ABCD2/3 Scores Calculator: Assessing Stroke Risk after a TIA

The ABCD2 score is a tool used for risk stratification and prediction of stroke following a transient ischemic attack (TIA). It can help healthcare professionals determine the appropriate course of action and management for patients who have experienced a TIA. Here's information on when and how to use the ABCD2 score:

1. When to Use the ABCD2 Score:
   • The ABCD2 score should be used after a patient has experienced a transient ischemic attack (TIA), also known as a mini-stroke.
   • It is typically used within the first 48 hours after a TIA occurs.
   • The score helps in assessing the short-term risk of stroke following a TIA.
2. How to Use the ABCD2 Score:
   • The ABCD2 score is calculated based on five factors:
   1. Age (A): Assign 1 point if the patient is 60 years or older, 0 points otherwise.
   2. Blood pressure (B): Assign 1 point if the systolic blood pressure is 140 mmHg or higher or the diastolic blood pressure is 90 mmHg or higher, 0 points otherwise.
   3. Clinical features (C): Assign 2 points if the patient had unilateral weakness, 1 point if speech impairment without weakness, and 0 points if other symptoms or no symptoms.
   4. Duration of symptoms (D): Assign 2 points if the symptoms lasted 60 minutes or longer, and 1 point if the symptoms lasted less than 60 minutes.
   5. Diabetes (D2): Assign 1 point if the patient has a history of diabetes mellitus, 0 points otherwise.
   • Each factor is assigned a specific point value, and the total score ranges from 0 to 7.
   • The higher the ABCD2 score, the greater the risk of stroke within the next few days.
   • The score helps in risk stratification, with scores of 4 or higher indicating a higher risk of stroke.
3. Interpretation and Actions Based on the ABCD2 Score:
   • The ABCD2 score provides a general indication of the risk of stroke following a TIA.
   • Based on the score, healthcare professionals can make decisions regarding the need for further investigations, urgent interventions, or preventive measures.
   • Scores of 0-3 usually indicate a low risk of stroke, and patients may receive outpatient evaluation and appropriate follow-up.
   • Scores of 4-5 suggest a moderate risk of stroke, and patients may require urgent evaluation, neuroimaging, and hospitalization for further management.
   • Scores of 6-7 indicate a high risk of stroke, and patients may require urgent intervention, close monitoring, and specialized care.

Additionally, besides the ABCD2 score, there are other scoring systems that can be used for risk stratification and prediction of stroke following a transient ischemic attack (TIA). Two notable examples are the ABCD3 score and the 3-I score. Here's some information on when and how to use them:

1. The ABCD3 Score:
   • The ABCD3 score is an extension of the ABCD2 score and includes additional factors to further refine stroke risk assessment.
   • In addition to the factors considered in the ABCD2 score, the ABCD3 score incorporates the presence of a previous TIA event within a week of the second one (dual TIA) (2 points).
   • The ABCD3 score provides a more detailed risk assessment and can help identify patients at higher risk of stroke after a TIA.
   • Similar to the ABCD2 score, higher ABCD3 scores indicate a greater risk of stroke.
   • Healthcare professionals can use the ABCD3 instead of the ABCD2 score to enhance risk stratification and inform treatment decisions, as the new score includes all the parameters also taken into account in the previous score.
2. The 3-I Score:
   • The 3-I score is another scoring system used for risk prediction following a TIA.
   • The 3-I score incorporates three components: Clinical features, Imaging findings, and Intervention.
   • The Clinical features component assesses factors such as age, blood pressure, and symptoms duration.
   • The Imaging findings component considers the presence of carotid stenosis or an abnormal DWI (Diffusion weighted imaging) on an MRI Scan.
   • The Intervention component evaluates whether immediate intervention, such as carotid endarterectomy or stenting, is planned or indicated.
   • The 3-I score provides a comprehensive assessment of stroke risk, incorporating both clinical and imaging factors.
   • Healthcare professionals can utilize the 3-I score in conjunction with other scoring systems to guide treatment decisions, including the need for urgent interventions.

When determining which scoring system to use, healthcare professionals should consider the available evidence, local guidelines, and institutional protocols. Clinical judgment and expertise are crucial in interpreting the scores and making informed decisions regarding patient management.

It's important to note that while the ABCD2, ABCD3, and 3-I scores are valuable tools, they are not the sole determining factors in assessing stroke risk after a TIA. A comprehensive evaluation, including patient history, physical examination, imaging studies, and consultation with specialists, is essential for appropriate risk assessment and management.

According to one study, approximately 240,000 TIAs (transient ischaemic attacks) are diagnosed annually in the USA, with a similar incidence to that of ischemic strokes ^[3] (data from 2007; in 2023, the CDC reports more than 795,000 annual strokes, with 1/4 being a repeating stroke; 87% are ischemic strokes ^[8]).

According to the CDC, more than half of people with stroke survivors have reduced mobility which is directly caused by the stroke ^[8]. Because the effects of a stroke are long-lasting and irreversible, efforts have been made to reduce the risk of stroke and find ways to predict strokes even before they happen.

After realizing that people at risk of ischemic strokes frequently experience a couple of precursory events before the actual stroke, like TIAs, the ABCD scores were developed. After the first stroke prediction score appeared, there have been numerous updates that can now accurately quantify the risk of stroke up to 90 days before it even happens.

According to one study on 713 patients, of which 90% had a TIA, 24% had a stroke by the 90th day after diagnosis ^[6]. In the group that was judged not to have a true TIA, only 1.4% developed a stroke within the next 90 days after the symptoms initially appeared. Besides this, the ABCD2 scores were higher in the first group, and the score increased proportionately to the risk of stroke, unlike those that didn't actually have a TIA ^[6].

In a study on a much bigger sample size of 13,766 TIA patients (in which the ABCD2 score was calculated retrospectively), results showed that the ABCD2 score had a good sensitivity for predicting stroke, particularly in patients whose score was ≥ 4 ^[4]. Additionally, a significant proportion of patients with a score lower than 4 were found to have a significant (>50%) stenosis of the carotid or AF (atrial fibrillation) (20% of patients overall) ^[4].

A study done in the UK also found out that age, diabetes mellitus, and a history of TIA were significantly associated with a higher risk of developing an ischemic stroke, thus validating the use of the ABCD2 score in stroke prevention ^[5]. They also investigated multiple studies showing the same results: a study done in California demonstrated the above findings ^[9]. Another study done in Canada showed that hypertension was also associated with a higher risk of developing a stroke ^[10], a variable which is also taken into consideration in the ABCD scores.

Another study found out that the score is also well-correlated with the risk of stroke within 2 days and 7 days. Even individual parameters of the ABCD2 score were found to be correlated with stroke risk, although the unified score was better at predicting such an event ^[7].

In conclusion, the ABCD2 score is highly correlated with the risk of stroke, and its use following a TIA is highly recommended for risk stratification and further patient management.