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Posted on: Honolulu Advertiser Health By Beverly Creamer On a double row of computer monitors
suspended above the patient, Dr. Felix Song watches the progress as he
manipulates a catheter thin as a paper clip into a small cut in the patient's
leg and up through the arterial pathways of his body to a clot deep inside
the man's brain.
The surgical theater at the Queen's With deliberate and delicate moves, Song
guides the catheter up through the patient's body until it stops just short
of the clot. Then, with a syringe connected to the catheter at its entry
point, he is ready to send the clot-busting drug TPA (tissue plasminogen
activator) deep inside the brain and dribble it with pinpoint accuracy onto
the blockage. "It's like putting something directly
into a clogged drain," said Song, O'ahu's only interventional
neuro-radiologist and a member of the stroke team at the Queen's Neuroscience
Institute. TPA which breaks up clots was
heralded as a breakthrough in stroke therapy when it was introduced here in
1996. Now this new delivery technique is another leap forward. It gives the
added precision of attacking only the damaging clot, with fewer side effects,
such as unexpected bleeding in other areas of the brain. Not everyone is a candidate for TPA
therapy. Reasons not to administer the drug include: if the patient is on
blood thinners or has suffered head trauma or a recent bleeding incident.
"We know patients can benefit, but we have to be very careful who we use
it on," said Dr. Cherylee Chang, director of the Neuroscience Institute
at Queen's. The new technique also opens the window
for TPA treatment wider than was previously considered effective. In the
past, TPA was only considered to be useful if it could be administered by IV
within three hours of the stroke's onset. With the new intra-arterial TPA
technique, treatment can be given with equally good results up to six hours
after the stroke. "You give just enough drug to open
everything and then you stop," said Song. "That way you use less
TPA, minimize side effects, and, within a few minutes, can confirm if it's
open." "Intra-arterial" TPA (also
called intra-cranial) administered by an interventional neuro-radiologist is
the latest dramatic improvement in stroke treatment since TPA was introduced
five years ago. "In a lot of ways this is
better," said Song, who in the year and a half he's been in "And if you do intra-arterial you
can do other fancy things. For instance, if there's a narrowing of the
artery, you can open it up or physically remove the clot with balloon
angioplasty (making the artery wider through the use of some device, usually
a balloon)." "It opens a whole new world for
people," said Song. "People who are too sick for surgery or have
other factors that make it too risky for surgery." A second physician trained in this
specialty will join the staff of Said the "It is a better therapy. The
difficulty we have on
Timing is crucial In the five years since TPA began
changing the outlook for some stroke victims, But, too often, strokes go unnoticed or
are dismissed as something else, or hidden by stroke sufferers reluctant to
admit what's happening to them with the result that too few people are
getting to the hospital in time to receive TPA treatment. "We're still missing the education
component," said Dr. Melvin Wong, a stroke neurologist who practices at Wong said that a program called
Operation Stroke is spending big money for TV ads in other states to make the
public aware of how quickly they need to reach a hospital. That's not
happening to the same extent here. Don Weisman, a spokesman for the
American Heart Association, which heads Operation Stroke, said there's little
money available for advertising and the organization must depend on public
service announcements, which are donated by radio and TV stations on a
limited basis, along with spreading the word at community health fairs where
people are also screened free for stroke risk. Another approach is to find
sponsors in the private sector willing to pay the air time for such
announcements, Weisman said. Strokes are a major killer nationally,
with an estimated 600,000-750,000 people suffering a potentially crippling or
life-threatening attack each year. Many more are hit by silent strokes that
may never be diagnosed but leave subtle memory problems, and place the person
at high risk for further brain attack. Only some can benefit There are essentially two types of
stroke: ischemic, caused by a blood clot, and accounting for from 70-83
percent of the total; and hemorrhagic, caused by a rupture of a vessel, which
then spills blood into brain tissue. Only the first can be treated with TPA. "TPA is not meant to be a drug
that's going to help everyone," said Wong. "It's only supposed to
help a small portion of the patients who come in." One patient who had the good fortune to
receive TPA within an hour of her stroke is Sally Antonio, a "The first person in the hallway, I
grabbed her and started talking, but my speech was already slurred,"
remembers Antonio, 53. "I knew what was happening but I couldn't say any
words anymore." By a lucky coincidence, Antonio works
with Kaiser chief of neurology Dr. Stuart Pang, who had her rushed
immediately to the emergency room. "I am very lucky," said Antonio.
"Everything was done right away." Doctors are convinced TPA works.
"We kept statistics initially (on TPA use) to see if it was helping
patients," said Pang. "When we found it did, we didn't follow up
with it. The majority who do take it have some improvement." Drug carries risks But the drug is not without risks.
National statistics put the death rate among those treated with TPA at
between 17 and 21 percent. The Queen's rate is about 19 percent. The primary concern is that the
clot-busting drug can promote internal bleeding in other areas of the brain.
That can be of special concern for older stroke patients who may have
suffered other small bleeds that have gone unrecognized. Pang said while there have been bleeds
with TPA at Kaiser, so far none has been the cause of death. According to two national studies
published recently in the Journal of the American Medical Association, half
of the patients receiving TPA nationally suffered complications because of
deviations from treatment guidelines. The drug was either given later than
the three-hour window of opportunity after a stroke, or to patients who
should never have had it because of other factors. Even though TPA therapy is becoming more
precise, researchers continue to look for what Chang calls a "magic
pill" to protect brain tissue from damage with either kind of stroke.
Queen's has participated in several clinical trials testing hopeful drugs,
but nothing yet has proven effective. "There have been at least 100
medications that have looked great in animals," said Chang, "and we
still haven't found any that are effective and safe in humans. We've tried
four (that were unsuccessful) and now we're trying a fifth." This one involves a chemical agent
called an AMPA antagonist meant to minimize the damage to brain tissue when
oxygen is cut off. "When we know there's a lack of
oxygen in the brain, there's a domino effect in the brain tissue where little
chemicals in the cells start an injury pattern which spreads inside the
tissue," said Chang. "The AMPA antagonist tries to block those
injury signals so it keeps the stroke smaller in size." Another trial involves cooling patients
by inserting a catheter in the bloodstream that contains tiny balloons filled
with a cool saline solution. As blood flows over this stationary item, it
becomes cooler, too. "Potentially, cooling patients may
help protect the brain as well. It works great in animals," said Chang,
"but we'll see." Most common warning signs of a stroke
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