Ultrasound Could Help Limit Stroke Damage
An ER nurse's observation led to study of the possibility
WEDNESDAY, Nov. 17, 2004 (HealthDayNews) -- A sharp-eyed observation by an emergency room nurse has led to the possibility of a new way to limit the damage suffered by people who have strokes, researchers report.
It happened at the University of Texas-Houston Medical School about five years ago, when Dr. Andrei V. Alexandrov, newly arrived from the University of Toronto, was using ultrasound technology to monitor the progress of stroke patients treated with tissue plasminogen activator (tPA), a clot-dissolving drug that had just been given approval by the U. S. Food and Drug Administration for use against strokes (it had been approved for use in heart attacks more than a decade earlier).
The nurse, Patti Bratina, noticed that many of the patients being monitored by Alexandrov were making remarkable recoveries, regaining use of their limbs and other faculties much faster than could be expected. Perhaps, she suggested, ultrasound had something to do with that.
Alexandrov, now an associate professor of neurology at the Houston medical school, picked up on the suggestion. He and his colleagues began studies, the latest of which has just been reported in the Nov. 18 issue of the New England Journal of Medicine, showing that Bratina was right. That study found a "strong and significant" beneficial effect of ultrasound for stroke patients, Alexandrov said.
The study included 126 patients who suffered ischemic strokes, in which a blood clot blocks a major brain artery. All were treated with tPA. Half received continuous ultrasound exposure, while the other half did not.
"Dramatic clinical improvement" -- specifically, a complete reopening of the blocked artery within two hours after tPA administration -- occurred in 49 percent of the patients exposed to ultrasound, compared to 30 percent of those who weren't exposed, the researchers report. Three months later, 42 percent of the patients who got ultrasound had favorable outcomes, compared to 29 percent of those who didn't.
The study results are best described as "promising," said Dr. Andrew M. Demchuk, an associate professor of neurology at the University of Calgary, who trained with Alexandrov in Houston and took part in the study.
"This data should be carefully discussed," Demchuk said. "It is not definitive, but it does demonstrate a relationship between ultrasound and promotion of clot breakup."
A larger study, to include several hundred patients, is being planned in hopes of getting definitive proof of the value of ultrasound for stroke patients, Demchuk and Alexandrov said. Meanwhile, there are several practical considerations standing in the way of its everyday use.
Most large hospitals have ultrasound equipment, but usually not in the emergency room. It is perhaps best known as the technique that lets parents-to-be see images of an unborn child. And "there are not enough skilled operators to deliver this kind of combination therapy for stroke patients," Alexandrov explained.
He and his colleagues are working to develop an ultrasound machine that would not require a highly skilled operator. They have also prepared tutorials to help train medical personnel to use the currently available technology in stroke treatment. "It takes one to six months of daily use to become skilled," Alexandrov said.
To explain how ultrasound can help break up a blood clot, he uses the analogy of a spoonful of sugar in a cup of water. "The sugar goes to the bottom and dissolves very slowly," he said. "If you take a spoon and stir, it dissolves faster. Ultrasound is that harmless spoon."
Patti Bratina, who started it all, is not working at the University of Texas-Houston Medical School just now. She is at home, looking after her twin babies.
Ultrasound technology and its medical uses are explained by the Radiological Society of North America.