A new technique to perform heart bypasses is unlikely to become standard practice in the UK, a leading cardiac surgeon has said.

Japanese surgeons have reported their success in carrying out the hi-tech procedure on two patients in The Lancet medical journal.

But David Anderson, a cardiac surgeon from Guy's Hospital in London, said the procedure could only be used for a very small number of patients.

And he said the large number of bypass operations carried out each day by NHS surgeons would make the complex new technique too time-consuming to perform.

Heart bypass operations are normally carried out when one or more of the arteries supplying blood to the heart muscle become hardened and clogged, interrupting the flow.

The operation involves taking arteries or veins from other parts of the body and using them to replace the affected sections.

Normally the heart is stopped while this is being done, and its job of pumping blood around the body is carried out by a heart-lung machine in the operating theatre.

Small incisions

The new technique, which was used successfully on a 68 and a 76-year-old by the Japanese surgeons, allows the heart to keep beating throughout.

Four small incisions were made in the chest, and a device - invented by the surgeons - was inserted to hold the arteries steady as they were cut and re-joined.

The joining process took between 25 and 40 minutes, and there were no surgical complications.

"Both patients were ready for discharge on the fourth post-operative day," said the researchers.

The advantages of a keyhole operation are mainly cosmetic - in theory, there should be slightly less scarring even though four cuts are made.

But the technical difficulty for the surgeon is far higher, with the problems of cutting and joining tiny arteries while the heart is jumping around.

Claims that keyhole operations mean less complications and a shorter recovery time have never been proven scientifically beyond doubt.

'Interesting technique'

Mr Anderson said: "I certainly wouldn't agree to be operated on this way, and I wouldn't let any member of my family either.

"It is an interesting technique, but it will only apply to a very small number of patients."

He explained that most heart bypass patients require at least a double or triple bypass, meaning two or three blood vessels have to be replaced.

This technique at the moment can be carried out on a single vessel - normally, UK doctors would try to unblock one with an inflatable balloon pushed up through the blocked artery.

Only if that failed would a full operation be an option.