Injury Due to Stroke Can Be Reversed

Embargoed for Release On or After March 29, 2000

Roxanne Yamaguchi Moster
(310) 794-0777
([email protected])

UCLA RESEARCHERS FIND NEW BRAIN IMAGING EVIDENCE THAT INJURY DUE TO STROKE CAN BE REVERSED

In a pioneering study, UCLA researchers have demonstrated for the first time that early injury to the human brain due to a stroke can be reversed by rapidly reopening blocked blood vessels with clot-busting drugs. They report that all patients in their study showed dramatic improvement.

The UCLA findings, published in the April issue of the Annals of Neurology, employed new magnetic resonance imaging (MRI) techniques to show that early clot-busting treatment can reverse initial brain injury in stroke patients. Although preliminary, the findings provide important insight into the dynamic nature of brain tissue injury during a stroke and its potential resulting through timely stroke treatment.

The researchers say no previous report has so uniformly shown reversal of stroke damage and linked that reversal to thrombolytic therapy. UCLA researchers demonstrated that lesion growth due to stroke could be arrested or even partially reversed with thrombolytic treatment and that MRI offers a method to monitor treatment response in individual patients.

Stroke is a "brain attack," cutting off vital blood and oxygen to the brain cells that control everything from speaking to walking to breathing. Most strokes occur when arteries are blocked by blood clots or by the gradual build-up of plaque and other fatty deposits. Some strokes can be caused by arteries rupturing when weak spots on the blood vessel wall break.

Seven patients in the UCLA study were treated with intra-arterial thrombolysis, a procedure in which a catheter is positioned in obstructing clots in the brain and clot-busting drugs are infused directly into the clot to dissolve the obstruction. Serial magnetic resonance images obtained before and after treatment showed that reopening the blocked blood vessels not only prevented further injury, but also reversed injury and cell swelling that had already occurred.

Prior to stroke treatment, all seven patients suffered from stroke symptoms ranging from limb weakness to difficulty in speaking. Once treatment was administered, all showed significant improvement.

"This dramatic observation confounds the previously conventional view that injured areas of the brain viewed on diffusion magnetic resonance images could not be reversed, and re-emphasizes the importance and benefits of early stroke thrombolytic treatment," said Dr. Jeffrey Saver, a study co-investigator and Neurology Director of the UCLA Stroke Center.

The researchers say their findings may have important implications for acute stroke management in the future, because early assessment of the extent and reversibility of stroke is needed to guide appropriate stroke intervention treatments. The researchers say there is a recognized need for objective neuroimaging methods to identify the best candidates for treatment and to monitor individual patient response to therapy. They confirm that diffusion MRI assessment of patients may help doctors increase the time frame for safely administering thrombolytic therapy for some patients.

Intravenous stroke thrombolytic treatment is of proven benefit for the treatment of acute ischemic stroke within three hours of the onset of stroke symptoms, and intra-arterial thrombolytic therapy shows promise up to six hours after stroke symptoms begin, according to UCLA researchers. Treatment of most patients, however, is limited by the narrow time frame recommended for initiation of therapy.

"Imaging could extend the time window available for treatment in some patients by allowing doctors to treat a physiologic clock rather than a time clock, said Dr. Chelsea Kidwell, the study's lead author and associate director of the UCLA Stroke Unit. "This MRI data enables doctors to identify what brain tissue is and isn't salvageable."

The UCLA study uniquely obtained pre- and post-MRI scans of all seven patients and synchronized early post-treatment MRI scans to thrombolytic treatment time, providing a snapshot of the brain's physiology at uniform time points across the different patients. The study provides new physiological insights into the way the human brain responds to rapid re-establishment of blood flow. The UCLA researchers suggest more studies to include larger numbers of patients undergoing thrombolytic therapy may allow more precise delineation of MRI markers of irreversible injury and of savageability.

Every year, stroke strikes approximately 730,000 Americans - killing 160,000 and forever changing the lives of those who survive. New treatments can help stop brain damage and disability, if symptoms are recognized and immediate medical attention is sought.

The UCLA Stroke Center is dedicated to research, patient care and education regarding all aspects of stroke. The Center includes a multidisciplinary team of researchers and clinicians from UCLA's divisions of emergency medicine, neurology, neurosurgery, neuro-rehabilitaion and radiological sciences.

In addition to Kidwell and Saver, other study authors include Jeffry R. Alger, Ph.D., Dr. Gary Duckwiler, Dr. Y. Pierre Gobin, Dr. Reza Jahan, Dr. Mary Kalafut, James Mattiello, PhD, Dr.Sidney Starkman, Dr. Paul Vespa and Dr. Fernando Vinuela, all members of the UCLA Stroke Center.

-UCLA-