Nearly one in eight patients who have an ischaemic stroke have a transient ischaemic attack (TIA) at some point in the previous seven days, according to a study published this week, indicating the need to treat TIA as a medical emergency to improve the prevention of subsequent stroke.
The study, which looked at data on 2416 patients who presented with a recent ischaemic stroke, showed that 549 (23%) had a history of a preceding TIA. Of these patients nearly half (43%) had had a TIA in the seven days before their stroke; and 17% of the TIAs occurred on the day of the stroke and 9% on the previous day. For nearly three quarters of these patients (70%) this was their first ever TIA (Neurology 2005;64: 817-20).
Figure 1.
Magnetic resonance angiogram of the neck of a stroke patient
Credit: SIMON FRASER/NEWCASTLE HOSPITALS NHS TRUST/SPL
Peter Rothwell, professor of clinical neurology at the University of Oxford and one of the authors of the study, said: “We have known for some time that TIAs are often a precursor to a major stroke. But there have previously been few data on the time window between TIA and stroke. Our results indicated that patients with TIA were at increased risk of ischaemic stroke in the next few days and required assessment and preventive treatment within this time frame.”
The patients in the study came from two population based studies (the Oxford vascular study and the Oxfordshire community stroke project) and two randomised trials (the UK TIA aspirin trial and the European carotid surgery trial). In each study patients were assessed by a neurologist and details of any previous TIAs were obtained from the patients and their medical records. Almost half of the most recent TIAs and about a third of the first TIAs occurred in the two weeks before the presenting stroke. Further results showed that in 92% of cases the stroke occurred in the same vascular territory as the stroke.
To prevent strokes, clinical guidelines should be changed to reflect the need for prompt intervention in patients having a TIA, Professor Rothwell said.