Death rates for children having heart surgery at Alder Hey Hospital are lower than average, an investigation has concluded.

The review was prompted by a "whistleblower" within the hospital staff who contacted the Royal College of Nursing and asked for an investigation.

The NHS review did find one "unacceptable" case, in which a boy died after his surgery was postponed three times.

But in general, the quality of surgery was described as "extremely high".

Professor John Ashton, NHS North West Regional Director of Health, answered the parents' fears by saying: "Parents of children with heart defects can have great faith in this service, which saves lives and gives hope to hundreds of children with heart defects.

"We are dealing here with children who often have very serious congenital abnormalities who, until relatively recently, the prospect of surviving at all or living a good quality life were very slim."

'Public attacks'

However, the concerns about standards at Alder Hey's cardiac unit had already prompted one surgeon, Roger Franks, to quit heart surgery, citing "increasing public attacks".

According to the report, overall death rates during or after heart surgery between 1991 and 1997 were 4.8%, compared to a national average of 6.9%.

In the last three years of that period, this fell to 2.5% compared to 5.2% in other paediatric cardiac units.

However, just as in the Bristol heart babies affair, there were concerns in the early to mid 1990s about the "switch" operation, a particularly difficult procedure involving the repositioning of the two key heart arteries.

Three times the average

Mr Franks started doing these operations in 1990, but stopped in 1993 because his post-operative death rates were three times higher than the then national average.

However, the report concluded that his action had been timely - and that there was no evidence that any of the babies who died would have fared better at another hospital.

Professor Ashton defended the way the unit had handled the issue: "It is not so much that he had a problem but that we have another surgeon who was so much better.

"Our analysis has shown this surgeon is a very good surgeon and he's got very good results."

However, Ian Cohen, a solicitor acting for 250 families of children who had surgery at Alder Hey, said that the matter was not closed.

He said: "There is already information in this report - factual evidence - to support some of the concerns of the parents. Those concerns need to be analysed.

"It would appear there is a particular operation and a particular surgeon and the figures do not compare favourably with a national average.

"But we need to go away, look at the figures and them probably raise some questions."

There were criticisms of the organisation of the unit, although the report noted that the management at Alder Hey had begun to address these issues.

Health minister Lord Hunt responded to the report by saying: "With regard to heart surgery itself, I am satisfied that over the years Alder Hey has provided a quality service, the equal of any in the country."

The concerns over the performance of the heart unit are separate from those over "organ retention" at Alder Hey.

A report on this was commissioned by the Chief Medical Officer Professor Liam Donaldson and is due before the end of the year.