Following an acute ischemic stroke – the kind caused by a blood clot – treatment to restore blood flow to the brain must be started as soon as possible. Every passing minute without treatment increases the likelihood of irreversible brain injury. The current time window for the only drug approved by the Food and Drug Administration (FDA) to treat stroke is 3 hours from symptom onset.
A new study will explore whether neuroimaging can be used to identify stroke patients who have salvageable brain tissue and are likely to benefit from therapies that open up blocked arteries up to 8 hours after the onset of stroke symptoms. The study is funded through the American Recovery and Reinvestment Act (ARRA) by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH).
The project will build upon findings from the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution, or DEFUSE study. The new program, called DEFUSE 2, is led by principal investigator Gregory Albers, M.D., director of the Stanford Stroke Center at Stanford University. The researchers will use magnetic resonance imaging (MRI) to scan patients who have had an acute ischemic stroke and are treated with clot-busting therapies.
Patients in the study will receive a clot-dissolving drug called tissue plasminogen activator (t-PA) and/or intra-arterial reperfusion therapy, which involves using mechanical devices to remove blood clots from the brain. Currently two devices are approved by the FDA for intra-arterial reperfusion therapy but clinicians have not yet identified the optimal candidates for this procedure.
Investigators in the first DEFUSE study found that MRI data identified a subgroup of people who appeared to benefit from therapy beyond the 3-hour time window. The goals for DEFUSE 2 are to validate that MRI profiles may help predict a patient's clinical response to opening blocked blood vessels within 3 to 8 hours following the onset of stroke symptoms. Secondly, the study aims to demonstrate that a computer-assisted analysis of MRI data can be performed quickly and accurately throughout multiple clinical sites using scanners made by different manufacturers. Researchers plan to enroll 100 patients over 2 years at several U.S. academic stroke centers.
Dr. Albers said, "We believe that the study will demonstrate that specific MRI findings can identify a large subgroup of patients who benefit from therapies that restore blood flow to the brain many hours after symptom onset." Such findings may eventually lead to effective therapies for a large population of stroke patients currently ineligible for treatment, and could substantially reduce stroke-related disability.
NINDS (www.ninds.nih.gov) is the nation's primary supporter of biomedical research on the brain and nervous system.
More information about NIH's ARRA grant funding opportunities can be found at http://grants.nih.gov/recovery/. To track the progress of HHS activities funded through the ARRA, visit www.hhs.gov/recovery. To track all federal funds provided through the ARRA, visit www.recovery.gov.
Last updated December 23, 2013