TIA Stroke Risk ABCD² Score

Predicts chances of stroke at 2, 7 and 90 days after a transient ischemic attack.

In the text below the calculator there is more information about the score and about TIA evaluation and management.


The ABCD2 score predicts risk of stroke in patients who have just suffered a transient ischemic attack, based on TIA duration and clinical features and on patient data (age, blood pressure and personal history of diabetes).

The administration of the score stratifies patients in risk groups, which in turn helps clinicians tailor TIA evaluation and initiate antithrombotic therapy if necessary.


Each of the five items in the ABCD2 score is awarded a number of points, depending on the individual prediction value.

The final score is associated with three types of score risks and stratifies patients in low, moderate and high risk groups.

ABCD2 score Risk group Stroke risk
2-day 7-day 90-day
0 - 3 Low 1.0% 1.2% 3.1%
4, 5 Moderate 4.1% 5.9% 9.8%
6, 7 High 8.1% 11.7% 17.8%

1

Age

2

Blood pressure

3

Clinical features

4

Duration of TIA symptoms

5

Diabetes history

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ABCD2 explained

After a transient ischemic attack, the patient is at risk of suffering from stroke. This is a risk prediction and stratification tool based on TIA characteristics and patient data:

ABCD2 item Answer choices (points) Description
Age 60 or more (1)
Less than 60 (0)
The higher the age, the greater the stroke risk.
Blood pressure SBP >140 mmHg or DBP >90 mmHg (1)
SBP <140 mmHg or DBP <90 mmHg (0)
The two values represent the cut-off for hypertension.
Clinical features Unilateral weakness with or without speech impairment (2)
Speech impairment without weakness (1)
Other symptoms (0)
These characteristics help determine the severity of the ischemic attack.
Duration of TIA symptoms Less than 10 minutes (0)
Between 10 and 59 minutes (1)
60 minutes or more (2)
Diabetes history Yes (1)
No (0)
Diabetes mellitus is one of the main risk factors for diabetes.

This stratification method has been criticised in numerous studies, in one of the latest having recorded a poor performance (low sensitivity and low specificity in ER setting). Therefore, clinical judgment should prevail and the score can continue to be used in outpatient (non-emergency) settings.

There are other prediction tools, like this prognosis calculator for TIA patients, that consists of similar stroke risk factors.

 

Score interpretation

The five items in the ABCD2 score are weighted depending on their contribution to stroke risk prediction.

The total score ranges between 0 and 7 and is associated with a risk group and stroke risk percentages at 2, 7 and 90 days after the transient ischemic attack:

ABCD2 score Risk group Stroke risk
2-day 7-day 90-day
0 - 3 Low 1.0% 1.2% 3.1%
4, 5 Moderate 4.1% 5.9% 9.8%
6, 7 High 8.1% 11.7% 17.8%

Patients classified in the low risk group and who don’t have any other concurrent conditions (e.g. atrial fibrillation) may be treated ambulatory.

Patients in the moderate risk group are likely to require hospitalization, even if they don’t have any concurrent conditions that may increase risk of stroke.

Patients in the high risk group should be hospitalized and initiated on antithrombotic therapy.

One opinion about the model is that high scores, rather separate patients with clear diagnosis of TIA from patients with alternative diagnoses (e.g. seizure, migraine or other nonvascular spells), than predict high risk of stroke occurrence.

 

About the study

The 2007 study by Johnston et al. was aimed at validating existing California and ABCD scores and deriving a new prediction model for 2-day stroke risk.

A cohort of 2,893 patients, diagnosed with TIA in ER units and clinics across the US and the UK, was separated in four independent groups. Logistic regression was used to identify the relevant variables.

The new score performed well in validation with c statistics: 0.62 - 0.83 and was deemed to be likely the most predictive of the current prognosis scores.

 

TIA evaluation and management

Evaluation and appropriate management of patients who are diagnosed with transient ischemic attack is capital in reducing the risk of stroke.

According to the National Stroke Association Guidelines:

■ Initial evaluation should take place within 12 hours of ischemic episode occurring;

■ Laboratory tests that should be performed include full blood count, serum electrolytes, fasting blood glucose, creatinine, lipids;

■ EKG should take place within 48 hours of TIA;

■ Brain imaging study via computed tomography or MRI within 48 hours;

■ Vascular imaging via carotid imaging, CT or MR angiography, or transcranial Doppler.

In patients deemed at risk of stroke, antithrombotic therapy is to be initiated and depends on the type of TIA (atherothrombotic or cardioembolic). Hypertension also requires medication and the patient should be advised towards a physical activity schedule, smoking cessation and a healthy diet.

In the case of patients with TIA caused by high grade internal carotid artery stenosis, surgical endarterectomy is scheduled.

 

Original source

Johnston SC, Rothwell PM, Nguyen-Huynh MN, Giles MF, Elkins JS, Bernstein AL, Sidney S. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007; 369(9558):283-92.

Validation

Josephson SA, Sidney S, Pham TN, Bernstein AL, Johnston SC. Higher ABCD2 score predicts patients most likely to have true transient ischemic attack. Stroke. 2008; 39(11):3096-8.

Other references

1. Rothwell PM, Giles MF, Flossmann E, Lovelock CE, Redgrave JN, Warlow CP, Mehta Z. A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack. Lancet. 2005; 366(9479):29-36.

2. Sanders LM, Srikanth VK, Blacker DJ, Jolley DJ, Cooper KA, Phan TG. Performance of the ABCD2 score for stroke risk post TIA: meta-analysis and probability modeling. Neurology. 2012; 79(10):971-80.


App Version: 1.0.1

Coded By: MDApp

Specialty: Neurology

System: Nervous

Objective: Risk Prediction

Type: Score

No. Of Items: 6

Year Of Study: 2007

Abbreviation: ABCD2

Article By: Denise Nedea

Published On: June 23, 2017 · 09:25 AM

Last Checked: June 23, 2017

Next Review: June 23, 2018