Prediction of early stroke risk in transient symptoms with infarction: relevance to the new tissue-based definition.

BACKGROUND AND PURPOSE The risk of stroke shortly after transient ischemic attack with infarction on diffusion-weighted images, also known as transient symptoms with infarction (TSI), is substantially higher than is the risk after imaging-normal transient ischemic attack. We sought to assess the utility of a Web-based recurrence risk estimator (RRE; http://www.nmr.mgh.harvard.edu/RRE/) originally developed for use in patients with ischemic stroke for predicting 7-day risk of stroke in patients with TSI. METHODS We calculated RRE and ABCD² scores in a retrospective series of 257 consecutive patients with TSI diagnosed by diffusion-weighted images within 24 hours of symptom onset. We defined subsequent stroke as clinical deterioration associated with new infarction spatially distinct from the index lesion. We assessed the predictive performance of each model by computing the area under receiver-operating characteristics curve. RESULTS Over 7-day follow-up, 16 patients developed a recurrent stroke (6.2%). The sensitivity and specificity of an RRE score of ≥ 2 for predicting 7-day stroke risk were 87% and 73%, respectively. The area under the receiver-operating characteristics curve was 0.85 (95% CI, 0.78-0.92) for RRE and 0.57 (95% CI, 0.45-0.69) for ABCD² score (z-test; P<0.001). CONCLUSIONS The RRE score seems to predict 7-day risk of stroke after a TSI. If further validated in larger data sets, the RRE score could be useful in identifying high-risk patients with TSI who may benefit from early intervention with targeted stroke prevention strategies.