Professor Massimo Caputo from the Bristol Heart Institute used pioneering stem cell injections to correct baby Finley's heart defect. He hopes to develop the technology so children born with the congenital cardiac disease will not need as many operations.
The child was born with the main arteries in his heart the wrong way around and had his first open-heart surgery at Bristol Royal Hospital for Children at just four days old.
However, the surgery did not solve the problem and his heart function deteriorated significantly, with the left side of the heart suffering from a severe lack of blood flow.
After weeks in intensive care, it looked like there was no conventional way to treat Finley's condition and he was reliant on drugs to keep his heart going. But a new procedure was tried, involving stem cells from a placenta bank.
Prof Caputo injected the cells directly into Finley's heart in the hope they would help damaged blood vessels grow. The so-called "allogeneic" cells were grown by scientists at the Royal Free Hospital in London, and millions of them were injected into Finley's heart muscle. Allogeneic cells have the ability to grow into tissue that is not rejected and in Finley's case, have regenerated damaged heart muscle.
Using a bio-printer, a stem cell scaffold is made to repair abnormalities to valves in blood vessels and to mend holes between the two main pumping chambers of the heart. Artificial tissue is normally used on babies for cardiac repairs, but it can fail and it does not grow with the heart, so as the children grow, they require more operations.
Prof Caputo hopes a clinical trial on the patches will happen in the next two years, after successful laboratory work. The trial of the stem cell plasters offers hope for patients like Louie from Wales, who has several congenital heart defects. The 13-year-old from Cardiff had his first open heart surgery with Prof Caputo at just two weeks old and then again aged four to replace the material fixing his heart. But because the materials are not completely biological, they are unable to grow with him and he needs repeat operations.
Like Louie, every day in the UK, around 13 babies are diagnosed with a congenital heart defect - a heart condition that develops before the baby is born, according to the British Heart Foundation. A child might therefore have to go through the same heart operation multiple times throughout his childhood - around 200 repeat operations for congenital heart defects are carried out every year in the UK.
Louie hopes the breakthrough means the number of operations he faces will be significantly reduced thanks to the stem cell technology and tissues able to grow with his body. Prof Caputo and his team say the stem cell technology could save the NHS an estimated £30,000 for every operation no longer needed, saving millions of pounds each year.