular segmentation without the need of any manual intervention as well as a method to skeletonize the binary segmented map to extract vascular geometric features and characterize vessel structure. We combine a Hessian-based probabilistic vessel-enhancing filtering with an active-contour-based technique to segment magnetic resonance and computed tomography angiograms (MRA and CTA) and subsequently extract the vessel centerlines and diameters to calculate the geometrical properties of the vasculature. Our method was validated using a 3D phantom of the Circle-of-Willis region, demonstrating 84% mean Dice similarity coefficient (DSC) and 85% mean Pearson's correlation coefficient (PCC) with minimal modified Hausdorff distance (MHD) error (3 surface pixels at most), and showed superior performance compared to existing segmentation algorithms upon quantitative comparison using DSC, PCC and MHD. We subsequently applied our algorithm to a dataset of 40 subjects, including 1) MRA scans of healthy subjects (n = 10, age = 30 ± 9), 2) MRA scans of stroke patients (n = 10, age = 51 ± 15), 3) CTA scans of healthy subjects (n = 10, age = 62 ± 12), and 4) CTA scans of stroke patients (n = 10, age = 68 ± 11), and obtained a quantitative comparison between the stroke and normal vasculature for both imaging modalities. The vascular network in stroke patients compared to age-adjusted healthy subjects was found to have a significantly (p < 0.05) higher tortuosity (3.24 ± 0.88 rad/cm vs. 7.17 ± 1.61 rad/cm for MRA, and 4.36 ± 1.32 rad/cm vs. 7.80 ± 0.92 rad/cm for CTA), higher fractal dimension (1.36 ± 0.28 vs. 1.71 ± 0.14 for MRA, and 1.56 ± 0.05 vs. 1.69 ± 0.20 for CTA), lower total length (3.46 ± 0.99 m vs. 2.20 ± 0.67 m for CTA), lower total volume (61.80 ± 18.79 ml vs. 34.43 ± 22.9 ml for CTA), lower average diameter (2.4 ± 0.21 mm vs. 2.18 ± 0.07 mm for CTA), and lower average branch length (4.81 ± 1.97 mm vs. 8.68 ± 2.03 mm for MRA), respectively. We additionally studied the change in vascular features with respect to aging and imaging modality. While we observed differences between features as a result of aging, statistical analysis did not show any significant differences, whereas we found that the number of branches were significantly different (p < 0.05) between the two imaging modalities (201 ± 73 for MRA vs. 189 ± 69 for CTA). Our segmentation and feature extraction algorithm can be applied on any imaging modality and can be used in the future to automatically obtain the 3D segmented vasculature for diagnosis and treatment planning as well as to study morphological changes due to stroke and other cerebrovascular diseases (CVD) in the clinic.

A Pooled Analysis of Diffusion-Weighted Imaging Lesions in Patients With Acute Intracerebral Hemorrhage

Importance

The etiology and significance of diffusion-weighted imaging (DWI) lesions in patients with acute intracerebral hemorrhage (ICH) remain unclear.

Objective

To evaluate which factors are associated with DWI lesions, whether associated factors differ by ICH location, and whether DWI lesions are associated with functional outcomes.

Design, Setting, and Participants

This analysis pooled individual patient data from 3 randomized clinical trials (Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation phase 3 trial, Antihypertensive Treatment of Acute Cerebral Hemorrhage trial, and Intracerebral Hemorrhage Deferoxamine phase 2 trial) and 1 multicenter prospective study (Ethnic/Racial Variations of Intracerebral Hemorrhage). Patients were enrolled from August 1, 2010, to September 30, 2018. Of the 4782 patients, 1788 who underwent magnetic resonance imaging scans of the brain were included. Data were analyzed from July 1 to December 31, 2019.

Main Outcomes and Measures

The primary outcome consisted of factors associated with DWI lesions. Secondary outcomes were poor functional outcome, defined as a modified Rankin score (mRS) of 4 to 6, and mortality, both assessed at 3 months. Mixed-effects logistic regression was used to evaluate the association between exposures and outcomes. Subgroup analyses stratified by hematoma location were performed.

Results

After exclusion of 36 patients with missing data on DWI lesions, 1752 patients were included in the analysis (1019 men [58.2%]; mean [SD] age, 60.8 [13.3] years). Diffusion-weighted imaging lesions occurred in 549 patients (31.3%). In mixed-effects regression models, factors associated with DWI lesions included younger age (odds ratio [OR] per year, 0.98; 95% CI, 0.97-0.99), black race (OR, 1.64; 95% CI, 1.17-2.30), admission systolic blood pressure (OR per 10-mm Hg increase, 1.13; 95% CI, 1.08-1.18), baseline hematoma volume (OR per 10-mL increase, 1.12; 95% CI, 1.02-1.22), cerebral microbleeds (OR, 1.85; 95% CI, 1.39-2.46), and leukoaraiosis (OR, 1.59; 95% CI, 1.67-2.17). Diffusion-weighted imaging lesions were independently associated with poor mRS (OR, 1.50; 95% CI, 1.13-2.00), but not with mortality (OR, 1.11; 95% CI, 0.72-1.71). In subgroup analyses, similar factors were associated with DWI lesions in lobar and deep ICH. Diffusion-weighted imaging lesions were associated with poor mRS in deep but not lobar ICH.

Conclusions and Relevance

In a large, heterogeneous cohort of prospectively identified patients with ICH, results were consistent with the hypothesis that DWI lesions represent acute sequelae of chronic cerebral small vessel disease, particularly hypertensive vasculopathy. Diffusion-weighted imaging lesions portend a worse prognosis after ICH, mainly deep hemorrhages.

Abstract 18: Diffusion Weighted Imaging Lesions in Patients With Acute Intracerebral Hemorrhage: A Pooled Analysis of Individual Patient Data From MISTIE-III, ATACH-II, I-DEF, and ERICH

Introduction: The etiology and significance of diffusion weighted imaging (DWI) lesions in patients with acute intracerebral hemorrhage (ICH) remain unclear. We evaluated which factors were associated with DWI lesions, whether associated factors differed by ICH location, and whether DWI lesions were associated with functional outcomes.

Methods: We pooled individual patient data from the MISTIE III trial, the ATACH-II trial, the i-DEF trial, and the ERICH study. We included only patients who underwent protocolized magnetic resonance imaging (MRI) of the brain. A poor functional outcome was defined as a modified Rankin Scale (mRS) score of 4-6 at 3-6 months. We used mixed effects logistic regression with the study database as a random effect.

Results: Among 1,775 ICH patients, there were 621 (35.6%) lobar, 978 (55.9%) deep, and 148 (8.5%) infratentorial ICHs. Median time to MRI scan was 1.5 days (IQR, 1-4). DWIHLs occurred in 559 (31.5%) patients, with 190 (34.3%) in lobar ICH and 320 (57.8%) in deep ICHs. In mixed effects regression models, factors associated with DWIHLs included younger age factors associated with DWIHLs after acute ICH included younger age (OR, 0.98; 95% CI, 0.97-0.99), black race (OR, 1.59; 95% CI, 1.18-2.16), admission systolic blood pressure (SBP per 10 mm Hg, OR, 1.13; 95% CI, 1.05-1.22), cerebral microbleeds (OR, 1.71, 95% CI, 1.24-2.35), and leukoaraiosis (OR, 1.60; 95% CI, 1.14-2.25). Patients with DWIHLs had higher odds of mRS 4-6 (OR, 1.57; 95% CI, 1.24-1.99) compared to those without, after adjustment for demographics and ICH severity. In subgroup analyses, similar factors influenced DWIHLs in deep ICH. However, in lobar ICH, younger age, admission SBP, and leukoaraiosis were associated with DWIHLs. Presence of DWIHLs was independently associated with poor mRS in deep ICH but not in lobar ICH. There was no relationship between acute BP lowering and DWIHLs, regardless of location.

Conclusions: In a large, heterogeneous cohort of ICH patients, our results are consistent with the hypothesis that DWIHLs represent the effects of chronic hypertensive vasculopathy and acute blood pressure elevation. Furthermore, DWIHLs portend poor prognosis after ICH, particularly in deep hemorrhages.

Hypertension and intracerebral hemorrhage recurrence among white, black, and Hispanic individuals

OBJECTIVE

To clarify whether recurrence risk for intracerebral hemorrhage (ICH) is higher among black and Hispanic individuals and whether this disparity is attributable to differences in blood pressure (BP) measurements and their variability.

METHODS

We analyzed data from survivors of primary ICH enrolled in 2 separate studies: (1) the longitudinal study conducted at Massachusetts General Hospital (n = 759), and (2) the ERICH (Ethnic/Racial Variations of Intracerebral Hemorrhage) study (n = 1,532). Participants underwent structured interview at enrollment (including self-report of race/ethnicity) and were followed longitudinally via phone calls and review of medical records. We captured systolic BP (SBP) and diastolic BP measurements, and quantified variability as SBP and diastolic BP variation coefficients. We used multivariable (Cox regression) survival analysis to identify risk factors for ICH recurrence.

RESULTS

We followed 2,291 ICH survivors (1,121 white, 529 black, 605 Hispanic, and 36 of other race/ethnicity). Both black and Hispanic patients displayed higher SBP during follow-up (p < 0.05). Black participants also displayed greater SBP variability during follow-up (p = 0.032). In univariable analyses, black and Hispanic patients were at higher ICH recurrence risk (p < 0.05). After adjusting for BP measurements and their variability, both Hispanic (hazard ratio = 1.51, 95% confidence interval 1.14-2.00, p = 0.004) and black (hazard ratio = 1.98, 95% confidence interval 1.36-2.86, p < 0.001) patients remained at higher risk of ICH recurrence.

CONCLUSION

Black and Hispanic patients are at higher risk of ICH recurrence; hypertension severity (average BP and its variability) does not fully account for this finding. Additional studies will be required to further elucidate determinants for this health disparity.

Factors Influencing Acute Stroke Thrombolytic Treatments in Hispanics In the San Diego Region

BACKGROUND

Since the introduction of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke, rt-PA rate and number of stroke centers have increased. Despite this, studies have shown racial and ethnic disparities in stroke care especially in Black and Hispanic populations. What factors are related to the administration of rt-PA within the Hispanic population has to date been unclear.

METHODS

We performed a retrospective review of IRB approved, prospectively collected data from the UC San Diego Stroke Registry from 7/2004-7/2016. Patients were included based on the primary diagnosis of Transient Ischemic Attack or Ischemic Stroke. Hispanic vs non-Hispanic patients were compared to assess for overall rt-PA treatment rates and process of care intervals. For the Hispanic cohort itself, demographics and NIHSS scores were assessed to determine why some Hispanics received rt-PA while others were not.

RESULTS

Overall, 1489 patients (300 Hispanic vs. 1189 non-Hispanic) were included. Comparing Hispanics to non-Hispanics, there was no difference in rt-PA rate (35.3% vs. 33.1%; p=0.49). In rt-PA treated patients, "onset to arrival" interval was higher in Hispanics (1.03 vs. 0.88 hours; p=0.04), while the "arrival to treatment" interval was not different (1.13 vs. 1.02 hours; p=0.07). When looking at Hispanic patients only, there was no difference in baseline characteristics except for initial NIHSS in treated vs. non-treated patients (13.27 vs. 7.24; p<.001).

CONCLUSION

Our analyses sought to determine the factors important to administration of rt-PA to Hispanic patients. These findings highlight the need for strategies to improve recognition and presentation pathways for Hispanics.

Abstract TP180: DERrAME: Disparities Among Ethnicities Regarding rt-PA in Acute Stroke Management and Evaluations

Background: Since the introduction of recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke, rt-PA rate and number of stroke centers have increased. Despite this, studies have shown racial and ethnic disparities in stroke care especially in Black and Hispanic populations. How Hispanic ethnicity affects rt-PA evaluations has to date been unclear. In our patient population, we investigated whether ethnicity is associated with rt-PA use for acute ischemic strokes in the Hispanic population.

Methods: We performed a retrospective review of IRB approved, prospectively collected data from the UC San Diego Stroke Registry. Patients were selected based on the presentation and primary diagnosis of Transient Ischemic Attack or Ischemic Stroke. Characteristics including risk factors were compared in Hispanic vs non-Hispanic samples to assess rt-PA treatment rates, process of care intervals for Hispanics vs non-Hispanics and rt-PA vs non-rt-PA patients.

Results: We assessed 1489 patients (300 Hispanic vs. 1189 non-Hispanic whites) from July 2004 to July 2016. Comparing Hispanics to non-Hispanics, there was no difference in rt-PA rate (35.3% vs. 33.1%; p=0.49). In a subset evaluation of Hispanics only, comparing rt-PA(-) to rt-PA(+), there was no difference for male sex (56%), Hypertension (71%), Hyperlipidemia (29%), Diabetes (43%), Atrial Fibrillation (23%), and Smoking (20%). There was a noted difference in the Hispanic-only untreated vs treated subset for initial NIHSS (7.24 vs. 13.27; p<.001). In rt-PA treated patients only, the “onset to treatment” interval was significantly higher in Hispanics (2.42 vs. 2.13 hours p=0.003), while the “door to treatment” interval was not different (1.13 vs. 1.02 hours; p=0.07).

Conclusions: This study shows the rate of rt-PA treatment and “door to treatment” intervals were not significantly different in Hispanic vs non-Hispanic patients. This data is supportive of current overall treatment decision models. However, the “onset to treatment” interval was significantly longer for Hispanic patients showing that it may take longer for this population to reach the treating hospital. This supports the need to develop culturally relevant education programs to address barriers in this population.

Identification of Barriers to Stroke Awareness and Risk Factor Management Unique to Hispanics

Barriers to risk factor control may differ by race/ethnicity. The goal of this study was to identify barriers to stroke awareness and risk factor management unique to Hispanics as compared to non-Hispanic whites (NHWs). We performed a prospective study of stroke patients from an academic Stroke Center in Arizona and surveyed members of the general community. Questionnaires included: the Duke Social Support Index (DSSI), the Multidimensional Health Locus of Control (MHLC) Scale, a stroke barriers questionnaire, and a Stroke Awareness Test. Of 145 stroke patients surveyed (72 Hispanic; 73 NHW), Hispanics scored lower on the Stroke Awareness Test compared to NHWs (72.5% vs. 79.1%, p = 0.029). Hispanic stroke patients also reported greater barriers related to medical knowledge, medication adherence, and healthcare access (p < 0.05 for all). Hispanics scored higher on the "powerful others" sub-scale (11.3 vs. 10, p < 0.05) of the MHLC. Of 177 members of the general public surveyed, Hispanics had lower stroke awareness compared to NHWs and tended to have lower awareness than Hispanic stroke patients. These results suggest that Hispanic stroke patients perceive less control over their health, experience more healthcare barriers, and demonstrate lower rates of stroke literacy. Interventions for stroke prevention and education in Hispanics should address these racial/ethnic differences in stroke awareness and barriers to risk factor control.

Abstract W P255: Prior Use of Statins May Reduce Hematoma Growth in Intracerebral Hemorrhage Patients

Introduction: Higher incidence and growth of intracerebral hemorrhage (ICH) has been reported with primary hypocholesterolemia. Statins have been associated with improved outcome in ICH patients, although they lower low density lipoprotein (LDL) cholesterol. Our study explores whether lower admission LDL secondary to statin use is associated with admission ICH hematoma volumes (HV) or hematoma growth (HG).

METHODS: Data from the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study, a multicenter case-control study designed to examine ethnic variations in the risk, presentation, and outcomes of ICH, were analyzed to explore the association of statin use and LDL with HV and HG. The Kruskal-Wallis test was used to examine differences in initial volume between groups, and the Wilcoxon Signed-Rank test was used to examine differences in HV between patients’ first two CT scans.

RESULTS: Among cases enrolled prior to January 2013, 544 (mean±SD age=60.9±14.1, 60.3% male) had both admission LDL data and CT scan within 24 hours of onset. Four groups were defined: 1) statin use and LDL<70, n=42 (7%); 2) statin use and LDL≥70, n=79 (14%); 3) no statin use and LDL<70, n=58 (10%); and 4) no statin use and LDL≥70, n=365 (67%). There was no difference in admission HV among groups (p=.69). Follow up (f/u) imaging was available for 350 (64.3%) cases: n for the 4 groups was 26 (7%), 47 (13%), 35 (10%), and 242 (69%). Compared with baseline CT, the non-statin users had significantly higher f/u HV (p<.0001), whereas f/u HV was unchanged for statin users (p=.529). Group analysis showed decreased HV in group 1 and increased HV in group 4 (Figure 1).

CONCLUSION: There was no association between LDL<70 with or without statin use and admission HV. When compared with non-statin users, statin users, especially with LDL<70, had reduced HG on f/u scans. Further studies are needed to explore these findings.

Abstract W MP54: Risk Factors for Nosocomial Infections after Intracerebral Hemorrhage and Their Impact on Outcome: The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) Study

Background: Risk factors for nosocomial infections and their impact on ICH outcomes are unclear. We hypothesized that factors present on admission are associated with developing infection, and patients who develop infections have worse outcomes.

Methods: We determined prevalence of infections among patients in ERICH, a multicenter, triethnic case-control study of ICH. Exclusion criteria specific to this analysis were incomplete CT data and death/withdrawal of care <72 hours after admission. Patients with infection <two weeks before ICH were excluded from risk factor analyses, but included for outcomes assessments. We compared prevalence of risk factors for infections using chi-square and non-parametric tests, and performed multivariate logistic regression for risk of infection.

Results: We enrolled 1397 individuals, 144 of whom died/had withdrawal of care within 72 hours and 210 with incomplete CT data, leaving 1043 patients. Nosocomial infections occurred in 300 patients (29%). Factors associated with presence of infections included ICH volume (13mL vs. 7mL, p <0.0001), GCS on admission (13 vs. 15, p <0.0001), WBC > 10 (42% vs. 32%), and higher CRP levels (4.9 vs. 1.8, p=0.01). Blacks had higher infection rates versus whites and Hispanics (33% vs. 27% and 24%, p=0.06). Procedural factors associated with infection included ventriculostomy, intrathecal-tPA, and intubation, while major neurosurgical procedures were associated with a 10-fold increase in CNS infection (all p <0.001). Infections were associated with bowel-bladder dysfunction, CHF/pulmonary edema, decubiti, DVT, dysphagia requiring PEG, and MI. Patients with infection were more likely to have DNR/DNI orders or to be dead at discharge (12.3% vs. 6.5%, p=0.0017). In a multivariate model for factors associated with infection, ICH volume, HIV history, intubation, CHF/pulmonary edema, and dysphagia requiring PEG were all associated with infection.

Conclusion: There are identifiable risk factors associated with nosocomial infection after ICH, and infections are associated with mortality. Identification of patients at risk for infections may improve outcomes after ICH.

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study protocol

BACKGROUND AND PURPOSE

Epidemiological studies of intracerebral hemorrhage (ICH) have consistently demonstrated variation in incidence, location, age at presentation, and outcomes among non-Hispanic white, black, and Hispanic populations. We report here the design and methods for this large, prospective, multi-center case-control study of ICH.

METHODS

The Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study is a multi-center, prospective case-control study of ICH. Cases are identified by hot-pursuit and enrolled using standard phenotype and risk factor information and include neuroimaging and blood sample collection. Controls are centrally identified by random digit dialing to match cases by age (±5 years), race, ethnicity, sex, and metropolitan region.

RESULTS

As of March 22, 2013, 1655 cases of ICH had been recruited into the study, which is 101.5% of the target for that date, and 851 controls had been recruited, which is 67.2% of the target for that date (1267 controls) for a total of 2506 subjects, which is 86.5% of the target for that date (2897 subjects). Of the 1655 cases enrolled, 1640 cases had the case interview entered into the database, of which 628 (38%) were non-Hispanic black, 458 (28%) were non-Hispanic white, and 554 (34%) were Hispanic. Of the 1197 cases with imaging submitted, 876 (73.2%) had a 24 hour follow-up CT available. In addition to CT imaging, 607 cases have had MRI evaluation.

CONCLUSIONS

The ERICH study is a large, case-control study of ICH with particular emphasis on recruitment of minority populations for the identification of genetic and epidemiological risk factors for ICH and outcomes after ICH.

Imaging recommendations for acute stroke and transient ischemic attack patients: A joint statement by the American Society of Neuroradiology, the American College of Radiology, and the Society of NeuroInterventional Surgery

SUMMARY

Stroke is a leading cause of death and disability worldwide. Imaging plays a critical role in evaluating patients suspected of acute stroke and transient ischemic attack, especially before initiating treatment. Over the past few decades, major advances have occurred in stroke imaging and treatment, including Food and Drug Administration approval of recanalization therapies for the treatment of acute ischemic stroke. A wide variety of imaging techniques has become available to assess vascular lesions and brain tissue status in acute stroke patients. However, the practical challenge for physicians is to understand the multiple facets of these imaging techniques, including which imaging techniques to implement and how to optimally use them, given available resources at their local institution. Important considerations include constraints of time, cost, access to imaging modalities, preferences of treating physicians, availability of expertise, and availability of endovascular therapy. The choice of which imaging techniques to employ is impacted by both the time urgency for evaluation of patients and the complexity of the literature on acute stroke imaging. Ideally, imaging algorithms should incorporate techniques that provide optimal benefit for improved patient outcomes without delaying treatment.

Abstract TP241: Race-ethnic Differentials Time and Acute Stroke Emergency Presentation: The ASPIRE Study

BACKGROUND: There is sparse data about the nature of race-ethnic disparities in the acute stroke setting including differentials in stroke preparedness. The aim of this analysis was to explore race-ethnic differentials in time to arrival for acute stroke in a racial and ethnically diverse urban setting.

METHODS: ASPIRE is a multi-dimensional intervention program (community, hospital, and EMS) for acute stroke preparedness targeted to increase IV tPA utilization in underserved black communities in the DC metro area. We prospectively identified stroke admissions and EMS utilization including acute stroke arrival time parameters for the 6 month pre and post intervention periods. Cox proportional hazards models were used to examine predictors of arrival time. Proportionality of the hazards was checked.

RESULTS: In the 6 month pre-intervention period, data was collected on 943 stroke cases; 53% female; 74% black; mean age 67 yrs. Of the subjects from the pre-intervention period with arrival times less than 48 hrs, the median arrival time to the emergency department (ED) was 9 hours; 20% presented under 3 hours. In multivariable Cox PH models, subjects were 38% more likely to arrive earlier if they had arrived by EMS (HR: 1.38, 95%CI: 1.21-1.58). Black subjects were 25% less likely to arrive earlier (HR: 0.75, 95%CI: 0.60-0.93), but this effect was dampened over time (p=0.03). The model included the interaction between black race and time and adjusted for insurance status, risk factors (hypertension and diabetes), gender, age and prior stroke. Ina gender by race analysis, there was a trend towards black women being less likely to arrive earlier to the ED (HR 0.78, 95% CI 0.6 -1.0). However, overall, there was no race-ethnic interaction with arrival by EMS.

CONCLUSIONS: Contrary to the perceived perception by the community suggesting there is a disparity in EMS utilization by the black DC community, we found no overall significant racial difference in EMS utilization for acute stroke. While there was a trend towards delayed overall arrival in black females, this was independent of EMS utilization.

Abstract 3333: Serum Lipids and Inflammatory Markers as Predictors of Thrombus Composition in Acute Ischemic Stroke

Introduction: Histopathology has shown that thrombi retrieved acutely from cerebral arteries in acute ischemic stroke patients typically have intermixed fibrin-platelet-dominant and red blood cell (RBC)-dominant regions. Knowledge of the proportions of fibrin-platelet and RBC components in an individual patient could help with pharmacologic and/or device intervention selection. Whether serum markers of inflammation and coagulation status reflect clot composition has not previously been investigated.

Methods: We analyzed consecutive patients undergoing mechanical thrombectomy for acute middle cerebral artery ischemic stroke with retrieved thrombi available for histopathologic analysis. Percent of retrieved thrombus that was RBC-dominant, WBC-dominant, and platelet/thrombin-dominant was calculated and compared with routine serum indices of inflammatory and coagulation status obtained on admission.

Results: Among the 50 patients meeting entry critera, mean age was 66 (SD 21), 48% were female, and median pretreatment NIHSS was 19 (IQR 15-22). Two serum indices demonstrated correlations with cerebral thrombus histopathology: serum WBC count inversely correlated with thrombus fibrin percentage (R -.317, p=0.024) and partial thromboplastin time positively correlated with thrombus WBC percentage (R 0.336, p=0.032). No relations were found for other serum tests, including hemoglobin, neutrophil count, lymphocyte count, prothrombin time, erythrocyte sedimentation rate, high sensitivity C-reactive protein, homocysteine, fibrinogen, factor VIII, total cholesterol, LDL, and HDL.

Conclusions: Serum measures of inflammation and coagulation may provide clues to target thrombus composition in acute ischemic stroke. Systemic inflammation, including during infections, may lead to upregulation of clotting factors and less fibrin-platelet and more RBC and WBC-laden clots.

Abstract 3655: Development of a Large Scale Predictive Atlas of Clinical Outcome in Acute Ischemic Stroke

Background: Neuroimaging studies including diffusion and perfusion-weighted imaging identify the location and neuroanatomic extent of brain ischemia in the acute phase of infarction. Although there has been substantial progress in using early neuroimaging studies to predict whether localized regions of brain tissue will proceed to infarction or recover, there has been little effort to define imaging parameters that predict which of the patient’s acute functional deficits will remain or resolve with potential recanalization/reperfusion treatments. This information may be particularly important in late time windows when the number of patients with salvageable penumbral tissue progressively declines. We previously reported development of a proof of concept acute stroke imaging atlas correlating DWI lesions and NIHSS items in a relatively small number of subjects. The goal of the current analysis was to expand this atlas to include a much larger number of cases.

Methods: As part of a global project aimed at creating a large scale stroke-specific predictive brain atlas, we correlated acute DWI lesion location with the presence of individual sub-item scores from the NIHSS. Inclusion criteria were: acute ischemic stroke; brain MRI (including DWI) performed within 24 hours of symptom onset; and baseline NIHSS score available. Intramural NINDS provided the imaging and clinical data. Acute DWI images from all subjects were aligned to a common neuroanatomic coordinate system. Chi square images were calculated on a voxel-by-voxel basis.

Results: A total of 400 patients were included in the analysis. Mean age was 69, range 21-98. Baseline NIHSS was median 5, mean 7, range 0-32. The figure shows representative axial slices from the atlas, including color-coded chi square values, using a false discovery rate of 5%, for anatomic regions in which there was a significant correlation between NIHSS sub-item symptom presence and DWI hyperintensity.

Conclusions: Employing a large dataset including 400 acute stroke patients, we have developed a large scale voxel-based stroke atlas correlating NIHSS sub-items employing acute DWI lesion data. The maps illustrate the neuroanatomic representation of the NIHSS sub-items in standardized space. An important next step will incorporate acute diffusion and perfusion MR imaging to predict long-term outcome for two scenarios: untreated vs. treated with recanalization therapy. This information may then assist in guiding treatment decisions for late recanalization therapies.

Abstract 3594: A Pilot Feasibility Study of Community Engaged Stroke Preparedness: The ASPIRE Project

BACKGROUND: Lack of culturally appropriate education about stroke may prevent people from recognizing symptoms and/or seeking immediate care. The Stroke Warning Information and Faster Treatment (SWIFT) intervention reports increasing the proportion of prevalent stroke/TIA cases arriving under 4.5 hours using culturally tailored strategies, but few interventions have rigorously evaluated preparedness strategies in community settings. ASPIRE is a multi-dimensional program with a three-pronged approach (community, hospital, EMS) to acute stroke preparedness targeted to increased IV tPA utilization in underserved black communities in the DC metro area.

METHODS: Using community engaged methodology, a skill-based approach to teaching community members to recognize acute stroke, call 911 and navigate the ER setting was developed. In the pilot phase, 50 education sessions were conducted in church, civic, educational and work organizations over a six month period in Ward 7 of the DC Metro area. Local ER and EMS staff were also in-serviced. We prospectively identified all hospital stroke admissions and EMS utilization information including acute stroke parameters for the 6 month pre and post intervention periods. Pre-post pilot intervention acute ischemic stroke parameters were compared.

RESULTS: In the pre-intervention period, we identified 142 ischemic strokes in Ward 7: mean age 63 yrs; 63% male; 96% blacks. Fifty-six percent arrived via EMS, with a mean and median time to arrival of 1600 minutes (27.0 hours), and 890 minutes (14.8 hours), respectively. Following the intervention we identified 115 ischemic stroke cases: 66 yrs; 47% male; 89% black. Fifty percent arrived via EMS, mean and median time to arrival was 1423 min (23.7 hours) and 815 min (13.6 hours). In addition to this modest decrease in overall arrival times, an increased proportion of cases arriving in the 4.5 hours group was noted [pre 25% vs. post 28%, p=NS]. We were also able to match 104 ischemic stroke cases to EMS utilization sheets demonstrating feasibility for larger evaluation.

CONCULSION: The ASPIRE pilot demonstrates feasibility of the multilevel community education intervention as well as feasibility of linking EMS and hospital records on a city wide scale. Despite the small number of ischemic strokes in this pilot phase, a modest reduction in hospital arrival times occurred in the post intervention phase. A city-wide intervention aimed at increasing the proportion of stroke patients treated with IV tPA is currently underway.

Secondary preventive medication persistence and adherence 1 year after stroke

OBJECTIVE

Data on long-term use of secondary prevention medications following stroke are limited. The Adherence eValuation After Ischemic stroke-Longitudinal (AVAIL) Registry assessed patient, provider, and system-level factors influencing continuation of prevention medications for 1 year following stroke hospitalization discharge.

METHODS

Patients with ischemic stroke or TIA discharged from 106 hospitals participating in the American Heart Association Get With The Guidelines-Stroke program were surveyed to determine their use of warfarin, antiplatelet, antihypertensive, lipid-lowering, and diabetes medications from discharge to 12 months. Reasons for stopping medications were ascertained. Persistence was defined as continuation of all secondary preventive medications prescribed at hospital discharge, and adherence as continuation of prescribed medications except those stopped according to health care provider instructions.

RESULTS

Of the 2,880 patients enrolled in AVAIL, 88.4% (2,457 patients) completed 1-year interviews. Of these, 65.9% were regimen persistent and 86.6% were regimen adherent. Independent predictors of 1-year medication persistence included fewer medications prescribed at discharge, having an adequate income, having an appointment with a primary care provider, and greater understanding of why medications were prescribed and their side effects. Independent predictors of adherence were similar to those for persistence.

CONCLUSIONS

Although up to one-third of stroke patients discontinued one or more secondary prevention medications within 1 year of hospital discharge, self-discontinuation of these medications is uncommon. Several potentially modifiable patient, provider, and system-level factors associated with persistence and adherence may be targets for future interventions.

Physician-Investigator Phone Elicitation of Consent in the Field: A Novel Method To Obtain Explicit Informed Consent For Prehospital Clinical Research

OBJECTIVE

To describe and report the feasibility of a novel field telephonic strategy to elicit explicit informed consent in prehospital trials for conditions in which patients retain decision-making capacity.

METHODS

In a pilot prehospital neuroprotective stroke therapy trial, ambulances carried written informed consent forms and dedicated trial cellular phones permitting rapid connection to on call physician-investigators. The physician-investigator discussed the trial with the consent provider [patient if competent, on scene legally authorized representative (LAR) if patient not competent] by phone, while paramedics carried out prehospital care duties unimpeded.

RESULTS

32 patients met consent elicitation criteria. 20 (63%) were enrolled. The most frequent reasons for non-enrollment were: patient not competent and no available on-scene LAR-5; patient/LAR declined participation-4. Among enrollees, 15 (75%) were competent and self-enrolled; 5 (25%) were not competent and were enrolled by LAR family members. Site of consent initiation was: patient home-15 (74 = 5%), work-2(10)%, other-3(15)%. Consent was elicited via cell phone in 11 (55%) and site landline in 9 (45%). Compared with patients enrolled in prior studies employing standard in-hospital consent, prehospital consent procedures reduced time from paramedic arrival on-scene to start of study agent (26 vs 139 mins, p < 0.0001), and did not prolong the on-scene to ED arrival time (37 vs 34 min, p = 0.50). No patient/family withdrew consent during the 3-month follow-up period.

CONCLUSION

Physician phone elicitation of prehospital research consent from individuals with retained competency or on-scene legally authorized representatives is feasible, permits rapid patient study entry, and does not delay field transport times.

The combined approach to lysis utilizing eptifibatide and rt-PA in acute ischemic stroke: the CLEAR stroke trial

BACKGROUND AND PURPOSE

Multiple approaches are being studied to enhance the rate of thrombolysis for acute ischemic stroke. Treatment of myocardial infarction with a combination of a reduced-dose fibrinolytic agent and a glycoprotein (GP) IIb/IIIa receptor antagonist has been shown to improve the rate of recanalization versus fibrinolysis alone. The combined approach to lysis utilizing eptifibatide and recombinant tissue-type plasminogen activator (rt-PA) (CLEAR) stroke trial assessed the safety of treating acute ischemic stroke patients within 3 hours of symptom onset with this combination.

METHODS

The CLEAR trial was a National Institutes of Health/National Institute of Neurological Disorders and Stroke-funded multicenter, double-blind, randomized, dose-escalation and safety study. Patients were randomized 3:1 to either low-dose rt-PA (tier 1=0.3 mg/kg, tier 2=0.45 mg/kg) plus eptifibatide (75 microg/kg bolus followed by 0.75 microg/kg per min infusion for 2 hours) or standard-dose rt-PA (0.9 mg/kg). The primary safety end point was the incidence of symptomatic intracerebral hemorrhage within 36 hours. Secondary analyses were performed regarding clinical efficacy.

RESULTS

Ninety-four patients (40 in tier 1 and 54 in tier 2) were enrolled. The combination group of the 2 dose tiers (n=69) had a median age of 71 years and a median baseline National Institutes of Health Stroke Scale (NIHSS) score of 14, and the standard-dose rt-PA group (n=25) had a median age of 61 years and a median baseline NIHSS score of 10 (P=0.01 for NIHSS score). Fifty-two (75%) of the combination treatment group and 24 (96%) of the standard treatment group had a baseline modified Rankin scale score of 0 (P=0.04). There was 1 (1.4%; 95% CI, 0% to 4.3%) symptomatic intracranial hemorrhage in the combination group and 2 (8.0%; 95% CI, 0% to 19.2%) in the rt-PA-only arm (P=0.17). During randomization in tier 2, a review by the independent data safety monitoring board demonstrated that the safety profile of combination therapy at the tier 2 doses was such that further enrollment was statistically unlikely to indicate inadequate safety for the combination treatment group, the ultimate outcome of the study. Thus, the study was halted. There was a trend toward increased clinical efficacy of standard-dose rt-PA compared with the combination treatment group.

CONCLUSIONS

The safety of the combination of reduced-dose rt-PA plus eptifibatide justifies further dose-ranging trials in acute ischemic stroke.

Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial

BACKGROUND AND PURPOSE

Endovascular mechanical thrombectomy may be used during acute ischemic stroke due to large vessel intracranial occlusion. First-generation MERCI devices achieved recanalization rates of 48% and, when coupled with intraarterial thrombolytic drugs, recanalization rates of 60% have been reported. Enhancements in embolectomy device design may improve recanalization rates.

METHODS

Multi MERCI was an international, multicenter, prospective, single-arm trial of thrombectomy in patients with large vessel stroke treated within 8 hours of symptom onset. Patients with persistent large vessel occlusion after IV tissue plasminogen activator treatment were included. Once the newer generation (L5 Retriever) device became available, investigators were instructed to use the L5 Retriever to open vessels and could subsequently use older generation devices and/or intraarterial tissue plasminogen activator. Primary outcome was recanalization of the target vessel.

RESULTS

One hundred sixty-four patients received thrombectomy and 131 were initially treated with the L5 Retriever. Mean age+/-SD was 68+/-16 years, and baseline median (interquartile range) National Institutes of Health Stroke Scale score was 19 (15 to 23). Treatment with the L5 Retriever resulted in successful recanalization in 75 of 131 (57.3%) treatable vessels and in 91 of 131 (69.5%) after adjunctive therapy (intraarterial tissue plasminogen activator, mechanical). Overall, favorable clinical outcomes (modified Rankin Scale 0 to 2) occurred in 36% and mortality was 34%; both outcomes were significantly related to vascular recanalization. Symptomatic intracerebral hemorrhage occurred in 16 patients (9.8%); 4 (2.4%) of these were parenchymal hematoma type II. Clinically significant procedural complications occurred in 9 (5.5%) patients.

CONCLUSIONS

Higher rates of recanalization were associated with a newer generation thrombectomy device compared with first-generation devices, but these differences did not achieve statistical significance. Mortality trended lower and the proportion of good clinical outcomes trended higher, consistent with better recanalization.

Guidelines for the Early Management of Adults With Ischemic Stroke

Purpose— Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

Methods— Members of the panel were appointed by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council’s Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

Results— Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists

PURPOSE

Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

METHODS

Members of the panel were appointed by the American Heart Association Stroke Council's Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council's Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

RESULTS

Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

Early MRI and outcomes of untreated patients with mild or improving ischemic stroke

OBJECTIVE

To determine the frequency of early neurologic deterioration with infarct expansion (ENDIE) and poor outcomes among ischemic stroke patients not treated with reperfusion therapies because of rapidly improving or mild symptoms (RIMS) and to study the predictive value of hyperacute MRI in these patients.

METHODS

We identified consecutive patients with symptoms of acute stroke undergoing multimodal MRI within 6 hours of onset without evidence of hemorrhage on imaging. Medical records were reviewed for evidence of early neurologic deterioration within 48 hours. All deteriorating patients had repeat MRI to ascertain causes of worsening. Poor outcome was defined as a discharge modified Rankin Scale (mRS) score of > or = 3.

RESULTS

We identified 74 patients with stroke symptoms < or = 6 hours from onset. Forty had RIMS, and 39 did not receive reperfusion therapies because of RIMS. Among these 39, 4 experienced ENDIE, and 8 were discharged with mRS score of > or = 3. Eight of the 39 patients had large-vessel occlusions on MR angiography. Three of 8 patients with large-vessel occlusion as against only one of 31 patients without occlusion had ENDIE (odds ratio [OR] 18, 95% CI 1.6 to 209, p = 0.02). Four of 8 patients with large-vessel occlusion as against 4 of 31 patients without occlusion had a discharge mRS score of > or = 3 (OR 7, 95% CI 1.2 to 38, p = 0.04).

CONCLUSIONS

About 10% of patients eligible for acute reperfusion therapy excluded on the basis of mild or rapidly improving symptoms show early neurologic deterioration with infarct expansion within 48 hours, and about 20% show poor outcome at discharge. Persisting large-vessel occlusion substantially increases the risk of early worsening and poor functional outcome.

Analysis of Thrombi Retrieved From Cerebral Arteries of Patients With Acute Ischemic Stroke

Background and Purpose— Information regarding the histological structure of thromboemboli that cause acute stroke provides insight into pathogenesis and clinical management.

Methods— This report describes the histological analysis of thromboemboli retrieved by endovascular mechanical extraction from the middle cerebral artery (MCA) and intracranial carotid artery (ICA) of 25 patients with acute ischemic stroke.

Results— The large majority (75%) of thromboemboli shared architectural features of random fibrin:platelet deposits interspersed with linear collections of nucleated cells (monocytes and neutrophils) and confined erythrocyte-rich regions. This histology was prevalent with both cardioembolic and atherosclerotic sources of embolism. “Red” clots composed uniquely of erythrocytes were uncommon and observed only with incomplete extractions, and cholesterol crystals were notably absent. The histology of thromboemboli that could not be retrieved from 29 concurrent patients may be different. No thrombus >3 mm wide caused stroke limited to the MCA, and no thrombus >5 mm wide was removed from the ICA. A mycotic embolus was successfully removed in 1 case, and a small atheroma and attached intima were removed without clinical consequence from another.

Conclusions— Thromboemboli retrieved from the MCA or intracranial ICA of patients with acute ischemic stroke have similar histological components, whether derived from cardiac or arterial sources. Embolus size determines ultimate destination, those >5 mm wide likely bypassing the cerebral vessels entirely. The fibrin:platelet pattern that dominates thromboembolic structure provides a foundation for both antiplatelet and anticoagulant treatment strategies in stroke prevention.

Frameless stereotactic aspiration and thrombolysis of deep intracerebral hemorrhage is associated with reduction of hemorrhage volume and neurological improvement

INTRODUCTION

This is a phase-2 safety trial to demonstrate the ability of frameless stereotactic aspiration and thrombolysis of ICH to safely remove blood.

METHODS

Patients with ICH in the deep basal ganglia and internal capsule of > 5 cc volume were consented to undergo computed tomographic imaging for frameless stereotactic guidance registration. Using the frameless stereotactic (CT) guidance, a 4-mm diameter catheter was inserted into the body of the hematoma using a frontal burr hole approach. The catheter was aspirated and then flushed with saline and aspirated to remove unclotted blood. After a confirmatory CT scan to localize the catheter, 1 mg of recombinant tissue plasminogen activator (t-PA) was infused into the clot, permitted to bathe the clot for 30 minutes, and then drained into a closed circuit collection system. t-PA was infused every 8 hours for 48 hours. A follow up CT scan was obtained at 48 hours.

RESULTS

28 patients with ICH (mean age 67.1) were admitted and underwent the procedure. Mean initial ICH volume was 54.6 cc +/-6 37.8. Mean time from onset to aspiration was 44 hours (range 7-180). Mean initial NIH Stroke scale (NIHSS) score was 24 (range 15-33). Compared with initial CT scan, there was a mean reduction of ICH volume by 77 +/-6 13% on final CT scan (p < 0.0002). Compared with initial NIHSS, the discharge mean NIHSS (16 +/- 6) was significantly improved (p < 0.001). There were no infectious, hemodynamic or neurologic complications. There were no episodes of symptomatic hemorrhagic enlargement and one case of asymptomatic bleeding along the catheter tract.

CONCLUSION

Frameless stereotactic aspiration and thrombolysis (FAST) of deep spontaneous intracerebral hemorrhage is a safe therapy that is associated with reduction in ICH volume, early improvement in NIHSS and potentially could be used to improve outcome.

Intracranial vascular stenosis and occlusive disease: evaluation with CT angiography, MR angiography, and digital subtraction angiography

BACKGROUND AND PURPOSE

Although digital subtraction angiography (DSA) provides excellent visualization of the intracranial vasculature, it has several limitations. Our purpose was to evaluate the ability of helical CT angiography (CTA) to help detect and quantify intracranial stenosis and occlusion compared with DSA and MR angiography (MRA).

METHODS

Twenty-eight patients underwent CTA, DSA, and 3D time-of-flight (TOF) MRA for suspected cerebrovascular lesions. All three studies were performed within a 30-day period. Two readers blinded to prior estimated or calculated stenoses, patient history and clinical information examined 672 vessel segments. Lesions were categorized as normal (0-9%), mild (10-29%), moderate (30-69%), severe (70-99%), or occluded (no flow detected). DSA was the reference standard. Unblinded consensus readings were obtained for all discrepancies.

RESULTS

A total of 115 diseased vessel segments were identified. After consensus interpretation, CTA revealed higher sensitivity than that of MRA for intracranial stenosis (98% versus 70%, P < .001) and occlusion (100% versus 87%, P = .02). CTA had a higher positive predictive value than that of MRA for both stenosis (93% versus 65%, P < .001) and occlusion (100% versus 59%, P < .001). CTA had a high interoperator reliability. In 6 of 28 patients (21%), all 6 with low-flow states in the posterior circulation, CTA was superior to DSA in detection of vessel patency.

CONCLUSION

CTA has a higher sensitivity and positive predictive value than MRA and is recommended over TOF MRA for detection of intracranial stenosis and occlusion. CTA has a high interoperator reliability. CTA is superior to DSA in the evaluation of posterior circulation steno-occlusive disease when slow flow is present. CTA results had a significant effect on patient clinical management.

Prehospital Neuroprotective Therapy for Acute Stroke

Background and Purpose— To demonstrate that paramedic initiation of intravenous magnesium sulfate (Mg) in the field in focal stroke patients is feasible, safe, and yields significant time-savings compared with in-hospital initiation of neuroprotective therapy.

Methods— We performed an open-label clinical trial. Inclusion criteria were: (1) likely stroke as identified by the Los Angeles Prehospital Stroke Screen; (2) age 45 to 95; and (3) treatment initiation within 12 hours of symptom onset. Paramedics initiated 4 g Mg loading dose in the field, followed by 16 g over 24 hours in hospital.

Results— Twenty patients were enrolled, with mean age 74 (range 44 to 92), and 50% were male. Final diagnosis was acute cerebrovascular disease in all (ischemic 80%, hemorrhagic 20%). Study agent infusion began a median of 100 minutes after symptom onset (range 24 to 703), and 70% received study agent within 2 hours of onset. The interval from paramedic arrival on scene to study agent start was: field-initiated, 26 minutes (range 15 to 64) versus in-hospital initiated (historic controls), 139 minutes (range 66 to 300; P <0.0001). Paramedics rated patient status on hospital arrival as improved 20%, worsened 5%, and unchanged 75%. Median NIHSS on hospital arrival was 11 in all patients and 16 in patients unchanged since field treatment start. Good functional outcome at 3 months (Rankin ≤ 2) occurred in 60%. No serious adverse events were associated with field therapy initiation.

Conclusions— Field initiation of Mg sulfate in acute stroke patients is feasible and safe. Prehospital trial conduct substantially reduces on-scene to needle time and permits hyperacute delivery of neuroprotective therapy.

Acute seizures after intracerebral hemorrhage: a factor in progressive midline shift and outcome

OBJECTIVE

To determine whether early seizures that occur frequently after intracerebral hemorrhage (ICH) lead to increased brain edema as manifested by increased midline shift.

METHODS

A total of 109 patients with ischemic stroke (n = 46) and intraparenchymal hemorrhage (n = 63) prospectively underwent continuous EEG monitoring after admission. The incidence, timing, and factors associated with seizures were defined. Serial CT brain imaging was conducted at admission, 24 hours, and 48 to 72 hours after hemorrhage and assessed for hemorrhage volume and midline shift. Outcome at time of discharge was assessed using the Glasgow Outcome Scale score.

RESULTS

Electrographic seizures occurred in 18 of 63 (28%) patients with ICH, compared with 3 of 46 (6%) patients with ischemic stroke (OR = 5.7, 95% CI 1.4 to 26.5, p < 0.004) during the initial 72 hours after admission. Seizures were most often focal with secondary generalization. Seizures were more common in lobar hemorrhages but occurred in 21% of subcortical hemorrhages. Posthemorrhagic seizures were associated with neurologic worsening on the NIH Stroke Scale (14.8 vs 18.6, p < 0.05) and with an increase in midline shift (+ 2.7 mm vs -2.4 mm, p < 0.03). There was a trend toward increased poor outcome (p < 0.06) in patients with posthemorrhagic seizures. On multivariate analysis, age and initial NIH Stroke Scale score were independent predictors of outcome.

CONCLUSION

Seizures occur commonly after ICH and may be nonconvulsive. Seizures are independently associated with increased midline shift after intraparenchymal hemorrhage.

Can Prophylactic Acetaminophen Prevent Hyperthermia in Acute Stroke?: Results of the Normothermia and Stroke Outcome (NOTHOT) Pilot Clinical Trial

P232

Objective: To explore the safety and efficacy of round-the-clock acetaminophen administration to prevent hyperthermia in acute ischemic stroke patients. Background: Fever is a frequent occurrence among stroke patients and large cohort studies have identified early fever as an independent risk factor for poor functional outcome. Conventional management is to use antipyretics only in response to the appearance of fever. A pre-emptive strategy of prophylactic antipyretic therapy has not been previously studied. Methods: Sixteen consecutive patients presenting within 24 hrs of ischemic infarction were given acetaminophen 650mg q 4 hrs for 72 hrs or until discharge. Oral temperatures were recorded q 4 hrs. Cooling blankets were ordered for T >37.6 0 C. These results were contrasted with a historical control cohort of 16 consecutive patients who were admitted within 24 hrs of stroke onset treated with conventional reactive antipyretic therapy. Results: In the acetaminophen group, mean age was 71.4 and 62.5% were male. Mean admission NIHSS score was 8.9. Mean time from stroke onset to first dose of acetaminophen was 12.9 hrs. Mean temperature at presentation was 36.6 0 C for the acetaminophen group vs. 36.4 0 C for controls (p=NS). 44% of the acetaminophen group developed elevated body temperature vs. 40% of controls (p=NS). Mean temperature during the first 24 hrs of treatment with acetaminophen was 36.8 0 C vs. 36.8 0 C for controls. Corresponding numbers for the second and third 24-hour periods were 36.9 0 C for the acetaminophen group vs. 37.1 0 C for controls (p=0.02) and 36.9 0 C for the acetaminophen group vs. 36.9 0 C for controls. Across the 72 hr treatment period, mean temperature was 36.9 0 C for the acetaminophen group vs. 37.0 0 C for controls (p=0.05). Conclusion: This pilot trial demonstrates acetaminophen administered round the clock significantly lowers average body temperature in the first 72 hrs after ischemic stroke. A randomized controlled clinical trial is needed to determine whether acetaminophen mediated body temperature lowering results in smaller infarct volume and improved clinical outcomes.

Endovascular treatment of dural sinus thrombosis with rheolytic thrombectomy and intra-arterial thrombolysis

BACKGROUND AND PURPOSE

Cerebral venous thrombosis is a rare entity that can be difficult to manage. Intrasinus thrombolysis is an increasingly applied intervention, but this modality carries an increased risk of hemorrhage. We describe for the first time an option with a potentially lower incidence of intracranial bleeding, the combination of the AngioJet rheolytic thrombectomy catheter with intra-arterial thrombolysis, in 2 patients with extensive dural sinus thromboses, preexisting intracranial hemorrhage, and severe progressive neurological deficits despite heparin therapy.

METHODS

Four procedures were performed in 2 patients with thromboses in the superior sagittal and transverse sinuses (right in 1 patient and bilateral in 1 patient) and cortical veins. Rheolytic thrombectomy was performed in the sigmoid, transverse, straight, and superior sagittal sinuses; this technique involves the use of the Bernoulli effect to create a vacuum that fragments and aspirates thrombus. For associated persistent cortical vein thromboses, low-dose intra-arterial thrombolysis was used.

RESULTS

Both patients had excellent angiographic results with sinus reopening after rheolytic thrombectomy and cortical vein reopening after intra-arterial thrombolysis. Follow-up CT showed no change in 1 patient and increased preexisting intracranial hemorrhage in the other. One patient had a negative hypercoagulable workup, and the other patient had probable anti-phospholipid antibody syndrome. At 6 months, both patients had excellent clinical outcome with no neurological deficits except mild short-term memory loss in 1 patient.

CONCLUSIONS

The combination of rheolytic thrombectomy with intra-arterial thrombolysis is a treatment modality that allows accelerated recanalization of occluded dural sinuses and cerebral veins with lower doses of thrombolytic agents.