Can the ABCD Score be dichotomised to identify high-risk patients with transient ischaemic attack in the emergency department?

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.

Systolic blood pressure as a predictor of transient ischemic attack/minor stroke in emergency department patients under age 80: a prospective cohort study

BACKGROUND

Elevated blood pressure (BP) at emergency department (ED) presentation and advancing age have been associated with risk of ischemic stroke; however, the relationship between BP, age, and transient ischemic attack/minor stroke (TIA/MS) is not clear.

METHODS

A multi-site, prospective, observational study of 1084 ED patients screened for suspected TIA/MS (symptom onset < 24 h, NIHSS< 4) between December 2013 and April 2016. Systolic and diastolic BP measurements (SBP, DBP) were taken at ED presentation. Final diagnosis was consensus adjudication by stroke neurologists; patients were diagnosed as either TIA/MS or stroke-mimic (non-cerebrovascular conditions). Conditional inference trees were used to define age cut-points for predicting binary diagnosis (TIA/MS or stroke-mimic). Logistic regression models were used to estimate the effect of BP, age, sex, and the age-BP interaction on predicting TIA/MS diagnosis.

RESULTS

Over a 28-month period, 768 (71%) patients were diagnosed with TIA/MS: these patients were older (mean 71.6 years) and more likely to be male (58%) than stroke-mimics (61.4 years, 41%; each p < 0.001). TIA/MS patients had higher SBP than stroke-mimics (p < 0.001). DBP did not differ between the two groups (p = 0.191). SBP was predictive of TIA/MS diagnosis in younger patients, after accounting for age and sex; an increase of 10 mmHg systolic increased the odds of TIA/MS 18% (odds ratio [OR] 1.18, 95% CI 1.00-1.39) in patients < 60 years, and 23% (OR 1.23, 95% CI 11.12-1.35) in those 60-79 years, while not affecting the odds of TIA/MS in patients ≥80 years (OR 0.99, 95% CI 0.89-1.07).

CONCLUSIONS

Raised SBP in patients younger than 80 with suspected TIA/MS may be a useful clinical indicator upon initial presentation to help increase clinicians' suspicion of TIA/MS.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03050099 (10-Feb-2017) and NCT03070067 (3-Mar-2017). Retrospectively registered.

Comparison of Recommendations and Use of Cardiovascular Risk Equations by Health Technology Assessment Agencies and Clinical Guidelines

OBJECTIVES

To identify risk equations for cardiovascular diseases (CVDs) in primary and secondary prevention settings that are used or recommended by health technology assessment (HTA) organizations and in clinical guidelines (CGs).

METHODS

A targeted literature review was conducted using a two-stage search strategy. First, HTA reviews of manufacturers' drug submissions, reports from established HTA organizations (Europe, Canada, and Australia), and CGs from countries with and without HTA organizations, including the United States, were identified. Documents published between September 30, 2006 and September 30, 2016, were examined for cardiovascular risk equations, recommendations, and commentaries. Next, publications associated with risk equations and cited by HTA and CG documents were retrieved. This literature was examined to extract commentaries and risk equation study characteristics.

RESULTS

The review identified 47 risk equations, 25 in the primary CVD prevention setting (i.e., patients with no CVD history), including 5 for CVD prevention in diabetes and 22 solely in secondary prevention settings; 11 were identified for heart failure, 3 for stroke or transient ischemic attack, 2 for stable angina, and 11 for acute coronary syndrome or related conditions. A small set of primary prevention equations was found to be commonly used by HTAs, whereas secondary prevention equations were less common in HTA documents. CGs provided more risk equations as options than HTA documents.

CONCLUSIONS

Although there is an abundance of risk equations developed for primary and secondary prevention, there remains a need for additional research to provide sufficient clinical and HTA guidance for risk estimation, particularly in high-risk or secondary prevention settings.

Motor Impairments in Transient Ischemic Attack Increase the Odds of a Subsequent Stroke: A Meta-Analysis

Background and purpose

Transient ischemic attack (TIA) increases the risk for a subsequent stroke. Typical symptoms include motor weakness, gait disturbance, and loss of coordination. The association between the presence of motor impairments during a TIA and the chances of a subsequent stroke has not been examined. In the current meta-analysis, we examine whether the odds of a stroke are greater in TIA individuals who experience motor impairments as compared with those who do not experience motor impairments.

Methods

We conducted a systematic search of electronic databases as well as manual searches of the reference lists of retrieved articles. The meta-analysis included studies that reported an odds ratio relating motor impairments to a subsequent stroke, or the number of individuals with or without motor impairments who experienced a subsequent stroke. We examined these studies using rigorous meta-analysis techniques including random effects model, forest and funnel plots, I², publication bias, and fail-safe analysis.

Results

Twenty-four studies with 15,129 participants from North America, Australia, Asia, and Europe qualified for inclusion. An odds ratio of 2.11 (95% CI, 1.67–2.65, p = 0.000) suggested that the chances of a subsequent stroke are increased by twofolds in individuals who experience motor impairments during a TIA compared with those individuals who have no motor impairments.

Conclusion

The presence of motor impairments during TIA is a significantly high-risk clinical characteristic for a subsequent stroke. The current evidence for motor impairments following TIA relies exclusively on the clinical reports of unilateral motor weakness. A comprehensive examination of motor impairments in TIA will enhance TIA prognosis and restoration of residual motor impairments.

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.

Admission rates of ED patients with transient ischemic attack have increased since 2000

OBJECTIVE

A study published in December 2000 showed that 5% of patients presenting with transient ischemic attacks (TIAs) developed a stroke within 48 hours. This finding has been corroborated in several other studies. We hypothesize that, influenced by this, emergency department (ED) physicians have been more reluctant to discharge TIA patients resulting in an increase in the percentage of TIA patients admitted.

METHODS

This is a retrospective cohort of consecutive ED visits. This study is conducted in 6 New Jersey EDs with annual ED visits from 25000 to 65000. Consecutive patients seen by ED physicians between January 1, 2000, and December 31, 2010, were included. We identified TIA visits using the International Classification of Diseases, Ninth Revision, code. We analyzed the admission rates for TIA testing for significant differences using the Student t test and calculated 95% confidence intervals.

RESULTS

Of the 2622659 visits in the database, 8216 (0.3%) were for TIA. Females comprised 57%. There was a statistically significant increase in the annual admission rates for TIA patients from 2000 to 2010, from 70% to 91%, respectively (difference, 22%; 95% confidence interval, 18%-26% [P < .001]). Separate analysis by sex showed similar increased admission rates for females and males.

CONCLUSIONS

We found that the admission rate for TIAs increased significantly from 2001 to 2010. This change in physicians' practice may be due to the body of evidence that TIA patients have a significant short-term risk of stroke.

Assessment of ABCD² scale in patients with transient ischaemic attack or stroke

BACKGROUND AND PURPOSE

Stroke risk prediction scores have been designed to stratify risk of recurrent cerebrovascular events in patients with transient ischaemic attack (TIA) or minor ischaemic stroke (MIS).

MATERIAL AND METHODS

Consecutive patients with TIA or MIS referring to Ghaem Hospital, Mashhad presenting within 24 hours from the onset of symptoms were recruited to the prospective cohort study between 2010 and 2011. MIS was defined as an ischaemic stroke with National Institutes of Health Stroke Scale (NIHSS) score < 4. The end-point of the study was a new ischaemic cerebrovascular event or vascular death at 90 days and, additionally, at 3 days after the index TIA or MIS. The decision to admit and of method of treatment in each case was left to the discretion of the stroke neurologist. The predictive accuracy of the ABCD2 scoring system for recurrent stroke or TIA was quantified by the area under the curve (AUC), using the c-statistics.

RESULTS

The study included 393 patients with TIA (238 males, 155 females) and 118 patients with MIS (77 males, 41 females). Among 511 patients with minor ischaemic events, 117 strokes (23.2%), 99 TIAs (19.6%), and 11 vascular deaths (2.2%) occurred within 3 months after the index event. The ABCD2 score had a weak predictive value for 3-month and 3-day recurrent stroke in patients with TIA (AUC = 0.599 and 0.591, respectively), but a high predictive value for 3-month and 3-day recurrent stroke in patients with MIS (AUC = 0.727 and 0.728, respectively).

CONCLUSION

The ABCD2 score is highly predictive for short-term recurrent stroke in patients with MIS but not in patients with TIA, although it was originally designed for patients with TIA.

The ABCD(2) Score is Highly Predictive of Stroke in Minor Ischemic Stroke Patients

Stroke risk prediction scores have been designed to stratify risk of recurrent cerebrovascular events in transient ischemic attack (TIA) and minor ischemic stroke (MIS) patients. Consecutive TIA or MIS patients referred to Ghaem Hospital, Mashhad were enrolled in a prospective cohort study during 2010-2011. Only TIA or MIS patients presenting within 24 h from the onset of symptoms were recruited. MIS was considered as ischemic stroke with NIHSS <4. The end point of the study was a new ischemic cerebrovascular event or vascular death at 90 days and additionally at 3 days. The decision to admit and treatment in each case was left to the discretion of the stroke neurologist. The predictive accuracy of the ABCD(2) scoring system for recurrent stroke or TIA was quantified by the area under the cure (AUC) using the c statistics. Three hundred ninety-three TIA patients (238 males, 155 females) and 118 MIS patients (77 males, 41 females) were enrolled in the study. One hundred seventeen strokes (23.2%), 99 TIA (19.6%), and 11 vascular death (2.2%) occurred within 3 months postevent in the whole of our 511 patients with minor ischemic events. The ABCD(2) score had a weak predictive value for 3 months and 3 days recurrent stroke in our TIA patients (AUC = 0.599, AUC = 0.591), but a high predictive value for 3 months and 3 days recurrent stroke in our MIS patients (AUC = 0.727, AUC = 0.728), respectively. The ABCD(2) score is highly predictive of short-term recurrent stroke in MIS patients but not TIA cases, despite its creation for TIA cohorts.

Incidence of Transient Ischemic Attack and Early Stroke Risk

Background and Purpose—

The importance of transient ischemic attack (TIA) lies on the short-term risk of stroke, and the ABCD2 score may improve early stroke risk prediction. However, population-based studies are still needed. We aimed to provide data on TIA incidence and to evaluate the ABCD2 predictive ability for early recurrent stroke in a population-based study.

Methods—

This study is part of a 2-year prospective community-based registry of all cerebrovascular events in the district of Udine (153 312 inhabitants), Friuli Venezia Giulia region, northeast of Italy, between April 1, 2007 and March 31, 2009. Multiple overlapping sources for finding cases were used, combining hot and cold pursuit.

Results—

We identified 178 TIA, 161 (90.4%) of which were incident. The crude overall annual TIA incidence rate per 1000 residents was 0.52 (95% confidence interval [CI], 0.45–0.61). Incidence rate was 0.45 (95% CI, 0.31–0.65) when standardized to the 2007 Italian population and 0.25 (95% CI, 0.16–0.39) when standardized to the European standard population. Estimates of stroke risk after the index TIA within 2, 7, 30, and 90 days were, respectively, 2.5% (95% CI, 0.7–6.2), 5.6% (95% CI, 2.6–10.3), 6.2% (95% CI, 3.0–11.1), and 11.2% (95% CI, 6.8–17.1). ABCD2 score was strongly associated with stroke occurrence after index TIA: the areas under the receiver operating characteristic curve at 2, 7, 30, and 90 days were, respectively, 0.85 (95% CI, 0.72–0.97), 0.69 (95% CI, 0.56–0.82), 0.69 (95% CI, 0.56–0.85), and 0.76 (95% CI, 0.67–0.86). No patients with an ABCD2 score <4 had a stroke within the 90-day follow-up period.

Conclusions—

This study adds new data on TIA incidence and prognosis and it further validates the ability of the ABCD2 score to identify patients at early risk for stroke.

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.

The ABCD and ABCD2 as predictors of stroke in transient ischemic attack clinic outpatients: a retrospective cohort study over 14 years

BACKGROUND

The ABCD and ABCD2 scores have been validated for use as predictors of stroke in community populations up to 90 days after a transient ischemic attack (TIA). TIA outpatient clinics may see a selective group of patients who have not had an early stroke but may be at raised risk in the medium to long term and therefore benefit from preventive treatment.

AIM

To describe the prognostic values of the ABCD and ABCD2 scores on long-term stroke risk.

DESIGN

Retrospective cohort study of TIA clinic outpatients followed for up to 14 years.

METHODS

Absolute and relative stroke risks, Kaplan-Meier survival curves and cumulative stroke incidence were calculated. Receiver Operating Characteristic curves (ROCs) and areas under the curve were calculated for both scores.

RESULTS

Seven hundred and ninety-five patients were included and 138 (17.3%) experienced a stroke within 13.8 years follow-up after first TIA clinic visit, a crude risk of 26.3 per 1000 person-years. Compared with baseline scores of 0-2, risk ratios for ABCD of 3-4 were 2.95 (95% CI 1.52-6.40), and for 5-6 were 3.42 (95% CI 1.72-7.54); for the ABCD2, risk ratios for 3-4 were 2.68 (95% CI 1.37-5.84), and for 5-7 were 3.55 (95% CI 1.80-7.79). Scores of > or = 3 for either ABCD or ABCD2 predicted raised stroke risks at 90 days, 1, 5 and 10 years. Areas under the curve were 0.619 (95% CI 0.571-0.668) and 0.630 (95% CI 0.582-0.677) for the ABCD and ABCD2 scores, respectively.

CONCLUSION

ABCD and ABCD2 scores of > or = 3 may be clinically useful in identifying TIA outpatients at raised risk of stroke in the medium to long term.

Can ABCD score predict the need for in-hospital intervention in patients with transient ischemic attacks?

Background

The ABCD² score is increasingly being used to triage patients with transient ischemic attack (TIA). Whether the score can predict the need for in-hospital intervention (IHI), other than initiation of antiplatelets and statins, is unknown.

Aims

The ability of the ABCD² score to predict IHI would strengthen the rationale to use it as a decision-making tool. We thus conducted this study to investigate the relationship between the ABCD² score and IHI.

Methods

We analyzed prospectively collected data from consecutive TIA patients over 12 months. We determined ABCD² upon admission and collected the results of in-hospital evaluation, treatments initiated during hospitalization, and follow-up status. We defined IHI as arterial revascularization or anticoagulation required during admission. We used chi-square for trend to examine the association between ABCD² and IHI.

Results

We studied 121 patients. Fourteen (12%) had small infarcts on diffusion magnetic resonance imaging; 38 (31%) had a new risk factor recognized during admission [hyperlipidemia (n = 9), hypertension (1), diabetes (1), carotid stenosis ≥ 50% (16), other arterial occlusive lesions (7), and potential cardioembolic source (4)]. Their percentages increased with higher ABCD² scores. However, among 12 patients (10%) with IHI, ABCD² score categories were equally distributed (10% in 0–3, 9% in 4–5, and 10% in 6–7; p = 0.8). One patient (0.8%) worsened during hospitalization; none had a stroke during follow-up.

Conclusion

Patients with an ABCD² score ≤ 3 had an equal chance of requiring IHI as those with a score of 4–7. The decision to admit TIA patients based on the ABCD² score alone is not supported by our experience and requires further study.

Systematic review and pooled analysis of published and unpublished validations of the ABCD and ABCD2 transient ischemic attack risk scores

BACKGROUND AND PURPOSE

The ABCD system was derived to predict early risk of stroke after transient ischemic attack. Independent validations have reported conflicting results. We therefore systematically reviewed published and unpublished data to determine predictive value and generalizability to different clinical settings and users.

METHODS

Validations of the ABCD and ABCD2 scores were identified by searching electronic databases, reference lists, relevant journals, and conference abstracts. Unpublished tabulated data were obtained where available. Predictive value, expressed as pooled areas under the receiver operator characteristic curves (AUC), was calculated using random-effects meta-analysis, and analyses for heterogeneity were performed by categorization according to study setting and method.

RESULTS

Twenty cohorts were identified reporting the performance of the ABCD system in 9808 subjects with 456 strokes at 7 days. Among the 16 studies of both the ABCD and ABCD2 scores, pooled AUC for the prediction of stroke at 7 days were 0.72 (0.66 to 0.78) and 0.72 (0.63 to 0.82), respectively (P diff=0.97). The pooled AUC for the ABCD and ABCD2 scores in all cohorts reporting relevant data were 0.72 (0.67 to 0.77) and 0.72 (0.63 to 0.80), respectively (both P<0.001). Predictive value varied significantly between studies (P<0.001), but 75% of the variance was accounted for by study method and setting, with the highest pooled AUC for face-to-face clinical evaluation and the lowest for retrospective extraction of data from emergency department records.

CONCLUSION

Independent validations of the ABCD system showed good predictive value, with the exception of studies based on retrospective extraction of nonsystematically collected data from emergency department records.

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.

Validation and refinement of the ABCD2 score: a population-based analysis

BACKGROUND AND PURPOSE

Transient ischemic attacks are a frequent diagnosis in the emergency department setting, yet expert opinion as to the proper follow-up and need for hospitalization differs widely. Recently, an effort has been made to risk-stratify patients presenting with transient ischemic attacks through scoring systems such as the ABCD and ABCD2 scales. The aim of our study was to independently validate these scores using a population-based cohort.

METHODS

Using the data from the Rochester Stroke and Transient Ischemic Attack Registry and resources of the Rochester Epidemiology Project, medical records of all residents of Rochester, Minn, with a diagnosis of incident transient ischemic attack from 1985 through 1994 were examined (N=284). Patients were scored on the ABCD and ABCD2 scales and new scores were created by adding hyperglycemia and a history of hypertension. The end points of stroke and death were collected previously and were verified through the Rochester Epidemiology Project data.

RESULTS

Although our study did find that scores >4 had a statistically significant predictive value for future stroke, a substantial proportion of strokes within 7 days (9 of 36 cases [25%]) occurred in patients with low or intermediate risk scores (< or =4) on the ABCD2 scale. Including history of hypertension and hyperglycemia on presentation increased the sensitivity of the score to identify patients who had a stroke within 7 days.

CONCLUSIONS

Reliance on the ABCD and ABCD2 scores misses some patients who will have a stroke within 7 days of a transient ischemic attack. Adding hyperglycemia and a history of hypertension to the predictive model could be useful, but the value of these additions need to be evaluated further.

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.

Clinical- and imaging-based prediction of stroke risk after transient ischemic attack: the CIP model

BACKGROUND AND PURPOSE

Predictive instruments based on clinical features for early stroke risk after transient ischemic attack suffer from limited specificity. We sought to combine imaging and clinical features to improve predictions for 7-day stroke risk after transient ischemic attack.

METHODS

We studied 601 consecutive patients with transient ischemic attack who had MRI within 24 hours of symptom onset. A logistic regression model was developed using stroke within 7 days as the response criterion and diffusion-weighted imaging findings and dichotomized ABCD(2) score (ABCD(2) >/=4) as covariates.

RESULTS

Subsequent stroke occurred in 25 patients (5.2%). Dichotomized ABCD(2) score and acute infarct on diffusion-weighted imaging were each independent predictors of stroke risk. The 7-day risk was 0.0% with no predictor, 2.0% with ABCD(2) score >/=4 alone, 4.9% with acute infarct on diffusion-weighted imaging alone, and 14.9% with both predictors (an automated calculator is available at http://cip.martinos.org). Adding imaging increased the area under the receiver operating characteristic curve from 0.66 (95% CI, 0.57 to 0.76) using the ABCD(2) score to 0.81 (95% CI, 0.74 to 0.88; P=0.003). The sensitivity of 80% on the receiver operating characteristic curve corresponded to a specificity of 73% for the CIP model and 47% for the ABCD(2) score.

CONCLUSIONS

Combining acute imaging findings with clinical transient ischemic attack features causes a dramatic boost in the accuracy of predictions with clinical features alone for early risk of stroke after transient ischemic attack. If validated in relevant clinical settings, risk stratification by the CIP model may assist in early implementation of therapeutic measures and effective use of hospital resources.

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.

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.