Surgeons have successfully completed a heart bypass operation on a patient who was left awake throughout.

The US operation is the first time such a procedure has been repeated outside the Turkish hospital which pioneered it.

But a British expert said that while giving only a local anaesthetic for such a major operation had advantages, it also involved extra risks for the patient.

The 51-year-old was given the latest in "minimally invasive" heart bypass surgery, in which one or more of the clogged arteries supplying the heart muscle with blood are replaced.

Standard heart bypasses are an extremely common operation - tens of thousands are carried out in the UK each year,

The latest techniques, used at Pittsburgh Medical Center, involve keeping the heart beating instead of stopping it and pumping the blood with a heart-lung machine.

In this case, however, the patient - a professional magician - was given an epidural anaesthetic, similar to that given to a woman during labour.

Although sedated, he was fully awake and even talked to operating room staff during the procedure.

His entire chest area was rendered numb by the epidural.

Professor Juhan Paiste, an anaesthetics expert, said: "Combining two well-established techniques - minimally invasive cardiac surgery and epidural anaesthesia - may become a new innovative approach to heart bypass surgery for select patients."

The advantages of avoiding a general anaesthetic are two-fold.

Firstly, there is a tiny extra risk of complications because of the general anaesthetic.

However, although this is significant when assessed in the light of a very minor operation, the extra risk is very small in comparison to the higher overall risk of major surgery like a heart bypass.

Another advantage is that the patient will in theory not need to be "intubated" - a breathing tube inserted down the throat, and this should aid his or her recovery.

Local risks

However, Professor Ara Darzi, from Imperial College in London, an expert in minimally-invasive surgery said that while the innovation was "interesting", he could not see the overall advantages of local as opposed to general anaesthetic.

He pointed out that, should serious complications occur suddenly in the middle of the operation, the patient would have to be given a general anaesthetic, and intubated, before surgeons could move to solve the problem.

He also doubted whether the anaesthetic would completely remove the sensation of the surgeon working, even if this was completely painless.

"It is certainly likely to be a very interesting experience for the patient," he said.