New Technique Makes Heart Transplant Possible for More Children in Need

A new technique developed by researchers BHF funded at Great Ormond Street Hospital for Children has doubled the number of children able to receive a heart transplant, giving them new hope of a longer and healthier life.

Right now, around 50 children are waiting for a heart transplant in the UK but small hearts are hard to find as the donated heart needs to come from a child roughly the same size. The agonising wait to find out if a suitable heart is available for an urgent transplant is over twice as long for children and babies – an average wait of 88 days compared to 35 days for an adult, while children deemed ‘non-urgent’ will wait over a year, on average.

Over the last 20 years, doctors have increased the number of organs available to children needing a heart transplant by using donor ‘ABO-incompatible’ hearts, where the donated heart doesn’t have the same blood type as the child receiving the transplant.

However, to ensure the ‘mismatched’ heart isn’t rejected, the child’s blood is removed and their circulation is ‘washed out’ with a blood type that matches the donated heart. This requires three times as much new blood as is being replaced, limiting this type of heart transplant to small children who weigh up to around 15 kg, or are just four years of age.

Allowing older children to have a transplant

Now, Dr Richard Issitt and his team at GOSH have found a way to use a special blood filtering device – called an immunoadsorption column – during the transplant operation to reduce the amount of blood needed and allow older children to receive the transplant they desperately need.

The device removes the mismatched antibodies in the blood that can lead to transplant rejection and is added into the heart and lung machine used to support the child during surgery. This machine keeps their blood flowing, delivering vital oxygen and nutrients throughout their body until the new heart is in place.

By filtering out the specific antibodies, the child’s blood doesn’t need to be completely removed and replaced. This consequently halves the amount of donated blood required during the transplant itself and in the intensive care unit afterwards, allowing larger, older children to have an ‘incompatible’ transplant – making them more likely to be matched with a suitable heart.

The team have now performed the ABO-incompatible heart transplant with the new antibody filtering device on 10 children, and compared their outcomes to 27 children who had the standard ABO-incompatible heart transplant technique, where all blood was removed and replaced.

All of the children who had a transplant using the new device survived, there was no need for re-transplantation and there was no difference in the length of hospital stay. The oldest child to receive a transplant using this technique was eight years old, double the age of the oldest child treated previously.

A transformational gift

They are now exploring ways to allow  children who have heightened immune systems – which make finding a suitable heart almost impossible – to have the chance of receiving a transplant that they desperately need.

Dr Richard Issitt, BHF-funded researcher and Senior Paediatric Perfusionist at Great Ormond Street Hospital, who led the study said:

“Some children and babies don’t have the luxury of a fully-functioning heart. Simply incorporating this new device into the current transplant procedure means we can increase the chances of giving them the transformational gift of a new heart.

“No child should start their first years of life longingly awaiting a heart transplant. We’re determined to build on this research to find new ways that will allow more children to have a life saving heart transplant.”

Providing hope to more children

BHF Medical Director, Professor Sir Nilesh Samani, said:
“This is a major advance in child heart transplantation, providing hope to more children who desperately need a new heart to survive.

“Less than 60 years ago heart transplantation was seen as an as impossible dream. Since then, research has turned this dream into a reality for thousands of people across the UK.”

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