ABCD 2 Score and 90-Day Stroke Risk After Transient Neurological Events by Diffusion-Weighted Imaging Positivity: An Analysis of Pooled Data From 3 Studies
Koji Tanaka, Shelagh B. Coutts, Raed A. Joundi, Nishita Singh, Toshiyuki Uehara, Tomoyuki Ohara, Kazunori Toyoda, Masatoshi Koga, Junpei Koge, Maximilian B. Bibok, Eric E. Smith, Kazuo Minematsu, Andrew M. DemchukBACKGROUND:
The ABCD 2 score is widely used to stratify stroke risk after transient neurological events. We aimed to evaluate the association between the ABCD 2 score and the risk of subsequent ischemic stroke among patients with diffusion-weighted imaging (DWI)–positive (DWI+) or DWI−negative (DWI−) findings for the index event.
METHODS:
We pooled individual participant data from 3 multicenter cohorts including patients presenting with transient or minor neurological events. Patients presenting with transient neurological symptoms, a normal neurological examination, and available DWI for the index event were included. Associations between the ABCD 2 score and 90-day ischemic stroke risk were analyzed separately in the DWI+ and DWI− groups using logistic regression models adjusted for sex, atrial fibrillation, and study source.
RESULTS:
Among 2014 patients (1143 [56.8%] men; median age 67 years), the median ABCD 2 score was 4 (interquartile range, 3–5), and 504 (25.0%) were DWI+. Ischemic stroke occurred within 90 days in 20 patients (4.0%) in the DWI+ group and 33 (2.2%) in the DWI− group. The ABCD 2 score was associated with stroke risk in the DWI− group (per 1-point increase, odds ratio, 1.36 [95% CI, 1.04–1.79]), but this relationship was not significant in the DWI+ group (per 1-point increase, odds ratio, 1.08 [95% CI, 0.76–1.53]). When stratified ABCD 2 score into 0 to 3, 4 to 5, and 6 to 7, the predicted 90-day stroke risks were 3.2%, 3.9%, and 4.5% in the DWI+ group (per 1-category increase, odds ratio, 1.23 [95% CI, 0.63–2.40]) and 1.0%, 2.3%, and 4.1% in the DWI− group (per 1-category increase, odds ratio, 1.88 [95% CI, 1.11–3.20]), respectively.
CONCLUSIONS:
The ABCD 2 score was associated with 90-day stroke risk among patients with DWI− findings. Patients with both a low ABCD 2 score and DWI− findings had a particularly low risk of subsequent stroke, which may inform risk stratification and clinical decision-making after transient neurological events.