Heart valve breakthrough

Many heart valves have to be replaced

Scientists in the US say they have developed an artificial heart valve that grows with the patient.

The discovery could mean an end to operations to replace faulty or damaged valves, which control the flow of blood through the heart.

The artificial valve is made of pig collagen but becomes virtually the patients' own as their cells grow in and around it.

The Synergraft valves starts out as a normal pig heart valve. Chemicals are used to strip all the cells away - cells that could cause infection or lead to rejection by the body.

The collagen structure that remains is implanted into the patient's heart.

Tests in sheep show that the patient's cells then grow in and on the collagen structure, and start building new collagen.

"It becomes the patient's own valve," said Roy Vogeltanz, from Cryolife, the company developing the valve.

Dr Stephen Goldstein added: "The valves remained competent. They weren't leaking. We suppose the valves actually increased in size."

Techniques that could reduce repeat surgery are an interesting prospect

British Heart Foundation spokeswoman

Pig valves are routinely used in humans but they tend to wear out, become calcified or are rejected by the immune system.

They must then be replaced which requires a major operation.

The company hopes its product will do none of these things

Its scientists are using the technology to see if they can use donated human heart valves in the same way.

However, a shortage in donated organs has led them to concentrate on developing the pig heart valves.

A spokeswoman for the British Heart Foundation said the organisation would welcome more research into the work being carried out by Cryolife.

"Newer techniques that could reduce repeat surgery are an interesting prospect.

"So far only six patients have been involved in in-patient trials so the new technique is unlikely to be an option for quite some time.

"However the British Heart Foundation welcomes more research on this 'growing heart valve' in the hope it may lead to future improvements in the outcome for heart patients."