Tragically many people still die while waiting for an organ transplant: up to 15% of patients each year in the UK who need a liver transplant, for example. As demand for donated organs grows, the supply of suitable organs is a critical issue for health systems in the UK and worldwide. Teams around the world have been working to tackle this issue, including the team led by Professor Chris Watson, Professor of Transplantation at the University of Cambridge School of Clinical Medicine. They have been investigating the possibilities provided by livers, kidneys and pancreases donated after circulatory-determined death – DCD organs - using funding from the Evelyn Trust. 

“After a circulatory-determined death, it has historically been very difficult to use donated organs that have been damaged by ischaemia - a lack of blood supply. A liver that has been without a blood supply for perhaps only 30 minutes will be four times more likely never to function again, or to fail after a short time. We have been experimenting very successfully with restoring circulation to the abdominal organs after death, perfusing both a liver and kidneys with oxygenated blood while still in the body and checking them to see how well they are working,” explains Chris.

This successful method of ‘normothermic regional perfusion’ (NRP) was developed in collaboration with Cambridge Perfusion Services, who helped to design and refine a circuit outside the body for supporting the circulation of oxygenated blood to the abdominal organs after the organ donor has died and their heart has stopped. The tricky issue of blood clotting in the circuit was overcome by incorporating a thin tube called a ‘shunt’ into the design to allow full mixing of anti-coagulants before the blood was exposed to the membrane oxygenator. The team is also collaborating with Paul Robertson in the University’s Engineering Department to try to simplify cardiopulmonary bypass pump technology to meet their specific needs. 

The NRP technique also allowed the evaluation of livers in the donor to assess their suitability for transplantation by measuring enzyme release from the liver, a marker of ischaemic damage, and lactate levels as a marker of function. NRP also gives the operating surgeon more time when removing organs from a donor, so reducing the chance of inadvertent damage.

“The main complication of liver transplantation from DCD donors is scarring of the bile ducts which leads to recurrent episodes of infection and which might mean the need for another liver transplant. This complication has not been seen in any of the livers transplanted after NRP,” says Chris.

Addenbrooke’s Hospital has been the first UK transplant centre to use the new technique and one of the first in the world using it in this setting. A research group has now been established to apply for funding for a national randomised trial.

To find out more about Professor Watson’s work, visit https://surgery.medschl.cam.ac.uk/divisions-and-groups/transplant-surgery/