News Release

Children with congenital heart disease at risk from harmful toxins

Peer-Reviewed Publication

Imperial College London

Babies and toddlers with congenital heart disease are at an increased risk of having harmful toxins in their blood, particularly following surgery, according to research by a team at Imperial College London.

The study, published today in the American Journal of Respiratory and Critical Care Medicine, found that children with high levels of toxins from gut bacteria in their blood are likely to take longer to recover from surgery and spend more time in intensive care.

The researchers say that more work needs to be done to protect children who have heart surgery from bacterial toxins, perhaps using drugs that neutralise them or treatments that protect the gut.

Congenital heart disease is one of the most common types of birth defect, affecting about 1 in every 145 births. Some abnormalities are minor and do not require treatment, but many babies and young children have to undergo surgery to correct the defect.

Dr Nazima Pathan, the lead author of the study from the National Heart and Lung Institute at Imperial College London, said: "The gut usually acts as a barrier that protects the body from toxins. However, our study suggests that in some babies with congenital heart disease, the gut isn't able to do this job properly. These babies are often small and undernourished, and the heart defect can mean that the blood supply to the gut is abnormal. On top of this they have to cope with the trauma of surgery and our study suggests that all these factors can affect the protective barrier function of the gut."

Bacterial fragments called endotoxins that cross into the blood from the gut stimulate the body's immune system and can affect the function of vital organs.

Dr Pathan and her team measured the levels of endotoxins in 40 children requiring surgery for congenital heart disease, admitted to the paediatric intensive care unit at Royal Brompton Hospital, where Dr Pathan is a paediatric consultant. The children ranged in age between 2 and 46 months.

The results showed that even before surgery, over a fifth of children had higher than normal levels of endotoxin, and levels rose after surgery. Overall 27.5 per cent of the children had raised endotoxin levels after surgery. The highest endotoxin levels were measured in small children and those whose heart defects resulted in compromised blood supply to the gut. Importantly, children with high endotoxin levels showed more signs of organ dysfunction and tended to spend longer in intensive care.

The children may have been exposed to bacterial toxins during surgery. However, the levels of toxins in the blood continued to rise in the days after surgery, suggesting that bacteria in the gut were the main source.

"We were surprised at how common endotoxaemia was in these children and how strongly endotoxin levels correlated with poor clinical outcomes," Dr Pathan added. "Most children recover well from surgery for congenital heart disease, but we want to reduce the chances of further complications so that young children don't have to spend as long in intensive care. We're now working with colleagues at Imperial to look at how we can protect vulnerable children from harmful toxins."

The study was funded by Heart Research UK and the Higher Education Funding Council for England (HEFCE). Barbara Harpham, National Director at Heart Research UK, said: "We're so pleased that the £84,500 research grant we awarded has provided such a valuable insight, which could help children with congenital heart disease. Obviously, more research is needed but these initial findings could lead to some important developments in treatments for children and babies undergoing lifesaving surgery."

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For further information please contact:

Sam Wong
Research Media Officer
Imperial College London
Email: sam.wong@imperial.ac.uk
Tel: +44(0)20 7594 2198
Out of hours duty press officer: +44(0)7803 886 248

Notes to editors:

Journal reference: N. Pathan et al. 'Intestinal injury and endotoxaemia in children undergoing surgery for congenital heart disease.' American Journal of Respiratory and Critical Care Medicine, 26 August 2011.

About Imperial College London

Consistently rated amongst the world's best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 14,000 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.

Since its foundation in 1907, Imperial's contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve global health, tackle climate change, develop sustainable sources of energy and address security challenges.

In 2007, Imperial College London and Imperial College Healthcare NHS Trust formed the UK's first Academic Health Science Centre. This unique partnership aims to improve the quality of life of patients and populations by taking new discoveries and translating them into new therapies as quickly as possible.

Website: www.imperial.ac.uk

About Heart Research UK

Heart Research UK is a visionary charity founded in 1967 by Mr David Watson, a working heart surgeon, who realised that patients were dying unnecessarily because of the lack of research into heart disease, especially surgical techniques. Having funded six of the first eight successful UK heart transplants the charity leads the way funding ground breaking, medical research projects into the prevention, treatment and cure of heart disease. There is a strong emphasis on supporting clinical and surgical projects and young researchers on their first steps into research. The charity currently funds over £4.1m of research projects at 32 hospitals and universities across the UK, funding over £860,000 last year alone. In addition, over £1m has been awarded, over the last 10 years, to community-based lifestyle projects that aim to prevent or reduce the risks of heart disease.

Website: www.heartresearch.org.uk

Royal Brompton & Harefield NHS Foundation Trust is a national and international specialist heart and lung centre based in Chelsea, London and Harefield, Middlesex. The Trust helps patients from all age groups who have heart and lung problems and is the country's largest centre for the treatment of adult congenital heart disease. For information visit www.rbht.nhs.uk


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