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

Archit Bhatt,Vishal Jani

doi:10.5402/2011/518621

Abstract

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.

Highlights

Approximately 240,000 TIAs are diagnosed in the United States [1]
These data indicate that individual clinical features and presence of high-signal on Diffusion Weighted Imaging abnormalities (DWI) are both critical in adjunct to use of ABCD/ABCD2 scores in predicting short-term post-TIA stroke risk
A study by Quinn et al [12] did not suggest any association of atrial fibrillation (P = .097) and ABCD2 score. These data make it clear that the presence of large artery atherosclerosis and atrial fibrillation cannot be completely predicted by ABCD/ABCD2 score, and their detection may be a key in short-term and long-term risk reduction

Summary

Introduction

Approximately 240,000 TIAs are diagnosed in the United States [1]. TIAs admissions represent approximately 0.3% of ED (Emergency Department) visits [2], and about 23% of strokes are preceded by a history of TIA [3]. Initially developed for prognostic purposes, some studies have assessed the diagnostic value of these rules for TIA [11, 12] These scoring systems are based on simple clinical information that are readily obtained at a first clinical encounter, that is, age, duration, and type of symptoms, and presence of elevated blood pressure or diabetes. The California Rule and the ABCD score (Table 1) were initially developed to predict short-term risk (2 days, 7 days, 30 days, and 90 days) of stroke in TIA patients. They were subsequently combined to create a new rule, called the ABCD2 score (Table 1), with the goal of creating a more comprehensive value [16]. These rules include presence of stroke risk factors like diabetes and hypertension, symptoms—unilateral weakness and speech impairment, and duration of these symptoms, which have shown to have an independent prognostic value because they improve the diagnosis of TIA from non-TIA disorders [17]

Short-Term Risk Prediction with ABCD and ABCD2 Score

ABCD and ABCD2 Scores with the Presence of Noncerebrovascular Diagnosis

Current Role and Limitations of ABCD and ABCD2 Scores

Findings

Conclusion