DETROIT - Stroke patients with brain changes caused by a lack of blood flow, as detected by CT scan, should not be excluded from treatment with the clot-dissolving drug t-PA, concluded a Henry Ford Hospital study published in this week's Journal of the American Medical Association.
"What we found was that patients who were treated with t-PA did better whether or not they had early ischemic changes in their brains on CT scans," said lead author, Suresh C, Patel, M.D., head of the Division of Neuroradiology at Henry Ford Hospital.
"The ischemic changes seen on the CT scan are not critical to the decision of whether or not to treat a t-PA candidate within three hours of stroke symptoms, except to exclude patients with intrracranial hemorrhage," he added.
CT scans (computed tomography) are used to exclude from the use of t-PA patients who may have intracranial hemorrhage because the assumed risk that the clot-dissolving drug would promote further bleeding and damage. But clinical trials for thrombolytic treatment carried out in Europe excluded patients if CT scans showed ischemic changes or swelling in the brain citing increased morbidity and mortality from increased bleeding. However, the European trials were carried out using a six hour treatment window and not the three hours used in the NINDs study.
The study found otherwise: "We could not detect an association with an increase risk of adverse outcome ... after t-PA treatment. In our study, after adjusting for baseline variables, patients treated with t-PA fared better whether or not they had EIC (early ischemic changes) on CT scans."
Each year, about 600,000 Americans suffer a stroke, which is a major cause of long-term disability. Most strokes are ischemic - caused by a blood clot that reduces blood flow to the brain. The remaining 20 percent are hemorrhagic, caused by bleeding within the brain. Stroke ranks as the third leading cause of death in the country after heart disease and cancer, killing about 160,000 Americans each year and major cause of disability.
In 1995, the National Institute of Neurological Disorders and Stroke (NINDS) t-PA Stroke Study Group, reported that carefully selected stroke patients who received t-PA treatment within three hours of their initial stroke symptoms were at least 30 percent more likely than untreated patients to recover from their stroke with little or no disability after three months and this benefit was sustained for one year. The group, comprised of eight clinical centers, was coordinated by the Henry Ford Health Sciences Center, the research arm of Henry Ford Health System.
The drug t-PA, (tissue plasminogen activator) works by dissolving blood clots that block brain arteries and cause more than 80 percent of all strokes. Thrombolytic therapy with t-PA is the only approved treatment for ischemic stroke if patients are brought to the emergency department within three hours of treatment and meet NINDS guidelines.
The Henry Ford study analyzed CT scans from 624 patients enrolled in the 1995 study.
Also co-authoring the study from Henry Ford is Mei Lu, Ph.D., from the Department of Biostatistics and Epidemiology and Christopher Lewandowski, M.D., from the Department of Emergency Medicine.
Journal
JAMA