Spring 1995 Mission

Devices may double life
of transplant organs in transit

By Will Sansom

Someday soon, preservation of donor organs for transplant will take a quantum leap forward, making it possible for a person in San Antonio to receive a heart or lung from someone a world away such as in Tokyo or Paris.

Someday, a donor heart won't have to be discarded because its intended recipient died before surgery. Instead, the heart will be rerouted to another city and another patient.

Someday, transplants will be performed electively, freeing professionals and resources now tied up in emergency situations.

Researchers at the Health Science Center are at the forefront of testing in organ preservation; in the past year alone, university scientists have patented two portable preservation systems that maintain organs much longer than is currently possible.

"Many organs, such as hearts, are dependent on oxygen and deteriorate rapidly outside the body. This lack of oxygen is called 'hypoxia,'" said Leonid Bunegin, assistant professor of anesthesiology and co-developer of one of the preservation devices. "The longest you can keep a heart outside the body is about four to six hours. During this time, the organ deteriorates because of the lack of oxygen, becoming unsuitable for transplant.

"This creates a very narrow window of opportunity people who need an organ transplant have to be available, surgeons must be on call day and night, and when an organ is available, they must immediately harvest it, return to the recipient site and do the transplant. Tissue matching and the fit of an organ are relegated to almost secondary importance, because of the lack of time.

"With a wider window, organs and patients could be matched much more precisely. And, if preservation time were increased, organs could be procured from a much larger geographic area, resulting in an increased availability of organs," Bunegin said.

John H. Calhoon, MD, associate professor and head of the division of cardiothoracic surgery, said more precise matches would improve patient outcome and reduce costs.

"The opportunity to cross-match organs and recipients could well increase the long-term survival in heart transplant recipients, as has been shown with other organs such as kidneys," he said. "Many transplant recipients must take cyclosporine and other drugs to prevent rejection of their new organs, at a cost of thousands of dollars per year. In some cases, precise cross-matching could diminish or maybe even eliminate the need for anti-rejection drugs."

A physician who has written widely on organ preservation, Si Pham, MD, director of the adult heart transplant program at the University of Pittsburgh Medical Center, added: "As long as the organ is functioning well, the cost of health care would decrease tremendously because the operation could be performed semi-electively instead of urgently."

Currently, organs are transported in a state of "simple hypothermic storage." They are immersed in a standard saline solution, placed in a bag over crushed ice and shipped in an ice chest.

Bobby J. O'Dell, a perfusionist in the Health Science Center's surgery department, originated the concept for a portable organ preservation device a decade ago and patented his own version in 1994. Bunegin contributed a substantial amount of reengineering and with O'Dell as lead inventor, ultimately patented a modified version of the same device.

Both devices provide simultaneous oxygenation and perfusion of a donor organ, and keep the organ chilled to reduce its metabolic need for oxygen. Perfusion involves immersing the organ in nutrient-filled fluid.

In experiments, one of the systems sustained the oxygen requirements of canine hearts for 12 hours. Experiments now under way are trying to maintain canine hearts for 24 hours.

"With a 12-hour preservation scenario, a patient in San Antonio could receive a heart or other organ from anywhere in the country and probably from almost anywhere in North or South America," Bunegin said. "Twenty-four hours would be anywhere in the world."

The preservation device forms several sealed compartments, including a perfusion chamber and container filled with nutrient fluids that holds the transplant organ. "The thing that makes this device unique is that it uses no electrical power," Bunegin said.

"Typically, a fully loaded system weighs under 40 pounds light enough for one person to pick up with one hand and carry. And we've designed it to be completely transportable it would not need someone to monitor it. We will soon complete experiments in which we are shipping the prototypes from Texas to California and back, and then evaluating the viability of the organ in the device after the shipment.

"We want to see what will happen to this device when it is jostled around, with an organ inside," Bunegin said.

"This system represents a quantum leap over current systems for organ transport," Dr. Calhoon said. "We are eagerly awaiting further investigation into its uses. It represents quite an impressive design in its uniqueness and portability, and there is a definite need for it."

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