An evaluation of the device's track record in the United Kingdom concluded that the UK's National Health Service should continue to restrict the technology's use at least for now. The review was published in the latest issue of Health Technology Assessment, the international journal series of the Health Technology Assessment Programme, part of the National Institute for Health Research in the United Kingdom.
An implantable pump can help heart failure patients live and recover strength while they wait for a transplant.
"Although we believe that the devices have been developed sufficiently to prolong life for some very sick patients who have rapidly deteriorating heart failure, we don't feel they've been developed quite enough yet for widespread use amongst the whole heart failure population," said lead researcher Linda Sharples.
When the heart's pumping chamber weakens, a ventricular assist device, or VAD, uses a battery or electricity-powered pump to send oxygen-rich blood throughout the body.
Sharples studied health outcomes and the cost effectiveness of heart assist devices for 70 UK patients who received the implant between April 2002 and December of 2004. More than 10,000 heart assist devices have been implanted worldwide.
Although researchers are testing ventricular assist devices as a long-term or permanent therapy, right now the heart pumps are generally used as a temporary fix for heart transplant candidates who aren't likely to survive until a suitable organ is found.
All of the cases studied in the Health Technology Assessment review were surgeries performed as a bridge to transplantation. Most of the patients received an early or first-generation model of the heart pump.
Thirty of the 70 patients with a heart assist device died before receiving a donor heart. "For the people who survive the implant, we know that their heart function improves immediately, not as much as after a heart transplantation, but it certainly improves," Sharples said.
The most common complications from the surgery were blood clots, infection and respiratory distress, the review found.
Monitoring and maintaining the heart pump usually requires patients to stay in the hospital during the entire time they wait for a donated heart. "That limits quality of life," Sharples said. "Patients don't get back to their normal way of life, their mobility, their ambulation is restricted and there are adverse events, but it's certainly better than before VAD implantation."
The small number of heart-pump implantations performed in the United Kingdom made it impossible for the reviewers to identify a fair patient group for comparison. But as an approximation, the reviewers compared health outcomes and costs for the VAD patients with patients on the UK's heart transplant waiting list.
The review estimates the average cost of a VAD implant operation is 63,830 British pounds (roughly $116,000). The average cost for health care and the stay in a hospital's intensive care unit was 14,500 British pounds (about $26,300).
"We compared the VAD group with the very sickest of the transplant candidates and found that the health care for those individuals was less costly. Those non-VAD patients also had greater survival," Sharples said.
Still, the overall survival rate for the heart assist patients was 52 percent after one year. The reviewers called that an "excellent clinical achievement" for a patient population with rapidly failing hearts. "In the UK, what we expect is that we will continue to use the devices in selected cases, and we will continue to use them in a small number of centers that have necessary surgical, cardiological and technical expertise," Sharples said.
"We recommend that the United Kingdom continue to monitor the development of the new devices," said Sharples. "I think we are all quite hopeful that they will progress and we will have more cost-effective and effective devices in the future."
While the UK study results were mixed, U.S. heart-failure and transplant expert Dr. Leslie Miller said he has more promising experience with ventricular assist devices.
Miller said candidates for a heart assist device are generally the sickest of heart failure patients who are no longer helped by drug treatment. In the United States, heart failure programs are increasingly performing heart pump implantations, because there is no other alternative when these patients become unresponsive, Miller said.
"These people are critically ill and would otherwise die without the heart assist device. So when you start with that group, it is quite remarkable the ability of these pumps to resurrect people," Miller said. "The fact that we see a 70 to 75 percent survival to a heart transplant with these devices is really a pretty extraordinary accomplishment."
Miller heads the cardiac program at the Georgetown University School of Medicine, Georgetown University Hospital and Washington Hospital Center. He said his successful heart pump patients often recover enough to exercise for 30 minutes on a treadmill. And he said that recovery makes heart pump patients more stable when they do undergo heart transplant surgery.
"It's a very dramatic change. That's why these people do as well as anybody on the transplant list. They are so stable, they are exercising daily," Miller said.