Delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: proposal of an evidence-based combined clinical and imaging reference standard

SUMMARY

Aneurysmal subarachnoid hemorrhage is associated with high morbidity and mortality, with delayed neurologic deficits from delayed cerebral ischemia contributing to a large portion of the adverse outcomes in this patient population. There is currently no consensus reference standard for establishing the diagnosis of delayed cerebral ischemia either in the research or clinical settings, ultimately limiting strategies for preventing delayed infarction and permanent neurologic deficits. There are currently both clinical and imaging-based criteria for the diagnosis of delayed neurologic deficits and vasospasm, respectively, however, neither clinical nor angiographic assessment alone has been shown to identify patients who develop adverse outcomes from delayed infarction. Thus, the purpose of this work is to propose a 3-tiered combined imaging and clinical reference standard based on evidence from the literature to standardize the diagnosis of delayed cerebral ischemia, both to allow consistency across research studies and to ultimately improve outcomes in the clinical setting.

Plaque echolucency and stroke risk in asymptomatic carotid stenosis: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Ultrasonographic plaque echolucency has been studied as a stroke risk marker in carotid atherosclerotic disease. We performed a systematic review and meta-analysis to summarize the association between ultrasound-determined carotid plaque echolucency and future ipsilateral stroke risk.

METHODS

We searched the medical literature for studies evaluating the association between carotid plaque echolucency and future stroke in asymptomatic patients. We included prospective observational studies with stroke outcome ascertainment after baseline carotid plaque echolucency assessment. We performed a meta-analysis and assessed study heterogeneity and publication bias. We also performed subgroup analyses limited to patients with stenosis ≥50%, studies in which plaque echolucency was determined via subjective visual interpretation, studies with a relatively lower risk of bias, and studies published after the year 2000.

RESULTS

We analyzed data from 7 studies on 7557 subjects with a mean follow-up of 37.2 months. We found a significant positive relationship between predominantly echolucent (compared with predominantly echogenic) plaques and the risk of future ipsilateral stroke across all stenosis severities (0% to 99%; relative risk, 2.31; 95% confidence interval, 1.58-3.39; P<0.001) and in subjects with ≥50% stenosis (relative risk, 2.61; 95% confidence interval, 1.47-4.63; P=0.001). A statistically significant increased relative risk for future stroke was preserved in all additional subgroup analyses. No statistically significant heterogeneity or publication bias was present in any of the meta-analyses.

CONCLUSIONS

The presence of ultrasound-determined carotid plaque echolucency provides predictive information in asymptomatic carotid artery stenosis beyond luminal stenosis. However, the magnitude of the increased risk is not sufficient on its own to iden tify patients likely to benefit from surgical revascularization.

Carotid artery stenosis: cost-effectiveness of assessment of cerebrovascular reserve to guide treatment of asymptomatic patients

PURPOSE

To project and compare the lifetime health benefits, health care costs, and incremental cost-effectiveness of a decision rule based on assessment of cerebrovascular reserve (CVR) compared with medical therapy and immediate revascularization in asymptomatic patients with carotid artery stenosis for prevention of stroke.

MATERIALS AND METHODS

The three strategies compared included immediate revascularization (carotid endarterectomy) and ongoing medical therapy (with antiplatelet, statin, and antihypertensive agents plus lifestyle modification), medical therapy-based treatment with revascularization only for patients who progressed, and use of a CVR-based decision rule for treatment in which patients with CVR impairment undergo immediate revascularization and all others receive medical therapy. A decision analytic model was developed to project lifetime quality-adjusted life years (QALYs) and costs for asymptomatic patients with carotid stenosis with 70%-89% carotid luminal narrowing at presentation. Risks of clinical events, costs, and quality-of-life values were estimated on the basis of those in published sources. The analysis was conducted from a health care system perspective, with health and cost outcomes discounted at 3%. Results Total costs per person and lifetime QALYs were lowest for the medical therapy-based strategy ($14 597, 9.848 QALYs), followed by CVR testing ($16 583, 9.934 QALYs) and immediate revascularization ($20 950, 9.940 QALYs). The incremental cost-effectiveness ratio for the CVR-based strategy compared with the medical therapy-based strategy was $23 000 per QALY and for the immediate revascularization versus the CVR-based strategy was $760 000 per QALY.

RESULTS

were sensitive to variations in model inputs for revascularization costs and complication risks and baseline stroke risk.

CONCLUSION

CVR testing can be a cost-effective tool to identify asymptomatic patients with carotid stenosis who are most likely to benefit from revascularization.

CT angiographic features of symptom-producing plaque in moderate-grade carotid artery stenosis

BACKGROUND AND PURPOSE

Emerging evidence indicates that plaque imaging can improve stroke risk stratification in patients with carotid artery atherosclerosis. We studied the association between soft and hard (calcified) plaque thickness measurements on CTA and symptomatic disease status (ipsilateral stroke or TIA) in patients with moderate-grade carotid artery stenosis.

MATERIALS AND METHODS

We measured soft-plaque and hard-plaque thickness on CTA axial source images in each carotid artery plaque in subjects with NASCET 50%-69% ICA stenosis. We used logistic regression and receiver operating characteristic analyses to assess the strength of the association between thickness measurements and prior stroke or TIA.

RESULTS

Twenty of 72 vessels studied (27.7%) had ischemic symptoms ipsilateral to the side of moderate-grade carotid stenosis. Each 1-mm increase in soft plaque resulted in a 3.7 times greater odds of a prior ipsilateral ischemic event (95% CI, 1.9-7.2). Conversely, for each 1-mm increase in hard plaque, the odds of being symptomatic decreased by approximately 80% (OR, 0.22; 95% CI, 0.10%-0.48%). Receiver operating characteristic analysis showed an area under the curve of 0.88 by using soft-plaque thickness measurements to discriminate between asymptomatic and symptomatic plaques. Sensitivity and specificity were optimized by using a maximum soft-plaque thickness of 2.2 mm, which provided a sensitivity of 85% and a specificity of 83%.

CONCLUSIONS

Simple CTA plaque-thickness measurements might differentiate symptomatic and asymptomatic moderate-grade carotid artery plaque. With further prospective validation, CTA plaque measures could function as an easily implementable tool for risk stratification in carotid artery disease.

Diagnostic yield of electroencephalography in the medical and surgical intensive care unit

BACKGROUND

To determine the incidence of electrographic seizures during continuous electroencephalography (cEEG) in the medical and surgical ICU.

METHODS

We retrospectively reviewed the records of all adults who underwent cEEG in our medical and surgical ICU over a 4.5 year period. Patients with acute brain injury were excluded. Our primary outcome was cEEG documentation of an electrographic seizure, defined as a rhythmic discharge or spike and wave pattern demonstrating definite evolution and lasting at least 10 s. To assess inter-rater variability in cEEG interpretation, two electrophysiologists independently reviewed all available cEEGs of subjects with electrographic seizures documented on their clinical cEEG report and those of an equal number of randomly selected subjects from the remaining cohort.

RESULTS

Kappa analysis showed a value of 0.88, indicating excellent inter-rater agreement. Electrographic seizures were identified in 12 of 105 patients (11 %, 95 % CI 5-18 %). This rate did not change after excluding patients with a history of seizure, remote brain injury, or seizure-like events before cEEG. In an ordinal logistic regression model controlling for age, sex, and SOFA score, electrographic seizures were associated with lower odds of good outcomes on the Glasgow Outcome Scale at discharge (OR 0.3, 95 % CI 0.1-0.8).

CONCLUSION

In a tertiary care medical and surgical ICU, electrographic seizures were seen on 11 % of cEEGs ordered for the evaluation of encephalopathy, and were associated with worse functional outcomes at discharge. Our findings confirm the results of a prior study suggesting a substantial burden of electrographic seizures in critically ill encephalopathic patients.

Perioperative atrial fibrillation and the long-term risk of ischemic stroke

IMPORTANCE

Clinically apparent atrial fibrillation increases the risk of ischemic stroke. In contrast, perioperative atrial fibrillation may be viewed as a transient response to physiological stress, and the long-term risk of stroke after perioperative atrial fibrillation is unclear.

OBJECTIVE

To examine the association between perioperative atrial fibrillation and the long-term risk of stroke.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study using administrative claims data on patients hospitalized for surgery (as defined by surgical diagnosis related group codes), and discharged alive and free of documented cerebrovascular disease or preexisting atrial fibrillation from nonfederal California acute care hospitals between 2007 and 2011. Patients undergoing cardiac vs other types of surgery were analyzed separately.

MAIN OUTCOMES AND MEASURES

Previously validated diagnosis codes were used to identify ischemic strokes after discharge from the index hospitalization for surgery. The primary predictor variable was atrial fibrillation newly diagnosed during the index hospitalization, as defined by previously validated present-on-admission codes. Patients were censored at postdischarge emergency department encounters or hospitalizations with a recorded diagnosis of atrial fibrillation.

RESULTS

Of 1,729,360 eligible patients, 24,711 (1.43%; 95% CI, 1.41%-1.45%) had new-onset perioperative atrial fibrillation during the index hospitalization and 13,952 (0.81%; 95% CI, 0.79%-0.82%) experienced a stroke after discharge. At 1 year after hospitalization for cardiac surgery, cumulative rates of stroke were 0.99% (95% CI, 0.81%-1.20%) in those with perioperative atrial fibrillation and 0.83% (95% CI, 0.76%-0.91%) in those without atrial fibrillation. At 1 year after noncardiac surgery, cumulative rates of stroke were 1.47% (95% CI, 1.24%-1.75%) in those with perioperative atrial fibrillation and 0.36% (95% CI, 0.35%-0.37%) in those without atrial fibrillation. In a Cox proportional hazards analysis accounting for potential confounders, perioperative atrial fibrillation was associated with subsequent stroke both after cardiac surgery (hazard ratio, 1.3; 95% CI, 1.1-1.6) and noncardiac surgery (hazard ratio, 2.0; 95% CI, 1.7-2.3). The association was significantly stronger for perioperative atrial fibrillation after noncardiac vs cardiac surgery (P < .001 for interaction).

CONCLUSIONS AND RELEVANCE

Among patients hospitalized for surgery, perioperative atrial fibrillation was associated with an increased long-term risk of ischemic stroke, especially following noncardiac surgery.

P-wave morphology and the risk of incident ischemic stroke in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND PURPOSE

Emerging data suggest that left atrial disease may cause ischemic stroke in the absence of atrial fibrillation or flutter (AF). If true, this condition may provide a cause for many strokes currently classified as cryptogenic.

METHODS

Among 6741 participants in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cerebrovascular or cardiovascular disease (including AF) at baseline, we examined the association between markers of left atrial abnormality on a standard 12-lead ECG-specifically P-wave area, duration, and terminal force in lead V1-and the subsequent risk of ischemic stroke while accounting for incident AF.

RESULTS

During a median follow-up of 8.5 years, 121 participants (1.8%) had a stroke and 541 participants (8.0%) were diagnosed with AF. In Cox proportional hazards models adjusting for potential baseline confounders, P-wave terminal force in lead V1 was more strongly associated with incident stroke (hazard ratio per 1 SD increase, 1.21; 95% confidence interval, 1.02-1.44) than with incident AF (hazard ratio per 1 SD, 1.11; 95% confidence interval, 1.03-1.21). The association between P-wave terminal force in lead V1 and stroke was robust in numerous sensitivity analyses accounting for AF, including analyses that excluded those with any incident AF or modeled any incident AF as having been present from baseline.

CONCLUSIONS

We found an association between baseline P-wave morphology and incident stroke even after accounting for AF. This association may reflect an atrial cardiopathy that leads to stroke in the absence of AF.

The THRIVE Score Predicts Symptomatic Intracerebral Hemorrhage after Intravenous tPA Administration in SITS-MOST

Background

The Totaled Health Risks in Vascular Events (THRIVE) score is a clinical prediction score that predicts ischemic stroke outcomes in patients receiving intravenous tissue plasminogen activator, endovascular stroke treatment, or no acute therapy. We have previously found an association between THRIVE and risk of post-tissue plasminogen activator symptomatic intracranial hemorrhage in the National Institute of Neurological Disorders and Stroke (NINDS) tissue plasminogen activator trial and risk of radiographic hemorrhage in Virtual International Stroke Trials Archive.

Aims

The study aims to validate the relationship between THRIVE and symptomatic intracranial hemorrhage among tissue plasminogen activator-treated patients in the large Safe Implementation of Thrombolysis in Stroke – Monitoring Study (SITS-MOST).

Methods

This is a retrospective analysis of the prospective SITS-MOST to examine the relationship between THRIVE and symptomatic intracranial hemorrhage after tissue plasminogen activator treatment. Symptomatic intracranial hemorrhage after tissue plasminogen activator was defined according to each of three standard definitions: the NINDS, European Cooperative Acute Stroke Study (ECASS), and Safe Implementation of Thrombolysis in Stroke (SITS) criteria. Multivariable logistic regression was used to confirm the relationship of THRIVE and individual THRIVE components with the risk of symptomatic intracranial hemorrhage and to examine the relationship of THRIVE, symptomatic intracranial hemorrhage, and functional outcome.

Results

The odds ratio for symptomatic intracranial hemorrhage at each increased level of THRIVE score is 1·34 (95% CI 1·27 to 1·41, P < 0·001) for symptomatic intracranial hemorrhage by NINDS criteria, 1·36 (95% CI 1·27 to 1·46, P < 0·001) for symptomatic intracranial hemorrhage by ECASS criteria, and 1·21 (95% CI 1·09 to 1·36, P < 0·001) for symptomatic intracranial hemorrhage by SITS criteria. In receiver-operator characteristics analysis, the C-statistic for THRIVE prediction of symptomatic intracranial hemorrhage was 0·65 (95% CI 0·62 to 0·67) for symptomatic intracranial hemorrhage by NINDS criteria, 0·66 (95% CI 0·63 to 0·69) for symptomatic intracranial hemorrhage by ECASS criteria, and 0·61 (95% CI 0·56 to 0·66) for symptomatic intracranial hemorrhage by SITS criteria. Each component of the THRIVE score predicts the risk of symptomatic intracranial hemorrhage, with independent impact of each component in multivariable analysis.

Conclusions

The THRIVE score predicts the risk of symptomatic intracranial hemorrhage after intravenous tissue plasminogen activator administration. This external validation of the relationship between THRIVE and symptomatic intracranial hemorrhage in a prospective study further strengthens the role of the THRIVE score in the prediction of poststroke outcomes.

Cryptogenic subtype predicts reduced survival among cancer patients with ischemic stroke

BACKGROUND AND PURPOSE

Cryptogenic stroke is common in patients with cancer. Autopsy studies suggest that many of these cases may be because of marantic endocarditis, which is closely linked to cancer activity. We, therefore, hypothesized that among patients with cancer and ischemic stroke, those with cryptogenic stroke would have shorter survival.

METHODS

We retrospectively analyzed all adult patients with active systemic cancer diagnosed with acute ischemic stroke at a tertiary care cancer center from 2005 through 2009. Two neurologists determined stroke mechanisms by consensus. Patients were diagnosed with cryptogenic stroke if no specific mechanism could be determined. The diagnosis of marantic endocarditis was restricted to patients with cardiac vegetations on echocardiography or autopsy and negative blood cultures. Patients were followed until July 31, 2012, for the primary outcome of death. Kaplan-Meier statistics and the log-rank test were used to compare survival between patients with cryptogenic stroke and patients with known stroke mechanisms. Multivariate Cox proportional hazard analysis evaluated the association between cryptogenic stroke and death after adjusting for potential confounders.

RESULTS

Among 263 patients with cancer and ischemic stroke, 133 (51%) were cryptogenic. Median survival in patients with cryptogenic stroke was 55 days (interquartile range, 21-240) versus 147 days (interquartile range, 33-735) in patients with known stroke mechanisms (P<0.01). Cryptogenic stroke was independently associated with death (hazard ratio, 1.64; 95% confidence interval, 1.25-2.14) after adjusting for age, systemic metastases, adenocarcinoma histology, and functional status.

CONCLUSIONS

Cryptogenic stroke is independently associated with reduced survival in patients with active cancer and ischemic stroke.

Acute cerebrovascular disease occurring after hospital discharge for labor and delivery

BACKGROUND AND PURPOSE

The risk of stroke and other postpartum cerebrovascular disease (CVD) occurring after hospital discharge for labor and delivery is uncertain.

METHODS

We performed a retrospective cohort study using administrative databases to identify all pregnant women who were hospitalized for labor and delivery at nonfederal, acute care hospitals in California from 2005 to 2011 and who were discharged without an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis of CVD. The primary outcome was an acute CVD composite defined as any ischemic stroke, intracranial hemorrhage, cerebral venous sinus thrombosis, pituitary apoplexy, carotid/vertebral artery dissection, hypertensive encephalopathy, or other acute CVD occurring after hospital discharge and before 6 weeks after labor and delivery. Descriptive statistics were used to estimate the incidence of postdischarge CVD. Multivariate logistic regression was used to evaluate the association between selected baseline factors and postdischarge CVD.

RESULTS

The rate of any postdischarge acute CVD was 14.8 per 100 000 patients (95% confidence interval [CI], 13.2-16.5). Risk factors for any acute CVD were eclampsia (odds ratio [OR], 10.1; 95% CI, 3.09-32.8), chronic kidney disease (OR, 5.4; 95% CI, 2.5-11.8), black race (OR, 2.5; 95% CI, 1.9-3.3), preeclampsia (OR, 2.1; 95% CI, 1.6-2.8), pregnancy-related hematologic disorders (OR, 1.8; 95% CI, 1.3-2.5), and age (OR, 1.5 per decade; 95% CI, 1.3-1.8).

CONCLUSIONS

The incidence of postpartum acute CVD after hospital discharge for labor and delivery is similar to rates reported for all postpartum events in previous publications, suggesting that a substantial proportion of postpartum CVD occurs after discharge.

Recurrent thromboembolic events after ischemic stroke in patients with cancer

OBJECTIVE

To determine the cumulative rate and characteristics of recurrent thromboembolic events after acute ischemic stroke in patients with cancer.

METHODS

We retrospectively identified consecutive adult patients with active systemic cancer diagnosed with acute ischemic stroke at a tertiary-care cancer center from 2005 through 2009. Two neurologists independently reviewed all electronic records to ascertain the composite outcome of recurrent ischemic stroke, myocardial infarction, systemic embolism, TIA, or venous thromboembolism. Kaplan-Meier statistics were used to determine cumulative outcome rates. In exploratory analyses, Cox proportional hazard analysis was used to evaluate potential independent associations between a priori selected clinical factors and recurrent thromboembolic events.

RESULTS

Among 263 study patients, complete follow-up until death was available in 230 (87%). Most patients had an adenocarcinoma as their underlying cancer (60%) and had systemic metastases (69%). Despite a median survival of 84 days (interquartile range 24-419 days), 90 patients (34%; 95% confidence interval 28%-40%) had 117 recurrent thromboembolic events, consisting of 57 cases of venous thromboembolism, 36 recurrent ischemic strokes, 13 myocardial infarctions, 10 cases of systemic embolism, and one TIA. Kaplan-Meier rates of recurrent thromboembolism were 21%, 31%, and 37% at 1, 3, and 6 months, respectively; cumulative rates of recurrent ischemic stroke were 7%, 13%, and 16%. Adenocarcinoma histology (hazard ratio 1.65, 95% confidence interval 1.02-2.68) was independently associated with recurrent thromboembolism.

CONCLUSIONS

Patients with acute ischemic stroke in the setting of active cancer (especially adenocarcinoma) face a substantial short-term risk of recurrent ischemic stroke and other types of thromboembolism.

Tracheostomy after severe ischemic stroke: a population-based study

BACKGROUND

Stroke can result in varying degrees of respiratory failure. Some patients require tracheostomy in order to facilitate weaning from mechanical ventilation, long-term airway protection, or a combination of the two. Little is known about the rate and predictors of this outcome in patients with severe stroke. We aim to determine the rate of tracheostomy after severe ischemic stroke.

METHODS

Using the Nationwide Inpatient Sample database from 2007 to 2009, patients hospitalized with ischemic stroke were identified based on validated International Classification of Diseases, 9th revision, Clinical Modification codes. Next, patients with stroke were stratified based on whether they were treated with or without decompressive craniectomy, and the rate of tracheostomy for each group was determined. A logistic regression analysis was used to identify predictors of tracheostomy after decompressive craniectomy. Survey weights were used to obtain nationally representative estimates.

RESULTS

In 1,550,000 patients discharged with ischemic stroke nationwide, the rate of tracheostomy was 1.3% (95% confidence interval [CI], 1.2-1.4%), with a 1.3% (95% CI, 1.1-1.4%) rate in patients without decompressive craniectomy and a 33% (95% CI, 26-39%) rate in the surgical treatment group. Logistic regression analysis identified pneumonia as being significantly associated with tracheostomy after decompressive craniectomy (odds ratio, 3.95; 95% CI, 1.95-6.91).

CONCLUSIONS

Tracheostomy is common after decompressive craniectomy and is strongly associated with the development of pneumonia. Given its impact on patient function and potentially modifiable associated factors, tracheostomy may warrant further study as an important patient-centered outcome among patients with stroke.

Preoperative steroid use and the risk of infectious complications after neurosurgery

BACKGROUND AND PURPOSE

The association between preoperative corticosteroid use and infectious complications after neurosurgical procedures is unclear. We aim to determine whether corticosteroids increase the risk of infectious complications after neurosurgery.

METHODS

We examined the association between preoperative corticosteroid use and postoperative infectious complications in a cohort of adults who underwent a neurosurgical procedure between 2005 and 2010 at centers participating in the National Surgical Quality Improvement Program. Corticosteroid use was defined as at least 10 days of oral or parental therapy in the 30 days prior to surgery. Our primary outcome was a composite of any infectious complications occurring within 30 days of surgery. We used propensity score analysis to examine the independent association between preoperative corticosteroid use and postoperative infections.

RESULTS

Among 26 634 neurosurgical procedures, 1228 (4.61%, 95% confidence interval [CI], 4.36-4.86) were preceded by preoperative corticosteroid use and 1469 (5.52%; 95% CI, 5.24-5.79) were followed by postoperative infections. In a propensity score analysis controlling for comorbidities, illness severity, and preexisting preoperative infections, corticosteroid use was independently associated with subsequent postoperative infections (odds ratio, 1.38; 95% CI, 1.11-1.70). Our results were unchanged in sensitivity analyses controlling for central nervous system tumors or active treatment with chemotherapy.

CONCLUSION

Our results suggest that preoperative corticosteroid use is associated with an increased risk of infectious complications after neurosurgery. These findings may aid physicians with preoperative treatment decisions and risk stratification. Future randomized trials are needed to guide preoperative use of corticosteroids in this population.

Amyloid β-Related Central Nervous System Angiitis Presenting With an Isolated Seizure

Amyloid beta-related angiitis (ABRA) of the central nervous system (CNS) is a very rare inflammatory disorder that causes destruction of CNS arteries and subsequent neuronal injury. Most patients with ABRA are old and present with cognitive dysfunction and stroke; however, some patients may present atypically. In this article, we report a 44-year-old man who presented with a first-time seizure but was otherwise neurologically intact and denied any headache. Brain MRI showed right hemispheric and bilateral medial frontal lobe hyperintensities and microhemorrhages that were most suspicious for a mass lesion. An extensive diagnostic evaluation including CSF analysis and catheter angiography was unremarkable. A brain biopsy with specific stains for amyloid surprisingly demonstrated ABRA and led to immunosuppressive treatment. The patient has remained neurologically intact and seizure-free 1 year after presentation. This case demonstrates that ABRA can occur in young patients without headache or neurologic deficits, and should be considered in patients with new-onset seizures and mass lesions. It also reinforces the need to consider a brain biopsy in patients with idiopathic brain lesions and negative non-invasive testing, as it is virtually impossible to confirm the diagnosis of ABRA otherwise.

Risk of a thrombotic event after the 6-week postpartum period

BACKGROUND

The postpartum state is associated with a substantially increased risk of thrombosis. It is uncertain to what extent this heightened risk persists beyond the conventionally defined 6-week postpartum period.

METHODS

Using claims data on all discharges from nonfederal emergency departments and acute care hospitals in California, we identified women who were hospitalized for labor and delivery between January 1, 2005, and June 30, 2010. We used validated diagnosis codes to identify a composite primary outcome of ischemic stroke, acute myocardial infarction, or venous thromboembolism. We then used conditional logistic regression to assess each patient's likelihood of a first thrombotic event during sequential 6-week periods after delivery, as compared with the corresponding 6-week period 1 year later.

RESULTS

Among the 1,687,930 women with a first recorded delivery, 1015 had a thrombotic event (248 cases of stroke, 47 cases of myocardial infarction, and 720 cases of venous thromboembolism) in the period of 1 year plus up to 24 weeks after delivery. The risk of primary thrombotic events was markedly higher within 6 weeks after delivery than in the same period 1 year later, with 411 events versus 38 events, for an absolute risk difference of 22.1 events (95% confidence interval [CI], 19.6 to 24.6) per 100,000 deliveries and an odds ratio of 10.8 (95% CI, 7.8 to 15.1). There was also a modest but significant increase in risk during the period of 7 to 12 weeks after delivery as compared with the same period 1 year later, with 95 versus 44 events, for an absolute risk difference of 3.0 events (95% CI, 1.6 to 4.5) per 100,000 deliveries and an odds ratio of 2.2 (95% CI, 1.5 to 3.1). Risks of thrombotic events were not significantly increased beyond the first 12 weeks after delivery.

CONCLUSIONS

Among patients in our study, an elevated risk of thrombosis persisted until at least 12 weeks after delivery. However, the absolute increase in risk beyond 6 weeks after delivery was low. (Funded by the National Institute of Neurological Disorders and Stroke.).

Predicting future brain tissue loss from white matter connectivity disruption in ischemic stroke

BACKGROUND AND PURPOSE

The Network Modification (NeMo) Tool uses a library of brain connectivity maps from normal subjects to quantify the amount of structural connectivity loss caused by focal brain lesions. We hypothesized that the Network Modification Tool could predict remote brain tissue loss caused by poststroke loss of connectivity.

METHODS

Baseline and follow-up MRIs (10.7±7.5 months apart) from 26 patients with acute ischemic stroke (age, 74.6±14.1 years, initial National Institutes of Health Stroke Scale, 3.1±3.1) were collected. Lesion masks derived from diffusion-weighted images were superimposed on the Network Modification Tool's connectivity maps, and regional structural connectivity losses were estimated via the Change in Connectivity (ChaCo) score (ie, the percentage of tracks connecting to a given region that pass through the lesion mask). ChaCo scores were correlated with subsequent atrophy.

RESULTS

Stroke lesions' size and location varied, but they were more frequent in the left hemisphere. ChaCo scores, generally higher in regions near stroke lesions, reflected this lateralization and heterogeneity. ChaCo scores were highest in the postcentral and precentral gyri, insula, middle cingulate, thalami, putamen, caudate nuclei, and pallidum. Moderate, significant partial correlations were found between baseline ChaCo scores and measures of subsequent tissue loss (r=0.43, P=4.6×10(-9); r=0.61, P=1.4×10(-18)), correcting for the time between scans.

CONCLUSIONS

ChaCo scores varied, but the most affected regions included those with sensorimotor, perception, learning, and memory functions. Correlations between baseline ChaCo and subsequent tissue loss suggest that the Network Modification Tool could be used to identify regions most susceptible to remote degeneration from acute infarcts.

Evaluation of computed tomography angiography plaque thickness measurements in high-grade carotid artery stenosis

BACKGROUND AND PURPOSE

Increasing evidence suggests that carotid artery imaging can identify vulnerable plaque elements that increase stroke risk. We correlated recently proposed markers, soft and hard plaque thickness measurements on axial computed tomography angiography source images, with symptomatic disease status (ipsilateral stroke or transient ischemic attack) in high-grade carotid disease.

METHODS

Soft plaque and hard plaque thickness were measured with a recently validated technique using computed tomography angiography source images in subjects with ≥70% extracranial carotid artery stenosis. Logistic regression analyses were used to assess the strength of association between soft and hard plaque thickness measurements and previous stroke or transient ischemic attack. Receiver operating characteristic analysis was also performed.

RESULTS

Compared with asymptomatic subjects, those with symptomatic carotid disease had significantly larger soft plaque and total plaque thickness measurements and smaller hard plaque thickness measurements. Each 1-mm increase in soft plaque resulted in a 2.7 times greater odds of previous stroke or transient ischemic attack. Soft plaque thickness measurements provided excellent discrimination between symptomatic and asymptomatic disease, with receiver operating characteristic analysis showing an area under the curve of 0.90. A cutoff of 3.5-mm maximum soft plaque thickness provided a sensitivity of 81%, specificity of 83%, positive predictive value of 85%, and a negative predictive value of 78%.

CONCLUSIONS

Increasing maximum soft plaque thickness measurements are strongly associated with symptomatic disease status in carotid artery stenosis. Prospective validation of these results may translate into a widely accessible stroke risk stratification tool in high-grade carotid artery atherosclerotic disease.

Abstract W P41: Predicting Future Atrophy from White Matter Connectivity Disruption in Ischemic Stroke

Background: The Network Modification (NeMo) Tool uses a library of brain connectivity maps from normal subjects to quantify the amount of structural connectivity loss caused by focal brain lesions. We hypothesized that the NeMo Tool could predict remote brain tissue loss caused by Wallerian degeneration after stroke.

Methods: Baseline and follow-up MRIs from 27 patients with acute ischemic stroke were collected (74±14 years, initial NIHSS 2±3, 5.7±2.8 months b/w scans). Diffusion-weighted image derived lesion masks were superimposed on the NeMo Tool’s connectivity maps in order to predict changes to the structural connectivity network and to investigate correlations with future atrophy. Regional connectivity losses were estimated via the Change in Connectivity (ChaCo) score, i.e. the percent of “injured” tracks going through lesions that connect to a given region. ChaCo scores and longitudinal tissue changes were calculated using a standard 116 region atlas.

Results: Lesion location and size varied greatly, but they occurred more frequently in the left hemisphere. The ChaCo scores, which were generally higher in regions near stroke lesions, reflected this heterogeneity. In general, ChaCo was higher in the left hemisphere than the right and was high in the postcentral and precentral gyri, insula, middle cingulate, thalami, putamen, caudate nuclei, and pallidum. Moderate correlations were found between ChaCo scores at baseline and measures of subsequent tissue loss (change in volume and average mean diffusivity [MD] from baseline to follow-up, see Figure 1).

Conclusions: ChaCo scores varied greatly, but the most affected regions included those with sensorimotor, perception, learning and memory functions. Moderate correlations were found between ChaCo scores at baseline and subsequent tissue loss. These results suggest that the NeMo Tool could enable more accurate prognosis, as it may identify regions most susceptible to degeneration from remote infarcts.

Abstract W MP53: Cerebrovascular Events Occurring after Hospital Discharge for Labor and Delivery

Introduction: Stroke and other cerebrovascular events (CVE) are feared complications of pregnancy. Prior studies have reported an increased risk of CVE during the postpartum period, but these studies have not reported event rates after hospital discharge for labor and delivery.

Methods: We performed a retrospective cohort study using the California State Inpatient and Emergency Department administrative databases to identify all pregnant women who went into labor at a non-federal, acute-care hospital from 2005 through 2011 and who were discharged without an ICD-9-CM diagnosis of cerebrovascular disease. The primary outcome was a CVE composite defined as any ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, subdural hemorrhage, cerebral sinus thrombosis, pituitary apoplexy, cerebral artery dissection, or hypertensive encephalopathy, occurring after hospital discharge and prior to 6 weeks after admission for labor and delivery. Descriptive statistics were used to calculate the incidence of postpartum CVE after hospital discharge and multivariate logistic regression was used to evaluate the association between several a priori selected clinical factors and postpartum CVE.

Results: A total of 2,065,330 patients were included in this analysis. The rate of any CVE was 9.97 per 100,000 patients (95% CI 8.61-11.3). The mortality rate in patients with CVE was 7.8% (95% CI 4.1-11%). The mean age of patients with a CVE was 31.0 years as compared to 28.3 years in patients without a CVE (p<0.001). Risk factors for any CVE were eclampsia (OR 19.9, 95% CI 6.43-61.4), chronic kidney disease (OR 3.88, 95% CI 1.02-14.8), black race (OR 3.19, 95% CI 2.26-4.50), preeclampsia (OR 2.67, 95% CI 1.99-3.59), and age (OR 1.07 per year, 95% CI 1.05-1.09).

Conclusion: The incidence of postpartum CVE after hospital discharge for labor and delivery is similar to rates reported for all postpartum events in prior publications. This suggests that a substantial proportion of postpartum cerebrovascular complications occur after hospital discharge. Therefore, clinicians should be aware that postpartum women remain at risk for stroke even if they have been discharged from their initial labor and delivery hospitalization without complication.

Abstract 60: Inpatient Statin Use in Intracerebral Hemorrhage is Strongly Associated With Improved Survival

Introduction: Inpatient statin use is associated with improved outcomes after ischemic stroke. The impact of inpatient statin use after intracerebral hemorrhage (ICH) is less clear.

Methods: We measured the impact of inpatient and outpatient statin use on 30-day survival among 3,481 patients with a primary discharge diagnosis of ICH over a 10-year period at 19 hospitals in an integrated care delivery system. We used multivariate logistic regression modeling mortality, controlling for patient characteristics, and allowing an interaction between inpatient and outpatient statin use. We also used last prior treatment analysis (LPTA), an instrumental variable reflecting local geographic and temporal treatment environment, to control for potential confounding in probit models.

Results: Kaplan-Meier analysis showed significant differences in survival after ICH among statin users before and during hospitalization (n=769), statin non-users before and during hospitalization (n=1,896), and patients who underwent statin withdrawal (n=391) (see Figure). Controlling for patient characteristics including initial severity, inpatient statin use was associated with lower mortality after ICH (odds ratio [OR] = 0.40, 95% C.I. 0.25 - 63, P<0.001) and withdrawal from statins was associated with higher mortality (OR = 2.30, 95% C.I. 1.40 - 3.91, P=0.002). LPTA models confirmed the association of inpatient statins with lower mortality (OR = 0.28, 95% C.I. 0.26 - 0.32, P=0.01).

Conclusions: Inpatient statin use is associated with improved survival after ICH, particularly among patients already on a statin as an outpatient at the time of the ICH.