OBJECTIVE: The Risk Adjusted classification for Congenital Heart Surgery (RACHS-1) was created in order to compare in-hospital mortality for groups of children undergoing surgery for congenital heart disease. The method was evaluated with two large multi-institutional data sets-the Paediatric Cardiac Care Consortium (PCCC) and Hospital Discharge (HD) data from three states in the USA. The RACHS-1 classification was later applied to a large German paediatric cardiac surgery population in Bad Oeynhausen (BO), where it was found that the RACHS-1 categories were also associated with length of stay. We applied the RACHS-1 classification to the 957 operations performed during January 1996 to December 2002 at Skejby Sygehus, Denmark and we examined the association between the RACHS-1 categories, in-hospital mortality and length of stay in the Intensive Care Unit.

METHODS: The operations were classified according to the six RACHS-1 categories by matching the procedure of each patient with a risk category. The ability of the RACHS-1 classification to predict mortality in our population was examined by estimating the area under the receiver operator characteristic (ROC) curve. Likelihood ratio chi(2) tests were used to compare the distribution of RACHS-1 categories and the distribution of mortality with PCCC, HD and BO. Linear regression was used to examine the correlation between the RACHS-1 categories and length of stay in the Intensive Care Unit.

RESULTS: The RACHS-1 category frequencies in our population were: category 1: 18.4%, category 2: 37.4%, category 3: 34.6%, category 4: 8.2%, category 5: 0% and category 6: 1.5%. The overall ability of the RACHS-1 classification to predict in-hospital mortality (area under the ROC curve 0.741; 95% confidence interval=0.690; 0.791) was equal to the findings from larger populations. We found no differences in the category specific mortality when comparing with the larger reported series. There was a positive association between RACHS-1 category and length of stay in the Intensive Care Unit.

CONCLUSIONS: The RACHS-1 classification can also be used to predict in-hospital mortality and length of stay in the Intensive Care Unit in a small volume centre.