Short -and Long- Term Prognoses After Tissue-Negative Transient Ischemic Attack

Abstract

Background: The tissue-based definition of transient ischemic attack (TIA), which requires the use of Diffusion-Weighted Imaging (DWI), has limitations in its applicability to clinical practice.This contributes to the limited evidence regarding the risk of subsequent stroke and the associated predictors in the group of patients who are tissue-negative on DWI.. Our aim was to assess the early and long-term prognosis of consecutive tissue-negative TIA patients attended at an emergency department

Methods: We carried out a prospective cohort study of consecutive patients with neurologist-confirmed TIA who were DWI-negative from January 2006 to June 2010. All patients underwent DWI on MRI (4.0 [SD 1.8] days) after the index event. The risk and predictors of SR were determined at 1 year and after a median follow-up time of 6.6 (interquartile range, 5.0-9.6) years.

Results: A total of 370 patients were included. Previously, 244 patients with positive DWI results and 109 patients without MRI performed were excluded. ABCD2 score>5 was determined in 95 (26.2%) patients. 15 (4.1%) patients suffered SR at 1 year and 18 (4.9%) beyond 1 year. Predictive models for short-term and long-term prognosis were different. Large artery atherosclerosis etiology (Hazard ratio [HR] 3.7 [1.2-11.0]) was the only predictor of 1 year SR. In contrast, male sex (HR 4.17 [95% CI 1.14-15.23]; P=0.031), speech impairment (HR 4.90 [95% CI 1.05-22.93]; P=0.044), and presence of chronic microangiopathy expressed as Fazekas score of 3 (HR 1.84 [95% CI 1.15-2.97]; P=0.012) were predictors of long-term SR follow-up.

Conclusion: DWI-negative patients have a clinically-important risk of recurrent vascular events and SR during medium and long-term follow-up. These patients warrant optimized secondary prevention to reduce their risk of recurrent vascular events over time. Predictors of SR varied over the follow-up.