Kawasaki disease breakthrough

Kawasaki disease mainly affects children under five

Combining exercise with a drug which helps boost blood vessel development could offer hope to children whose hearts have been affected by a rare disease.

Kawasaki disease (KD), discovered in Japan, mainly strikes children under five. In up to 20% of cases the heart is affected.

Researchers gave children with KD the anti-clotting drug heparin.

What is Kawasaki disease

Also known as Kawasaki syndrome or mucocutaneous lymph node syndrome

Commonly affects one child in a family

The heart is affected in 20% of children with the disease

80% of children affected are under 5

Occurs most in boys, and in those of Asian ancestry

Death rate of under 1%

Symptoms include fever, rash, swollen hands, feet and lymph glands

Combined with a series of 10-minute exercise sessions, it helped new blood vessels grow and widened blocked arteries.

Dr Masaru Terai of the Chiba University School of Medicine in Japan, who carried out the study, said the treatment was "remarkably safe, inexpensive and easy to perform".

KD can damage children's arteries or the heart muscle itself. They can also be susceptible to atherosclerosis - the progressive narrowing of the arteries.

Some patients with more severe forms of the disease are unable to have operations to open up existing blood vessels or encourage new ones to form.

There are around 1,800 cases in the US every year, but the cause of the condition is unknown, though scientists believe it could be caused by an infectious agent such as a virus.

Dr Terai said: "Our study may provide another therapeutic option for those cases."

Exercise

The study, published in Circulation: Journal of the American Heart Association, looked at seven children aged six to 19 years old.

All had a totally blocked coronary artery and were not suitable for surgery.

Our study may provide another therapeutic option

Dr Masaru Terai

They spent 10 minutes on an exercise bike twice a day for 10 days.

Beforehand, they were given heparin, a drug which promotes the development of new blood vessels.

A special X-ray was taken of the blood flow around the blockage one to three months before the treatment and within three months following it. One child did not receive a second X-ray.

Of the six who did, the size of the blocked artery had grown in size, allowing more blood through. In two, a network of tiny new blood vessels had formed.

A second type of X-ray of the amount of blood flowing to the heart was also carried out.

Children were studied while at rest, and after being given the drug dipyridamole, which mimics the effects of physical stress on the heart.

In all seven children, the readings after the treatment showed increased blood flow to the heart.

None showed any signs of heart damage.

Three children with KD who did not receive the treatment showed either an unaltered or increased incidence of stress-related heart damage in the tests.

Dr Terai said: "Previous studies of patients with angina have shown that exercise capacity was not improved by heparin or exercise alone.

'Step forward'

"This implies that the combination of heparin and physical stress is required for improvement in collateral circulation.

Dr Kathryn Taubert, vice president of science and medicine for the American Heart Foundation said: "Kawasaki disease and acute rheumatic fever are the two leading causes of acquired heart disease in children in the United States.

"The findings from this study provide an encouraging step forward in treating children with this disease."

Dr Terai's team are now looking at the longer term effects of the treatment.