Jan. 31, 2011 -- An implantable pump that assists with the work of a weakened heart may, in rare cases, help some people recover a significant amount of heart function, a new study shows.
The new review, which is published in the Feb. 8 issue of the Journal of the American College of Cardiology, summarizes international research on recipients of left ventricular assist devices, or LVADs, including1,092 LVAD patients enrolled in a government-funded registry.
"I think that the significance of this paper is what they've done is that they have kind of collated together the various studies that have been done looking at what happens to a failing heart once you put an LVAD in it on the molecular and structural and genomic levels," says Samer S. Najjar, MD, director of heart failure at Washington Hospital Center in Washington, D.C., who was not involved in the study.
In some rare cases, the changes may be beneficial enough to help people who have been diagnosed with heart failure to recover.
“What we’ve learned is that we can put in this pump and 5% or 10% of patients recover,” says study researcher Leslie W. Miller, MD, chairman of the department of cardiovascular science at the University of South Florida in Tampa.
“It’s an exciting time to think we can intervene and recover hearts. Heart failure may not be a one-way street,” Miller says.
A left-ventricular assist device is a battery-operated pump that is implanted in the chest, where it drains blood from the heart’s lower left chamber and pushes it up through the aorta, the body’s largest artery.
It’s about the size of a tennis ball and weighs a bit more than 1/2 pound.
Versions of these pumps have been in use for about 25 years, Miller says, first as a way to help extend life until a heart transplant could be performed and, more recently, as a “destination therapy” in patients who are ineligible for transplants.
Perhaps the most well-known recipient of an LVAD is former Vice President Dick Cheney.
Among people with LVADs followed by the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS), 74% survived for one year after implantation; 55% were alive at two years.
Heart Failure Therapies
Miller says that most patients who recover completely after using an LVAD experienced heart failure as the result of a viral infection.
In those cases, a virus attacks the heart and can cause it to become weakened and enlarged.
Research on tissue samples taken at the time an LVAD device is implanted and then later removed show heart muscle cells may contract and relax more effectively after the use of one of these pumps, and the study’s researchers think that by giving the heart time to rest, it may be able to somewhat repair itself.
Additionally, Najjar says if scientists can better understand these rare cases of recovery, therapies may be developed to help the much larger percentage of people who develop heart failure as a result of damage to the heart muscles caused by coronary artery disease and heart attacks.
"The other sort of long-reaching tentacle, if you will, is that as we understand the changes that happen when you put in an LVAD that may lead to a better understanding of heart failure. ... Down the line we may be able to develop new treatments that we wouldn't have thought of," Najjar says.