To preserve more livers for transplant patients who desperately need them, surgeons should take newly harvested organs out of their ice baths and immerse them instead in a warm, nutrient-rich soup, new research suggests.
In a head-to-head comparison of the two methods, preserving donor livers in conditions that mimic a living body resulted in 20 percent more organs being transplanted into patients, according to a study published Wednesday in the journal Nature.
"The ability to make good use of every possible donor we have is crucial" to saving lives and reducing the backlog of patients in need of a new liver, said Oxford University bioengineer Constantin Coussios, one of the study's authors.
For 30 years, newly harvested livers have been flushed with preservation fluid, then stored on ice until their prospective recipients were ready for surgery.
The new technique, called "normothermic preservation," keeps the liver at body temperature and nourishes it with a continuous flow of oxygenated blood and other nutrients.
The researchers tested the two methods in a rigorous, first-of-its-kind clinical trial.
Compared to the "cold storage" approach, the new practice caused less damage to donor livers, slashing the rate at which livers were "discarded" _ harvested but never transplanted _ in half.
After accounting for unavoidable rates of discard among all livers harvested for transplant, the researchers calculated that the warm-body approach resulted in 20 percent more transplanted organs.
That's a lifesaving leap forward in a field where the demand for transplantable organs far outstrips supply. Although just under 14,000 patients are waiting for livers in the United States, only about 7,500 liver transplant surgeries were performed in the United States in 2016.
Moreover, while liver failure is on the rise in the United States, the quality and quantity of livers suitable for transplant appears to be declining as obesity, infectious disease and other societal ills erode the organs of prospective donors.
In virtually all of the 121 transplants involving a liver maintained at body temperature, the organ continued to make bile, a key measure of its viability once transplanted, Coussios said.
An organ kept perfused with blood at 98.6 degrees Fahrenheit is "pretty much pink by time it's delivered and makes a very rapid transition to normality once transplanted," he said.
A number of complications that can doom a transplant recipient _ from blood pressure changes in the operating room to organ failure or rejection after surgery _ appeared to be reduced when the organ was essentially kept alive after it was harvested from its original body.
Normothermic preservation also allowed more time to elapse between the moment when an organ was removed from its original owner and the time when it reached its new home in a transplant patient.
Coussios said the research team is confident that exchanging normothermic storage for cold storage will offer benefits for other organs as well. The new clinical trial results should be "a real watershed moment" for organ transplant practices, he said.
