WASHINGTON (AP) - A type of artificial heart under government scrutiny may keep some near-death patients alive long enough to receive transplants, but there are serious questions about its scientific backing and whom it might benefit, advisers said Wednesday.
The advisers to the Food and Drug Administration wrestled with whether the CardioWest Total Artificial Heart should be sold. It's the first mechanical device that promises to replace part of the hearts of dying patients while they await donors.
It's a complex and somewhat risky device: Surgeons have to actually cut off the bottom pumping chambers, or ventricles, of a patient's heart and then sew the CardioWest into place. That's more radical than today's practice of simply attaching ventricular assist devices, or VADs, to boost a weakened heart's pumping power.
Some 3,460 people were on the national waiting list for a heart transplant as of Wednesday; just over 2,000 receive a heart each year. If the FDA allowed sale of the CardioWest, it's not clear how many of the rest would qualify to try it while they await a donor.
"This is going to be a niche technology," acknowledged Dr. James Long of the University of Utah, who helped test the CardioWest and says his own hospital treats no more than two to four patients a year who could benefit from it.
But, "these are very sick patients who are dying. They have no alternative," added Dr. Jack G. Copeland, who led the CardioWest's development at the University of Arizona.
The CardioWest is not what the average person thinks of when hearing "artificial heart." Initial attempts to use the device as a permanent heart replacement 22 years ago, when it was called the Jarvik-7, failed; experiments are under way with other, more advanced technology that might one day offer that medical leap.
Instead, its inventors hope the CardioWest will offer a temporary fix for patients with end-stage congestive heart failure who have had both of their ventricles quit working, something doctors find difficult to fully help with today's VADs.
Unlike VADs, though, the CardioWest would be for in-hospital use only: Tubes snake out from the patient's chest to a washing machine-sized generator that powers the implanted device.
"I came to know (it) fondly as Big Blue," Leo Corbet, 67, of Phoenix said of the contraption, which he was hooked to for 110 days before his 2001 heart transplant. He'd listen to the machine's loud whirring, and "I knew I was alive."
Of 81 patients implanted with the device in a study spanning the 1990s, 79 percent survived long enough to get a transplant, Copeland said. The longest use of the device was 414 days.
A month after transplant, 69 percent of the one-time CardioWest recipients were out of bed and recovering well.
The study attempted to compare CardioWest recipients to people awaiting a heart transplant in the early 1990s who didn't have that option, hoping to prove the CardioWest improved care. But the FDA said the groups weren't comparable - leaving the advisory panel struggling to decide if using the device was better than doing nothing.
"This leaves all of us in a hamstrung position," complained Dr. Mitchell Krucoff of Duke University.
After all, it's a rigorous surgery that brings some risks: 40 percent of patients suffered bleeding, 22 percent developed device-related infections, and 8 percent had blood clots, FDA scientists said.
But a look at the history of competing VADS shows they typically have survival-to-transplant rates around 70 percent with similar side effects, suggesting the CardioWest is equivalent, said FDA reviewer Dr. Julie Swain.
