Stratification of complexity in congenital heart surgery: comparative study of the Risk Adjustment for Congenital Heart Surgery (RACHS-1) method, Aristotle basic score and Society of Thoracic Surgeons-European Association for Cardio- Thoracic Surgery (STS-EACTS) mortality score

Objective

To determine whether stratification of complexity models in congenital heartsurgery (RACHS-1, Aristotle basic score and STS-EACTS mortality score) fitto our center and determine the best method of discriminating hospitalmortality.

Methods

Surgical procedures in congenital heart diseases in patients under 18 yearsof age were allocated to the categories proposed by the stratification ofcomplexity methods currently available. The outcome hospital mortality wascalculated for each category from the three models. Statistical analysis wasperformed to verify whether the categories presented different mortalities.The discriminatory ability of the models was determined by calculating thearea under the ROC curve and a comparison between the curves of the threemodels was performed.

Results

360 patients were allocated according to the three methods. There was astatistically significant difference between the mortality categories:RACHS-1 (1) - 1.3%, (2) - 11.4%, (3)-27.3%, (4) - 50 %,(P<0.001); Aristotle basic score (1) - 1.1%, (2) -12.2%, (3) - 34%, (4) - 64.7%, (P<0.001); and STS-EACTSmortality score (1) - 5.5 %, (2) - 13.6%, (3) - 18.7%, (4) - 35.8%,(P<0.001). The three models had similar accuracy bycalculating the area under the ROC curve: RACHS-1- 0.738; STS-EACTS-0.739;Aristotle- 0.766.

Conclusion

The three models of stratification of complexity currently available in theliterature are useful with different mortalities between the proposedcategories with similar discriminatory capacity for hospital mortality.