University of Pittsburgh Medical Center Stroke Institute Begins Study to Extend Limits of tPA Use Following Stroke
PITTSBURGH, February 13, 2001 — Physicians at University of Pittsburgh Medical Center Stroke Institute are beginning a National Institutes of Health (NIH) study using MRI scans to determine whether selected stroke patients may benefit from tissue plasminogen activator (tPA) therapy administered between three and six hours after the onset of a stroke.
The current time window of up to three hours after a stroke significantly limits the number of patients that can receive this important treatment since only a small fraction of stroke patients currently reach the hospital in this time frame. This study hopes to extend the benefits of tPA to many more patients with stroke by selecting those patients beyond three hours who are likely to benefit from this treatment.
TPA is a clot busting drug that is an approved and effective treatment when given intravenously to patients who have strokes due to an artery blockage in the brain (called an ischemic stroke), if the drug can be given within three hours from the onset of symptoms. It dissolves the clot and allows blood flow to the brain to be restored.
"Although tPA is beneficial when administered within three hours of stroke onset, clinical trials have failed to document significant benefits when given beyond that time frame," said Lawrence Wechsler, M.D., professor of neurology and neurosurgery at the University of Pittsburgh School of Medicine, director of the University of Pittsburgh Medical Center Stroke Institute and principal investigator in the study. "MRI imaging may allow us to identify those patients who are likely to benefit from tPA therapy beyond the three hour limit."
The study is called the Diffusion-weighted imaging Evaluation For Understanding Stroke Evolution (DEFUSE) study. If they agree to participate in this research study, patients who are brought to UPMC Presbyterian emergency department and diagnosed as having an ischemic stroke (caused by a blockage), will undergo MRI scanning. The scans will include diffusion-weighted imaging, perfusion-weighted imaging and MRI angiography.
"These are new MRI imaging techniques that show us very early changes in the brain with stroke," Dr. Wechsler said. "Diffusion tells us which part of the brain is already damaged and perfusion tells us which areas of the brain do not have sufficient blood flow. We may be able to save the part of the brain that has abnormal perfusion but not abnormal diffusion."
All eligible patients will receive intravenous tPA therapy immediately following their initial MRI scan, but no later than six hours from the onset of stroke symptoms. A total of 80 patients will be enrolled over three years at five centers nationwide.
Stroke is the third most common cause of death and the leading cause of adult disability in the United States. Some 700,000 Americans suffer a stroke each year; 70 percent are ischemic strokes in which a clot blocks oxygen delivery to a portion of the brain. On average, someone in the United States suffers a stroke every 53 seconds and 160,000 Americans die annually from stroke.
Stroke should be treated as a medical emergency. Symptoms include: weakness or paralysis on one side of the body, numbness or loss of sensation on one side of the body, difficulty with speech or inability to speak, sudden onset of loss of balance or dizziness, and sudden loss of vision in one eye.
The University of Pittsburgh Medical Center Stroke Institute is dedicated to the treatment, prevention and research of strokes and stroke-related conditions. UPMC physicians in a wide variety of specialties join together to provide the very latest techniques for diagnosing and treatment. This multi-disciplinary approach allows them to treat stroke patients and patients at risk for stroke who also suffer from diseases that can lead to stroke, such as heart disease and diabetes.