Background Many guidelines recommend urgent intervention for patients with 2 or more transient ischaemic attacks (TIAs) within 7 days irrespective of ABCD2 score, perhaps in recognition of capsular warning syndrome (CWS). However, whether all patients with multiple TIAs are at high early risk of stroke is unknown.
Methods We studied clinical characteristics of all incident and recurrent TIAs and subsequent stroke in a population-based study (Oxford Vascular Study) from 2002 to 2009. Aetiology of TIA was categorised using the TOAST classification.
Results Of 703 patients with TIA, 105 had a further TIA within 7 days (70 within 24 h). Subsequent risks of stroke in these patients at 7, 30 and 90 days after the second TIA were 11.4%, 13.3% and 14.3% respectively, which were similar to those after a single TIA (7 day risk: 12/105 vs 57/598 p=0.67). The risk of stroke at 7 days was highest after recurrent TIAs of small vessel origin (7/17 vs 5/88, OR 11.62, 95% CI 2.6 to 53.9, p=0.00003). Of these seven cases with stroke following recurrent small vessel TIA, all had the recurrent TIA within 24 h after the first TIA, and the subsequent stroke occurred within 24 h of the second TIA in five, consistent with CWS. The ABCD2 score of the second TIA was six in four cases and ≥4 in six of the seven cases.
Conclusions Recurrent TIA within 7 days is not associated with a greater stroke risk than after a single TIA, other than in the CWS. The ABCD2 score appropriately classifies these high-risk small vessel TIAs.