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Stroke Drug Still Meets Resistance from Doctors Wary
of Its Risks
May 6, 2005 - Forty percent of emergency physicians
say they're unlikely to give stroke patients the only FDA-approved drug
- tPA - shown to improve their prognosis, even in an ideal setting,
mostly because of the fear of causing brain bleeding.
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Researchers Seek Answers to Gender Difference in
Stroke Symptoms
Women most often late to emergency room, most likely
to die
April 28, 2005 - What does it feel like to have a stroke? For some
people, the ability to speak or walk disappears in a moment. For others,
arms, legs and faces suddenly go numb. And for others, its a rush of
confusion or dizziness. Those differences could help explain things that
have puzzled stroke specialists for years: why women often get to the
emergency room too late for stroke treatment, and why theyre more
likely to die or be disabled by their stroke than men.
Read more...
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But the majority of the doctors surveyed said that
if they had appropriate backup from neurologists and a brain scanner
available to help them diagnose and treat appropriate patients, they'd
give the drug, called tPA. And if the risk of bleeding associated with
tPA could be reduced, more physicians said they'd use it.
The findings are from a newly published survey of
1,105 emergency physicians conducted by University of Michigan Stroke
Program researchers and published early online in the Annals of
Emergency Medicine. The authors say it shows there's still controversy
over the use of tPA, or tissue plasminogen activator -- and a long way
to go to improve access to the therapy.
The authors also emphasize that safe and
appropriate use of tPA should involve team-based approaches, where
neurologists, radiologists and other specialists work with emergency
physicians to diagnose stroke and choose the best treatment.
In fact, the authors predict that tPA use will
increase as hospitals increasingly form stroke teams and write plans for
what to do when a stroke patient comes through the emergency department
door. Primary Stroke Centers are now recognized by the main hospital
accreditation organization, JCAHO; U-M is one of the nation's 113
centers certified so far.
"This survey shows that there's still major
resistance to tPA use in the emergency medicine community, but we
shouldn't blame ED physicians or ask them to handle this decision
alone," says lead author Devin Brown, M.D., a U-M stroke neurologist.
"Only through team decision-making will we be able to change current
practice and improve acute stroke care delivery."
Used within the first three hours of a stroke's
onset, tPA can break up the blood clots that cause 80 percent of all
strokes (known as ischemic). This can restore blood flow in the brain,
and reduce or prevent the risk of permanent damage. But tPA also carries
a 1-in-15 risk of causing intracranial hemorrhage (bleeding) that can be
fatal. Nearly 10 years after its approval by the FDA, tPA is still only
used in about 10 percent of patients eligible to receive it, and in
about 2 percent of all stroke patients.
Emergency stroke care should be more like trauma
care, says study co- author and U-M Emergency Medicine chair William
Barsan, M.D. He notes, "Not every hospital is a trauma center, but every
hospital knows what to do when a trauma patient arrives -- and that
response may entail treatment or transfer."
"If a hospital is going to treat strokes, it should
have the specialists and standard protocols in place to make the care
the best it can be, including appropriate tPA use," he continues. "But
if a hospital can't make that commitment, it should transfer stroke
patients or make it known to EMS agencies that stroke patients should be
directed elsewhere." Barsan treated the first patient ever to receive
tPA, during a clinical trial while he was at the University of
Cincinnati in the early 1980s. He also co-chaired a National Institutes
of Health consensus conference on acute stroke treatment.
Stroke is the third most common cause of death in
the United States, and the leading cause of disability. More than
700,000 Americans suffer strokes each year, and about 170,000 of them
die.
The survey is the first and largest of its kind. It
was sent to 2,600 randomly selected members of the American College of
Emergency Physicians, and asked doctors how likely they'd be to use tPA
in an ideal patient if they had access to a computed tomography (CT)
machine and specialists to consult with. CT scans can show immediately
whether a stroke is caused by a clot or by a bleeding blood vessel; tPA
can kill if given to patients with bleeding strokes.
The survey also asked them what would be the
maximum risk of intracranial hemorrhage they'd tolerate from tPA, and
what would be the lowest acceptable improvement in patients'
neurological state that would convince them tPA was beneficial enough to
warrant the bleeding risk. The authors performed cross- analyses of
answers according to physician age, gender, training background, year of
medical school graduation and type of hospital and population center.
In all, 40 percent of the physicians said it was
very unlikely, unlikely or uncertain that they would give tPA to an
ideal patient in an ideal setting. Thirty-six percent said it was likely
they would give the drug, and the remaining 24 percent said they were
very likely to give it.
When asked why they wouldn't give tPA, 65 percent
of the reluctant or resistant physicians cited the concern over
hemorrhage, 23 percent said they didn't perceive that the drug would
provide benefit, and 12 percent gave both reasons.
In all, the physicians set an average upper limit
of 3.4 percent intracranial hemorrhage risk as acceptable, and an
average lower limit of neurological improvement of 40 percent. Those who
were unlikely to use tPA set the bar higher: They wanted a maximum
bleeding risk of 2.1 percent and a benefit of 45 percent relative
improvement. Currently, research shows tPA bleeding risk to be about 6.4
percent, and its benefit to range from a 30 percent to 50 percent
greater chance of complete or almost-complete recovery. Bleeding risk
from clot-busting therapy for heart attack is 1 percent.
There was no significant difference among doctors
in urban, rural and suburban settings, or teaching and non-teaching
hospitals. Women doctors were twice as likely as men to be willing to
use tPA.
Interestingly, 30 percent of all the physicians
said that their own personal experience with tPA had influenced their
answers on the survey -- including 30 percent of those who said they'd
be likely to use tPA in an ideal setting, and 29 percent of those who
said they wouldn't. "It appears that individual anecdotal experience is
influencing decision-making, when it should be the medical literature
that leads the way," says Brown.
No matter what, Brown and her colleagues say, it
will be important to find alternatives or additions to tPA. She cites
current and planned clinical trials of drugs that may reduce the risk of
hemorrhage, such as beta blockers or other adjuvant drugs, or new
experimental clot-busters.
"According to those surveyed, risk from tPA would
have to be cut in half before more doctors would use it," says Barsan.
"Now, we need to get to that lower risk level. In the meantime, leaving
the ED physician as the at-fault person is not what needs to be done.
Just like with major trauma it's not just one doctor, it's a system --
and you need dedication and teamwork to have a system that works."
The study was funded internally by the U-M Health
System. In addition to Brown and Barsan, the study's authors are Lynda
Lisabeth, Ph.D., a research investigator in the U-M Department of
Neurology; Lewis Morgenstern, M.D., director of the U-M Stroke Program
and a stroke neurologist, and Michael Gallery, Ph.D. of ACEP.
Source: University of Michigan Health System
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