Transplant device keeps heart beating

These days, a heart being readied for transplant is unceremoniously placed in an ice chest before being rushed to the recipient. Doctors have about four hours to get the silent heart stitched into its new owner.

But an Andover company and a researcher who will move to Massachusetts General Hospital next month have come up with what could be a better way: They can keep a heart beating while it is transported, which they believe will allow donor hearts to last longer without damage and potentially give the recipient a healthier heart.

If proven successful, said several specialists with no tie to the company, the device could revolutionize the transplant process. It could be an opportunity ``to save more people's lives," said Robert C. Robbins, director of the Cardiovascular Institute at Stanford University.

The beating-heart device, now undergoing clinical trials in England and Germany, has been used in seven successful surgeries to date. TransMedics Inc. of Andover, which developed the organ care system, is hoping to get approval from the US Food and Drug Administration to begin trials in the United States this fall.

Dr. Bruce R. Rosengard , who has led the trials in England and is moving to Mass. General, has transplanted a beating donor heart into three patients so far.

All the patients have done well with the transplants, he and other doctors said, suggesting that since hearts kept beating suffer less damage, they are easier for the recipient's body to accept.

``Our transplants have been right at the top of the heap in terms of clinical performance," Rosengard said during a recent visit to Boston. ``They had no setbacks, no issues at all."

Ordinarily, after surgeons remove a heart from a brain-dead donor, they replace the blood with a salt-water solution and place it on ice. The ice slows the activity of heart cells, preserving the heart for about four hours.

But the cells still consume energy, weakening the heart, and without new blood, some of the cells die, leaving damaged tissue.

With the new device, a transplantable heart is removed from a donor's body and hooked to plastic tubes at its aorta, pulmonary artery, and left atrium. The instrument continually flushes blood through the heart's chambers. A computerized control system monitors the heart's metabolism, blood pressure, and electrical state.

As soon as the heart receives the flow of warm, nutrient-rich blood, the muscle resumes its normal cycle of contraction and relaxation. Completely separate from the human body within the open plastic bed of the device, the heart beats steadily -- a natural but eerie sight reminiscent of the writings of Edgar Allen Poe.

The whole machine fits on a cart that can be wheeled into the operating room or stowed on an airplane.

In one of the German cases, a human heart was successfully transplanted after six hours on the device. In the laboratory, a pig's heart continued functioning for 12 hours. Eventually, doctors hope, the instrument will keep hearts alive even longer -- meaning they could travel farther and more donor hearts could be used.

Hillel Laks, director of the Heart and Heart-Lung Transplant Program at the University of California, Los Angeles, Medical Center, said that if hearts could be kept alive for 18 hours, doctors would have time to match the donor's tissue type to that of the intended recipient, which would aid acceptance. That's now done with kidney transplants but not hearts.

``If that could be accomplished, it would add a lot to heart transplantation," Laks said.

About 2,200 patients in the United States receive heart transplants each year, a number that has remained nearly unchanged since 1990. But more than 2,800 people are waiting for heart transplants, and last year, 411 people died while on the waiting list, according to the Organ Procurement and Transplant Network .

``The whole field of transplantation is completely limited by the availability of suitable organs from suitable donors," said Gregory S. Couper , who serves on the advisory board for TransMedics and is the surgical director of heart transplantation at Brigham and Women's Hospital .

Besides keeping hearts undamaged longer, the beating-heart machine might be able to revive organs otherwise too damaged to transplant, doctors speculate.

During the time it takes for a donor to be pronounced dead, hearts are often damaged by inflammation. However, when the heart is removed from the body and quickly filled with healthy blood, it begins a recovery process.

``There may be whole categories of hearts that we can't currently use that we can use after resuscitating them with this device," Rosengard said.

Today, only about half the people who are willing to donate their hearts have an organ that's acceptable for donation, said Joren C. Madsen, the surgical director of cardiac transplantation at Mass. General.

``This machine . . . will allow us to take hearts that are either further away than we normally take or that are not as healthy as we normally take," he said.

Prior efforts to build a beating-heart instrument have ended in glitches, disappointments, and failures. The only other similar instrument used in the clinic, built at the University of Pittsburgh in the early 1980s, successfully transferred entire heart-lung systems to 14 patients. At that time, surgeons couldn't keep blood oxygenated without the lungs.

But within the clumsy machine, the complex vein systems of the heart-lung combination tended to leak. When one serious leak developed en route to a patient, surgeon Robert L. Hardesty lay down in the back of the plane and donated his blood for the machine, said surgeon Bartley P. Griffith , chief of the Division of Cardiac Surgery at the University of Maryland Medical Center. He helped design the heart-lung device and now serves on the TransMedics advisory board.

In contrast, the TransMedics instrument -- which simplifies the task by transporting only the heart and has had no technical problems in trials so far, according to Rosengard -- has captured surgeons' hopes.

``We think it's going to improve the prospects of the recipient five and 10 years down the line," Griffith said.