Novel Treatments for Transient Ischemic Attack and Acute Ischemic Stroke

The treatment of acute ischemic stroke is one of the most rapidly evolving areas in medicine. Like all ischemic vascular emergencies, the priority is reperfusion before irreversible infarction. The central nervous system is sensitive to brief periods of hypoperfusion, making stroke a golden hour diagnosis. Although the phrase "time is brain" is relevant today, emerging treatment strategies use more specific markers for consideration of reperfusion than time alone. Innovations in early stroke detection and individualized patient selection for reperfusion therapies have equipped the emergency medicine clinician with more opportunities to help stroke patients and minimize the impact of this disease.

High-Risk Chief Complaints III: Neurologic Emergencies

A careful history and thorough physical examination are necessary in patients presenting with acute neurologic dysfunction. Patients presenting with headache should be screened for red-flag criteria that suggest a dangerous secondary cause warranting imaging and further diagnostic workup. Dizziness is a vague complaint; focusing on timing, triggers, and examination findings can help reduce diagnostic error. Most patients presenting with back pain do not require emergent imaging, but those with new neurologic deficits or signs/symptoms concerning for acute infection or cord compression warrant MRI. Delay to diagnosis and treatment of acute ischemic stroke is a frequent reason for medical malpractice claims.

Abstract TP294: Women Admitted for Suspected TIA are Less Likely to Have Imaging Evidence of Infarction than Men: Results from the Rhode Island Hospital Prospective TIA unit cohort

Introduction: Previous studies have shown sex differences in the presentation and management of patients with transient ischemic attack (TIA), but little is known about how outcomes differ by sex among those admitted to emergency department observation units (ED OU), an increasingly common ED disposition for patients with suspected TIA.

Objective: To determine if there are sex differences in the rate of positive diffusion weighted MRIs (DWI) among patients with suspected TIA admitted to an ED OU.

Methods: Patients in a large, urban, academic ED admitted to the ED OU for suspected TIA from 4/2013 - 7/2018 were included. Patients with persistent deficits, fever, heart rate <60 / >100, SBP >180 / < 100 mm Hg, pulse ox <93%, or other competing diagnoses were excluded. Standard blood tests, EKG, echocardiogram, MRI, and neurology consultation were performed. Rates of acute infarct on DWI were compared between women and men in unadjusted analyses, followed by multivariable logistic regression. The final model included covariates that were significantly associated with infarct on DWI in unadjusted analyses (p<0.05).

Results: 1208 patients were included; (52.9% women, 24.3% non-white). Women and men were of similar age (63.4 vs. 64.8) and had similar median duration of symptoms (45: IQR (15-90) vs 30 (10-90) min, p=0.51). Less women than men had hypertension (59.0% vs. 66.6%, p=0.02) or diabetes (17.5% vs. 22.5%, p=0.01), while more women had histories of migraines (12.8% vs. 3.5%, p<0.001). More women than men had pain on presentation (30.5% vs. 21.4%, p=0.001) and had a discharge diagnosis of something other than TIA/stroke (45.3% vs. 35.5%, p=0.002). Unadjusted, 19.1% vs. 13.0% had acute infarcts on DWI (p=0.08). After adjusting for age, race, history of hypertension, prior stroke/ TIA, and presenting symptoms (TABLE), women were less likely than men to have infarcts on DWI (aOR 0.55, 95% CI 0.38-0.79, p=0.001).

Conclusions: Among patients with suspected TIA admitted to an ED OU, women were less likely to have acute infarcts on DWI. Our findings of sex differences in DWI infarct rate as well as co-morbidities and presenting symptoms may suggest a sex difference in diagnostic uncertainty and/or stroke mimics among those with suspected TIA/mild stroke.

Abstract TP267: Performance of Components of the Canadian TIA Score to Predict Acute InfarctionAmong Patients Managed in an Emergency Department Observation Unit

Introduction: TIA risk stratification can help inform of impending stroke, but some scores lack sensitivity while others are impractical in the emergency department (ED) setting. The Canadian TIA Score has shown good discriminative ability at predicting early stroke recurrence and is designed to be applied in the ED, but awaits further validation.

Objective: We assessed the performance components of the Canadian TIA Score in predicting diffusion weighted MRI (DWI) abnormalities and 30-day adverse events in a cohort of clinically suspected TIAs placed in an ED observation unit (OU).

Methods: Patients in a large, urban, academic ED with suspected TIA deemed appropriate for the OU from 4/2013-7/2018 were included. Rates of acute infarct on DWI and adverse 30-day events were assessed. Logistic regression was performed to determine the odds of DWI-confirmed stroke from 12 of the 13 items on the weighted Canadian TIA Score (we did not collect platelet count); and for poor versus good health outcomes at 30-days. The AUC with 95% CIs were also calculated for significant models, and the The Youden index (J statistic) was determined to assess maximum effectiveness of diagnostic test across a range of cut-points.

Results: Of 1208 patients admitted over the time period, 1097 had DWI performed (90.1%). Clinical features are described in Table 1 . The logistic regression model for the Canadian TIA Score predicting acute stroke on DWI was significant (Wald χ2 (1) = 36.6, p < 0.001), with an odds ratio of 1.27 (95%CI: 1.16, 1.33), and AUC = 0.65 (95%CI: 0.61, 0.69). In predicting acute stroke, the maximum J value = 0.20; Canadian rule score ≥ 4; sensitivity = 0.68, specificity = 0.52. Of 593 patients reached at 30-days, 510 (86%) reported no adverse events. Of the 83 who did not, 1 had a disabling stroke and 1 had died.

Discussion: In this overall low-risk cohort of ED patients with suspected TIA managed in an OU, the Canadian TIA Score performed reasonably well at predicting acute DWI abnormalities.

Sex differences in 90-day outcomes after mechanical thrombectomy for acute ischemic stroke

Background

It is largely unknown whether functional outcomes after mechanical thrombectomy for large vessel occlusion (LVO) ischemic strokes differ by sex in non-clinical trial populations. We investigated sex differences in 90-day outcomes among ischemic stroke patients receiving mechanical thrombectomy.

Methods

This was a prospective cohort of adults treated with mechanical thrombectomy for LVO at a single academic comprehensive stroke center from July 2015 to April 2017. Data on independence (mRS ≤2) at hospital discharge and 90 days were collected prospectively. Multiple logistic regression was used to determine the association between sex and 90-day independence, first adjusting for demographics, pre-stroke mRS, and NIHSS, then by co-morbidities and time to thrombectomy, and finally by vessel recanalization and use of intravenous thrombolysis.

Results

We included 279 patients, 52% of whom were female. Compared with males, females were older (median years (IQR) 81 (75–88) vs. 71.5 (60–81), P<0.001) and had higher baseline NIHSS (mean SD 18.2±7.5 vs . 16.0±7.1, P=0.02). Similar proportions of males and females had pre-stroke mRS ≤2 (73.3% vs.67.1%, P=0.27). In multivariate analyses, males and females had a similar likelihood of being independent at discharge (aOR 0.71 (95%CI 0.32 to 1.58)), but females were less likely to be independent at 90 days (aOR 0.37 95% CI 0.16 to 0.87).

Conclusions

In patients treated with mechanical thrombectomy for LVOs at a large comprehensive stroke center, females were less likely to be independent at 90 days. Future research should investigate contributors to poor outcomes post-discharge in females with LVOs, along with potential interventions to improve outcomes.

Baseline NIH Stroke Scale is an inferior predictor of functional outcome in the era of acute stroke intervention

Background and aims Baseline National Institutes of Health Stroke Scale (NIHSS) scores have frequently been used for prognostication after ischemic stroke. With the increasing utilization of acute stroke interventions, we aimed to determine whether baseline NIHSS scores are still able to reliably predict post-stroke functional outcome. Methods We retrospectively analyzed prospectively collected data from a high-volume tertiary-care center. We tested strength of association between NIHSS scores at baseline and 24 h with discharge NIHSS using Spearman correlation, and diagnostic accuracy of NIHSS scores in predicting favorable outcome at three months (defined as modified Rankin Scale 0-2) using receiver operating characteristic curve analysis with area under the curve. Results There were 1183 patients in our cohort, with median baseline NIHSS 8 (IQR 3-17), 24-h NIHSS 4 (IQR 1-11), and discharge NIHSS 2 (IQR 1-8). Correlation with discharge NIHSS was r = 0.60 for baseline NIHSS and r = 0.88 for 24-h NIHSS. Of all patients with follow-up data, 425/1037 (41%) had favorable functional outcome at three months. Receiver operating characteristic curve analysis for predicting favorable outcome showed area under the curve 0.698 (95% CI 0.664-0.732) for baseline NIHSS, 0.800 (95% CI 0.772-0.827) for 24-h NIHSS, and 0.819 (95% CI 0.793-0.845) for discharge NIHSS; 24 h and discharge NIHSS maintained robust predictive accuracy for patients receiving mechanical thrombectomy (AUC 0.846, 95% CI 0.798-0.895; AUC 0.873, 95% CI 0.832-0.914, respectively), while accuracy for baseline NIHSS decreased (AUC 0.635, 95% CI 0.566-0.704). Conclusion Baseline NIHSS scores are inferior to 24 h and discharge scores in predicting post-stroke functional outcomes, especially in patients receiving mechanical thrombectomy.

New biomarker for acute ischaemic stroke: plasma glycogen phosphorylase isoenzyme BB

BACKGROUND

Glycogen phosphorylase is the key enzyme that breaks down glycogen to yield glucose-1-phosphate in order to restore depleted energy stores during cerebral ischaemia. We sought to determine whether plasma levels of glycogen phosphorylase BB (GPBB) isoform increased in patients with acute ischaemic stroke (AIS).

METHODS

We studied plasma GPBB levels within 12 hours and again at 48±24 hours of symptom onset in 172 patients with imaging-confirmed AIS and 133 stroke-free individuals. We determined the ability of plasma GPBB to discriminate between cases and controls and examined the predictive value of plasma GPBB for 90-day functional outcome, 90-day survival and acute lesion volumes on neuroimaging.

RESULTS

The mean (SD) GPBB levels were higher in cases (46.3±38.6 ng/mL at first measurement and 38.6±36.5 ng/mL at second measurement) than in controls (4.1±7.6 ng/mL, p<0.01 for both). The area under the receiver operating characteristic (ROC) curve for case-control discrimination based on first GPBB measurement was 0.96 (95% CI 0.93 to 0.98). The sensitivity and specificity based on optimal operating point on the ROC curve (7.0 ng/mL) were both 93%. GPBB levels increased in 90% of patients with punctate infarcts (<1.5 mL) and in all patients admitted within the first 4.5 hours of onset. There was no correlation between GPBB concentration and either clinical outcome or acute infarct volume.

CONCLUSION

GPBB demonstrates robust response to acute ischaemia and high sensitivity for small infarcts. If confirmed in more diverse populations that also include stroke mimics, GPBB could find utility as a stand-alone marker for acute brain ischaemia.

Perfusion imaging and recurrent cerebrovascular events in intracranial atherosclerotic disease or carotid occlusion

Background

Large vessel disease stroke subtype carries the highest risk of early recurrent stroke. In this study we aim to look at the association between impaired perfusion and early stroke recurrence in patients with intracranial atherosclerotic disease or total cervical carotid occlusion.

Methods

This is a retrospective study from a comprehensive stroke center where we included consecutive patients 18 years or older with intracranial atherosclerotic disease or total cervical carotid occlusion admitted with a diagnosis of ischemic stroke within 24 h from symptom onset with National Institute Health Stroke Scale < 15, between 1 December 2016 and 30 June 2017. Patients with (1) evidence of ≥ 50% stenosis of a large intracranial artery or total carotid artery occlusion, (2) symptoms referable to the territory of the affected artery, and (3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable perfusion imaging defined as Tmax > 6 s mismatch volume (penumbra volume–infarct volume) of 15 ml or more. The outcome was recurrent cerebrovascular events at 90 days defined as worsening or new neurological symptoms in the absence of a nonvascular cause attributable to the decline, or new infarct or infarct extension in the territory of the affected artery. We used Cox proportional hazards models to determine the association between impaired perfusion and recurrent cerebrovascular events.

Results

Sixty-two patients met our inclusion criteria; mean age 66.4 ± 13.1 years, 64.5% male (40/62) and 50.0% (31/62) with intracranial atherosclerotic disease. When compared to patients with favorable perfusion pattern, patients with unfavorable perfusion pattern were more likely to have recurrent cerebrovascular events (55.6% (10/18) versus 9.1% (4/44), p < 0.001). This association persisted after adjusting for potential confounders (adjusted hazard ratio 10.44, 95% confidence interval 2.30–47.42, p = 0.002).

Conclusion

Perfusion mismatch predicts recurrent cerebrovascular events in patients with ischemic stroke due to intracranial atherosclerotic disease or total cervical carotid occlusion. Studies are needed to determine the utility of revascularization strategies in this patient population.

Abstract TMP17: Impaired Perfusion Imaging Predicts Recurrent Cerebrovascular Events in Symptomatic Large Vessel Stenosis

Importance: Large vessel disease (LVD) stroke subtype carries the highest risk of early recurrent stroke, reaching up to 30% in the first few days. Predictors of early recurrence have been previously described, but less is known regarding infarct expansion and other causes of neurological worsening. We aim to determine the association between impaired perfusion and neurological decline in patients with LVD subtype.

Methods: This is a single center retrospective cohort study of all consecutive patients 18 years or older with LVD admitted with a diagnosis of ischemic stroke within 24 hours from symptom onset (12/1/2016 to 3/31/2017). Patients with 1) evidence of ≥ 50% stenosis of a large intra- or extracranial artery on computerized tomography angiography (CTA); 2) symptoms referable to the territory of the affected artery and NIHSS < 15 and 3) perfusion imaging data using the RAPID processing software were included. The primary predictor was unfavorable mismatch volume ≥15 mL, defined as perfusion deficit of Tmax > 6sec volume minus infarct volume similar to neuro-interventional trials. The outcome was recurrent cerebrovascular events (RCVE) at 90 days (adjudicated independently by two vascular neurologists) defined as a decline in neurologic function in the absence of a medical cause, or new infarct or infarct extension in the territory of the affected artery. We estimated the hazard ratio (HR) and 95% confidence interval (CI) for unfavorable perfusion imaging as predictor of RCVE using univariable and multivariable Cox proportional hazards models.

Results: Sixty-eight patients met our inclusion criteria (mean age 64.7 years; 61.8% male; 58.8% intracranial LVD). When compared to patients without RCVE, patients with RCVE were more likely to have unfavorable mismatch volume [71.4% vs. 14.8%, p<0.001]. This association persisted after adjusting for sex, dual antiplatelet therapy, initial stroke severity, and intracranial location of LVD (adjusted HR 15.6, 95% CI 3.7-66.7, p<0.001).

Conclusion: Perfusion mismatch is associated with RCVE in patients with ischemic stroke due to LVD. Pursuit of more aggressive treatment and management strategies may be warranted in this population.

Abstract WP208: Elevated Troponin Levels in Ischemic Stroke is Independently Associated With Cardioembolism

Background: Elevated cardiac troponin is a marker of cardiac disease and has been recently shown to be associated with embolic stroke risk in the general population. In the acute stroke setting, we hypothesize that elevated troponin levels are more prevalent in patients with embolic stroke subtypes [cardioembolic (CE) and embolic stroke of unknown source (ESUS)] as opposed to known non cardioembolic subtypes (NE) (large vessel disease, small vessel disease, and other).

Methods: We abstracted data from our prospective stroke database and included all patients with ischemic stroke over a 22 month period. We defined positive troponin as ≥ 0.1 ng/mL. Patients diagnosed with acute myocardial infarction were excluded (n = 3).We compared clinical, laboratory and echocardiographic findings, and stroke subtypes using ESUS criteria between the two groups: Troponin+ and Troponin-.

Results: We identified 1231 patients; 1129 had troponin levels available and 10.0% (113/1129) were trop+. On univariate analyses, Troponin+ patients were more likely to be older (77.4 ± 12.6 vs. 70.8 ± 15.0, p<0.001), have hypertension (85.8% vs. 74.2%, p=0.003), coronary heart disease (31.3% vs. 20.1%, p=0.003), congestive heart failure (20.9% vs. 9.5%,p<0.001), smoking (42.5% vs. 26.4%, p<0.001), and atrial fibrillation (42.5% vs. 26.4%, p<0.001), higher admission NIHSS (14 vs. 6, p<0.001), eGFR < 60 (53.7% vs. 33.4%), larger left atrial diameter (40.9 ± 8.8 vs.37.1 ± 7.6, P<0.001), lower ejection fraction (60 vs. 65, p<0.001), and wall motion abnormalities (26.1% vs. 11.5%, p<0.001) compared troponin- patients. When compared to NE subtype, troponin+ patients were more likely to have CE (79.0% vs. 52.4%, p<0.001) and ESUS (75.0% vs. 58.9%, p=0.001) subtypes. In multivariable models, factors associated with troponin+ are NIHSS (adjusted OR per 1 unit increase1.05, 95% 1.02-1.08; p<0.001), eGFR < 60 (adjusted OR 2.41 95% CI 1.40-4.13; p=0.001), CE subtype (adjusted OR 3.37 95% CI 1.35-8.43,p=0.009), and ESUS subtype (adjusted OR 2.77 95% CI 1.15-6.66,p=0.023).

Conclusion: Elevated troponin levels in ischemic stroke is independently associated with a cardiac embolic source. Studies are needed to test anticoagulation vs. antiplatelet in patients with ESUS and elevated troponin.

Abstract WP235: Should a Transthoracic Echocardiogram be a Routine Part of the Diagnostic Evaluation of Transient Ischemic Attack in an Emergency Department Observation Unit?

Introduction: ED observation units offer an alternative to hospitalization for the rapid diagnosis and etiologic evaluation of clinically suspected TIA. While cardiac embolism is thought to account for at least 25% of ischemic cerebrovascular events, the diagnostic yield and clinical impact of TTE in an ED observation unit has yet to be determined.

Methods: We conducted a retrospective review of 676 patients with suspected TIA within prospectively collected registry data of an ED observation unit between 2013-2017. Patients were considered eligible regardless of clinical risk score and routinely underwent DW-MRI/MRA and TTE. New onset atrial fibrillation was considered an exclusion criterion. A multivariable logistic regression was used to identify clinical predictors of abnormal TTE findings of possible cardioembolic etiology. Fisher’s exact test was performed to compare 30-day outcomes of patients who did or did not receive a TTE.

Results: Among 676 patients with clinically suspected TIA who underwent ED observation, a TTE was performed on 69% (n=465). After completion of the observation period, a final diagnosis of ischemic stroke, TIA, or mimic accounted for 14%, 44%, and 42% respectively. Of those diagnosed with stroke or TIA, abnormal TTE findings suggestive of a low or high-risk source occurred in 12% (n=35) and 2% (n=6) respectively. Age, gender, ECG abnormalities, heart murmur, history of diabetes, hypertension, hyperlipidemia, atrial fibrillation, anticoagulant use, cardiac surgery, coronary disease or stenting did not predict abnormal TTE findings (chi 2 p=.78 for low-risk, p=.31 for high-risk TTE findings). These findings led to initiation of anticoagulation in 2 patients (0.7%). There was no difference in 30-day clinical outcomes (recurrent TIA/stroke, ED recidivism or hospital admission) in patients that did or did not have a TTE (p=0.92).

Conclusions: In our cohort of ED patients undergoing ED observation for clinically suspected TIA, a TTE informed of a possible cardioembolic source in 14% of patients with a final diagnosis of TIA or ischemic stroke. These abnormalities were not predicted by clinical variables alone and tended to not lead to a change in clinical management.

Imaging Parameters and Recurrent Cerebrovascular Events in Patients With Minor Stroke or Transient Ischemic Attack

IMPORTANCE

Neurological worsening and recurrent stroke contribute substantially to morbidity associated with transient ischemic attacks and strokes (TIA-S).

OBJECTIVE

To determine predictors of early recurrent cerebrovascular events (RCVEs) among patients with TIA-S and National Institutes of Health Stroke Scale scores of 0 to 3.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted at 2 tertiary care centers (Columbia University Medical Center, New York, New York, and Tulane University Medical Center, New Orleans, Louisiana) between January 1, 2010, and December 31, 2014. All patients with neurologist-diagnosed TIA-S with a National Institutes of Health Stroke Scale score of 0 to 3 who presented to the emergency department were included.

MAIN OUTCOMES AND MEASURES

The primary outcome (adjudicated by 3 vascular neurologists) was RCVE: neurological deterioration in the absence of a medical explanation or recurrent TIA-S during hospitalization.

RESULTS

Of the 1258 total patients, 1187 had no RCVEs and 71 had RCVEs; of this group, 750 patients (63.2%) and 39 patients (54.9%), respectively, were aged 60 years or older. There were 505 patients with TIA-S at Columbia University; 31 (6.1%) had RCVEs (15 patients had neurological deterioration only, 11 had recurrent TIA-S only, and 5 had both). The validation cohort at Tulane University consisted of 753 patients; 40 (5.3%) had RCVEs (24 patients had neurological deterioration only and 16 had both). Predictors of RCVE in multivariate models in both cohorts were infarct on neuroimaging (computed tomographic scan or diffusion-weighted imaging sequences on magnetic resonance imaging) (Columbia University: not applicable and Tulane University: odds ratio, 1.75; 95% CI, 0.82-3.74; P = .15) and large-vessel disease etiology (Columbia University: odds ratio, 6.69; 95% CI, 3.10-14.50 and Tulane University: odds ratio, 8.13; 95% CI, 3.86-17.12; P < .001). There was an increase in the percentage of patients with RCVEs when both predictors were present. When neither predictor was present, the rate of RCVE was extremely low (up to 2%). Patients with RCVEs were less likely to be discharged home in both cohorts.

CONCLUSIONS AND RELEVANCE

In patients with minor stroke, vessel imaging and perhaps neuroimaging parameters, but not clinical scores, were associated with RCVEs in 2 independent data sets. Prospective studies are needed to validate these predictors.

Treatment of Acute Ischemic Stroke

Although stroke declined from the third to fifth most common cause of death in the United States, the annual incidence and overall prevalence continue to increase. Since the available US Food and Drug Administration-approved treatment options are time dependent, improving early stroke care may have more of a public health impact than any other phase of care. Timely and efficient stroke treatment should be a priority for emergency department and prehospital providers. This article discusses currently available and emerging treatment options in acute ischemic stroke focusing on the preservation of salvageable brain tissue, minimizing complications, and secondary prevention.

Minor Stroke and Transient Ischemic Attack: Research and Practice

A majority of patients with ischemic stroke present with mild deficits for which aggressive management is not often pursued. Comprehensive work-up and appropriate intervention for minor strokes and transient ischemic attacks (TIAs) point toward better patient outcomes, lower costs, and fewer cases of disability. Imaging is a key modality to guide treatment and predict stroke recurrence. Patients with large vessel occlusions have been found to suffer worse outcomes and could benefit from intervention. Whether intravenous thrombolytic therapy decreases disability in minor stroke patients and whether acute endovascular intervention improves functional outcomes in patients with minor stroke and known large vessel occlusion remain controversial. Studies are ongoing to determine ideal antiplatelet therapy for stroke and TIA, while ongoing statin therapy, surgical management for patients with carotid stenosis, and anticoagulation for patients with atrial fibrillation have all been proven to decrease the rate of stroke recurrence and improve outcomes. This review summarizes the current evidence and discusses the standard of care for patients with minor stroke and TIA.

Developing a statewide protocol to ensure patients with suspected emergent large vessel occlusion are directly triaged in the field to a comprehensive stroke center: how we did it

We describe the process by which we developed a statewide field destination protocol to transport patients with suspected emergent large vessel occlusion to a comprehensive stroke center.

Abstract W P185: Clinical Predictors of Stroke, TIA and Mimic among Patients with Transient Neurological Dysfunction Admitted to an Emergency Department Observation Unit

Background: In patients with resolved symptoms, transient ischemic attack (TIA) is distinguished from ischemic stroke by neuroimaging evidence of acute infarction. DW-MRI has been shown to be more sensitive at detecting infarction than CT, but is not uniformly available in the acute setting.

Hypothesis: We sought to identify predictors of stroke diagnosis among a cohort of clinically suspected TIA patients undergoing an accelerated diagnostic protocol in an emergency department observation unit (EDOU).

Methods: We prospectively studied 189 patients treated in the EDOU of a single tertiary care academic medical center. Patients underwent DW-MRI of the brain (unless contraindicated), and bedside neurologist evaluation. A CT scan of the brain was considered optional prior to EDOU admission. We compared the odds of extremity weakness, sensory loss, facial droop, visual disturbance, slurred speech, aphasia, dizziness, and headache between patients with final diagnosis of stroke, TIA and mimic. This study was approved by the hospital IRB.

Results: Thirty-one patients (16%) were diagnosed with an acute ischemic stroke, 85 (45%) TIA, and 73 (39%) mimic. Mean age was 64.8 years (SD = 15.5; range = 30-90). DW-MRI was performed on 92% of patients. A CT scan was also performed in 80% of patients diagnosed with stroke and 0 were diagnostic. Median ABCD2 scores were 4 for stroke and TIA (IQR 3-5) and 3 for mimic (IQR 2-4). Only headache symptoms predicted lower odds of stroke (OR 0.22; 95% CI: 0.05-0.96). Both headache (OR 1.44; 95% CI: 1.03-2.03) and visual disturbance (OR 3.14; 95% CI: 1.49-6.65) increased the odds of mimic diagnosis, but were also present in 13% and 10% of stroke patients respectively. Slurred speech (OR 0.48: 95% CI: 0.25-0.93); aphasia (OR 0.34 95% CI: 0.15-0.76) and facial droop (OR 90.36: 95% CI: 0.14-0.94) significantly predicted lower odds of mimic diagnosis.

Conclusions: In our investigation of patients with transient neurologic dysfunction in an EDOU, stroke diagnosis was common and could not be predicted by clinical variables alone. Early DW-MRI should be considered in all TIA patients, especially those reporting slurred speech, aphasia or facial droop.

Abstract T MP74: The Diagnosis, Etiologic Classification, and Safe Discharge of Ischemic Strokes with Transient Symptoms from an Emergency Department Observation Unit

Background: Patients with a clinical diagnosis of transient ischemic attack (TIA) who have imaging evidence of infarction portend a high risk of short-term recurrent stroke. Emergency Department Observation Units (EDOU) offer an alternative to hospital admission and are becoming increasingly utilized for acute cerebrovascular emergencies.

Hypothesis: We sought to determine whether an EDOU protocol emphasizing etiologic determination and individualized secondary prevention could be a safe alternative to hospital admission for suspected TIA patients with and without brain infarction.

Methods: We prospectively studied 189 patients admitted to the TIA EDOU of a single tertiary care academic medical center. There was no ABCD2 cutoff for eligibility and exclusion criteria included persistent deficits or another diagnosis warranting hospitalization. Patients underwent DW-MRI/MRA of the head and neck unless contraindicated, transthoracic echocardiogram and bedside neurologist evaluation. Etiologic subtyping was determined using the Causative Classification System (CCS). 30-day follow-up was performed on all patients by telephone and/or review of medical records. This study was approved by the hospital IRB.

Results: Acute ischemic stroke was diagnosed in 31 (16%) of patients, including 30 with DWI lesions and 1 in whom MRI was contraindicated, but had clinical worsening while in the EDOU. An evident or probable etiology was determined by CCS subtyping in 38% of strokes and 32% of TIAs (17% atherosclerosis, 12% cardioembolism, 5% small vessel). Of the total cohort, 84% were discharged from the EDOU including 16 (52%) with confirmed stroke. Median LOS was 22 hours (IQR: 17-25). At 30 days, one patient was found to have a small recurrent stroke (0.7%). There was 1 non-stroke related death. Twenty (11%) overall returned to the ED, the vast majority (70%) from the non-stroke cohort.

Conclusions: Not all ischemic stroke patients require hospitalization. An EDOU is a safe and effective alternative for the complete diagnostic evaluation and management of patients with transient neurologic symptoms. Further study of cost and quality effectiveness in warranted.

Abstract T P43: Detection of Advanced Leukoaraiosis Does Not Augment Imaging-Enhanced Prediction of Early Stroke Risk in Transient Ischemic Attack

Background: The risk of stroke following transient ischemic attack (TIA) is high in patients with evidence of transient symptoms with infarction (TSI) on CT or diffusion-weighted imaging (DWI). The extent to which leukoaraiosis augments imaging-based risk prediction is unresolved. We sought to determine whether the presence of advanced leukoaraiosis improves the predictive performance of early CT and MR-based neuroimaging modalities in patients diagnosed with clinical TIA.

Methods: We retrospectively identified 37 cases of 30-day recurrent stroke that had MRI performed within 1 day of presentation, and compared to 43 patients without recurrence from a larger cohort of 1250 patients admitted to the hospital from a single emergency department with suspected TIA between 1/1/2000 and 7/16/2011. In all subjects (n=80), CT and MR (DWI and T2Flair)images were reviewed by a physician reader blinded to outcome and graded for the presence of abnormalities such as acute infarction, prior infarction, and advanced leukoaraiosis as defined by a Van Sweiten scale of 2 in either the anterior or posterior regions. We assessed the predictive performance of DWI alone, CT for infarction, CT for any abnormality and MRI for any abnormality by computing the area under the receiver-operating characteristics curve.

Results: The sensitivity of CT increased from 14% to 71% and MR from 68% to 93% in predicting 30-day stroke recurrence upon inclusion of acute or old infarction or advanced leukoaraiosis. Specificity decreased from 100% to 44% and 67% to 30% respectively. The area under the receiver-operating characteristic curve was 0.57 for CT for infarction alone and 0.58 for CT including leukoaraiosis; 0.68 for DWI alone and 0.61 for DWI or T2Flair evidence of old infarction or advanced leukoaraiosis.

Conclusions: The addition of advanced leukoaraiosis does not appear to add to the predictive ability of CT or MRI-based neuroimaging in the early risk stratification of patients with TIA.

Abstract T P183: Transient Neurological Symptoms with MRI Evidence of Infarction in an Emergency Department Observation Unit

Background: Transient symptoms with infarction (TSI) is distinguished from transient ischemic attack (TIA) by the presence of diffusion-weighted imaging (DWI) lesions on MRI. We report a series of patients with DWI lesions identified in an emergency department observation unit (EDOU) TIA protocol.

Methods: Patients were treated in the ED of a tertiary care center (annual census=100,000 visits). In the first 3 months of operation of an EDOU for TIA, 50 patients met inclusion criteria of sudden/transient neurological deficit in the absence of known metabolic or cardiac source. Patients were excluded from the study if they demonstrated: persistent or stuttering deficits; fever >100.4F, heart rate <60 or >100 bpm; SBP >180 or <100mmHg; pulse ox <93%; or positive CT. Evaluation included: laboratory analyses; CT/MRI/MRA of the head/neck; EKG; echocardiogram, and neurology consult. MR data (ED 1.5T MR unit) include: DWI, ADC, GRE, and T2FLAIR images. Patients with TSI, were identified by the presence of 1 or more DWI bright and ADC dark lesions on ED MRI. All patients completed CT and MR imaging within < 24 hours of admission. This study was approved by the hospital IRB.

Results: TSI was identified in 10/50 EDOU patients (Mdn age 72.5, ABCD2 score 5). Two patients demonstrated infarcts in multiple vascular territories. Table 1 illustrates patient demographics, comorbidities, presentations, and outcome. Fifty percent of TSI patients were admitted from EDOU, 3 patients returned to the ED within 30 days , and no 30 day distinct recurrent events, such as recurrent stroke were identified.

Conclusions: EDOU for TIA including DW-MRI resulted in TSI diagnosis in 20% of patients. In the TSI cases identified, infarct locations were heterogeneous; vascular and/or cardiac etiology must be considered. Longitudinal analysis is recommended to further assess the relationship between presentation, TSI risk, risk of recurrent stroke, and need for hospital admission.

Transient ischemic attack: an evidence-based update

Transient ischemic attack represents a medical emergency and warns of an impending stroke in roughly one-third of patients who experience it. The risk of stroke is highest in the first 48 hours following a transient ischemic attack, and the initial evaluation in the emergency department is the best opportunity to identify those at highest risk of stroke recurrence. The focus should be on differentiating transient ischemic attack from stroke and common mimics. Accurate diagnosis is achieved by obtaining a history of abrupt onset of negative symptoms of ischemic origin fitting a vascular territory, accompanied by a normal examination and the absence of neuroimaging evidence of infarction. Transient ischemic attacks rarely last longer than 1 hour, and the classic 24-hour time-based definition is no longer relevant. Once the diagnosis has been made, clinical risk criteria may augment imaging findings to identify patients at highest and lowest risk of early recurrence. Early etiologic evaluation, including neurovascular and cardiac investigations, allows for catered secondary prevention strategies. Specialized transient ischemic attack clinics and emergency department observation units are safe and efficient alternatives to hospital admission for many transient ischemic attack patients.

Physician discretion is safe and may lower stress test utilization in emergency department chest pain unit patients

INTRODUCTION

Chest pain unit (CPU) observation with defined stress utilization protocols is a common management option for low-risk emergency department patients. We sought to evaluate the safety of a joint emergency medicine and cardiology staffed CPU.

METHODS

Prospective observational trial of consecutive patients admitted to an emergency department CPU was conducted. A standard 6-hour observation protocol was followed by cardiology consultation and stress utilization largely at their discretion. Included patients were at low/intermediate risk by the American Heart Association, had nondiagnostic electrocardiograms, and a normal initial troponin. Excluded patients were those with an acute comorbidity, age >75, and a history of coronary artery disease, or had a coexistent problem restricting 24-hour observation. Primary outcome was 30-day major adverse cardiovascular events-defined as death, nonfatal acute myocardial infarction, revascularization, or out-of-hospital cardiac arrest.

RESULTS

A total of 1063 patients were enrolled over 8 months. The mean age of the patients was 52.8 ± 11.8 years, and 51% (95% confidence interval [CI], 48-54) were female. The mean thrombolysis in myocardial infarction and Diamond & Forrester scores were 0.6% (95% CI, 0.51-0.62) and 33% (95% CI, 31-35), respectively. In all, 51% (95% CI, 48-54) received stress testing (52% nuclear stress, 39% stress echocardiogram, 5% exercise, 4% other). In all, 0.9% patients (n = 10, 95% CI, 0.4-1.5) were diagnosed with a non-ST elevation myocardial infarction and 2.2% (n = 23, 95% CI, 1.3-3) with acute coronary syndrome. There was 1 (95% CI, 0%-0.3%) case of a 30-day major adverse cardiovascular events. The 51% stress test utilization rate was less than the range reported in previous CPU studies (P < 0.05).

CONCLUSIONS

Joint emergency medicine and cardiology management of patients within a CPU protocol is safe, efficacious, and may safely reduce stress testing rates.

Psychogenic seizures: A review and description of pitfalls in their acute diagnosis and management in the emergency department

Patients with psychogenic (nonepileptic) seizures (PS) are frequently encountered by clinicians in the emergency medicine setting. Despite the tendency for these patients to seek frequent medical attention, the time between onset of symptoms and diagnosis is often more than 7 years. The cause of PS is multifactorial, but most patients are thought to have an underlying dissociative condition. The diagnostic evaluation in the emergency department is challenging and relies heavily on clinical suspicion, based on historical and physical features. Laboratory testing and therapeutic maneuvers are of limited utility; prolonged video electroencephalography is the diagnostic gold standard. Once the diagnosis has been secured, the mainstay of treatment involves addressing the underlying psychological distress.