PITTSBURGH - Transplant surgeons removed a heart from an elderly, brain-dead patient Saturday and, at approximately 9 a.m. EDT, placed it in a special machine where it continued to beat - the first in a series of experiments that could have a profound impact on the future of heart transplantation.
The machine keeps the heart alive and beating by circulating oxygen-rich blood and electrolytes through its arteries and keeping it warm and humid. Researchers hope the machine will extend the time that hearts and organs can be kept in transplantable condition and might eventually be used routinely not only for transporting organs but for testing and preparing them prior to transplant.
The heart was still beating at 4 p.m. Saturday, during a news conference at the University of Pittsburgh Medical Center.
The wheeled machine, similar in size and height to a baby carriage, was pushed into a conference room. Dr. Waleed Hassanein pushed back the machine's rounded plastic lid and lowered its sides, revealing a clear, plastic Tupperware-style container with the beating heart visible inside and coils of blood-filled plastic tubing beneath it.
When the container's lid was swung out of the way, the softball-sized heart could be seen, backside-up, lying in the slanted tray. Though the heart was beating it wasn't pumping blood. The machine, however, was pumping blood into the arteries that fed the heart muscle.
Expectations were that the heart would continue to pump through the night. Plans called for disconnecting it at about 9 a.m. Sunday.
It was a "rather unique" exercise, said Dr. Robert Kormos. Though the machine, called the Portable Organ Preservation System by its maker, TransMedics Inc. of Woburn, Mass., has been tested using hundreds of animal organs, the experiment Saturday was the first using a human heart.
The heart was unsuitable for transplant because the donor was almost 80 years old, noted Kormos, director of thoracic transplantation and the university's artificial heart program. It was removed from the donor in the same way as any other transplant heart, its beat temporarily stilled. When it was warmed and reperfused with blood, however, it began to beat again on its own.
Additional such hearts will be used in further experiments, perhaps once every week or two, as the machine is further tested and methods developed for assessing the functional ability of hearts while they are attached to the machine.
Hassanein, founder and CEO of TransMedics, said the machine can be used to preserve livers, lungs, intestines and pancreases as well. Its ability to sustain human kidneys for 24 hours was demonstrated last month at the University of Chicago, where the kidney continued to produce urine while connected to POPS.
The most obvious use for the machine will be to extend the time that hearts can be kept alive outside the body, thus increasing the distance that they can be transported. Hearts now are preserved by flushing them free of blood and cooling them - usually by placing them on a bed of ice in a plastic cooler. But hearts - and lungs - can be preserved for only about six hours this way.
Other organs can be preserved longer - livers for 24 hours or so, kidneys for 36 hours, even 72 hours in a pinch. But the longer they remain on ice, the more likely it is that they will be damaged or have trouble functioning when they are transplanted, said Dr. Kenneth McCurry, director of lung and heart-lung transplantation.
Surgeons prefer to keep that period as short as possible - maybe three hours for hearts, or 10 hours for a liver.