An inquiry into child death rates at Harefield Hospital has shrugged off claims that mortality for patients treated for congenital heart problems increased as a result of 'major clinical failure'.

The inquiry led by Dr Stewart Hunter, consultant in paediatric cardiology at Newcastle's Freeman Hospital, found evidence of high rates for specific groups in several periods examined between 1984 and 1999.

Although the report flags up Harefield's reputation for accepting difficult cases, and action taken by the hospital to modify surgical practices, which had the effect of lowering death rates, it says 'clear inadequacies' in national and trust data to compare mortality rates meant it was 'extraordinarily difficult to compare 'like with like''.

The report highlights a 'serious inadequacy' in the Hospital Episodes Statistics and the Cardiac Surgical Register which made 'assessment of outcomes, risk stratification and comparison between units very difficult and, in some instances, impossible'.

This could raise questions over its conclusion that there is 'no evidence to suggest that there was a major clinical failure in the treatment of patients' at Harefield.

The review of surgical outcomes in children with congenital heart disease treated at Harefield Hospital describes the children's heart unit as small, 'chronically understaffed and under-funded'.

The report, published last week, endorsed the decision to close the existing heart unit at Harefield and move it into the Royal Brompton Hospital this spring, highlighting the 'considerable argument for concentrating resources into larger centres'.

The review was prompted by evidence given to the Bristol Royal Infirmary inquiry. It follows a similar review by Dr Hunter of mortality rates at the Royal Brompton Hospital, part of the same trust.

Dr Hunter's review of the Royal Brompton said its surgical results were in line with national data, and found no evidence that children with Down's syndrome suffered discrimination, but felt the concerns of 42 families should be considered more fully by an independent panel.

In September 1999 the trust commissioned a panel chaired by Ruth Evans, director of the National Consumer Council, 'to consider the complaints and concerns of parents whose children had received paediatric cardiac services at the Royal Brompton Hospital between 1987 and 1999'. Its report - due out next month - will also consider concerns surrounding seven patients treated at the Harefield.