From: Spudboy100@aol.com
Date: Sat May 31 2003 - 01:22:05 MDT
LVAD has entered the building...
05.29.03
http://www.sciencentral.com/articles/
<<Can some heart failure patients recover without a heart transplant? As this
ScienCentral News video reports, researchers at Duke University say a heart
assist device now used as a bridge to a transplant could be a bridge to
recovery.
Heart Break
Thousands of Americans would benefit from a life-saving heart transplant each
year. To keep heart failure patients alive while they wait for a new heart,
doctors sometimes use a device called the Left Ventricular Assist Device, or
LVAD (pronounced “el-vad”). The left ventricle is the chamber in the heart that
pumps blood throughout the body (except the lungs). It’s the ventricle that
needs help in heart failure, which is where the LVAD comes in, essentially “
becoming” the left ventricle for the patient until a new heart becomes available.
For a patient with a failing heart, the LVAD provides a welcome break. “The
assist device actually provides a semi-vacation of sorts to the heart,” says
Burns Blaxall, postdoctoral fellow in the Department of Experimental Surgery at <A HREF="http://www.mc.duke.edu/index3.htm">
Duke University Medical Center</A>. “And that is also most likely why the heart
recovers, because it’s been given this vacation to kind of relax and recover.”
The LVAD can even lead to structural improvements in heart muscle, which is
called remodeling. “The reason that these [devices] are so important is because
fewer than 3,000 transplant hearts are available per year, and obviously
there are many more people who require them. So these devices are used and
approved as a bridge to transplant.”
Now researchers are finding that some patients can use this “bridge to
transplant” as an actual bridge to recovery, and avoid transplant surgery entirely.
Blaxall and his team, who published their report in the April 2, 2003 issue of
the Journal of the American College of Cardiology, used high-tech gene chips
to analyze samples of patients' heart tissue that were taken when the LVAD was
implanted, and then when it was removed. Also known as DNA micro arrays, gene
chips tell researchers which genes are switched on or off within a cell. “The
micro array has representation of several thousand known human genes,”
explains Blaxall. “We extract information from the tissue by incubating it with
these micro arrays. Then they can help us determine the changes in gene expression
that have occurred during the heart’s vacation, while it’s been supported
with the ventricular assist device.”
The researchers found that the LVAD changes the activity of genes in the heart
’s cells, and those changes have a specific pattern in patients whose hearts
were strengthened with the device. Specifically, some genes were either more
or less active after the implant surgery. This provided the scientists with
kind of an overview of the genetics of remodeling. Scientists now need to
determine which genes are associated with remodeling.
The study is preliminary, but it represents a first step toward predicting
how heart failure patients will respond when supported by a LVAD. “Our hope is
that we may be able to determine beforehand whether a patient will respond
favorably to ventricular assist device support or whether indeed they may require
a transplant,” says Blaxall.>>
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