Elsevier

The Lancet Neurology

Volume 9, Issue 11, November 2010, Pages 1060-1069
The Lancet Neurology

Fast track — Articles
Addition of brain and carotid imaging to the ABCD2 score to identify patients at early risk of stroke after transient ischaemic attack: a multicentre observational study

https://doi.org/10.1016/S1474-4422(10)70240-4Get rights and content

Summary

Background

The ABCD2 score improves stratification of patients with transient ischaemic attack by early stroke risk. We aimed to develop two new versions of the score: one that was based on preclinical information and one that was based on imaging and other secondary care assessments.

Methods

We analysed pooled data from patients with clinically defined transient ischaemic attack who were investigated while in secondary care. Items that contribute to the ABCD2 score (age, blood pressure, clinical weakness, duration, and diabetes), other clinical variables, carotid stenosis, and abnormal acute diffusion-weighted imaging (DWI) were recorded and were included in multivariate logistic regression analysis of stroke occurrence at early time intervals after onset of transient ischaemic attack. Scores based on the findings of this analysis were validated in patients with transient ischaemic attack from two independent population-based cohorts.

Findings

3886 patients were included in the study: 2654 in the derivation sample and 1232 in the validation sample. We derived the ABCD3 score (range 0–9 points) by assigning 2 points for dual transient ischaemic attack (an earlier transient ischaemic attack within 7 days of the index event). C statistics (which indicate discrimination better than chance at >0·5) for the ABCD3 score were 0·78 at 2 days, 0·80 at 7 days, 0·79 at 28 days, and 0·77 at 90 days, compared with C statistics for the ABCD2 score of 0·71 at 2 days (p=0·083), 0·71 at 7 days (p=0·012), 0·71 at 28 days (p=0·021), and 0·69 at 90 days (p=0·018). We included stenosis of at least 50% on carotid imaging (2 points) and abnormal DWI (2 points) in the ABCD3-imaging (ABCD3-I) score (0–13 points). C statistics for the ABCD3-I score were 0·90 at 2 days (compared with ABCD2 score p=0·035), 0·92 at 7 days (p=0·001), 0·85 at 28 days (p=0·028), and 0·79 at 90 days (p=0·073). The 90-day net reclassification improvement compared with ABCD2 was 29·1% for ABCD3 (p=0·0003) and 39·4% for ABCD3-I (p=0·034). In the validation sample, the ABCD3 and ABCD3-I scores predicted early stroke at 7, 28, and 90 days. However, discrimination and net reclassification of patients with early stroke were similar with ABCD3 compared with ABCD2.

Interpretation

The ABCD3-I score can improve risk stratification after transient ischaemic attack in secondary care settings. However, use of ABCD3 cannot be recommended without further validation.

Funding

Health Research Board of Ireland, Irish Heart Foundation, and Irish National Lottery.

Introduction

Transient ischaemic attack (TIA) is associated with high risk of early recurrent stroke, with stroke rates as high as 35% in some subgroups by 7 days.1 Clinical prediction scores such as the ABCD2 score (age ≥60 years [1 point]; blood pressure ≥140/90 mm Hg [1 point]; clinical features of weakness [2 points] or speech impairment [1 point]; duration of symptoms ≥60 min [2 points] or 10–59 min [1 point]; diabetes mellitus [1 point]) have been developed to improve early stroke risk stratification after TIA1, 2, 3 and have been recommended for use in international guidelines.4, 5, 6 Although not intended to replace clinical judgment in the assessment of individual patients, the ABCD2 score provided clinically useful risk stratification in independent cohorts from Oxfordshire, UK, and California, USA, and in a recent meta-analysis of several other validation studies.2, 7

The ABCD2 score was originally intended for use at the initial assessment of patients with suspected TIA by primary care and emergency department physicians to help with triage decisions for hospital admission and urgent referral to specialist stroke services.1, 2, 3 The score deliberately does not include information that is often obtained from initial investigations done in secondary care, including carotid and brain imaging and electrocardiography (ECG), which might provide additional predictive information.6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 The need to develop a version of the ABCD2 score for use in secondary care was recognised in the report of the initial derivation and validation of the score;1 this extended version of the score would allow inclusion of information from initial diagnostic investigations that might be useful for prognosis.9, 11, 12, 13, 14, 15, 16, 17, 18, 19

In addition to the ABCD2 items, several other variables might be useful markers of unstable vascular disease that is associated with high risk of early stroke after TIA. Recent earlier TIA has been associated with high risk of early stroke, possibly because of repeated emboli, poor collateral circulation, or impaired cerebral autoregulation.4, 20, 21 Carotid stenosis has been associated with increased stroke risk after TIA, probably because of recurrent embolisation from unstable carotid plaques.9, 12, 22 Acute diffusion-weighted imaging (DWI) hyperintensity after TIA has been associated with predictors of stroke risk and early stroke in several studies, but statistical power has been inadequate to allow reliable integration of DWI with other predictors.14, 15, 16, 17, 23 Inclusion of these variables might improve the ability of the ABCD2 score to identify patients who can be safely treated without hospital admission and those who require intensive measures to prevent and treat early stroke recurrence.14, 15, 16

We aimed to assess whether the ABCD2 score could be developed to improve prediction of stroke on the basis of preclinical information (ABCD3) and after completion of initial investigations in secondary care settings (ABCD3-I).

Section snippets

Participants

We did a pooled international multicentre analysis of patients with TIA. For the derivation sample, centres with large numbers of patients with TIA who had early DWI and were followed up were identified from studies of specialist-treated patients in hospital-based settings, and lead investigators were invited to include data from individual patients for analysis. Follow-up was done in person, by telephone interview, or by medical chart review; follow-up periods varied across studies. Inclusion

Results

3886 patients were included in the study: 2654 in the derivation sample and 1232 in the validation sample. Table 1 and the webappendix (pp 2–3) describe the clinical characteristics of the patients. Eight centres from Europe and North America contributed data to the derivation sample; seven centres contributed data from patients admitted to hospital and one from patients who visited a 7-day TIA clinic that was run by a stroke specialist.8, 12, 15, 17, 19, 30, 31, 32 In the derivation sample,

Discussion

Our data show the value of recent TIA, carotid stenosis, and acute DWI hyperintensity as markers for the identification of patients with TIA who are at high risk of stroke as early as 2 days after assessment (panel). We found that patients with symptomatic carotid stenosis, recent earlier TIA, and DWI abnormality were at 3–7 times higher risk of stroke, after adjusting for other known risk factors for early recurrence (table 3 and table 6). The high risk of stroke within 7 days of symptom onset

References (42)

  • JD Easton et al.

    Definition and evaluation of transient ischemic attack: a scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease

    Stroke

    (2009)
  • MF Giles et al.

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

    Stroke

    (2010)
  • BL Cucchiara et al.

    Is the ABCD score useful for risk stratification of patients with acute transient ischemic attack?

    Stroke

    (2006)
  • O Sheehan et al.

    A population-based study of ABCD2 score, carotid stenosis, and atrial fibrillation for early stroke prediction after TIA: the North Dublin TIA Study

    Stroke

    (2010)
  • A Fothergill et al.

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

    Stroke

    (2009)
  • AW Asimos et al.

    Early diffusion weighted MRI as a negative predictor for disabling stroke after ABCD2 score risk categorization in transient ischemic attack patients

    Stroke

    (2009)
  • F Purroy et al.

    Patterns and predictors of early risk of recurrence after transient ischemic attack with respect to etiologic subtypes

    Stroke

    (2007)
  • R Sciolla et al.

    Rapid identification of high-risk transient ischemic attacks: prospective validation of the ABCD score

    Stroke

    (2008)
  • S Prabhakaran et al.

    Impact of abnormal diffusion weighted imaging results on short-term outcome following transient ischemic attack

    Arch Neurol

    (2007)
  • H Ay et al.

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

    Stroke

    (2009)
  • SB Coutts et al.

    Triaging transient ischemic attack and minor stroke patients using acute magnetic resonance imaging

    Ann Neurol

    (2005)
  • Cited by (257)

    View all citing articles on Scopus
    View full text