Patients who wake up in the morning with stroke symptoms, and therefore do not know what time their stroke began, are not routinely eligible for clot-busting treatment, which can only be used within 4.5 hours after symptoms start.
The WAKE-UP trail, which was led in the UK by the university of Glasgow, saw doctors use two types of MRI scan to figure out when a stroke started. The first scan, called diffusion weighted imaging (DWI), shows early changes in the brain after stroke, whereas changes take several hours to become obvious in the second type of scan, called fluid-attenuated inversion recovery (FLAIR). If changes are visible on one type of scan (DWI) but not the other (FLAIR), then a patient’s stroke is likely to have happened in the preceding 4.5 hours.
Doctors used these scans to select patients they thought would benefit from treatment with clot-busting drug altephase. This treatment gave a significantly higher rate of full or nearly-full recovery three months after the stroke: 53 per cent of patients treated with alteplase made a full or nearly-full recovery compared to 42 per cent in the placebo group, representing an absolute increase of 11.5 per cent. This means that for every nine people treated, one extra person made a complete recovery.
Professor Keith Muir, SINAPSE chair of clinical imaging at the university’s Institute of Neuroscience & Psychology, was chief investigator and coordinator of the trial in the UK. He said: “Clot-busting drug treatment is effective only in the first few hours after a stroke, so it has not been possible up until now to treat patients when the stroke happens during sleep, for example. This involves as many as one in five people affected by a stroke.
“The WAKE-UP trial proves that we can use MRI scanning effectively as a timer, and that treating people with an MRI pattern indicating likely onset in the preceding few hours is highly beneficial.
“The trial should significantly increase the opportunities for treatment in stroke. Around 1 in 3 of the patients enrolled in the trial had the MRI signature of recent onset, and could be expected to be eligible for treatment that they have been unable to receive in the past. This translates into several thousand additional people per year in the UK.
“This important advance brings the possibility of treatment to many more stroke patients, but the challenge is to ensure availability of immediate MRI scanning. Unlike other countries, the UK has very poor access to emergency MRI, so it will need the UK to make immediate access to MRI scanning a priority.”
Every year there are estimated to be over 100,000 strokes in the UK, including over 20,000 in patients with ‘wake-up stroke’ or who otherwise have an unknown time of symptom onset.
The study was published in New England Journal of Medicine and the findings were presented at the European Stroke Organisation Conference (ESOC).