The ascendra procedure
used by Dr Lichtenstein. |
Bud Boyer's ticker needed fixing
and it wasn't looking good. "He would have been a fourth
time redo," says Dr Samuel Lichtenstein, Head of Cardiovascular
Surgery at the University of British Columbia. "Plus
he had vascular disease and non-bypassable vessels —
he was really just not a surgical candidate."
But in the end, all it took was
an incision the size of a toonie to perform what his
patient deemed "magic." Dr Lichtenstein put a new, hi-tech
valve in Mr Boyer's heart using an experimental, minimally
invasive technique some have dubbed "closed-heart" surgery,
and his patient walked out of the hospital the very
next day. "Basically, it's a large stent that has a
valve within it," explains Dr Lichtenstein. "Just as
a normal stent opens an artery, these ones open the
aortic valve and the artificial one is positioned inside."
Dr Lichtenstein readily admits
that the highly experimental procedure is still quite
a ways off from superseding traditional valve replacements,
where surgeons crack open the breastbone, put the heart
on bypass, cut out the old valve and sew in a new one.
So far, only about 150 heart valves — either like
the one used on Mr Boyer, or a competing type that's
introduced through the femoral artery — have been
implanted worldwide. "It's in clinical trials but we're
only doing it on the basis of compassionate use —
for people who aren't surgical candidates and for whom
no other therapy is available," says Dr Lichtenstein.
VALVE
THE IMPALER?
Of course, there are unique risks that come with inserting
these devices. "The major danger is embolization of
the valve, where it goes off somewhere and we have to
retrieve it," explains Dr Lichtenstein. The other smaller
but significant issue is that artificial valves carry
a larger risk of leakage — called perivalvular
leaks. "So far it's been quite small and reasonable.
We've had no patients who've had any serious problems
due to perivalvular leaks," he says. "The reason the
valves tend to leak is because you're forcing calcium
that's there from the existing valve apart and the replacement
valve doesn't conform to the existing one perfectly
all the time."
Durability also remains something
of a question mark with these new artificial heart valves,
but for Dr Lichtenstein, it isn't a black-and-white
issue. "They've been tested in vitro with a pulse
duplicator for more than five years." Of course, he
says, the whole issue of durability takes on a different
meaning when a heart valve can be implanted without
performing open-heart surgery. "If these things last
anywhere within reason, it would be a reasonable alternative
to traditional open-heart surgery for high risk patients."
WILL
MY HEART GO ON?
Traditional aortic valves can work for 10 to 15 years
in an elderly patient. But even if these newer valves
were to deteriorate after say, only five years, they
can actually be replaced. "You can make a tiny incision
when the valve wears out and put another one right inside
it," says Dr Lichtenstein.
Dr Lichtenstein is hopeful that
these new valves will make heart surgery less of a 'big
deal' in coming years. "We tend to want to keep the
experimental patients in the hospital to watch them
because we don't know exactly what complications we're
looking for," he says.
In fact, Mr Boyer is unique among
the other patients who have received the procedure —
most are hospitalized for other reasons, so they can't
be discharged very quickly. "But somebody who's otherwise
well yet still high-risk for surgery — like Bud
Boyer — he was home on the second day," Dr Lichtenstein
adds.
"[Health Canada and the FDA] will
want a whole bunch of data on a whole bunch of people
and that's fine — that's what they're supposed
to do," says Dr Lichtenstein. "I think it'll be a while
before it will be open for all usage, depending on the
judgement of the surgeon of course — but five years
from now it might be an option for younger, healthier
patients as well."
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