WEDNESDAY, May 9, 2007 (HealthDay News) -- In some end-stage heart failure patients awaiting transplant, implantable heart pumps can improve heart function enough to enable them to be discharged from hospital without a pump or a new heart, a new U.S. study finds.
In end-stage heart failure, the heart weakens, grows larger and shows other signs of deterioration. Implantable left ventricular assist devices (LVADs) pump blood through the body and allow the heart's main pumping chamber to rest.
This multi-center study, published in the May 8 issue of Circulation, included 67 end-stage heart failure patients with four different types of LVADs. The patients were evaluated every 30 days for several months after they received their LVADs.
"There are two contrasting, important findings in our study," lead author Dr. Simon Maybaum, medical director of the Center for Advanced Cardiac Therapy at the Albert Einstein College of Medicine's Montefiore Medical Center in New York City, said in a prepared statement.
"One, the ability to remove an LVAD from a patient with end-stage heart failure was low. Two, there was a high degree of improvement in heart function during the use of the assist device," he said.
Six (9 percent) of the patients had their LVAD's removed without needing a heart transplant, but six others died before the end of the data collection period.
The study also found that after 30 days with an LVAD, about one-third of the patients had a left ventricular ejection fraction (percentage of blood pumped out of the left ventricle with one beat) greater than 40 percent, measured when the pump flow was decreased. Healthy hearts typically have an ejection fraction of 55 percent to 60 percent.
However, the percentage of patients with a 40 percent ejection fraction decreased as the study progressed: 27 percent at 60 days; 19 percent at 90 days; and six percent at 120 days.
The researchers also measured the patients' exercise capacity after LVAD implantation and found that, between 30 days and 120 days, the patients showed improvements in peak oxygen consumption and exercise endurance.
"We now have a much more reliable description of the natural history of the changes in heart function during LVAD support. That makes us optimistic that other strategies (such as drug or stem cell therapy) may allow us to further improve cardiac function," Maybaum said.
The study was funded by LVAD maker Thoratec Corp. and the Foundation for the Advancement of Cardiac Therapy.
The U.S. National Heart, Lung, and Blood Institute has more about heart failure.