| WASHINGTON, March 30
WASHINGTON, March 30 A non-surgically implanted
heart valve meant to delay open heart surgery in children with
congenital heart defects worked well for all but a few patients
during a year of follow-up observation, in line with favorable
results seen in original clinical trials of the Medtronic Inc
The Melody transcatheter pulmonary valve was approved in
2010 under a U.S. humanitarian device exemption, which allowed
it on the market as long as a follow-up study was conducted to
assess the product's reliability and safety. The valve is guided
to the heart by a catheter, a minimally invasive procedure, and
patients typically go home after only one night in the hospital.
In the study of patients who had been implanted with the
valve there was no narrowing of the valve, or stenosis, after
six months in some 96.7 percent of the 90 patients for whom data
After a year, there was no narrowing, significant leakage or
need for additional intervention in 94 percent of patients,
researchers said on Sunday.
"The valves had excellent function during the first year,
judged by no more than mild leakage and very few patients had
narrowing of the valve," said Dr. Aimee Armstrong of the
University of Michigan C.S. Mott Children's Hospital Cardiac
Catheterization Laboratories, who was lead investigator for the
follow-up study sponsored by Medtronic.
The mean age of patients in the trial was 20, with ages
ranging from 5 to 45. The valve is made from a cow's jugular
vein that is sewn into a metal stent, and then inserted into the
patient's leg and advanced to the heart.
Within the first year of the study, eight adverse events
were seen, including three cases of heart infections, two
abnormal heart rhythms and one case each of bacterial infection,
major stent fracture and blood clot in the lung.
Patients will continue to be followed for five years.
Results of the multi-center study were released at the
annual scientific sessions of the American College of Cardiology
Congenital heart defects are the most common type of birth
defect in the United States, affecting an estimated one million
adults and 800,000 children. Many patients are born with no
pulmonary valve, which carries blood from the heart's right
ventricle to the lungs, or only a very small pulmonary valve.
Some patients receive a connecting tube, or conduit, early
in life, to provide blood flow. The conduits, typically made
from cadaver pulmonary valves, from pig valves or bioprosthetic
materials, are implanted during open heart surgery and
essentially bypass the missing or inadequate pulmonary valve.
But the conduits over time can become leaky and narrowed,
putting stress on the right ventricle and preventing it from
squeezing properly. As a result, patients can develop abnormal
life-threatening heart rhythms and symptoms such as inability to
At that point, patients have traditionally required open
heart surgery to replace the pulmonary valve. But such surgery,
which requires cutting open the rib cage to get direct access to
the heart, causes scar tissue that makes future surgery much
Medtronic's Melody valve is meant to provide additional
blood flow when conduits become faulty, and thereby delay the
need for more open heart surgery.
"Every time you do open heart surgery, more scar tissue
develops, with more potential damage to the heart," said lead
She said it was too early to determine just how long the
Melody valve would last, or how long it would delay the need for
more open heart surgery. But she said patients in other trials
have had the Medtronic valve for 5 to 7 years, with no need for
To date, over 6,000 patients have received the Melody
valves, with more than half of them having congenital heart
(Reporting by Ransdell Pierson; Editing by Rosalind Russell)