Medicine Can Limit Damage From Strokes But It’s Deadly For Some Patients
For the first time, a study has shown that it’s possible to reduce the damage strokes cause.
But experts aren’t yet ready to recommend the treatment for widespread use because it involves a perilous balance between risks and benefits.
The medicine is tissue plasminogen activator - TPA a genetically engineered protein that is already a mainstay of heart attack therapy.
About 500,000 Americans suffer strokes annually. They are the leading source of adult disability and the No. 3 cause of death after heart disease and cancer. Until now, there has been no proven treatment to limit the damage in the first hours after they occur.
A European team reported Friday that TPA significantly reduces the amount of brain injury resulting from strokes if given quick- ly after the onset of symptoms - but only when reserved for a carefully selected group of patients, probably half to three-quarters of all victims.
The difficulty of deciding precisely who these patients are is likely to curtail its widespread use, at least until experts sort out better guidelines for emergency-room doctors.
The dilemma for doctors is simple: If given to the right patients, TPA can prevent a lifetime of paralysis and other crippling disabilities. If given to the wrong ones, it can trigger bleeding in the brain that makes the strokes even worse.
“The patients who we really want to treat benefit a lot. Treating those who we don’t want to can be a disaster,” said Dr. Werner Hacke of the University of Heidelberg in Germany, the study’s director.
The study was conducted on 620 stroke patients who were given TPA within six hours of the start of their symptoms. The results were released at a conference sponsored by the American Heart Association.
Most strokes occur when a blood clot lodges in the brain, cutting off circulation. However, about 20 percent result when a blood vessel bursts. TPA is a natural protein that works by dissolving clots.
In their study, the doctors intended to treat only those whose strokes resulted from clots. They performed CT scans first and excluded patients whose strokes had already resulted in large areas of dying brain tissue.
When they looked at the 511 patients who met these criteria, TPA was clearly beneficial. While their death rate was about the same, they suffered less brain damage. Forty-one percent of them suffered little or no lingering effects from their strokes, compared with 29 percent who got dummy injections.
However, it turned out later that 109 patients had been let into the study by mistake. Most of them already had large areas of damaged brain tissue. And for them, TPA was more dangerous.
Thirty-five percent of these patients who unintentionally got TPA died, compared with 21 percent with equally severe disease who were not treated.
“It’s not a home run. The ques tion is whether it’s a double or a single,” commented Dr. David Sherman of the University of Texas in San Antonio.
Dr. James Grotta of the University of Texas in Houston, who is participating in a similar U.S. study, said he believes TPA eventually will become a routine therapy.
“This is extremely encouraging,” Grotta said. “It is a giant step, although we cannot at this point recommend this drug for everyone with stroke.”
xxxx Deadly mix-up The study mistakenly included 109 patients. Thirty-five percent of these patients died, compared with 21 percent with equally severe disease who were not treated.