Population-Based Study of Capsular Warning Syndrome and Prognosis After Early Recurrent TIA

Abstract

Conclusions: Capsular warning syndrome comprises 1.5% of transient ischemic attack (TIA) presentations but has a poor prognosis, with a 7-day stroke risk of 60%. With the exception of capsular warning syndrome, recurrent TIAs ≤7 days are not associated with a greater stroke risk than a single TIA. Summary: Stroke risk after TIA is highest within the first 7 days (Hill MD et al, Neurology 2004;62:2015-20). In addition, many guidelines recommend urgent evaluation for carotid stenosis for patients with more than two TIAs ≤7 days (Johnston SC et al, Ann Neurology 2006;60:301-13). Capsular warning syndrome, manifested by multiple stereotype motor TIAs, is thought to place patients at particular risk and precedes capsular infarction (Donnan GA et al, Neurology 1993;43:957-62). However, it is unclear whether patients with multiple TIAs have relatively untreatable or treatable underlying pathologic conditions such as carotid stenosis or atrial fibrillation. The authors used data from the Oxford Vascular Study (OXVASC) to delineate whether patients with multiple TIAs are at high early stroke risk and whether a treatable underlying condition is more common in patients with multiple TIAs. They studied clinical characteristics, acute STROKE treatment (TOAST) classification, and risk of stroke in 1000 consecutive patients with incident and recurrent TIAs as part of the prospective, population-based Oxford Vascular Study. Of the 1000 patients with TIAs, 170 had a further TIA ≤7 days (105 ≤24 hours). Multiple TIAs were not associated with carotid stenosis or atrial fibrillation. Much of the 10.6% (95% confidence interval [CI], 6.5%-15.9%) risk of stroke in the first 7 days after the an initial TIA was due to patients with small-vessel disease (SVD) etiology (10 of 24 vs 8 of 146; odds ratio, 12.3; 95% confidence interval, 3.7-41.9; P = .0001), particularly in those with motor weakness (ie, 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 = .03). The 7-day risk of stroke after 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%]; odds ratio, 0.58; 95% CI, 0.25-1.3; P = .20). All of the nine patients with stroke after a capsular warning syndrome had recurrent TIA ≤24 hours after the first TIA, and the subsequent stroke occurred ≤72 hours of the second TIA in eight patients. The ABCDE2 scores of all preceding TIAs were ≤4 in all nine patients with capsular warning syndrome before their stroke. Comment: The data point out that not all TIAs have the same prognosis for stroke. In particular, multiple TIAs without association with large-vessel disease may have the worst prognosis of all. The implication is that the emphasis on recurrent TIAs in many societal guidelines scores may not be justified. At least in this study, multiple TIAs were not associated with medically (atrial fibulation) or surgical (cervical carotid stenosis) correctable conditions. Patients with capsular warning syndrome should have treatment emphasis on hydration, antiplatelet, and anticoagulation therapies and, perhaps, thrombolysis rather than a search for an underlying surgically correctable large-vessel problem.