Non-cardioembolic TIA and ischemic stroke: Implications of severity

Our purpose was to explore major vascular and bleeding outcomes in relation to risk and severity scores (ABCD2 or NIHSS) in patients with transient ischemic attack (TIA) or acute ischemic stroke (AIS).

This nationwide observational study was based on data from 4 national registries. Outcomes were assessed by Kaplan-Meier and Cox regression analyses.

The total cohort comprised 21 268 patients (median age 73 years, 47.6% females). Based on ABCD2-score, the TIA-population (n = 10 174) was divided into low-risk (0-3 p, n = 3463) and high-risk (4-7 p, n = 6711). Based on NIHSS-score, the AIS-population (n = 11 454) was divided into minor (0-5 p, n = 8596), moderate (6-10 p, n = 1630) and severe (≥11 p, n = 1228). During follow-up (mean 1.7 years), the composite endpoint of stroke, myocardial infarction or death occurred in 3572 (16.5%) of all the patients, and major bleeding in 668 (3.1%) patients. Using low-risk TIA as reference, the adjusted hazard ratios (HR, 95% CI) of the composite endpoint were 1.41 (1.23-1.62) for high-risk TIA, 1.94 (1.70-2.22) for minor, 2.86 (2.45-3.34) for moderate and 4.18 (3.57-4.90) for severe stroke. When analyzed separately, the association with increased risk remained significant for stroke and death, but not for myocardial infarction. The HR of major bleeding were 1.31 (0.99-1.73) for high-risk TIA, 1.49 (1.13-1.95) for minor, 1.54 (1.08-2.21) for moderate and 2.10 (1.44-3.05) for severe stroke.

This study confirms the association between severity of the index ischemic stroke and risk of future major vascular and bleeding events, and highlights the increased risk also for patients with high-risk TIA.