Management and Outcome of Patients with Transient Ischemic Attack Admitted to a Stroke Unit

Emergency medicine updates: Transient ischemic attack

INTRODUCTION

Transient ischemic attack (TIA) is a condition commonly evaluated for in the emergency department (ED). Therefore, it is important for emergency clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning TIA for the emergency clinician.

DISCUSSION

TIA is a harbinger of ischemic stroke and can result from a variety of pathologic causes. While prior definitions incorporated symptoms resolving within 24 h, modern definitions recommend a tissue-based definition utilizing advanced imaging to evaluate for neurologic injury and the etiology. In the ED, emergent evaluation includes assessing for current signs and symptoms of neurologic dysfunction, appropriate imaging to investigate for minor stroke or stroke risk, and arranging appropriate disposition and follow up to mitigate risk of subsequent ischemic stroke. Imaging should include evaluation of great vessels and intracranial arteries, as well as advanced cerebral imaging to evaluate for minor or subclinical stroke. Non-contrast computed tomography (CT) has limited utility for this situation; it can rule out hemorrhage or a large mass causing symptoms but should not be relied on for any definitive diagnosis. Noninvasive imaging of the cervical vessels can also be used (CT angiography or Doppler ultrasound). Treatment includes antithrombotic medications if there are no contraindications. Dual antiplatelet therapy may reduce the risk of recurrent ischemic events in higher risk patients, while anticoagulation is recommended in patients with a cardioembolic source. A variety of scoring systems or tools are available that seek to predict stroke risk after a TIA. The Canadian TIA risk score appears to have the best diagnostic accuracy. However, these scores should not be used in isolation. Disposition may include admission, management in an ED-based observation unit with rapid diagnostic protocol, or expedited follow-up in a specialty clinic.

CONCLUSIONS

An understanding of literature updates concerning TIA can improve the ED care of patients with TIA.

Efficacy and Safety of Adherence to dl-3-n-Butylphthalide Treatment in Patients With Non-disabling Minor Stroke and TIA-Analysis From a Nationwide, Multicenter Registry

Background: Dl-3-n-Butylphthalide (NBP) has the potential to improve clinical outcomes in acute ischemic stroke patients by improving collateral circulation. We aimed to evaluate the efficacy and safety of NBP in patients with non-disabling minor ischemic stroke and transient ischemic attack (TIA).

Methods: The BRIDGE (the observation study on clinical effectiveness of NBP on patients with non-disabling ischemic cerebrovascular disease) is a prospective registry to monitor the efficacy and safety of NBP therapy in acute non-disabling ischemic stroke or high-risk TIA. Non-disabling minor ischemic stroke patients within 48 h were enrolled across 51 stroke centers in China. We divided patients into NBP compliance or non-compliance groups according to their adherence to NBP. The primary outcome was the favorable functional outcome at 90 days, defined as a modified Rankin scale (mRS) <2.

Results: Between 10th October 2016 and 25th June 2019, 3,118 patients were included in this analysis. In multivariable analysis, after adjusting for common risk factors and demographic factors, NBP-compliance group has a higher proportion of favorable functional outcome (92.1 vs. 87.4%, adjusted odds ratio 2.00, 95% confidence interval, 1.50–2.65), and a higher stroke recurrence rate (2.40 vs. 0.31%, adjusted odds ratio 8.86, 95% confidence interval, 3.37–23.30) than the NBP-non-compliance group. There was no significant difference in death and intracranial hemorrhage rate between the two groups. In subgroup analysis, patients with National Institutes of Health Stroke Scale (NIHSS) scores from 3 to 5 who complied to NBP therapy had a higher rate of favorable functional outcomes than the NBP-non-compliance group. [88.82 vs. 76.21%, adjusted odds ratio 2.52 (1.81–3.50), adjusted interaction P = 0.00].

Conclusion: In non-disabling minor ischemic stroke or TIA patients, compliance with NBP therapy led to better 90-day functional outcomes despite a higher risk of recurrence, and this effect seems to be stronger in patients with NIHSS scores of 3–5. Further large randomized, double-blind controlled studies to analyse the association between NBP and functional outcome is warranted in the coming future.

Clinical Risk Score for Predicting Recurrence Following a Cerebral Ischemic Event

Introduction: Recurrent stroke has a higher rate of death and disability. A number of risk scores have been developed to predict short-term and long-term risk of stroke following an initial episode of stroke or transient ischemic attack (TIA) with limited clinical utilities. In this paper, we review different risk score models and discuss their validity and clinical utilities.

Methods: The PubMed bibliographic database was searched for original research articles on the various risk scores for risk of stroke following an initial episode of stroke or TIA. The validation of the models was evaluated by examining the internal and external validation process as well as statistical methodology, the study power, as well as the accuracy and metrics such as sensitivity and specificity.

Results: Different risk score models have been derived from different study populations. Validation studies for these risk scores have produced conflicting results. Currently, ABCD² score with diffusion weighted imaging (DWI) and Recurrence Risk Estimator at 90 days (RRE-90) are the two acceptable models for short-term risk prediction whereas Essen Stroke Risk Score (ESRS) and Stroke Prognosis Instrument-II (SPI-II) can be useful for prediction of long-term risk.

Conclusion: The clinical risk scores that currently exist for predicting short-term and long-term risk of recurrent cerebral ischemia are limited in their performance and clinical utilities. There is a need for a better predictive tool which can overcome the limitations of current predictive models. Application of machine learning methods in combination with electronic health records may provide platform for development of new-generation predictive tools.

Contemporary prognosis of transient ischemic attack patients: A systematic review and meta-analysis

Background

Transient ischemic attacks are common and place patients at risk of subsequent stroke. The 2007 EXPRESS and SOS-TIA studies demonstrated the efficacy of rapid treatment initiation. We hypothesized that with these findings having informed subsequent transient ischemic attacks management protocols, transient ischemic attacks prognosis in contemporary (2008 and later) patient cohorts would be more favorable than in historical cohorts.

Methods

A systematic review and meta-analysis of cohort studies and randomized control trial placebo-arms of transient ischemic attack (published 2008–2015). The primary outcome was stroke. Secondary outcomes were mortality, transient ischemic attack, and myocardial infarction. Studies were excluded if the outcome of transient ischemic attack patients was not reported separately. The systematic review included all studies of transient ischemic attack. The meta-analysis excluded studies of restricted transient ischemic attack patient types (e.g. only patients with atrial fibrillation). The pooled cumulative risks of stroke recurrence were estimated from study-specific estimates at 2, 7, 30, and 90 days post-transient ischemic attack, using a multivariate Bayesian model.

Results

We included 47 studies in the systematic review and 40 studies in the meta-analysis. In the systematic review (191,202 patients), stroke at 2 days was reported in 13/47 (27.7%) of studies, at 7 days in 20/47 (42.6%), at 30 days in 12/47 (25.5%), and at 90 days in 33/47 (70.2%). Studies included in the meta-analysis recruited 68,563 patients. The cumulative risk of stroke was 1.2% (95% credible interval (CI) 0.6–2.2), 3.4% (95% CI 2.0–5.5), 5.0% (95% CI 2.9–8.9), and 7.4% (95% CI 4.3–12.4) at 2, 7, 30, and 90 days post-transient ischemic attack, respectively.

Conclusion

In contemporary settings, transient ischemic attack prognosis is more favorable than reported in historical cohorts where a meta-analysis suggests stroke risk of 3.1% at two days.

Differences in Clinical Characteristics between Patients with Transient Ischemic Attack Whose Symptoms Do and Do Not Persist on Arrival

BACKGROUND

Symptoms of transient ischemic attack (TIA) persist on arrival and subsequently resolve in some patients admitted to hospitals early after onset. Differences in clinical characteristics between patients with acute TIA whose symptoms do and do not persist on arrival remain unclear.

METHODS

We retrospectively extracted data of consecutive TIA patients with an onset-to-door time (ODT) of 24 hours or less and without a history of stroke from a multicenter TIA database. Clinical characteristics were compared between patients with and without persisting symptoms on arrival.

RESULTS

Two hundred sixty-six patients (158 men, 68.0 ± 12.9 years) were included. Of the total number of patients, 105 (39.5%) had persisting symptoms with a mean National Institutes of Health Stroke Scale score of 2.4 (median, 1.0). Patients with persisting symptoms were more likely to have sensory disorder, ambulance-transported admission, long-duration TIA (≥60 minutes), and shorter ODT than those without. Multivariate analysis showed that sensory disorder (odds ratio [OR] 2.52, 95% confidence interval [CI] 1.35-4.77), ambulance-transported admission (OR 1.80, 95% CI 1.00-3.28), and long-duration TIA (OR 3.96, 95% CI 2.12-7.71) were positively associated and that an ODT of more than 12 hours (OR .18, 95% CI .04-.63) was inversely associated with the presence ofpersisting symptoms. Patients with persisting symptoms were more likely to be examined by a stroke physician at first (69% versus 57%, P = .049) and then hospitalized in a stroke unit (59% versus 43%, P = .010).

CONCLUSION

Clinical manifestations and management after admission might differ between patients with acute TIA whose symptoms do and do not persist on arrival.

An assessment of the cost-effectiveness of magnetic resonance, including diffusion-weighted imaging, in patients with transient ischaemic attack and minor stroke: a systematic review, meta-analysis and economic evaluation

BACKGROUND

Patients with transient ischaemic attack (TIA) or minor stroke need rapid treatment of risk factors to prevent recurrent stroke. ABCD2 score or magnetic resonance diffusion-weighted brain imaging (MR DWI) may help assessment and treatment.

OBJECTIVES

Is MR with DWI cost-effective in stroke prevention compared with computed tomography (CT) brain scanning in all patients, in specific subgroups or as 'one-stop' brain-carotid imaging? What is the current UK availability of services for stroke prevention?

DATA SOURCES

Published literature; stroke registries, audit and randomised clinical trials; national databases; survey of UK clinical and imaging services for stroke; expert opinion.

REVIEW METHODS

Systematic reviews and meta-analyses of published/unpublished data. Decision-analytic model of stroke prevention including on a 20-year time horizon including nine representative imaging scenarios.

RESULTS

The pooled recurrent stroke rate after TIA (53 studies, 30,558 patients) is 5.2% [95% confidence interval (CI) 3.9% to 5.9%] by 7 days, and 6.7% (5.2% to 8.7%) at 90 days. ABCD2 score does not identify patients with key stroke causes or identify mimics: 66% of specialist-diagnosed true TIAs and 35-41% of mimics had an ABCD2 score of ≥ 4; 20% of true TIAs with ABCD2 score of < 4 had key risk factors. MR DWI (45 studies, 9078 patients) showed an acute ischaemic lesion in 34.3% (95% CI 30.5% to 38.4%) of TIA, 69% of minor stroke patients, i.e. two-thirds of TIA patients are DWI negative. TIA mimics (16 studies, 14,542 patients) make up 40-45% of patients attending clinics. UK survey (45% response) showed most secondary prevention started prior to clinic, 85% of primary brain imaging was same-day CT; 51-54% of patients had MR, mostly additional to CT, on average 1 week later; 55% omitted blood-sensitive MR sequences. Compared with 'CT scan all patients' MR was more expensive and no more cost-effective, except for patients presenting at > 1 week after symptoms to diagnose haemorrhage; strategies that triaged patients with low ABCD2 scores for slow investigation or treated DWI-negative patients as non-TIA/minor stroke prevented fewer strokes and increased costs. 'One-stop' CT/MR angiographic-plus-brain imaging was not cost-effective.

LIMITATIONS

Data on sensitivity/specificity of MR in TIA/minor stroke, stroke costs, prognosis of TIA mimics and accuracy of ABCD2 score by non-specialists are sparse or absent; all analysis had substantial heterogeneity.

CONCLUSIONS

Magnetic resonance with DWI is not cost-effective for secondary stroke prevention. MR was most helpful in patients presenting at > 1 week after symptoms if blood-sensitive sequences were used. ABCD2 score is unlikely to facilitate patient triage by non-stroke specialists. Rapid specialist assessment, CT brain scanning and identification of serious underlying stroke causes is the most cost-effective stroke prevention strategy.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Rapid diagnosis and treatment of TIA results in low rates of stroke, myocardial infarction and vascular death

INTRODUCTION

The 90-day risk of cerebral infarction in patients with transient ischaemic attack (TIA) is estimated at between 8% and 20%. There is little consensus as to which diagnostic strategy is most effective. This study evaluates the benefits of early transthoracic echocardiography (TTE) with carotid and transcranial Doppler ultrasound in patients with TIA.

METHODS

Prospective study of patients with TIA in an emergency department setting. Demographic data, vascular risk factors, and ABCD(2) score were analysed. TIA aetiology was classified according to TOAST criteria. All patients underwent early vascular studies (<72hours), including TTE, carotid ultrasound, and transcranial Doppler. Primary endpoints were recurrence of stroke or TIA, myocardial infarction (MI), or vascular death during the first year.

RESULTS

We evaluated 92 patients enrolled over 24 months. Mean age was 68.3±13 years and 61% were male. The mean ABCD(2) score was 3 points (≥5 in 30%). The distribution of TIA subtypes was as follows: 12% large-artery atherosclerosis; 30% cardioembolism; 10% small-vessel occlusion; 40% undetermined cause; and 8% rare causes. Findings from the early TTE led to a change in treatment strategy in 6 patients (6.5%) who displayed normal physical examination and ECG findings. At one year of follow-up, 3 patients had experienced stroke (3.2%) and 1 patient experienced MI (1%); no vascular deaths were identified.

CONCLUSIONS

In our TIA patients, early vascular study and detecting patients with silent cardiomyopathy may have contributed to the low rate of vascular disease recurrence.

Transient ischemic attacks: predictability of future ischemic stroke or transient ischemic attack events

The short-term risk of an ischemic stroke after a transient ischemic attack (TIA) is estimated to be approximately 3%–10% at 2 days, 5% at 7 days, and 9%–17% at 90 days, depending on active or passive ascertainment of ischemic stroke. Various risk prediction scores are available to identify high-risk patients. We present here a pragmatic review of the literature discussing the main scoring systems. We also provide the sensitivity, specificity, positive predictive value, and negative predictive value for each scoring system. Our review shows that scoring systems including brain imaging and vascular imaging are better at risk prediction than scores that do not include this information.

Correlation between ABCD, ABCD2 scores and craniocervical artery stenosis in patients with transient ischemic attack

BACKGROUND AND PURPOSE

Craniocervical artery stenosis is an important etiology for transient ischemic attack (TIA). We hypothesized ABCD and ABCD2 scores can predict craniocervical artery stenosis in patients with TIA.

METHODS

ABCD and ABCD2 scores were calculated in a total of 479 consecutive first-ever TIA patients in Nanjing Stroke Registry Program and compared with angiographic imaging derived from MRI or invasive catheter-based angiography.

RESULTS

Overall craniocervical artery (O-CA) stenosis was found in 197 (41.1%) patients. Extracranial craniocervical artery (E-CA) and intracranial craniocervical artery (I-CA) stenosis was found in 101 (21.1%) and 110 (23%) cases, respectively. ABCD and ABCD2 scores with similar accuracy for O-CA (AUCABCD 0.71, AUCABCD2 0.70), E-CA (AUCABCD 0.72, AUCABCD2 0.72) and I-CA stenosis (AUCABCD 0.62, AUCABCD2 0.62) were both independent predictors for various categories of artery stenosis after being adjusted for non-ABCD2 parameters. The cut-off points were equally 4 in both predicting rules. For ABCD, sensitivity was 57.4, 65.3 and 52.7% and specificity 77.0, 70.4 and 67.5% for O-CA/E-CA/I-CA, respectively. For ABCD2, sensitivity was 61.9, 69.3 and 58.2% and specificity 72.3, 65.6 and 63.1%.

CONCLUSIONS

In patients with TIA, despite an association between ABCD and ABCD2 scores and underlying craniocervical artery stenosis, the clinical utility was limited by unsatisfactory sensitivity and specificity.

Death and rehospitalization after transient ischemic attack or acute ischemic stroke: one-year outcomes from the adherence evaluation of acute ischemic stroke-longitudinal registry

BACKGROUND

Longitudinal data directly comparing the rates of death and rehospitalization of patients discharged after transient ischemic attack (TIA) versus acute ischemic stroke (AIS) are lacking.

METHODS

Data were analyzed from 2802 patients (TIA n = 552; AIS n = 2250) admitted to 100 U.S. hospitals participating in the Get With The Guidelines-Stroke and the Adherence Evaluation of Acute Ischemic Stroke-Longitudinal registry. The primary composite outcome was the adjusted rate of all-cause death and rehospitalization over 1 year after discharge. Four additional single or combined outcomes were explored.

RESULTS

Compared with AIS, TIA patients were older (median 69 v 66 years; P = .007) and more likely female (53.3% v 44.2%; P < .0001). Secondary prevention medication use after hospital discharge was less intensive after TIA, with underuse for both conditions. All-cause death or rehospitalization at 1 year was similar for TIA and AIS patients (37.7% v 34.6%; P = .271); the frequency for TIA patients was higher after covariate adjustment (hazard ratio [HR] 1.19; 95% confidence interval [CI] 1.01-1.41). One-year all-cause mortality was similar among those with TIA compared to AIS patients (3.8% v 5.7%; P = .071; adjusted HR 0.86; 95% CI 0.52-1.42). All-cause rehospitalizations were higher for TIA compared to AIS patients (36.4% v 33.0%; P = .186; adjusted HR 1.20; 95% CI 1.02-1.42), but similar for stroke rehospitalizations (10.1% v 7.4%; P = .037; adjusted HR 1.38, 95% CI 0.997-1.92).

CONCLUSIONS

Patients with TIA have similar or worse 12-month postdischarge risk of death or rehospitalization as compared with those with AIS. Outcomes after TIA and AIS might be improved with better adherence to secondary preventive guidelines.

The prognostic impact of the stroke unit concept after transient ischemic attack

BACKGROUND AND PURPOSE

Transient ischemic attack (TIA) is associated with high short-term risk of stroke, especially in the early phase following the event. Data about the impact of the early hospitalization in a stroke unit on patients with TIA are sparse. This study compares the prognostic impact of the stroke unit concept with conventional care on patients with TIA.

METHODS

During a 30-month period (beginning April 2005), 878 patients (mean age, 70±12years; 44.3% female) with TIA admitted within 24h of symptom onset were prospectively evaluated. The adjusted logistic regression analyses were used to estimate the odds ratio for the stroke risk during hospitalization and the 90-day mortality.

RESULTS

Of 878 patients, 591 (67.3%) were treated in the stroke unit, and 287 (32.7%) underwent conventional care. Patients receiving stroke-unit care had significantly higher rates of cranial computed tomography (96.3% vs. 88.1%; P<.001) and brain-supplying artery ultrasound (97.1% vs. 91.3%; P<.001) investigations. The stroke risk during hospitalization was 1.7% in patients treated in stroke unit and 2.4% in patients received a conventional care. A relevant difference between the groups was not found (1.7% vs. 2.4%; P=.45). The 90-day mortality rate was 1.7% in the stroke unit group compared to 2.2% in the conventional care group (1.7% vs. 2.2%; P=.66). The adjusted logistic regression analyses revealed no difference in stroke rates (odds ratio, 0.68; 95% confidence interval, 0.24-1.9) and in the 90-day mortality (odds ratio, 0.63; 95% confidence interval, 0.2-1.96) between the stroke unit concept and conventional care.

CONCLUSION

The prognostic impact of the stroke unit care for patients with transient ischemic attack appears to be similar to that of the conventional care. Further randomized studies are needed to investigate the impact of stroke-unit care on patients with transient ischemic attack.

Improving the prediction of stroke or death after transient ischemic attack (TIA) by adding diffusion-weighted imaging lesions and TIA etiology to the ABCD2 score

The present study investigated the addition of transient ischemic attack (TIA) etiology and diffusion-weighted imaging (DWI) to the ABCD2 score, creating the ABCDE+ score, to improve the predictive ability of stroke risk or death at 6 months after TIA. We performed a cohort study of 150 consecutive patients with TIA. All patients underwent DWI and all had an etiologic workup and were followed up for 6 months. The area under the receiver operating characteristic curve (AUC) was used to compare the scores' ability to predict the outcome of stroke or death. Multivariate Cox regression analysis was performed to evaluate the association between the measured variables and subsequent stroke or death. Thirty patients (20%) experienced future stroke, and 12 patients (8%) died within the 6-month follow-up. A comparison of AUCs demonstrated the superiority of the ABCDE+ score over the ABCD2 score for predicting stroke (0.64 vs 0.60) and for predicting death (0.62 vs 0.56). ABCD2 score >4, ABCDE+ score >6, large-artery disease, and lesions detected on DWI were found to be independent predictors of future stroke, and ABCDE+ score >6, age, and heart disease were independent predictors of death. We conclude that incorporating DWI positivity and etiology of TIA into the ABCD2 score can improve the ability to predict stroke and death within 6 months after TIA.

Recommendations for management of patients with carotid stenosis

Stroke is a one of the leading causes of morbidity and mortality in the world. Carotid atherosclerosis is recognized as an important factor in stroke pathophysiology and represents a key target in stroke prevention; multiple treatment modalities have been developed to battle this disease. Multiple randomized trials have shown the efficacy of carotid endarterectomy in secondary stroke prevention. Carotid stenting, a newer treatment option, presents a less invasive alternative to the surgical intervention on carotid arteries. Advances in medical therapy have also enabled further risk reduction in the overall incidence of stroke. Despite numerous trials and decades of clinical research, the optimal management of symptomatic and asymptomatic carotid disease remains controversial. We will attempt to highlight some of the pivotal trials already completed, discuss the current controversies and complexities in the treatment decision-making, and postulate on what likely lies ahead. This paper will highlight the complexities of decision-making optimal treatment recommendations for patients with symptomatic and asymptomatic carotid stenosis.

Contribution of high-b-value diffusion-weighted imaging in determination of brain ischemia in transient ischemic attack patients

BACKGROUND AND PURPOSE

High-b-value diffusion-weighted imaging (DWI) (b = 2,000 and b = 3,000 second/mm(2)) offers theoretical advantages over DWI examinations at b = 1,000 second/mm(2) for detection of acute ischemic stroke. The purpose of this study was to determine whether high-b-value DWI are better than b = 1,000 images in TIA patients.

METHODS

We compared DWI obtained with 3 different b-values (1,000, 2,000, and 3,000 second/mm(2)) and fluid-attenuated inversion recovery (FLAIR) sequences in 75 consecutive TIA patients. DWI examinations were performed within 3.25 ± 1.5 days after the onset of symptoms. Presence of ischemic lesion, volume, lesion conspicuity, and lesion distinction were determined.

RESULTS

A total of 40 (53.3%) patients revealed ischemic acute lesions with b = 1,000 while 34 (45.3%) were positive on FLAIR. High-b-value DWI did not increase the sensitivity for the detection of acute brain ischemia. The median lesion value increased as the b-value did: .17 mL (interquartile range [IQR] .12-.78) at b = 1,000; .19 mL (IQR .13-1.00) at b = 2,000; .29 mL (IQR .14-1.02) at b = 3,000; and .12 mL (IQR .04-.62 mL) on FLAIR (P < .001). As b-value increased, we observed hyperintensities in white matter that could erroneously be considered as acute ischemia.

CONCLUSION

High-b-value DWI did not improve the conspicuity and distinction of the ischemic lesions.

The ABCD and ABCD2 Scores and the Risk of Stroke following a TIA: A Narrative Review

The California, ABCD, and ABCD2 risk scores (ABCD system) were developed to help stratify short-term stroke risk in patients with TIA (transient ischemic attack). Beyond this scope, the ABCD system has been extensively used to study other prognostic information such as DWI (diffusion-weighted imaging) abnormalities, large artery stenosis, atrial fibrillation and its diagnostic accuracy in TIA patients, which are independent predictors of subsequent stroke in TIA patients. Our comprehensive paper suggested that all scores have and equivalent prognostic value in predicting short-term risk of stroke; however, the ABCD2 score is being predominantly used at most centers. The majority of studies have shown that more than half of the strokes in the first 90 days, occur in the first 7 days. The majority of patients studied were predominantly classified to have a higher ABCD/ABCD2 > 3 scores and were particularly at a higher short-term risk of stroke or TIA and other vascular events. However, patients with low risk ABCD2 score < 4 may have high-risk prognostic indicators, such as diffusion weighted imaging (DWI) abnormalities, large artery atherosclerosis (LAA), and atrial fibrillation (AF). The prognostic value of these scores improved if used in conjunction with clinical information, vascular imaging data, and brain imaging data. Before more data become available, the diagnostic value of these scores, its applicability in triaging patients, and its use in evaluating long-term prognosis are rather secondary; thus, indicating that the primary significance of these scores is for short-term prognostic purposes.

Transient ischemic attack evaluation models: hospitalization, same-day clinics, or rapid evaluation units

Transient ischemic attack (TIA) has been well established as a risk factor for future stroke. Therefore, the diagnosis of TIA may serve as a golden opportunity for providing early time sensitive therapies to this high-risk group. Currently, there is no standardized algorithm for triaging suspected TIA, leading to errors in diagnosis, significant delays in evaluation and treatment, and greater morbidity and mortality. There are several proposed methods for triaging patients: hospitalization, same-day clinics, and rapid evaluation units. We review the benefits and limitations for each model, focusing on stroke risk reduction, costs, and feasibility.

Yield of systematic transcranial Doppler in patients with transient ischemic attack

OBJECTIVE

Urgent evaluation and treatment of transient ischemic attack (TIA) patients in a dedicated TIA clinic may reduce the 90-day stroke risk by 80%. ABCD2 (Age, Blood pressure, Clinical features, Duration, Diabetes) score and magnetic resonance imaging abnormalities help to identify patients at high risk of stroke. Our aim was to determine whether the use of transcranial Doppler (TCD) examination on arrival at the TIA clinic yields additional information that facilitates the identification of patients at high risk of stroke recurrence.

METHODS

Between January 2003 and December 2007, 1,881 patients were admitted to SOS-TIA clinic (a TIA clinic with around-the-clock access). Clinical and vascular assessment included TCD performed by a neurologist immediately after admission. Stroke prevention measures were initiated on arrival, in accordance with guidelines. All patients were followed for 1 year after presentation to the SOS-TIA clinic.

RESULTS

A total of 1,823 TCD examinations were performed within 4 hours of admission. Intracranial narrowing or occlusion was found in 8.8% of patients, and was independently associated with age, hypertension, and diabetes. After 1-year follow-up on best preventive therapy, the incidence of recurrent vascular events (intracranial revascularization for TIA recurrence, stroke, myocardial infarction, and vascular death combined) was 7.0% in patients with intracranial narrowing or occlusion and 2.4% in those without (log-rank, p = 0.007). The hazard ratio of combined outcome for the presence of intracranial narrowing or occlusion was 2.29 (95% confidence interval [CI], 1.15-4.56; p = 0.02) in multivariate analysis including age, gender, hypertension, and diabetes, and was 2.50 (95%CI, 1.24-5.05; p = 0.01) in multivariate analysis including ABCD2 score > or =4.

INTERPRETATION

Immediate TCD examination on arrival at the TIA clinic is feasible and could help to identify patients at high risk of vascular events recurrence. This study supports a systematic intracranial vascular examination in the initial management of TIA.

D-dimer, magnetic resonance imaging diffusion-weighted imaging, and ABCD2 score for transient ischemic attack risk stratification

BACKGROUND

We sought to determine whether measurement of D-dimer (DD) would improve risk stratification after transient ischemic attack (TIA).

METHODS

We enrolled 167 patients with acute TIA in a prospective observational study. DD was measured using rapid enzyme-linked immunosorbent assay. The primary outcome measure was a composite end point consisting of stroke or death within 90 days or the identification of a high-risk stroke mechanism requiring specific early intervention (defined as > or =50% stenosis in a vessel referable to symptoms or a cardioembolic source warranting anticoagulation).

RESULTS

The composite end point occurred in 41 patients (25%). A 50% or greater stenosis was found in 25 patients (15%), a cardioembolic source in 14 (8%), and clinical events in 8 (5 strokes, 3 deaths), 6 of whom also had a high-risk cause of TIA. ABCD(2) score was associated with outcome (P for trend = .017, c-statistic 0.63). DD levels did not differ based on outcome status (geometric mean 0.75 v 0.82 microg fibrinogen equivalent unit/mL, P = .56), and DD had little use for predicting outcome (c-statistic 0.57), even when combined with ABCD(2) score. Of 96 patients with early magnetic resonance imaging (MRI), 23% had diffusion-weighted imaging (DWI) abnormalities, and MRI DWI was predictive of outcome (c-statistic 0.76). The addition of MRI DWI to ABCD(2) improved predictive accuracy (c-statistic 0.83) compared with either alone.

CONCLUSIONS

Many patients with TIA have a high-risk mechanism (large vessel stenosis or cardioembolism) or will experience stroke/death within 90 days. Increasing ABCD(2) scores were associated with this composite end point. Measurement of DD did not provide additional prognostic information.

Population-based study of risk and predictors of stroke in the first few hours after a TIA

BACKGROUND

Several recent guidelines recommend assessment of patients with TIA within 24 hours, but it is uncertain how many recurrent strokes occur within 24 hours. It is also unclear whether the ABCD2 risk score reliably identifies recurrences in the first few hours.

METHODS

In a prospective, population-based incidence study of TIA and stroke with complete follow-up (Oxford Vascular Study), we determined the 6-, 12-, and 24-hour risks of recurrent stroke, defined as new neurologic symptoms of sudden onset after initial recovery.

RESULTS

Of 1,247 first TIA or strokes, 35 had recurrent strokes within 24 hours, all in the same arterial territory. The initial event had recovered prior to the recurrent stroke (i.e., was a TIA) in 25 cases. The 6-, 12-, and 24-hour stroke risks after 488 first TIAs were 1.2% (95% confidence interval [CI]: 0.2-2.2), 2.1% (0.8-3.2), and 5.1% (3.1-7.1), with 42% of all strokes during the 30 days after a first TIA occurring within the first 24 hours. The 12- and 24-hour risks were strongly related to ABCD2 score (p = 0.02 and p = 0.0003). Sixteen (64%) of the 25 cases sought urgent medical attention prior to the recurrent stroke, but none received antiplatelet treatment acutely.

CONCLUSION

That about half of all recurrent strokes during the 7 days after a TIA occur in the first 24 hours highlights the need for emergency assessment. That the ABCD2 score is reliable in the hyperacute phase shows that appropriately triaged emergency assessment and treatment are feasible.

Risk stratification tools for transient ischemic attack: which patients require hospital admission?

Stroke and transient ischemic attack (TIA) arise from identical etiologies and many fatal or disabling strokes are preceded by a TIA. Ten percent of patients presenting with a TIA will suffer a stroke within 3 months with half occurring in the first 48 hours. Still, many patients with a TIA do not receive timely evaluation or therapy. Hospitalization offers the opportunity for rapid evaluation and secondary prevention, reduced time to thrombolysis for early second strokes, and can be cost effective for high risk patients. Stratification tools are now available which allow individualized assessment of risk for early second strokes based on patient characteristics on presentation. The use of scoring systems such as the ABCD(2) score to predict risk of stroke after TIA are useful in making an evidence-based judgment regarding need for hospitalization. High-risk patients have an 8.1% risk for stroke in the 48 hours after a TIA and warrant hospital admission. Intermediate-risk patients have a 4.1% risk of early second stroke and may be considered for admission, observation, or expedited clinic evaluation. Low-risk patients have a 2-day stroke risk of only 1% and are likely appropriate for prompt outpatient evaluation. TIA is a medical emergency, similar to unstable angina, and high risk patients should receive treatment and prevention measures instituted with comparable urgency.

Stroke Units: Many Questions, Some Answers

Background The development of specialized stroke units has been a landmark innovation in acute stroke care. However, the high scientific evidence level for the recommendation for stroke units to provide clinical attention for acute stroke patients does not correspond to the level of stroke unit implementation. A narrative, nonsystematic review on published studies on stroke units was conducted, with special emphasis on those demonstrating their efficacy and effectiveness. We also attempt to provide some answers to several open questions regarding practical issues of stroke units.

Post-transient ischemic attack early stroke stratification: the ABCD(2) prognostic aid

BACKGROUND

In many patients, transient ischemic attack (TIA) precedes stroke. Prompt recognition of TIA patients who are at increased short-term risk for stroke may facilitate efficient resource utilization and improved patient outcomes. Three prognostic decision aids have been derived and validated to empower emergency physicians to stratify TIA patients for 2-day stroke risk based upon information readily available at the bedside.

CLINICAL QUESTION

Can a TIA stratification tool predict short-term stroke risk?

EVIDENCE REVIEW

Two relevant tool derivation studies and one validation study were selected from an evidence search and a structured review.

RESULTS

The three tools reveal similar prognostic capabilities, although the ABCD(2) prognostic guide may be slightly superior. A proposal scoring system for TIA patients at low risk for stroke within 90 days is presented.

CONCLUSION

Stroke risk stratification is possible with a simple prediction rule.

DWI lesions and TIA etiology improve the prediction of stroke after TIA

BACKGROUND AND PURPOSE

The ABCD(2) score has been shown to predict the early risk of stroke after transient ischemic attack (TIA). The additional predictive value of diffusion-weighted imaging (DWI) and TIA etiology is not well known.

METHODS

From January 2003 to June 2007, 343 consecutive patients (mean+/-SD age, 62.4+/-15.4 years) with TIA were admitted to our stroke unit. Most (339) patients underwent DWI and all had an etiologic work-up and were followed up for 3 months. The predictive value of the ABCD(2) score, positive DWI findings, large-artery atherosclerosis (LAA), and atrial fibrillation (AF) with respect to occurrence of ischemic stroke at 1 week and 3 months was assessed.

RESULTS

DWI was positive in 136 (40%) patients. Sixty (17%) patients had LAA and 27 (8%) had AF. Patients with positive DWI findings were more likely to have unilateral weakness (odds ratio [OR]=2.2; 95% CI, 1.3 to 3.7), TIA duration >/=60 minutes (OR=2.6; 95% CI, 1.3 to 5.2), ABCD(2) >5 (OR=4.7; 95% CI, 2.0 to 11.0), LAA (OR=1.8; 95% CI, 1.0 to 3.1), and AF (OR=3.5; 95% CI, 1.5 to 8.0). During follow-up, 5 patients had a stroke within 7 days (absolute risk=1.5%, 95% CI, 0.3% to 2.7%), and 10 had a stroke within 3 months (absolute risk=2.9%; 95% CI, 1.1% to 4.7%). All early strokes but 1 occurred in patients with positive DWI findings. ABCD(2) score and positive DWI findings were associated with an increased 7-day and 3-month risk of stroke. At 3 months, ABCD(2) score >5 (hazard ratio=10.1; 95% CI, 1.1 to 93.4), positive DWI result (hazard ratio=8.7; 95% CI, 1.1 to 71.0), and LAA (hazard ratio=3.4; 95% CI, 1.0 to 11.8) were independently associated with an increased risk of stroke. There was no association with AF.

CONCLUSIONS

Taking DWI and TIA etiology into account in addition to the ABCD(2) score improves the prediction of the early risk of stroke after TIA.

Transient ischemic attack: diagnostic evaluation

A transient ischemic attack portends significant risk of a stroke. Consequently, the diagnostic evaluation in the emergency department is focused on identifying high-risk causes so that preventive strategies can be implemented. The evaluation consists of a facilitated evaluation of the patient's metabolic, cardiac, and neurovascular systems. At a minimum, the following tests are recommended: fingerstick glucose level, electrolyte levels, CBC count, urinalysis, and coagulation studies; noncontrast computed tomography (CT) of the head; electrocardiography; and continuous telemetry monitoring. Vascular imaging studies, such as carotid ultrasonography, CT angiography, or magnetic resonance angiography, should be performed on an urgent basis and prioritized according to the patient's risk stratification for disease. Consideration should be given for echocardiography if no large vessel abnormality is identified.

Transient ischemic attack: risk stratification and treatment

A major challenge facing the physician evaluating patients with transient ischemic attack is determining which patients are at highest short-term risk of stroke. A number of stratification schemes have been recently developed incorporating easily obtainable clinical information about the individual patient. Further, emerging data suggest a role for brain and vascular imaging in risk stratification. Many aspects of acute management of transient ischemic attack, such as which patients should be hospitalized and choice of acute antithrombotic therapy, remain controversial because of a lack of evidence from controlled trials. For longer-term prevention, there is much firmer evidence from multiple large randomized trials, and these data are reviewed in this article.

A transient ischaemic attack clinic with round-the-clock access (SOS-TIA): feasibility and effects

BACKGROUND

Diagnosis and treatment of cerebral and retinal transient ischaemic attacks (TIAs) are often delayed by the lack of immediate access to a dedicated TIA clinic. We evaluated the effects of rapid assessment of patients with TIA on clinical decision making, length of hospital stay, and subsequent stroke rates.

METHODS

We set up SOS-TIA, a hospital clinic with 24-h access. Patients were admitted if they had sudden retinal or cerebral focal symptoms judged to relate to ischaemia and if they made a total recovery. Assessment, which included neurological, arterial, and cardiac imaging, was within 4 h of admission. A leaflet about TIA with a toll-free telephone number for SOS-TIA was sent to 15 000 family doctors, cardiologists, neurologists, and ophthalmologists in Paris and its administrative region. Endpoints were stroke within 90 days, and stroke, myocardial infarction, and vascular death within 1 year.

FINDINGS

Between January, 2003, and December, 2005, we admitted 1085 patients with suspected TIA; 574 (53%) were seen within 24 h of symptom onset. 701 (65%) patients had confirmed TIA or minor stroke, and 144 (13%) had possible TIA. 108 (17%) of the 643 patients with confirmed TIA had brain tissue damage. Median duration of symptoms was 15 min (IQR 5-75 min). Of the patients with confirmed or possible TIA, all started a stroke prevention programme, 43 (5%) had urgent carotid revascularisation, and 44 (5%) were treated for atrial fibrillation with anticoagulants. 808 (74%) of all patients seen were sent home on the same day. The 90-day stroke rate was 1.24% (95% CI 0.72-2.12), whereas the rate predicted from ABCD(2) scores was 5.96%.

INTERPRETATION

Use of TIA clinics with 24-h access and immediate initiation of preventive treatment might greatly reduce length of hospital stay and risk of stroke compared with expected risk.

Risk of stroke early after transient ischaemic attack: a systematic review and meta-analysis

BACKGROUND

Stroke is often preceded by transient ischaemic attack (TIA), but studies of stroke risk after TIA are logistically difficult and have yielded conflicting results. However, reliable estimation of this risk is necessary for planning effective service provision, clinical trials, and public education. We therefore did a systematic review of all studies of stroke risk early after TIA.

METHODS

All studies of stroke risk within 7 days of TIA were identified by use of electronic databases and by hand searches of reference lists, relevant journals, and conference abstracts. Stroke risks at 2 days and 7 days after TIA were calculated overall and analyses for heterogeneity were done, if possible, after categorisation by study method, setting, population, and treatment.

FINDINGS

18 independent cohorts were included, which reported stroke risk in 10 126 TIA patients. The pooled stroke risk was 5.2% (95% CI 3.9-6.5) at 7 days, but there was substantial heterogeneity between studies (p<0.0001), with risks ranging from 0% to 12.8%. However, the risks reported in individual studies over different durations of follow-up were highly correlated (0-7 days vs 8-90 days, r=0.89, p<0.0001), and the heterogeneity between studies was almost fully explained by study method, setting, and treatment. The lowest risks were seen in studies of emergency treatment in specialist stroke services (0.9% [95% CI 0.0-1.9], four studies) and the highest risks in population-based studies without urgent treatment (11.0% [8.6-13.5], three studies). Results were similar for stroke risk at 2 days.

INTERPRETATION

The reported early risks of stroke after TIA were highly heterogeneous, but this could be largely accounted for by differences in study method, setting, and treatment, with lowest risks in studies of emergency treatment in specialist stroke services.