Researchers have pioneered a method to keep hearts alive outside of the body for more than a full day. 

Currently, human hearts are preserved on ice for transplantation, a process that starts to diminish in effectiveness after six hours. 

The new approach, ‘normothermic ex-vivo heart perfusion’ (NEHP), has been used to keep pig hearts at room temperature while circulating an oxygen-rich fluid through it, extending the preservation time significantly.

Research so far has kept the hearts alive for extended periods using NEHP, testing different modifications to enhance its effectiveness. 

The team says it is consistently getting hearts to survive the full 24 hours - a big improvement over current preservation methods.

“If translated to humans, this would be a major improvement to the six-hour-long time window in standard clinical practice,” says Dr Robert Bartlett, the head of the Extracorporeal Life Support Laboratory at the University of Michigan Medical School at Ann Arbor.

By extending the viable preservation time of donor hearts, the procedure could significantly increase the pool of available organs, thus saving more lives. 

Additionally, the technique offers a more objective assessment of a heart's viability before transplantation, potentially reducing the number of discarded organs.

The techniques require further validation in humans. The team is already taking steps towards this goal by working with human hearts rejected for transplantation. 

More details are accessible here.