New model for predicting stroke outcome

A new model incorporating imaging and clinical assessment could more accurately predict patients' outcome after stroke, conclude authors of a study in this week's issue of THE LANCET. The accurate assessment of prognosis in the first hours of stroke is desirable for best patient management, as it is often not clear for some days after stroke onset how patients are likely to fare. Patients with initially similar clinical deficits can improve dramatically or worsen during the first two or three days. Alison Baird and colleagues from the National Institutes of Health, Bethesda, USA, aimed to assess whether the extent of ischaemic brain injury on magnetic resonance diffusion-weighted imaging (MR DWI) could provide additional prognostic information to clinical factors.

In a three-phase study, the investigators studied 66 patients from a North American teaching hospital who had: MR DWI within 36 hours of stroke onset; the National Institutes of Health Stroke Scale (NIHSS) score measured at the time of scanning; and the Barthel Index measured no later than 3 months after stroke. They used statistical assessment to derive a predictive model for good recovery; this model was applied to an independent series of 63 patients from an Australian teaching hospital. They then developed a three-item scale for the early prediction of stroke recovery.

Combined measurements of the NIHSS score, time in hours from stroke onset to MR DWI, and the volume of ischaemic brain tissue on MR DWI gave the best prediction of stroke recovery. The model was externally validated on the Australian sample. Three likelihood levels for stroke recovery-low (0-2), medium (3-4), and high (5-7)-were identified on the three-item scale.

The investigators comment that their results show that a new technology (MR DWI) can potentially add to early clinical management both in terms of improved diagnostic accuracy and improved efficiency.

Contact: Dr Steven Warach, Section on Stroke Diagnostics & Therapeutics, Stroke Branch, National Institute of Neurological Disorders & Stroke, 36 Convent Drive, MSC 4129, Room 4A03, Bethesda, MD 20892 - 4129, USA; T) +1 301 896 4003; F) +1 301 480 0413; E) WarachS@ninds.nih.gov

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