Population-based study of capsular warning syndrome and prognosis after early recurrent TIA

Abstract

Objective: Many guidelines recommend emergency assessment for patients with ≥2 TIAs within 7 days, perhaps in recognition of the capsular warning syndrome. However, it is unclear whether all patients with multiple TIAs are at high early risk of stroke and whether treatable underlying pathologies are more prevalent in this group.

Methods: We studied clinical characteristics, Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification, and risk of stroke in 1,000 consecutive patients with incident and recurrent TIAs in a prospective, population-based study (Oxford Vascular Study).

Results: Of 1,000 patients with TIAs, 170 had a further TIA within 7 days (105 within 24 hours). Multiple TIAs were not associated with carotid stenosis or atrial fibrillation, and much of the 10.6 (95% confidence interval [CI] 6.5-15.9) risk of stroke during the 7 days after the first TIA was due to patients with small-vessel disease (SVD) etiology (10 of 24 vs 8 of 146, odds ratio [OR] = 12.3, 95% CI 3.7-41.9, p < 0.0001), particularly those with motor weakness (i.e., capsular warning syndrome) compared with hemisensory events (9 of 15 [60%], 95% CI 35.3-84.7 vs 1 of 9 [11.1%], 95% CI 0-31.7, p = 0.03). The 7-day risk of stroke after a recurrent TIA was similar to the risk after a single TIA in patients with non-SVD TIA (8 of 146 [5.5%] vs 76 of 830 [9.2%], OR = 0.58, 95% CI 0.25-1.3, p = 0.20). Of the 9 patients with stroke after a capsular warning syndrome, all had the recurrent TIA within 24 hours after the first TIA, and the subsequent stroke occurred within 72 hours of the second TIA in 8. The ABCD2 scores of all preceding TIAs were ≥4 in all 9 patients with capsular warning syndrome before stroke.

Conclusions: Capsular warning syndrome is rare (1.5% of TIA presentations) but has a poor prognosis (7-day stroke risk of 60%). Otherwise, recurrent TIA within 7 days is not associated with a greater stroke risk than that after a single TIA.

Figure 1. Seven-day stroke risk after the first TIA in single and recurrent TIA of lacunar and nonlacunar type

Figure 2. Thirty-day stroke risk after the first TIA in those with recurrent TIA and capsular warning syndrome, ≥50% symptomatic carotid stenosis, atrial fibrillation (AF), or neither of these etiologies