Findings of DAWN trial may influence treatment of stroke
Results of the DAWN trial published in the New England Journal of Medicine shows that clot removal up to 24 hours after stroke led to significantly reduced disability for properly selected patients.
The international multi-center DAWN trial randomized 206 patients of acute stroke who arrived at the hospital within six to 24 hours to either standard medical therapy alone or to endovascular clot removal therapy plus standard care.
It is currently recommended that clot removal should be done only within 6 hours of stroke onset of stroke.
Patients were selected for the trial based on brain imaging (diffusion-weighted MRI or perfusion CT) to assess the extent of irreversible brain damage plus clinical criteria to help decide if thrombectomy would help the patient even if he/she arrives after 6 hours but within 24 hours, rather than just using the 6-hour window as the cut-off.
Almost 50% of patients with stroke due to occlusion of the intracranial internal carotid artery or proximal middle cerebral artery and who had a mismatch between the severity of the clinical deficit and the infarct volume, who underwent clot removal reported significant decrease in disability at 90 days post- treatment. On the other hand, only 13.1% patients who received medical treatment showed such reduction in disability. Decrease in disability means more independence in activities of daily life. Mortality and other safety end-points were similar between the two groups.
“Time is brain”. The trial abides by this and re-emphasizes the importance of reaching the hospital as early as possible after the onset of stroke. The findings of the trial though may influence management of some selected patients who present to the hospital late, outside the 6-hour window period. “Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy.”
The DAWN trial is published online November 11, 2017 in the New England Journal of Medicine.