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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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