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01-10-2009 | Stroke | Article

Prodromal TIA heralds one in eight ischemic strokes



MedWire News: Ischemic stroke is preceded by a transient ischemic attack (TIA) – or “warning stroke” – in one out of eight cases, a cohort study suggests.

The finding suggests that more intensive management of patients with TIA might be able to prevent at least some cases of ischemic stroke in the general population.

Longitudinal studies with active surveillance have shown that the risk for stroke in the 3 months following TIA is high, at approximately 17%, but it is unclear how often stroke is preceded by TIA.

To investigate, a team led by Daniel Hackam (University of Western Ontario, Canada) used data from the Registry of the Canadian Stroke Network to ascertain the frequency, characteristics, and outcomes of acute stroke patients with a prior TIA.

Of 16,409 consecutive patients with a final diagnosis of acute stroke in the Registry, just 2032 (12.4%) had a prior TIA.

Prior TIA was more frequent in patients with a large artery ischemic stroke (20.5%) and less frequent in those with hemorrhagic stroke (4.6%), Hackam’s team reports in Neurology journal.

Patients with a prior TIA also tended to be older than those without a prior TIA and were more likely to have diabetes, hypertension, atrial fibrillation, angina, peripheral arterial disease, and heart failure.

Furthermore, patients without prior TIA were significantly more likely to die during hospitalization (15.2% vs 12.7%) than those without TIA, experience an inhospital cardiorespiratory arrest (4.8% vs 3.1%) or seizure (2.7% vs 1.5%), and were less likely to be discharged to home (40.1% vs 43.1%).

Indeed, a lack of prior TIA predicted poor prognosis after multivariate adjustment, a finding that may be explained by a lack of ischemic preconditioning, say the study authors.

“In summary, only 1 in 8 patients with acute stroke had a previous TIA,” Hackam and co-authors conclude.

“Widely implemented urgent TIA clinics might therefore prevent a small but significant fraction of the current stroke burden. In addition, these data highlight a need for risk profiles that accurately identify and stratify individual risk for first stroke.”

MedWire ( is an independent clinical news service provided by Current Medicine Group, a part of Springer Science+Business Media. © Current Medicine Group Ltd; 2009

By Joanna Lyford