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January
18,
2011 -- 9:00pm EST
From Angioplasty and Stents to Aortic
Valve Replacement
34
years ago, Andreas Gruentzig performed the first coronary angioplasty.
Rather than cutting open the chest, sawing through the sternum and
sewing a bypass conduit (harvested from the leg or internal mammary
artery) into the coronary artery, he elegantly threaded a balloon
catheter to the blockage through a small incision in the femoral
(groin) artery, in an awake patient. He then inflated the
balloon, compressing the
plaque against the arterial wall and opening the artery. The procedure
was
a total
success and his first patient, Adolph Bachmann, is alive and well
today! (see
video clip: " The 1st Angioplasty".)
But more importantly than
just inventing angioplasty, Gruentzig invented a method for treating
patients non-surgically, from the inside-out! What Gruentzig
said was:
"Whatever becomes of the method, I have
left one mark on medicine: I have shown that man can work
therapeutically within the coronary arteries themselves in
the face of an alert comfortable patient."
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Gruentzig's
proclamation was a fitting answer to a thought expressed exactly
two centuries earlier!
Englishman John Hunter, considered
the founder of "scientific surgery" and the first physician to
treat an aneurysm successfully, wrote the following in his 1777
treatise, "The True Principles of Surgery":
"This last part...namely operations...is
a tacit acknowledgement of the insufficiency of surgery. It
is like an armed savage who attempts to get that by force which
a civilized man would get by stratagem."
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So, rather than requiring the "armed savagery" of
open surgery, in the 21st century, Gruentzig's "civilized stratagem" is
now being applied to areas of
medicine that he could only have
imagined.
For example, diseased aortic valves, previously only
repaired via open heart surgery, are now successfully being replaced
via catheter-based technologies.
There are two major percutaneous (i.e. nonsurgical)
devices currently being studied as an alternative to surgically
replacing aortic valves in the heart: the Sapien valve, manufactured
by Edwards
Lifesciences and the CoreValve, manufactured by Medtronic. The PARTNER
trial one-year
results of the Sapien valve, showed
a 46%
relative risk reduction in
mortality over medical therapy for patients who were too sick to
have open surgery, as
reported last October in the New England Journal of Medicine.
So
today, the
FDA conditionally approved changes in the just-beginning
U.S. trial for Medtronic's percutaneous CoreValve. (By the way, the CoreValve
has been approved in Europe since March 2007 and has since been
implanted in thousands
of patients.) Rather than requiring
that the company test their device against "best medical therapy",
the FDA agreed with Medtronic that it would not be ethical
to randomize patients to medical therapy vs. the percutaneous
valve since the data from the PARTNER trial was so compelling
as to the advantages of the percutaneous valve.
A further boost to the CoreValve trial is that
the FDA also approved inclusion of the subclavian approach.
Some patients do not have large enough femoral arteries to accept
the equipment, or their femoral arteries are too diseased. So now
the subclavian artery can be used, although it is somewhat more invasive,
and the number of patients who might benefit from this therapy is
significantly expanded.
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