Pulmonary valve implants:
Transcatheter valve-in-valve implants
are 98% effective
When bioprosthetic valves fail,
implantation may be a viable option
used to mend aortic, pulmonary, mitral
and tricuspid tissue valves.
Pulmonary procedures are performed
using percutaneous transvenous
access. Small incisions are made
between patient’s ribs or through a
puncture site in a blood vessel of the
leg where the artificial valves are
placed inside the old surgical valve
and expanded with a balloon-
In the so-called "valve-in-valve"
procedure, the new transcatheter
valve is jammed tightly into the orifice
of the failed prosthetic valve, pushing
the old valve leaflets aside.
Both the CoreValve (Medtronic,
Minneapolis, MN) and Edwards's
Sapien transcatheter aortic devices
are already marketed and widely used
in Europe, while American physicians
are looking forward to FDA approval.
Bioprosthetic heart valves are often
preferred over mechanical valves
because they have a lower risk of
thrombosis, but they don't last as long.
The standard treatment for a failed
valve that has stenosed or is
regurgitant has been surgery, but
repeat surgery carries significant risks,
especially for older patients.
Transcatheter valves can be installed
without cracking open patients' chests.
This makes them an option for patients
who can't withstand regular surgery
and a sought-after technology for
Medtronic already sells so-called
transcatheter heart valves, which don't
require open heart surgery to install,
outside the U.S. It competes closely
with Edwards Lifesciences Corp. in a
small but fast-growing market where
sales are likely to be roughly $400
million this year, but analysts see multi-
Edwards is likely years ahead in the
race to the U.S. market, based on
favorable U.S. trial data released in
September 2010. Medtronic needs to
get its own U.S. trial off the ground.
Medtronic received FDA approval to
start a clinical trial in the US.
Medtronic's CoreValve System is
designed with self-expandable
technology to replace a diseased
aortic valve, usually through the
femoral artery, without open-heart
surgery or surgical removal of the
native valve. Since receipt of CE
(Conformité Européenne) Mark in
March 2007, the system has been
implanted in more than 12,000 patients
worldwide in more than 34 countries
outside the U.S.
The Medtronic trial will include more
than 1,200 patients at 40 U.S. clinical
sites. It will include two different
studies, one examining patients
deemed a high risk for regular valve
surgery, and another for patients
deemed an extreme risk. The high-risk
patients will either receive a Medtronic
valve via catheter or a replacement
valve through traditional open-heart
surgery, with a goal of measuring
freedom from death at 12 months.