Revolutionary Unit to Aid Transplant of Hearts Developed

In a development that could revolutionize human heart transplants, UC Irvine researchers announced Tuesday that they have invented a box-like device that will keep a heart beating outside the body for up to 24 hours.

The device, called a “human organ transport system” so far has been used only with pig, dog and sheep hearts. It still needs at least three more years of testing before it could be available for use in human heart transplants, said Ralph Purdy, a UC Irvine associate professor of pharmacology who was one of four researchers involved in the 3-year-old project.

Currently a human heart will remain viable outside the body for at most four hours. But this device will bathe the heart in a “blood substitute,” cool it to about 50 degrees Fahrenheit, slow its contractions to 10 beats per minute and thereby keep a beating heart viable for transplant for as long as 24 hours, Purdy said.

That time extension opens up the possibility that human hearts can not only be donated within the geographic region where the organ becomes available but also could be sent around the world, Purdy said.

For more than 20 years, experts in heart transplantation have been seeking to lengthen the so-called “ischemic time,” the time a donor heart is outside the body. Currently about 30% of the nation’s heart transplant candidates die while waiting for a new heart because no donor heart was available in their region.

Late Tuesday, some transplant experts, including officials from the United Organ Sharing Network in Richmond, Va., expressed excitement and hope that UC Irvine’s device will “increase organ sharing on a national level.”

However, Purdy and a co-researcher, Newport Beach inventor James Martindale, cautioned that neither their device nor their blood substitute are currently patented, although UC applications for both have been pending since October. In addition, Purdy and Martingale have not written up their research for any scientific journal, although they expect to do so as soon as the patents are approved. So their claims about the effectiveness of the device and the blood substitute have not undergone the intense peer review process.

Further, although the device has kept a sheep heart beating outside its body for from 18 to 24 hours, Purdy and his fellow researchers have not yet attempted to re-implant the heart and therefore do not know how it would function after transplantation.

Purdy and Martindale also estimated that they may need another three years of research to create a prototype device, probably about the size of a 24-inch TV set, that is small and portable enough to be useful in heart transplants and can receive approval from the Food and Drug Administration.

Component Parts

Currently, the device consists of a series of component parts, including a computer, an oxygenator and blood flow and temperature monitoring devices, that “would fit on a large kitchen table,” Purdy said. Both Purdy and Martindale conceded that creation of such a heart device opens a Pandora’s box of ethical issues.

Chief among these is the fact that there are currently no federal, state or university guidelines for research with human hearts.

Until there are, Martindale vowed, the researchers plan to continue animal experiments as soon as their patents are approved but will not attempt any research using a human heart.

Medical ethicist Arthur Caplan--who Tuesday jokingly dubbed the UC Irvine researchers’ device “a Poe box” after writer Edgar Allen Poe’s horror story, “The Tell-Tale Heart”--applauded the scientists for “raising these questions before going to human trials. . . .”