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Brain attack. It’s a term commonly applied to
stroke. Strokes occur when the blood vessels to the
brain become narrowed, clogged, or rupture, resulting
in the lack of blood flow to brain cells. Thanks to
the collaborative efforts of several local physicians,
Chattanooga is being heralded as a community model nationwide
for acute stroke treatment and prevention.
Included in this team of local “stroke busters”
are neurologist
Dr. Thomas Devlin, neurosurgeon Dr. Phil Megison and
radiology interventionalist, Dr. Blaise Baxter.
What they face in their efforts to manage brain attack
is daunting. The earlier one reaches the hospital, the
better the outcome. Currently the only FDA approved
therapy for stroke, tPA, requires the patient receive
the therapy within three hours of onset of symptoms.
Once that three-hour “golden window” closes,
tPA is no longer a viable treatment option.
VAMPIRE BAT SPIT
“Before tPA became a treatment option, all our
attention was focused on rehab and preventing future
strokes,” acknowledges neurologist Dr. Thomas
Devlin. Hence “the huge push forcoming up with
better devices and better drugs. Once such drug, Desmoteplase,
is now in the clinical trial phase.
Desmoteplase is a clot-busting substance derived from
the saliva of vampire bats. Its newfound value to humans?
When the bat bites an animal, a powerful clot-dissolving
secretion in its saliva allows it to drink its victim’s
blood freely. Although the drug is still being evaluated
worldwide, Erlanger’s stroke program enrolled
the first person in the U.S. study and is currently
number one in the nation in number of enrollees. Preliminary
results look promising.
“Desmotaplase is the most exciting stroke treatment
trial going on in the world today,” states Dr.
Devlin. Unlike tPA, it works only at the site of the
clot, eliminating increased risk of bleeding. Best of
all, says the local specialist, it has the potential
to be administered as long as nine hours after the onset
of stroke.
BsLOOD-CHILLING, A “COOL” PROTOCOL
Another revolutionary treatment for stroke stems from
an earlier clinical study called the “Cool-Aid
Trial.” Erlanger was one of only five (stroke)
centers in the world participating in this trial, according
to Dr. Devlin, who hails it a “landmark study.”
This hypothermic treatment basically involves lowering
the temperature of one’s blood in order to salvage
the brain. “What you want to do when the brain
becomes hyper-excited, and the nerves are wildly firing,
is to quiet this activity as quickly as possible,”
explains Dr. Devlin. By inserting a chilled catheter
into the femoral vein, the surrounding blood is cooled
as it flows to the brain – thus limiting the extent
of injury. This “cool” protocol has become
so successful it is now being used in the treatment
of cardiac arrest as well, reports Dr. Devlin.
COILING
Due to the expertise of radiological interventionalists
like Chattanooga’s Dr. Blaise Baxter and another
unique procedure known as “coiling,” many
local residents have received a new lease on life.
“Once an aneurysm has ruptured it becomes deadly,
so most of our work is pre-hemorrhage,” says Dr.
Baxter. What his “work” involves is threading
a catheter up from a leg artery into the brain aneurysm.
A tiny platinum coil, similar to a miniature Slinky,
is then maneuvered through a microcatheter and positioned
inside the aneurysm - causing it to clot, seal itself
off from connecting arteries and preventing more blood
from getting in and making the aneurysm burst.
“Think of a balloon at the end of a garden hose,”
Dr. Baxter explains. “We pack the coil into that
‘balloon’ so it completely frames the outside
part of the aneurysm. There’s no ill effect on
the body. It stays forever and all that’s required
after that are periodic angiograms to ensure the coil
has stayed in place.”
Even bleeding aneurysms have been successfully treated
by coiling, reports the local doctor. “Medicines
delivered intravenously to a hemorrhaging aneurysm can
be slow,” says the radiologist. “Time is
of the essence and the more brain we can salvage (using
this method) the better,” he says, noting that
his team can also “mechanically retrieve a clot
and pull it out through the catheter.”
Well tolerated by all age groups, the coiling procedure
is continually being refined. “We’re now
able to use new techniques to deal with more difficult
(aneurysm) shapes,” he says. Most importantly,
reports Dr. Baxter, Chattanooga’s team of specialists
“can customize and tailor the treatment to meet
the needs of the patient.”
BRAIN SURGERY
Not all aneurysms, obviously, can be treated via catheters
or coils. Local neurosurgeon Dr. Phil Megison has performed
close to 550 aneurysm surgeries at Erlanger and says
local residents are fortunate to have the variety of
treatment options, clinical trials and specialists available
to them. “We have the latest and greatest resources
to treat brain attack and aneurysms right here in Chattanooga,”
he says. “There is no need to go anywhere else,”
he stresses.
A strong record of positive outcomes bears this out.
“If we operate before an aneurysm ruptures, 99%
of our patients do well; most of them go home within
four days” reports the local neurosurgeon. Another
plus is that more people are undergoing imaging studies
that reveal life-threatening aneurysms. “Thanks
to new MRI scans, we’re finding more unruptured
aneurysms than ever before,” Dr. Megison says,
noting that people are also becoming more aware that
stroke can be an inherited problem.
“I recommend that anyone aged 16 or older whose
parent or sibling has had a stroke or been treated for
an aneurysm, have an MRI or angiogram, ” he stresses.
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