A widely used method for predicting stroke in patients following a transient ischaemic attack (TIA) has limited predictive value, according to a study published in the latest Medical Journal of Australia.
According to the researchers, TIA carries a high risk of subsequent stroke, and it is desirable to identify TIA patients at high risk of stroke. The ABCD2 score (Age, Blood pressure, Clinical features, Duration and Diabetes), which was developed for this purpose, has poor predictive value for early stroke after transient ischaemic attack (TIA) in patients presenting to Australian tertiary hospitals if used alone.
Assoc Prof Velandai Srikanth, Head of the Stroke and Ageing Research Group and Stroke Physician in the Department of Neurology at Southern Health in Melbourne, and co-authors, examined, the predictive value of the ABCD2 score for the early risk of stroke in Australian patients presenting with TIA.
The authors conducted a cohort study of 512 consecutive patients with suspected TIA referred by the emergency department to the acute stroke unit of an urban tertiary referral hospital between June 2004 and November 2007.
Assoc Prof Srikanth said that the findings showed that the ABCD2 score, by itself, had poor clinical predictive value for stroke within 90 days of TIA.
“The use of cut-off scores previously recommended in Australia may lead to almost half of TIA patients being misclassified as being at low risk of stroke,” Assoc Prof Srikanth said.
“There may be no substitute for careful and rapid clinical evaluation and individualizing management based on the underlying stroke mechanisms, paying particular attention to factors such as atrial fibrillation (irregular heart) and carotid artery stenosis.”
Of 301 patients with confirmed TIA, most had a complete follow-up. Stroke had occurred in 1.37 per cent of these patients at two days, and 2.42 per cent at 90 days.
At a cut-off score of five or greater, as recommended in Australian guidelines, the ABCD2 score had only modest specificity for stroke within two days and 90 days, and poor positive predictive values and positive likelihood ratios. The score performed similarly poorly at other pre-specified cut-off scores.
The Medical Journal of Australia is a publication of the Australian Medical Association.
Source: Medical Journal of Australia