Abstract 159: Recurrent Ischemic Stroke And Cigarette Smoking: A Secondary Analysis Of The POINT Trial

Background: Recent data suggest that in patients with acute myocardial infarction (MI), the effect of clopidogrel on risk reduction of cardiovascular outcomes is more pronounced in smokers. The aim of this study was to determine the effect of smoking status on subsequent stroke risk in patients with minor ischemic stroke or TIA and determine whether smoking improves the effect of clopidogrel treatment on subsequent stroke risk reduction.

Methods: This was a post-hoc analysis of the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial. The POINT trial compared clopidogrel plus aspirin (DAPT) to aspirin alone for prevention of recurrent stroke, myocardial infarction, or vascular death within 3 months of a high-risk TIA or minor ischemic stroke. We used multivariable cox-regression models to determine the effect of smoking on the risk of subsequent ischemic stroke. We also performed interaction analyses to determine whether the effect of clopidogrel on subsequent ischemic stroke differed with respect to smoking status.

Results: Data from 4,877 participants enrolled in the POINT trial were analyzed. Among these, 1,004 were current smokers and 3,873 were non-smokers. Smoking was associated with a non-significantly increased risk of recurrent ischemic stroke during follow up (hazard ratio, 1.31 [95% CI, 0.97 - 1.78], P=0.076). The effect of clopidogrel on ischemic stroke was not significantly different in non-smokers (hazard ratio, 0.74 [95% CI, 0.56 - 0.98], P=0.03) compared to smokers (adjusted hazard ratio, 0.63 [95% CI, 0.37 - 1.05], P=0.078), P for interaction = 0.572. In addition, the effect of clopidogrel on major hemorrhage was not significantly different in current smokers (hazard ratio, 2.59 [95% CI, 1.08 - 6.21], P=0.032) compared to non-smokers (hazard ratio, 1.67 [95% CI, 0.40 - 7.00], P=0.481), P for interaction = 0.613.

Conclusions: Cigarette smoking was associated with a non-significantly higher risk of subsequent ischemic stroke and smoking did not modify the effect of clopidogrel-based dual antiplatelet therapy on subsequent ischemic stroke risk reduction. Every effort should be made to encourage tobacco dependence treatment and cessation in patients with minor ischemic stroke and TIA.

Can machine learning augment clinician adjudication of events in cardiovascular trials? A case study of major adverse cardiovascular events (MACE) across CVRM trials

Background and introduction

Accurate identification of clinical outcome events is critical to obtaining reliable results in cardiovascular outcomes trials (CVOTs). Current processes for event adjudication are expensive and hampered by delays. As part of a larger project to more reliably identify outcomes, we evaluated the use of machine learning to automate event adjudication using data from the SOCRATES trial (NCT01994720), a large randomized trial comparing ticagrelor and aspirin in reducing risk of major cardiovascular events after acute ischemic stroke or transient ischemic attack (TIA).

Purpose

We studied whether machine learning algorithms could replicate the outcome of the expert adjudication process for clinical events of ischemic stroke and TIA. Could classification models be trained on historical CVOT data and demonstrate performance comparable to human adjudicators?

Methods

Using data from the SOCRATES trial, multiple machine learning algorithms were tested using grid search and cross validation. Models tested included Support Vector Machines, Random Forest and XGBoost. Performance was assessed on a validation subset of the adjudication data not used for training or testing in model development. Metrics used to evaluate model performance were Receiver Operating Characteristic (ROC), Matthews Correlation Coefficient, Precision and Recall. The contribution of features, attributes of data used by the algorithm as it is trained to classify an event, that contributed to a classification were examined using both Mutual Information and Recursive Feature Elimination.

Results

Classification models were trained on historical CVOT data using adjudicator consensus decision as the ground truth. Best performance was observed on models trained to classify ischemic stroke (ROC 0.95) and TIA (ROC 0.97). Top ranked features that contributed to classification of Ischemic Stroke or TIA corresponded to site investigator decision or variables used to define the event in the trial charter, such as duration of symptoms. Model performance was comparable across the different machine learning algorithms tested with XGBoost demonstrating the best ROC on the validation set for correctly classifying both stroke and TIA.

Conclusions

Our results indicate that machine learning may augment or even replace clinician adjudication in clinical trials, with potential to gain efficiencies, speed up clinical development, and retain reliability. Our current models demonstrate good performance at binary classification of ischemic stroke and TIA within a single CVOT with high consistency and accuracy between automated and clinician adjudication. Further work will focus on harmonizing features between multiple historical clinical trials and training models to classify several different endpoint events across trials. Our aim is to utilize these clinical trial datasets to optimize the delivery of CVOTs in further cardiovascular drug development.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): AstraZenca Plc

Health-related quality of life in patients with myalgic encephalomyelitis/chronic fatigue syndrome: an Australian cross-sectional study

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious and debilitating disorder associated with significant disruptions in daily life including. This study aimed to examine the impact of sociodemographic and patient symptom characteristics on health-related quality of life (HRQoL) of Australians with ME/CFS.

METHODS

Self-reported data collected from 480 individuals diagnosed with ME/CFS were obtained between August 2014 and August 2018. This cross-sectional survey analysed sociodemographic, symptom characteristics and HRQoL according to the 36-Item Health Survey (SF-36). Multivariate linear regression models were used to determine ME/CFS symptoms associated with eight domains of HRQoL.

RESULTS

Reported HRQoL was significantly impaired in ME/CFS patients across all domains compared with the general population. Scores were the lowest for physical role (4.11 ± 15.07) and energy/fatigue (13.54 ± 13.94). Associations with females, higher body mass index (BMI), employment status, cognitive difficulties, sensory disturbances and cardiovascular symptoms were observed in the physical functioning domain. Impaired pain domain scores were associated with high BMI, annual visits to their general practitioner, flu-like symptoms and fluctuations in body temperature. Reduced well-being scores were associated with smoking status, psychiatric comorbidity, cognitive difficulties, sleep disturbances and gastrointestinal difficulties.

CONCLUSION

This study provides evidence that ME/CFS has a profound and negative impact on HRQoL in an Australian cohort.

Oxidative lipoprotein markers predict poor functional outcome in patients with minor stroke or transient ischaemic attack

BACKGROUND AND PURPOSE

Oxidative stress plays an important role in acute ischaemic stroke. However, the association of oxidative lipoprotein markers, including oxidized low-density lipoprotein (oxLDL), oxLDL:high-density lipoprotein (HDL) and oxLDL:low-density lipoprotein (LDL), with functional outcome of minor stroke or transient ischaemic attack (TIA) remains unclear. We aimed to investigate the association between oxidative lipoprotein markers and poor functional outcome in patients with minor stroke or TIA.

METHODS

All patients with minor stroke or TIA were recruited from the Clopidogrel in High-Risk Patients With Acute Non-Disabling Cerebrovascular Events (CHANCE) trial. The poor functional outcome included modified Rankin Scale (mRS) score 2-6 and 3-6 at 90-day and 12-month follow-up. Multivariate logistic regression was used to investigate the associations of oxLDL, oxLDL:HDL and oxLDL:LDL with poor functional outcome.

RESULTS

Among 3019 patients included in this study, the median (interquartile range) oxLDL, oxLDL:HDL and oxLDL:LDL were 13.96 (6.65-28.81), 4.52 (2.08-9.32) and 11.73 (5.27-24.85) μg/dL, respectively. After adjusted for confounding factors, patients in the highest oxLDL quartile had a higher proportion of mRS score 2-6 at 90 days [hazard ratio (HR), 1.78; 95% confidence interval (CI), 1.26-2.52] and 12 months (HR, 1.42; 95% CI, 1.01-1.99), and mRS score 3-6 at 90 days (HR, 1.98; 95% CI, 1.29-3.04) and 12 months (HR, 1.77; 95% CI, 1.09-2.89) when compared with the lowest oxLDL quartile (P < 0.05). Similar results were found for oxLDL:HDL and oxLDL:LDL.

CONCLUSIONS

Higher levels of oxidative lipoprotein markers are independent predictors of poor functional outcome in patients with minor stroke or TIA at 90 days and 12 months.

Advance Directives: From the Perspective of the Patient and the Physician

American physicians and patients share some common ground in their perspectives on advance directives. The majority in both groups strongly endorse the use of these documents. Both groups believe it is the physician's responsibility to initiate the discussion about advance directives. However, a gap between the two perspectives can be defined. In end-of-life decision making, physicians balance the ethical principle of patient autonomy with other principles such as appropriate withholding of care in the setting of futility. Patients’ preferences for end-of-life care are most influenced by expected outcomes. Physicians tend to be selective in their indications for initiating a discussion about advance directives, according to clinical factors. In contrast, most patients want to discuss advance directives with their physician under all circumstances.

Measurement of the Q^{2} Dependence of the Deuteron Spin Structure Function g_{1} and its Moments at Low Q^{2} with CLAS

We measured the g_{1} spin structure function of the deuteron at low Q^{2}, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W≈1.9  GeV. The generalized Gerasimov-Drell-Hearn sum, the moment Γ_{1}^{d} and the spin polarizability γ_{0}^{d} are precisely determined down to a minimum Q^{2} of 0.02  GeV^{2} for the first time, about 2.5 times lower than that of previous data. We compare them to several χPT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χPT domain.

Abstract TMP16: Efficacy and Safety of Ticagrelor in Relation to Time to Loading Dose in the SOCRATES Trial

Background: The risk of recurrent ischemia is high in the acute period after transient ischemic attack (TIA) and minor stroke. Therefore, event rates and treatment effects may vary in relation to time to loading dose (TLD) of antiplatelet treatment. We aimed to explore safety and efficacy of ticagrelor in relation to TLD from the onset of the index event.

Methods: In the SOCRATES trial (NCT01994720), we randomized 13,199 patients with a non-cardioembolic, non-severe ischemic stroke or high-risk TIA to ticagrelor (180 mg loading dose on day 1, followed by 90 mg twice daily for days 2-90) or aspirin (300 mg on day 1, followed by 100 mg daily for days 2-90) within 24 hours of symptom onset. Ticagrelor was not found to be superior to aspirin in reducing the rate of the primary composite endpoint of stroke, myocardial infarction, or death at 90 days. Patients were categorized according to TLD as <12 h and ≥12h from index event for this pre-specified exploratory analysis. The primary endpoint was time to the occurrence of stroke, myocardial infarction, or death within 90 days. The first secondary endpoint was ischemic stroke, with major bleeding serving as the primary safety endpoint.

Results: TLD was <12 h in 4,403 (33.4%) and ≥12 h in 8,723 (66.1%). Among TLD <12 h patients, the primary endpoint occurred in 147/2196 (6.7%) patients randomized to ticagrelor and in 184/2207 (8.3%) randomized to aspirin (HR 0.79; 95% CI 0.64-0.98, p=0.036); ischemic stroke was less frequent in those treated with ticagrelor (6.0% vs 7.5%, HR 0.79; 95% CI 0.63-0.99, p=0.041). Among patients with TLD ≥12 h, there were no differences in the treatment groups for the primary endpoint (6.7 vs 7.0%) or for ischemic stroke (5.8% vs 6.2%). There were no significant treatment-by-TLD interactions. Major bleeding was comparable in TLD <12 h patients (0.5% vs 0.7%, p=0.25) and TLD ≥12 h (0.5% vs 0.5%, p=0.95) on ticagrelor and aspirin, respectively.

Conclusion: In this pre-specified exploratory analysis, ticagrelor showed a greater treatment effect over aspirin in patients with TLD <12 h, although the interaction terms for treatment by TLD were not significant. Event rates for primary and secondary endpoints tended to be higher in patients randomized <12 h. Major bleeding was unrelated to TLD.

Abstract TMP20: Efficacy and Safety of Ticagrelor in Relation to Prior Aspirin Usage in the SOCRATES Trial

Background: In the SOCRATES study (NCT01994720), addition of ticagrelor to patients on aspirin treatment before randomization may confer the effect of dual antiplatelet therapy as the antiplatelet effect of aspirin persists for more than a week. We aimed to explore safety and efficacy of ticagrelor in this pre-specified group of patients who had received aspirin prior to randomization.

Methods: We randomized 13,199 patients with a non-cardioembolic, non-severe ischemic stroke or high-risk transient ischemic attack (TIA) to ticagrelor (180mg loading dose on day 1 followed by 90mg twice daily for days 2-90) or aspirin (300mg on day 1 followed by 100mg daily for days 2-90) within 24 hours of symptom onset. The prior aspirin group consisted of patients who had received aspirin within 7 days before randomization. The primary endpoint was the time to the occurrence of stroke, myocardial infarction, or death within 90 days.

Results: The 4,232 patients with prior aspirin usage were older, had more vascular risk factors and vascular disease than the 8,967 patients with no prior aspirin usage. In the prior aspirin group, a primary endpoint occurred in 138/2,130 (6.5%) patients randomized to ticagrelor and in 177/2,102 (8.3%) patients randomized to aspirin (HR 0.76; 95% CI, 0.61-0.95, P=0.016) while for the non-aspirin group in 304/4,459 (6.9%) patients randomized to ticagrelor and in 320/4,508 (7.1%) patients randomized to aspirin (HR 0.96; 95%CI, 0.82-1.12, P=0.59). There was no significant treatment-by-prior-aspirin interaction (P=0.098). Major bleeding occurred in 0.7% of patients randomized to ticagrelor and in 0.4% randomized to aspirin (HR 1.58; 95% CI 0.68-3.65, P=0.28) in the prior aspirin group.

Conclusion: In this pre-specified exploratory analysis, ticagrelor showed a numerically greater treatment effect over aspirin in patients taking prior aspirin, although the interaction for treatment by prior aspirin was not statistically significant. Further study is needed to evaluate the combination of ticagrelor and aspirin in patients with minor stroke/TIA.

Geographic Differences in Endovascular Treatment and Retreatment of Cerebral Aneurysms

BACKGROUND AND PURPOSE

Comparing outcomes between endovascular aneurysm coiling trials can be difficult because of heterogeneity in patients and end points. We sought to understand the impact of geography on aneurysm retreatment in patients enrolled in the Matrix and Platinum Science Trial.

MATERIALS AND METHODS

Post hoc analysis was performed on data from the Matrix and Platinum Science trial. Patients were stratified as either North American or international. Baseline patient demographics, comorbidities, aneurysm characteristics, procedural complications, and clinical and angiographic outcomes were compared.

RESULTS

We evaluated 407 patients from 28 North American sites and 219 patients from 15 international sites. Patient demographics differed significantly between North American and international sites. Aneurysms were well occluded postprocedure more often at international than North American sites (P < .001). Stents were used significantly more often at North American sites (32.7% [133 of 407]) compared with international sites (10.0% [22 of 219]; P < .001). At 455 days, there was no difference in the proportion of patients alive and free of disability (P = .56) or with residual aneurysm filling (P = .10). Ruptured aneurysms were significantly more likely to have been retreated at North American sites within the first year (P < .001) and at 2 years (P < .001). Among all patients for whom the treating physician believed there to be Raymond 3 aneurysm filling at follow-up, absolute rates of retreatment at international and North American sites were similar by 2-year follow-up.

CONCLUSIONS

Data from the Matrix and Platinum Science Trial demonstrate that aneurysm retreatment occurs with different frequency and at different times in different regions of the world. This trend has critical value when interpreting trials reporting short-term outcomes, especially when judgment-based metrics such as retreatment are primary end points that may or may not take place within the defined study follow-up period. Though these variations can be controlled for and balanced within a given randomized trial, such differences in practice patterns must be accounted for in any attempt to compare outcomes between different trials. Despite these differences, endovascular-treated intracranial aneurysms around the world have similar clinical outcomes.

Stent-assisted coiling versus coiling alone in unruptured intracranial aneurysms in the matrix and platinum science trial: safety, efficacy, and mid-term outcomes

BACKGROUND AND PURPOSE

Stent-assisted coiling may result in less aneurysm recanalization but more complications than coiling alone. We evaluated outcomes of coiling with and without stents in the multicenter Matrix and Platinum Science Trial.

MATERIALS AND METHODS

All patients in the Matrix and Platinum Science Trial with unruptured intracranial aneurysms treated per protocol were included. Baseline patient and aneurysm characteristics, procedural details, neurologic outcomes, angiographic outcomes, and safety data were analyzed.

RESULTS

Overall, 137 of 361 (38%) patients were treated with a stent. Stent-coiled aneurysms had wider necks (≥4 mm in 62% with stents versus 33% without, P < .0001) and lower dome-to-neck ratios (1.3 versus 1.8, P < .0001). Periprocedural serious adverse events occurred infrequently in those treated with and without stents (6.6% versus 4.5%, P = .39). At 1 year, total significant adverse events, mortality, and worsening of mRS were similar in treatment groups, but ischemic strokes were more common in stent-coiled patients than in coiled patients (8.8% versus 2.2%, P = .005). However, multivariate analysis confirmed that at 2 years after treatment, prior cerebrovascular accident (OR, 4.7; P = .0089) and aneurysm neck width ≥4 mm (OR, 4.5; P = .02) were the only independent predictors of ischemic stroke. Stent use was not an independent predictor of ischemic stroke at 2 years (OR, 1.1; P = .94). Stent use did not predict target aneurysm recurrence at 2 years, but aneurysm dome size ≥10 mm (OR, 9.94; P < .0001) did predict target aneurysm recurrence.

CONCLUSIONS

Stent-coiling had similar outcomes as coiling despite stented aneurysms having more difficult morphology than coiled aneurysms. Increased ischemic events in stent-coiled aneurysms were attributable to baseline risk factors and aneurysm morphology.

Abstract 154: Acute Stroke Recognition by Paramedics after Regionalization of Stroke Care: Outcomes Based Study

Background: Early evidence supports preferential transport of patients with stroke symptoms to primary stroke centers. While validated stroke tools exist for screening of stroke symptoms in the prehospital setting, system wide triage performance of prehospital providers in a regionalized system has not been reported. The objective of this study is to assess the diagnostic ability of prehospital providers, before and after regionalization of care, using outcomes based approach.

Methods: This is a cross-sectional study of all patients who were transported to hospitals in two Northern California counties by providers of a single EMS agency during a three year period. One county remained non-regionalized (NR) during the study period and the other initiated and completed regionalization(R) of the system during the study period. Patient demographic data, prehospital provider clinical assessment was obtained from the computerized prehospital transport records and physician diagnosis was obtained from statewide administrative patient discharge data. The data sources were linked using probabilistic linkage methodology. Patients ≥18 years of age with validated ICD- 9 code for stroke were included. We excluded inter-facility transports and direct admissions. Sensitivity, specificity and predictive values for were determined before and after implementation of regionalization. Data analysis was performed using SAS version 9.2.

Results: The total number of medical related EMS transports for 3 years was 310,731 and the number of patient discharges with a primary diagnosis of stroke was 10,298. We were able to link 3736 stroke records which indicate EMS use by 36% (3736/10,298) stroke patients. The sensitivity, specificity, PPV and NPV in the pre-regionalization phase was 28%, 80%, 53%, 58% and during the implementation phase of regionalization was 39% 78%,57% and 63% (p <0.05). The performance in the NR County during the entire period was 23%, 76%, 40% and 58%.

Conclusions: Diagnostic accuracy remained low although improved prehospital provider performance was observed after regionalization of stroke care.

Preparedness of the CTSA's structural and scientific assets to support the mission of the National Center for Advancing Translational Sciences (NCATS)

The formation of the National Center for Advancing Translational Sciences (NCATS) brings new promise for moving basic science discoveries to clinical practice, ultimately improving the health of the nation. The Clinical and Translational Science Award (CTSA) sites, now housed with NCATS, are organized and prepared to support in this endeavor. The CTSAs provide a foundation for capitalizing on such promise through provision of a disease-agnostic infrastructure devoted to clinical and translational (C&T) science, maintenance of training programs designed for C&T investigators of the future, by incentivizing institutional reorganization and by cultivating institutional support.

Abstract 2721: Probabilistic Matching of Computerized Emergency Medical Services (EMS) records and Emergency Department and Patient Discharge Data: a Novel Approach to Evaluation of Prehospital Stroke Care

Background and Purpose: Emergency Medical Services is an important element of acute stroke care. However, evaluation of prehospital stroke care is limited by lack of exchange of patient outcome data between hospitals and emergency medical services (EMS) agencies. In this study, we describe and demonstrate the feasibility of linking county wide patient level ambulance data with emergency department (EDD) and patient discharge data (PDD) using a probabilistic matching algorithm.

Methods: Probabilistic linkage was used to match county-wide ambulance data from 2005-2007 to hospital (EDD and PDD) records with a final ICD -9 diagnosis of stroke (430-436). The linkage model was based on the patient’s transport/admission date, date of birth, race, sex, county of residence, and destination hospital. Probabilistic linkage was performed using LinkSolv version 8.29746 which calculates the probability that a pair of records is a true match based on agreement/disagreement patterns of the linkage variables. Pairs of records with a match probability of 0.8 or higher were considered true matches. All other pairs were false matches and rejected.

Results: During 2005 - 2007 there were 310,731 patients transported to a facility in county and 34,785 hospital records with a diagnosis of stroke. Using the linkage algorithm we identified 11,473 (33%) matches with EMS records. Linkage rates increased each year with 30%, 34%, and 36% of hospital patients matching EMS record for 2005, 2006, and 2007 respectively. The median match probability was 0.993 and the IQR was 0.974 to 0.9996. By taking the compliment of the match probability we estimate our linked sample to include 255 (2%) false matches. Date of treatment/admission and the patient’s sex were observed to be the most reliable, disagreeing on less than one percent (1%) of all matched pairs. Patient’s zip code was the least reliable, disagreeing on one third of matched pairs.

Conclusions: Our study demonstrates that probabilistic matching can be used to create a comprehensive patient care record which in turn can provide opportunities for researchers to study different phases of stroke care.

Transient ischemic attacks characterized by RNA profiles in blood

OBJECTIVE

Transient ischemic attacks (TIA) are common. Though systemic inflammation and thrombosis are associated with TIA, further study may provide insight into TIA pathophysiology and possibly lead to the development of treatments specifically targeted to TIA. We sought to determine whether gene expression profiles in blood could better characterize the proinflammatory and procoagulant states in TIA patients.

METHODS

RNA expression in blood of TIA patients (n = 26) was compared to vascular risk factor control subjects without symptomatic cardiovascular disease (n = 26) using Affymetrix U133 Plus 2.0 microarrays. Differentially expressed genes in TIA were identified by analysis of covariance and evaluated with cross-validation and functional analyses.

RESULTS

Patients with TIA had different patterns of gene expression compared to controls. There were 480 probe sets, corresponding to 449 genes, differentially expressed between TIA and controls (false discovery rate correction for multiple comparisons, p ≤ 0.05, absolute fold change ≥1.2). These genes were associated with systemic inflammation, platelet activation, and prothrombin activation. Hierarchical cluster analysis of the identified genes suggested the presence of 2 patterns of RNA expression in patients with TIA. Prediction analysis identified a set of 34 genes that discriminated TIA from controls with 100% sensitivity and 100% specificity.

CONCLUSION

Patients with recent TIA have differences of gene expression in blood compared to controls. The 2 gene expression profiles associated with TIA suggests heterogeneous responses between subjects with TIA that may provide insight into cause, risk of stroke, and other TIA pathophysiology.

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.

A randomized trial of hypothesis-driven vs screening neurologic examination

OBJECTIVE

We hypothesized that trainees would perform better using a hypothesis-driven rather than a traditional screening approach to the neurologic examination.

METHODS

We randomly assigned 16 medical students to perform screening examinations of all major aspects of neurologic function or hypothesis-driven examinations focused on aspects suggested by the history. Each student examined 4 patients, 2 of whom had focal deficits. Outcomes of interest were the correct identification of patients with focal deficits, number of specific deficits detected, and examination duration. Outcomes were assessed by an investigator blinded to group assignments. The McNemar test was used to compare the sensitivity and specificity of the 2 examination methods.

RESULTS

Sensitivity was higher with hypothesis-driven examinations than with screening examinations (78% vs 56%; p = 0.046), although specificity was lower (71% vs 100%; p = 0.046). The hypothesis-driven group identified 61% of specific examination abnormalities, whereas the screening group identified 53% (p = 0.008). Median examination duration was 1 minute shorter in the hypothesis-driven group (7.0 minutes vs 8.0 minutes; p = 0.13).

CONCLUSIONS

In this randomized trial comparing 2 methods of neurologic examination, a hypothesis-driven approach resulted in greater sensitivity and a trend toward faster examinations, at the cost of lower specificity, compared with the traditional screening approach. Our findings suggest that a hypothesis-driven approach may be superior when the history is concerning for an acute focal neurologic process.

Early stroke risk and ABCD2 score performance in tissue- vs time-defined TIA: a multicenter study

OBJECTIVES

Stroke risk immediately after TIA defined by time-based criteria is high, and prognostic scores (ABCD2 and ABCD3-I) have been developed to assist management. The American Stroke Association has proposed changing the criteria for the distinction between TIA and stroke from time-based to tissue-based. Research using these definitions is lacking. In a multicenter observational cohort study, we have investigated prognosis and performance of the ABCD2 score in TIA, subcategorized as tissue-positive or tissue-negative on diffusion-weighted imaging (DWI) or CT imaging according to the newly proposed criteria.

METHODS

Twelve centers provided data on ABCD2 scores, DWI or CT brain imaging, and follow-up in cohorts of patients with TIA diagnosed by time-based criteria. Stroke rates at 7 and 90 days were studied in relation to tissue-positive or tissue-negative subcategorization, according to the presence or absence of brain infarction. The predictive power of the ABCD2 score was determined using area under receiver operator characteristic curve (AUC) analyses.

RESULTS

A total of 4,574 patients were included. Among DWI patients (n = 3,206), recurrent stroke rates at 7 days were 7.1%(95% confidence interval 5.5-9.1) after tissue-positive and 0.4% (0.2-0.7) after tissue-negative events (p diff < 0.0001). Corresponding rates in CT-imaged patients were 12.8% (9.3-17.4) and 3.0% (2.0-4.2), respectively (p diff < 0.0001). The ABCD2 score had predictive value in tissue-positive and tissue-negative events (AUC = 0.68 [95% confidence interval 0.63-0.73] and 0.73 [0.67-0.80], respectively; p sig < 0.0001 for both results, p diff = 0.17). Tissue-positive events with low ABCD2 scores and tissue-negative events with high ABCD2 scores had similar stroke risks, especially after a 90-day follow-up.

CONCLUSIONS

Our findings support the concept of a tissue-based definition of TIA and stroke, at least on prognostic grounds.

Is mechanical clot removal or disruption a cost-effective treatment for acute stroke?

BACKGROUND AND PURPOSE

It is unclear whether the costs and risks of mechanical therapies make them cost-effective. We examined whether interventions such as mechanical clot removal or disruption with angioplasty are cost-effective for acute ischemic stroke compared with best medical therapy.

MATERIALS AND METHODS

We performed a cost-utility analysis of patients with acute stroke due to large intracranial artery occlusion presenting beyond the 3-hour window for IV tPA. Model inputs for the mechanical arm were derived from Multi MERCI trial data and a recent meta-analysis. For best medical therapy, we used rates of spontaneous recanalization, ICH, and functional outcomes based on a systematic literature review. Discounted QALYs were determined by using the Markov modeling for 65-year-old patients with acute ischemic stroke.

RESULTS

On the basis of a systematic literature review, we modeled an 84% rate of recanalization with mechanical intervention and a 6.3% rate of symptomatic ICH. For best medical therapy, we modeled a spontaneous recanalization rate of 24% with a 2% rate of symptomatic ICH. Mechanical therapies were associated with a $7718 net cost and a gain of a 0.82 QALYs for each use, thus yielding a net of $9386/QALY gained. In sensitivity analyses, results were dependent on the rates of recanalization, symptomatic ICH rates, and costs of treatment.

CONCLUSIONS

On the basis of available data, mechanical therapies in qualified patients with acute stroke beyond the window for IV tPA appear to be cost-effective. However, the inputs are not derived from randomized trials, and results are sensitive to several assumptions.

The 5-year direct medical cost of neonatal and childhood stroke in a population-based cohort

BACKGROUND

Despite increasing awareness of the long-term impact of pediatric stroke, there are few estimates of the costs of care. We examined acute and 5-year direct costs of neonatal and childhood stroke in a population-based cohort in Northern California.

METHODS

We obtained electronic cost data for 266 children with neurologist-confirmed strokes, and 786 age-matched stroke-free controls, within the population of all children (<20 years) enrolled in a large managed care plan from 1996 through 2003. Cost data included all inpatient and outpatient health service costs including care at out-of-plan facilities. Costs were assessed for 5 years after stroke, expressed in 2003 US dollars, and stratified by age at stroke onset (neonatal, defined as <29 days of life, vs childhood). Stroke costs were adjusted for costs in stroke-free age-matched controls.

RESULTS

Average adjusted 5-year costs for pediatric stroke are substantial: $51,719 for neonatal stroke and $135,161 for childhood stroke. The average cost of a childhood stroke admission was $81,869. The average birth admission cost for a neonatal stroke was $39,613; adjustment for control birth admission costs reduced this by only $4,792, suggesting the stroke accounted for 88% of costs. Even among neonates whose strokes were not recognized until later in childhood ("presumed perinatal strokes"), admission costs exceeded those of controls. Chronic costs were highest in the first year poststroke, but continued to exceed control costs even in the fifth year by an average of $2,016.

CONCLUSIONS

The economic burden of neonatal and childhood stroke is both large and sustained.

Trial on endovascular treatment of unruptured aneurysms (TEAM): study monitoring and rationale for trial interruption or continuation

Preventive treatment of unruptured intracranial aneurysms is often performed but has never been proved beneficial as compared to conservative management. In a context of uncertainty, the 'best treatment' that can be offered to each individual is a chance to be treated and thus to be protected from rupture of the aneurysm, and an equal chance not to be treated, and hence to be exempted from possible immediate complications, using randomization. Such action is optimal unless or until an independent committee with privileged access to data judges that, given the comparative outcome of the 2 groups, preventive treatment or conservative management, is generally warranted. Potential reasons to interrupt such a study are reviewed, including insufficient recruitment, poor compliance, excessive cross-overs, unacceptable iatrogenia, and treatments being convincingly different or equivalent. We conclude that insufficient recruitment is the sole realistic event that could lead to premature interruption. This review may provide a deeper understanding of the principles justifying the necessity of the study.

Education and the cognitive decline associated with MRI-defined brain infarct

OBJECTIVE

To assess whether educational attainment, a correlate of cognitive reserve, predicts the amount of cognitive decline associated with a new brain infarct.

METHODS

The Cardiovascular Health Study is a population-based, longitudinal study of people aged 65 years and older. Cognitive function was measured annually using the Modified Mini-Mental State Examination (3MS) and the Digit-Symbol Substitution Test (DSST). The authors tested whether education level modified 1) the cross-sectional association between cognitive performance and MRI-defined infarct and 2) the change in cognitive function associated with an incident infarct at a follow-up MRI.

RESULTS

In cross-sectional analysis (n = 3,660), MRI-defined infarct was associated with a greater impact on 3MS performance in the lowest education quartile when compared with others (p for heterogeneity = 0.012). Among those with a follow-up MRI who had no infarct on initial MRI (n = 1,433), education level was not associated with the incidence, size, or location of new brain infarct. However, a new MRI-defined infarct predicted substantially greater decline in 3MS scores in the lowest education group compared with the others (6.3, 95% CI 4.4- to 8.2-point decline vs 1.7, 95% CI 0.7- to 2.7-point decline; p for heterogeneity < 0.001). Higher education was not associated with smaller declines in DSST performance in the setting of MRI-defined infarct.

CONCLUSIONS

Education seems to modify an individual's decline on a test of general cognitive function when there is incident brain infarct. These findings are consistent with the hypothesis that cognitive reserve influences the impact of vascular injury in the brain.

Do the Brain Attack Coalition's criteria for stroke centers improve care for ischemic stroke?

BACKGROUND

In 2000, the Brain Attack Coalition (BAC) recommended 11 major criteria for the establishment of primary stroke centers. The BAC relied heavily on expert opinion because evidence supporting the criteria was sparse.

OBJECTIVE

To assess primary stroke center elements, based on the criteria proposed by the BAC, with a questionnaire at 34 academic medical centers.

METHODS

Patient characteristics and outcomes were collected for all patients (n = 16,853) admitted with ischemic stroke to each hospital from 1999 to 2001. Stroke center elements were evaluated as predictors of treatment with tissue plasminogen activator (tPA) and outcomes after adjustment for patient characteristics.

RESULTS

The in-hospital mortality rate was 6.3% (n = 1,062), and 2.4% (n = 399) of patients received tPA. None of the 11 major stroke center elements was associated with decreased in-hospital mortality or increased frequency of discharge home. However, four elements predicted increased tPA use, including written care protocols, integrated emergency medical services, organized emergency departments, and continuing medical/public education in stroke (each odds ratio [OR] > 2.0, p < 0.05). Use of tPA also tended to be greater at centers with an acute stroke team, a stroke unit, or rapid neuroimaging (each OR > 2.0, p < 0.10). Institutions with a greater number of major stroke center elements used tPA more frequently.

CONCLUSIONS

Of the 11 stroke center elements recommended by the BAC, 7 were associated with increased tPA use. Institutions with a greater number of these seven features used tPA more often, suggesting these key elements may be most important for primary stroke center designation, at least in terms of identifying centers that deliver IV tPA frequently.

Stroke risk factors and loss of high cognitive function

BACKGROUND

Modifiable stroke risk factors may contribute to age-associated declines in cognitive function. Individuals with high levels of cognitive function after midlife may have less exposure to these stroke risk factors or may be less susceptible to their effects on cognition.

METHODS

The Cardiovascular Health Study (CHS)* is a population-based, longitudinal cohort study of 5,888 people age 65 years and older. Participants (n = 4,129) who were free of dementia, stroke, or TIA at the time of baseline cranial MRI were selected for analysis. High cognitive function at baseline was defined by performance at or above midlife norms on the Modified Mini-Mental State Examination (3MS).

RESULTS

The odds of having high cognitive function at baseline decreased by quartile of stroke risk (highest vs lowest risk quartile, adjusted odds ratio [OR] 0.68; 95% CI 0.52 to 0.88; p for trend = 0.005). Stroke risk was a predictor of decline on the 3MS in those with typical levels of cognitive function at baseline, even in the absence of incident stroke or TIA (highest vs lowest risk quartile for 3MS decline, adjusted OR 2.11; 95% CI 1.42 to 3.13; p for trend < 0.001). In contrast, stroke risk was not associated with decline on the 3MS in those with high cognitive function at baseline (p = 0.03 for interaction).

CONCLUSIONS

In a cohort of older adults without stroke, TIA, or dementia, cognitive function and incident cognitive decline were associated with risk for stroke. Additional studies are needed to determine whether modification of stroke risk factors can reduce the cognitive decline that is often attributed to normal aging.

Evaluation of carotid stenosis using CT angiography in the initial evaluation of stroke and TIA

BACKGROUND

Imaging of the carotid arteries is important for the evaluation of patients with ischemic stroke or TIA. CT angiography (CTA) of the head and neck is readily available and can be part of the routine imaging of stroke patients. To evaluate the accuracy of CTA, the authors compared the degree of stenosis found using CTA with digital subtraction angiography (DSA) in consecutive patients during a 3-year period.

METHODS

The authors included all patients with interpretable CTA and DSA of the cervical carotid arteries from April 2000 to November 2002 at a single academic medical center. This yielded a total of 81 vessels. Stenosis on CTA of the internal carotid artery was measured in the axial plane at the point of maximum stenosis and referenced to the distal cervical internal carotid by two blinded readers. Two blinded readers measured stenosis from the DSA using the North American Symptomatic Carotid Endarterectomy Trial method.

RESULTS

Using a 70% cutoff value for stenosis, CTA and DSA were in agreement in 78 of 81 (96%; 95% CI, 90 to 99%) vessels. CTA was 100% sensitive (n = 5) and 63% specific (95% CI, 25 to 88%), and the negative predictive value of a CTA demonstrating <70% stenosis was 100% (n = 73).

CONCLUSIONS

In this consecutive series of patients with CT angiography of the neck and digital subtraction angiography, the authors found that CT angiography has a high sensitivity and high negative predictive value for carotid disease. CT angiography appears to be an excellent screening test for internal carotid artery stenosis, and the authors advocate its use for the initial imaging of patients with suspected stroke or TIA.

The thickness of the temporal squama and its implication for transcranial sonography

BACKGROUND AND PURPOSE

The difficult transtemporal ultrasound window is a relatively frequent occurrence. The authors assessed if the thickness of the temporal bone squama as measured in the "bone window" of the head computerized tomography (CT) scan can predict the transtemporal acoustic window.

METHODS

The authors retrospectively reviewed the head CTs on their bone window setting of patients in which nonimaging transcranial Dopplers (TCDs) had been performed. The thickness of the temporal squama in its thinnest portion was measured. The temporal TCD windows were graded in three classes: class 1 as good, class 2 when only a partial study is possible, and class 3 as an impossible ultrasonic window. In a case-control design, for every patient with any class 2 and 3 TCD temporal window, a patient with a class 1 window was randomly included from the same time period.

RESULTS

Fifty-five temporal bones (56%) were class 1, 17 (17%) were class 2, and 27 (27%) were class 3. Bone thicknesses (in mm, mean +/- SD) were greater in those with poorer windows: class 1 = 2.67 +/- 0.70, class 2 = 4.06 +/- 0.56, and class 3 = 5.04 +/- 1.06, P < or = .0001 by Cusick's nonparametric test of trend. Temporal squama thickness of > or = 5 mm portends 86% sensitivity, 90% specificity, 70% positive predictive value, and a positive likelihood ratio of 8.6 for a class 3 transtemporal ultrasound window.

CONCLUSION

Measurement of temporal bone thickness on the bone window setting of the head CT scan may be useful in identifying patients who are poor candidates for transcranial ultrasound.

Distinguishing intracerebral hemorrhages caused by arteriovenous malformations

BACKGROUND

There is a shortage of data addressing the clinical characteristics of patients with arteriovenous malformations (AVMs) who present with intracerebral hemorrhages (ICH).

METHODS

A retrospective cohort study of members of a large, pre-paid health care program was conducted to identify factors that distinguish ICH secondary to cerebral AVMs from all other causes. Univariate and multivariate analysis was performed using Student's t test, Wilcoxon rank-sum test, and logistic regression.

RESULTS

Patients with an underlying AVM were younger and more likely to be female, non-smokers with lower blood pressures, lower cholesterol, and lower white blood cell counts on presentation.

CONCLUSIONS

These clinical characteristics may be useful in defining potential risk factors in future prospective studies as well as targeting candidates for additional imaging studies after ICH with no apparent etiology.

Prevalence and knowledge of transient ischemic attack among US adults

BACKGROUND

Little information is available about public knowledge of TIA and prevalence of a TIA diagnosis.

METHODS

The National Stroke Association sponsored a telephone survey by single-stage random-digit dialing of noninstitutionalized US residents > or =18 years old, which was conducted in 1999. Demographic characteristics of participants were compared to the US population to produce weights for projections. Independent predictors of knowledge and diagnosis of TIA were determined by including all demographic characteristics in logistic regression models.

RESULTS

Among 10,112 participants, 2.3% reported having been told by a physician that they had a TIA. Older age, lower income, and fewer years of education were independently associated with a diagnosis of TIA. Of those with TIA, only 64% saw a physician within 24 hours of the event. A physician diagnosis of stroke was reported by 2.3% of participants, of whom 19% recalled having had a TIA before the stroke. An additional 3.2% of participants recalled symptoms consistent with TIA but did not seek medical attention. Only 8.2% correctly related the definition of TIA and 8.6% could identify a typical symptom. Men, nonwhites, and those with lower income and fewer years of education were less likely to be knowledgeable about TIA.

CONCLUSIONS

An estimated 4.9 million people in the US report a diagnosis of TIA, and many more recall symptoms consistent with TIA but do not seek medical attention. Reducing stroke risk after TIA could have substantial impact on public health but will require public education about the importance of having stroke symptoms evaluated, even if they resolve.

Spinal manipulative therapy is an independent risk factor for vertebral artery dissection

OBJECTIVE

To determine whether spinal manipulative therapy (SMT) is an independent risk factor for cervical artery dissection.

METHODS

Using a nested case-control design, the authors reviewed all patients under age 60 with cervical arterial dissection (n = 151) and ischemic stroke or TIA from between 1995 and 2000 at two academic stroke centers. Controls (n = 306) were selected to match cases by sex and within age strata. Cases and controls were solicited by mail, and respondents were interviewed using a structured questionnaire. The medical records of interviewed patients were reviewed by two blinded neurologists to confirm that the patient had stroke or TIA and to determine whether there was evidence of arterial dissection.

RESULTS

After interview and blinded chart review, 51 patients with dissection (mean age 41 +/- 10 years; 59% female) and 100 control patients (44 +/- 9 years; 58% female) were studied. In univariate analysis, patients with dissection were more likely to have had SMT within 30 days (14% vs 3%, p = 0.032), to have had neck or head pain preceding stroke or TIA (76% vs 40%, p < 0.001), and to be current consumers of alcohol (76% vs 57%, p = 0.021). In multivariate analysis, vertebral artery dissections were independently associated with SMT within 30 days (OR 6.62, 95% CI 1.4 to 30) and pain before stroke/TIA (OR 3.76, 95% CI 1.3 to 11).

CONCLUSIONS

This case-controlled study of the influence of SMT and cervical arterial dissection shows that SMT is independently associated with vertebral arterial dissection, even after controlling for neck pain. Patients undergoing SMT should be consented for risk of stroke or vascular injury from the procedure. A significant increase in neck pain following spinal manipulative therapy warrants immediate medical evaluation.

Deaths from stroke in US children, 1979 to 1998

BACKGROUND

Studies have documented declining mortality from stroke in adults over the past two decades, with black adults at greater risk of death from stroke than whites in all years. As these findings have been attributed to control of stroke risk factors that are less important in children, trends and demographics of childhood stroke mortality are of interest, but have not been explored.

METHODS

The authors analyzed death certificate data for ischemic and hemorrhagic stroke (subarachnoid hemorrhage [SAH] and intracerebral hemorrhage [ICH]) in children under 20 years of age in the United States for the years 1979 through 1998, covering approximately 1.5 billion person-years.

RESULTS

Childhood mortality from stroke declined by 58% overall, with reductions in all major subtypes (ischemic stroke decreased by 19%; SAH, by 79%; ICH, by 54%). Black ethnicity was a risk factor for mortality from all stroke types (relative risk 1.74 for ischemic stroke; 1.76 for SAH; 2.06 for ICH; p < 0.0001 for all types). Male sex was a risk factor for mortality from SAH (relative risk 1.30, p < 0.0001) and ICH (relative risk 1.21, p < 0.0001), but not from ischemic stroke (relative risk 1.02, p = 0.76).

CONCLUSIONS

Mortality from stroke in US children has decreased dramatically over the last 20 years. Black children are at greater risk of death from all stroke types than are white children. As control of known stroke risk factors is unlikely to account for declining stroke mortality and ethnic differences in children, unrecognized stroke risk factors may be important.

Incidence and mortality of generalized convulsive status epilepticus in California

BACKGROUND

Few population-based studies of status epilepticus have been performed in the United States.

OBJECTIVE

To determine the incidence, case fatality, and demographics of generalized convulsive status epilepticus (GCSE) in the state of California.

METHODS

Using a state-wide hospital discharge database, the authors identified all hospitalizations from 1991 through 1998 with a discharge diagnosis of convulsive status epilepticus. They identified the first admission for each individual to estimate the incidence of GCSE. In-hospital case fatality rates were calculated, and multivariate analysis was performed to determine predictors of death during hospitalization. Secondary diagnoses were analyzed by retrieving all discharge diagnoses accompanying the diagnosis of GCSE.

RESULTS

The incidence rate of GCSE was 6.2/100,000 population and fell by 42% between the years 1991 and 1998 from 8.5 to 4.9/100,000. The rate of GCSE was highest among children under the age of 5 (7.5/100,000) and among the elderly (22.3/100,000). Blacks also demonstrated a relatively high incidence of GCSE (13.4/100,000). The case fatality for incident admissions was 10.7%, with increasing age being the only significant predictor in multivariate analysis. Case fatality was highest in patients who also carried a diagnosis of anoxia, CNS infection, or stroke.

CONCLUSIONS

The incidence of GCSE requiring hospitalization has fallen over the last decade and is lower than that reported in previous studies. The case fatality is also lower than that reported previously. Further studies are needed to determine the cause of this decline in incidence and mortality of GCSE.

Chronic dyspnea and hyperventilation in an awake patient with small subcortical infarcts

A 79-year-old woman presented with chronic dyspnea and hyperventilation. There was no evidence of pulmonary disease. Hyperventilation persisted during sleep and after high-dose administration of a narcotic. A head MRI revealed bilateral medial thalamic infarctions. Central neurogenic hyperventilation was diagnosed in this alert patient. The case may illustrate a role for the thalamus in regulating ventilation, but another small infarct not visible on MRI also could be responsible.

C-reactive protein levels and viable Chlamydia pneumoniae in carotid artery atherosclerosis

BACKGROUND AND PURPOSE

An elevated serum level of C-reactive protein, an inflammatory marker, is an independent predictor of stroke and coronary artery disease. To determine whether chronic infection with Chlamydia pneumoniae, which has been identified in atherosclerotic plaques, is responsible for systemic inflammation, we studied the association between serum C-reactive protein levels and infection of carotid artery atherosclerotic plaque with viable C pneumoniae.

METHODS

Serum C-reactive protein levels were obtained before endarterectomy for carotid artery stenosis. Plaques were tested for C pneumoniae mRNA, an indicator of viability, and DNA by polymerase chain reaction of DNA and cDNA, respectively.

RESULTS

Forty-eight samples were studied, of which 18 (38%; 95% CI, 23 to 50) were infected with viable C pneumoniae as evidenced by isolated chlamydial mRNA. All 18 of these samples, plus 1 additional sample, were positive for chlamydial DNA. Serum C-reactive protein levels were higher in those with viable C pneumoniae compared with those without infection (median, 8 mg/L versus undetectable; P=0.045 by Wilcoxon rank-sum test). In multivariable models, the only independent predictor of the presence of viable C pneumoniae was a detectable C-reactive protein level (odds ratio, 4.2; 95% CI, 1.1 to 17; P=0.04).

CONCLUSIONS

Viable C pneumoniae are present in a substantial portion of carotid artery atherosclerotic plaques and are associated with increased serum C-reactive protein levels. These findings may explain the link between elevated C-reactive protein levels and the risk of cardiovascular disease and stroke but should be reproduced in a larger cohort.

Hormone therapy and the risk of stroke after acute myocardial infarction in postmenopausal women

OBJECTIVES

We examined the association of hormone therapy (HRT) with hemorrhagic and ischemic stroke among postmenopausal women with acute myocardial infarction (AMI).

BACKGROUND

Hemorrhagic and ischemic strokes are common complications of AMI, and women are at increased risk for hemorrhagic stroke after thrombolytic therapy. This risk may be related to female hormones.

METHODS

Using data from the National Registry of Myocardial Infarction-3, we studied 114,724 women age 55 years or older admitted to the hospital for AMI, of whom 7,353 reported HRT use on admission. We determined rates of in-hospital hemorrhagic and ischemic stroke stratified by HRT use and estimated the independent association of HRT with each stroke type using multivariable logistic regression.

RESULTS

The HRT users were younger than non-users, had fewer risk factors for stroke including diabetes and prior stroke, and received more pharmacologic and invasive therapy including cardiac catheterization. A total of 2,152 (1.9%) in-hospital strokes occurred, with 442 (0.4%) hemorrhagic, 1,017 (0.9%) ischemic and 693 (0.6%) unspecified. Among HRT users and non-users, the rates of hemorrhagic stroke (0.40% vs. 0.42%, p = 1.00) and ischemic stroke (0.80% vs. 0.96%, p = 0.11) were similar. Among 13,328 women who received thrombolytic therapy, the rate of hemorrhagic stroke was not significantly different for users and non-users (1.6% vs. 2.1%, p = 0.22). After adjustment for baseline and treatment differences, HRT was not associated with hemorrhagic (odds ratio [OR], 0.88; 95% confidence intervals [CI], 0.58 to 1.35) or ischemic stroke (OR, 0.89; CI, 0.66 to 1.18).

CONCLUSIONS

Acute myocardial infarction is a high-risk setting for stroke among postmenopausal women, but HRT does not appear to modify that risk. Clinicians should not alter their approach to thrombolytic therapy based on HRT use.

Arterial dissection and stroke in children

OBJECTIVE

To describe the clinical characteristics of dissections of cerebral arteries in children.

METHODS

Searches of MEDLINE (1966-2000) and bibliographies were systematically performed for English-language publications that described patients <18 years old with anterior circulation arterial dissections (ACAD) or posterior circulation arterial dissections (PCAD).

RESULTS

A total of 2,027 studies were reviewed; 118 patients were identified in 79 studies. Seventy-four percent of patients with ACAD (n = 73) and 87% with PCAD (n = 47) were male (p < 0.0001). When patients with preceding trauma were excluded, this male predominance persisted. All patients had evidence of cerebral ischemia at the time of diagnosis. Headache was reported in approximately half of patients. Sixty percent of ACAD were intracranial. ACAD with no preceding trauma were more commonly intracranial than those preceded by significant trauma (86 vs 25%, p = 0.002). The most common location for PCAD was the vertebral artery at the level of the C1-C2 vertebral bodies (53%). Recurrent ischemic events after the diagnosis of dissection were reported in 15% of PCAD and 5% of ACAD cases. None of the PCAD group and 10% of the ACAD group had recurrent dissections.

CONCLUSIONS

There is a marked male predominance among children with cerebral arterial dissections that is not explained by trauma. Unlike adult ACAD, childhood ACAD are most commonly intracranial. Spontaneous ACAD, in particular, tend to be intracranial, while post-traumatic ACAD are more often extracranial. The vertebral artery segment most susceptible to dissection is similar between children and adults.

Characteristics of academic medical centers and ischemic stroke outcomes

BACKGROUND AND PURPOSE

Data supporting the efficacy of stroke center characteristics are limited.

METHODS

A questionnaire detailing stroke treatment practices was sent to 42 academic medical centers in the University Health Systems Consortium. In-hospital mortality of all emergency department admissions for ischemic stroke at these institutions was evaluated in a database of discharge abstracts during 1997-1999. Institutional characteristics were evaluated as predictors of in-hospital mortality after adjustment for age, sex, race, hospital treatment volume of ischemic stroke, and admission status (emergent, urgent, elective). Length of stay (LOS), total hospital charges, and frequency of tissue plasminogen activator (tPA) administration were evaluated as secondary outcomes. We used a multivariable method called generalized estimating equations, which broadens confidence intervals to adjust for clustering of variables at institutions.

RESULTS

Thirty-two institutions completed the questionnaire, and 29 of these were included in the database of discharge abstracts. In-hospital deaths occurred in 758 (7.0%) of the 10 880 ischemic stroke patients admitted through the emergency department. In-hospital deaths were less frequent at hospitals with a vascular neurologist (odds ratio [OR] 0.51; 95% CI, 0.36 to 0.74; P<0.0001) and at those with guidelines stating that only neurologists could administer tPA (OR, 0.65; 95% CI, 0.49 to 0.88; P=0.004). There was a trend toward fewer deaths at hospitals with a dedicated stroke team available by pager (OR, 0.76; 95% CI, 0.56 to 1.04; P=0.09). The presence of a dedicated neurological intensive care unit, stroke unit, and written clinical pathway for stroke were not significantly associated with in-hospital death. LOS was shorter at hospitals with a vascular neurologist (P=0.01).

CONCLUSIONS

Academic medical centers with a vascular neurologist and those with written guidelines limiting tPA administration to neurologists had lower rates of in-hospital mortality for ischemic stroke patients.

Identifying confounding by indication through blinded prospective review

Confounding by indication is a relentless threat to validity in observational studies of treatment effects. Multivariable models allow adjustment for known and readily measurable prognostic factors, but they may incompletely or inaccurately represent the underlying overall perceived risk of treatment. To incorporate practitioners' judgments about treatment indication and preprocedural prognosis into an observational study of cerebral aneurysm treatments, the author and colleagues presented patient characteristics and radiographic images from 179 aneurysm cases (University of California, San Francisco, 1990--1997) to panels of practitioners who were blinded as to actual treatment selection and outcome. In this way, the review process was designed to recreate the presentation of information in a prospective study. Judgments about inclusion and prognosis were reproducible. Perceived prognosis correlated with complication rates and provided information not present in a multivariable model including all available clinical characteristics. The association between treatment modality and outcome was examined while stratifying and adjusting for differences in perceived prognosis. Blinded prospective review may provide an unbiased observational study design with which to define a cohort that could have received any of the treatments being compared and to measure and adjust for overall perceived procedural risk.

Reporting terminology for brain arteriovenous malformation clinical and radiographic features for use in clinical trials

“If you wish to converse with me,” said Voltaire, “define your terms.” How many a debate would have been deflated into a paragraph if the disputants had dared to define their terms!

Will Durant: The Story of Philosophy

Utilization of intravenous tissue-type plasminogen activator for ischemic stroke at academic medical centers: the influence of ethnicity

BACKGROUND AND PURPOSE

We sought to measure the overall rate of usage of tissue-type plasminogen activator (tPA) for ischemic stroke at academic medical centers, and to determine whether ethnicity was associated with usage.

METHODS

Between June and December 1999, 42 academic medical centers in the United States each identified 30 consecutive ischemic stroke cases. Medical records were reviewed and information on demographics, medical history, and treatment were abstracted. Rates of tPA use were compared for African Americans and whites in univariate analysis and after adjustment for age, gender, stroke severity, and type of medical insurance with multivariable logistic regression.

RESULTS

Complete information was available for 1195 ischemic stroke patients; 788 were whites and 285 were African Americans: Overall, 49 patients (4.1%) received tPA. In the subgroup of 189 patients without a documented contraindication to therapy, 39 (20.6%) received tPA. Ten (20%) of those receiving tPA had documented contraindication. African Americans were one fifth as likely to receive tPA as whites (1.1% African Americans versus 5.3%; P=0.001), and the difference persisted after adjustment (OR 0.21, 95% CI 0.06 to 0.68; P=0.01). When comparison was restricted to those without a documented contraindication to tPA, the difference remained significant (OR 0.24, 95% CI 0.06 to 0.93; P=0.04). Medical insurance type was independently associated with tPA treatment. After adjustment for ethnicity and other demographic characteristics, those with Medicaid or no insurance were one ninth as likely to receive tPA as those with private medical insurance (OR 0.11, 95% CI 0.02 to 0.17; P=0.003).

CONCLUSIONS

tPA is used infrequently for ischemic stroke at US academic medical centers, even among qualifying candidates. African Americans are significantly less likely to receive tPA for ischemic stroke. Contraindications to treatment do not appear to account for the difference.

The ICH score: a simple, reliable grading scale for intracerebral hemorrhage

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) constitutes 10% to 15% of all strokes and remains without a treatment of proven benefit. Despite several existing outcome prediction models for ICH, there is no standard clinical grading scale for ICH analogous to those for traumatic brain injury, subarachnoid hemorrhage, or ischemic stroke.

METHODS

Records of all patients with acute ICH presenting to the University of California, San Francisco during 1997-1998 were reviewed. Independent predictors of 30-day mortality were identified by logistic regression. A risk stratification scale (the ICH Score) was developed with weighting of independent predictors based on strength of association.

RESULTS

Factors independently associated with 30-day mortality were Glasgow Coma Scale score (P<0.001), age >/=80 years (P=0.001), infratentorial origin of ICH (P=0.03), ICH volume (P=0.047), and presence of intraventricular hemorrhage (P=0.052). The ICH Score was the sum of individual points assigned as follows: GCS score 3 to 4 (=2 points), 5 to 12 (=1), 13 to 15 (=0); age >/=80 years yes (=1), no (=0); infratentorial origin yes (=1), no (=0); ICH volume >/=30 cm(3) (=1), <30 cm(3) (=0); and intraventricular hemorrhage yes (=1), no (=0). All 26 patients with an ICH Score of 0 survived, and all 6 patients with an ICH Score of 5 died. Thirty-day mortality increased steadily with ICH Score (P<0.005).

CONCLUSIONS

The ICH Score is a simple clinical grading scale that allows risk stratification on presentation with ICH. The use of a scale such as the ICH Score could improve standardization of clinical treatment protocols and clinical research studies in ICH.

The ICH score: a simple, reliable grading scale for intracerebral hemorrhage

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) constitutes 10% to 15% of all strokes and remains without a treatment of proven benefit. Despite several existing outcome prediction models for ICH, there is no standard clinical grading scale for ICH analogous to those for traumatic brain injury, subarachnoid hemorrhage, or ischemic stroke.

METHODS

Records of all patients with acute ICH presenting to the University of California, San Francisco during 1997-1998 were reviewed. Independent predictors of 30-day mortality were identified by logistic regression. A risk stratification scale (the ICH Score) was developed with weighting of independent predictors based on strength of association.

RESULTS

Factors independently associated with 30-day mortality were Glasgow Coma Scale score (P<0.001), age >/=80 years (P=0.001), infratentorial origin of ICH (P=0.03), ICH volume (P=0.047), and presence of intraventricular hemorrhage (P=0.052). The ICH Score was the sum of individual points assigned as follows: GCS score 3 to 4 (=2 points), 5 to 12 (=1), 13 to 15 (=0); age >/=80 years yes (=1), no (=0); infratentorial origin yes (=1), no (=0); ICH volume >/=30 cm(3) (=1), <30 cm(3) (=0); and intraventricular hemorrhage yes (=1), no (=0). All 26 patients with an ICH Score of 0 survived, and all 6 patients with an ICH Score of 5 died. Thirty-day mortality increased steadily with ICH Score (P<0.005).

CONCLUSIONS

The ICH Score is a simple clinical grading scale that allows risk stratification on presentation with ICH. The use of a scale such as the ICH Score could improve standardization of clinical treatment protocols and clinical research studies in ICH.

Treatment of unruptured cerebral aneurysms in California

BACKGROUND AND PURPOSE

The impact of endovascular therapy on treatment outcomes of unruptured cerebral aneurysms has not been studied in a defined geographic area.

METHODS

All primary diagnoses of unruptured aneurysms were retrieved from a statewide database of hospital discharges in California from January 1990 through December 1998. Admissions for initial treatment and all follow-up care were combined to reflect the entire course of therapy. An adverse outcome was defined as an in-hospital death or discharge to nursing home or rehabilitation hospital at any point during the treatment course. Multivariable analyses were performed with generalized estimating equations with adjustment for age, sex, ethnicity, source of admission, year of treatment, hospital volume, and clustering of observations at institutions.

RESULTS

A total of 2069 patients were treated for unruptured aneurysms. Adverse outcomes were more frequent in the 1699 patients treated with surgery (25%) than in those treated with endovascular therapy (10%; P:<0.001). The difference persisted after multivariable adjustment (surgery versus endovascular therapy: odds ratio for adverse outcomes, 3.1; 95% CI, 2.5 to 4.0; P:<0.001). Adverse outcomes declined from 1991 to 1998 in patients treated with endovascular therapy (P:<0.005) but not for surgery. In-hospital deaths occurred in 3.5% of surgical cases and 0.5% of endovascular cases (P:=0.003), and the difference remained significant after adjustment (odds ratio, 6.3; 95% CI, 3.5 to 11.4; P:<0.001). Total length of stay and hospital charges were greater in surgical cases (both P:<0.001). Results were similar in a confirmatory analysis focusing on treatment differences between institutions. Institutional treatment volume was also associated with outcome but did not account for the differences between surgery and endovascular therapy.

CONCLUSIONS

In California, endovascular therapy of unruptured aneurysms is associated with less risk of adverse outcomes and in-hospital death, lower hospital charges, and shorter hospital stays compared with surgery. Differences between therapies became more distinct through the years. Uncontrolled differences in prognosis of patients receiving endovascular therapy and surgery cannot be ruled out in this study of discharge abstracts.

Short-term prognosis after emergency department diagnosis of TIA

CONTEXT

Management of patients with acute transient ischemic attack (TIA) varies widely, with some institutions admitting all patients and others proceeding with outpatient evaluations. Defining the short-term prognosis and risk factors for stroke after TIA may provide guidance in determining which patients need rapid evaluation.

OBJECTIVE

To determine the short-term risk of stroke and other adverse events after emergency department (ED) diagnosis of TIA.

DESIGN AND SETTING

Cohort study conducted from March 1997 through February 1998 in 16 hospitals in a health maintenance organization in northern California. Patients A total of 1707 patients (mean age, 72 years) identified by ED physicians as having presented with TIA.

MAIN OUTCOME MEASURES

Risk of stroke during the 90 days after index TIA; other events, including death, recurrent TIA, and hospitalization for cardiovascular events.

RESULTS

During the 90 days after index TIA, 180 patients (10.5%) returned to the ED with a stroke, 91 of which occurred in the first 2 days. Five factors were independently associated with stroke: age greater than 60 years (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.1-2.7; P=.01), diabetes mellitus (OR, 2.0; 95% CI, 1.4-2.9; P<.001), symptom duration longer than 10 minutes (OR, 2.3; 95% CI, 1.3-4.2; P=.005), weakness (OR, 1.9; 95% CI, 1.4-2.6; P<.001), and speech impairment (OR, 1.5; 95% CI, 1.1-2.1; P=.01). Stroke or other adverse events occurred in 428 patients (25.1%) in the 90 days after the TIA and included 44 hospitalizations for cardiovascular events (2.6%), 45 deaths (2.6%), and 216 recurrent TIAs (12.7%).

CONCLUSIONS

Our results indicate that the short-term risk of stroke and other adverse events among patients who present to an ED with a TIA is substantial. Characteristics of the patient and the TIA may be useful for identifying patients who may benefit from expeditious evaluation and treatment.

Combining ecological and individual variables to reduce confounding by indication: case study--subarachnoid hemorrhage treatment

Ecological studies may reduce the problem of confounding by indication; however, these studies introduce new biases not present in individual-level analyses. To study the potential for ecological variables to reduce confounding by indication, we used a large database of admissions for ruptured cerebral aneurysms to evaluate the association of in-hospital death with treatment type-surgery or endovascular therapy. We compared results of three multivariable models: individual-level, ecological, and a two-level model with an ecological treatment variable and individual-level covariates and outcome. Trends in the individual-level and ecological models were in opposite directions, suggesting confounding by indication in the individual-level analysis. The two-level analysis revealed a strong association between institutional utilization of endovascular therapy and reduced individual risk of in-hospital death. Using an ecological treatment variable in an individual analysis may combine reduced confounding by indication in ecological analyses with increased power and more precise specification of outcomes and covariates in individual-level analyses.

Charged residues dominate a unique interlocking topography in the heterodimeric cytokine interleukin-12

Human interleukin-12 (IL-12, p70) is an early pro-inflammatory cytokine, comprising two disulfide-linked subunits, p35 and p40. We solved the crystal structures of monomeric human p40 at 2.5 A and the human p70 complex at 2.8 A resolution, which reveals that IL-12 is similar to class 1 cytokine-receptor complexes. They also include the first description of an N-terminal immunoglobulin-like domain, found on the p40 subunit. Several charged residues from p35 and p40 intercalate to form a unique interlocking topography, shown by mutagenesis to be critical for p70 formation. A central arginine residue from p35 projects into a deep pocket on p40, which may be an ideal target for a small molecule antagonist of IL-12 formation.

Ischemic stroke risk with oral contraceptives: A meta-analysis

CONTEXT

The relationship between ischemic stroke and oral contraceptive (OC) use has been studied for 40 years, but disagreement about an association persists.

OBJECTIVE

To review available literature to determine whether OC use is associated with increased stroke risk.

DATA SOURCES

Studies published from January 1960 through November 1999 were identified from electronic databases (MEDLINE, BIOSIS, and Dissertation Abstracts Online), Index Medicus, bibliographies of pertinent review articles and pertinent original articles, textbooks, and expert consultation.

STUDY SELECTION

From 804 potentially relevant references retrieved, 73 were studies investigating risk of ischemic stroke with OC use. Two reviewers independently applied the following inclusion criteria: more than 10 stroke cases sampled, clear stroke subtype differentiation, concurrent controls included, adequate data included to determine relative risks (RRs) and confidence intervals (CIs), analysis controlled for age, and no later publication of identical data. A third investigator adjudicated disagreements. Sixteen studies met all inclusion criteria and were included in the meta-analysis.

DATA EXTRACTION

Two investigators independently extracted data, with disagreements resolved through discussion.

DATA SYNTHESIS

The 16 studies were analyzed using random effects modeling. Current OC use was associated with increased risk of ischemic stroke (RR, 2.75; 95% CI, 2.24-3.38). Smaller estrogen dosages were associated with lower risk (P=.01 for trend), but risk was significantly elevated for all dosages. Studies that did not control for smoking (P=.01) and those using hospital-based controls (P<.001) found higher RRs, but no other patient characteristics or elements of study design were important. The summary RR was 1.93 (95% CI, 1.35-2.74) for low-estrogen preparations in population-based studies that controlled for smoking and hypertension. This translates to an additional 4.1 ischemic strokes per 100,000 nonsmoking, normotensive women using low-estrogen OCs, or 1 additional ischemic stroke per year per 24,000 such women. The RR of stroke due to OC use was not different in women who smoked, had migraines, or had hypertension.

CONCLUSIONS

Summary results indicate that risk of ischemic stroke is increased in current OC users, even with newer low-estrogen preparations. However, the absolute increase in stroke risk is expected to be small since incidence is very low in this population. JAMA. 2000;284:72-78

Endovascular and surgical treatment of unruptured cerebral aneurysms: comparison of risks

Unruptured cerebral aneurysms are commonly treated by surgical clipping, but endovascular coil embolization is increasingly employed as an alternative. In a blinded review of unruptured aneurysms treated at our institution since 1990, we identified patients whose aneurysms were judged to be treatable by both neurosurgeons and neurointerventional radiologists. A change in Rankin Scale score of 2 or more from hospital admission to discharge, indicating a new moderate disability or worse, was predefined as the primary outcome measure. Long-term follow-up was obtained by mailed questionnaire and telephone interview. Length of stay and hospital charges were totaled for all hospitalizations, including follow-up. Sixty-eight patients treated surgically and 62 patients treated with endovascular coil embolization were considered candidates for either procedure on blinded review, and overall anticipated procedure risk was rated as identical. A larger proportion of patients in the surgical group developed a change in Rankin Scale score of 2 or more (25% of surgical patients vs 8% of endovascular patients). Total length of stay was longer (mean days: 7.7 for surgical patients vs 5.0 for endovascular patients) and hospital charges were greater (mean, $38,000 for surgical patients vs $33,400 for endovascular patients) for the surgical patients. At follow-up, an average of 3.9 years after the procedure, surgical patients were more likely to report persistent new symptoms or disability since treatment (34% of surgical patients vs 8% of endovascular patients) and a longer period for recovery to normal (50% returning to normal in 1 year for surgery and in 27 days for coil embolization). Coil embolization of unruptured cerebral aneurysms seems to be associated with significantly fewer complications than surgical clipping. More long-term data on aneurysm rupture rates are required to confirm efficacy.