Abstract

ITHURALDE, Mariano et al. Assessment of Mortality and Distribution of Surgery Procedures in Congenital Heart Disease Using the RACHS-1 Risk Adjustment Method. Rev. argent. cardiol. [online]. 2007, vol.75, n.3, pp.179-184. ISSN 1850-3748.

Background The RACHS method is widely used to predict mortality and risk adjustment in pediatric cardiovascular surgery, and constitutes a valid tool to compare the results between different health centers. Objectives 1) Statistical comparison of the distribution of our procedures according to RACHS classification, 2) validation of the RACHS Model in a cardiovascular surgery center in Argentina, 3) obtain an adjusted mortality rate to compare our results to a standard population. Methods 1) From March/2001 to March/2006 all consecutive patients under 18 years of age who underwent cardiovascular surgery in our institution were included. The procedures were grouped by the 6 RACHS-1 categories and patients' age. 2) Model validation: Hosmer-Lemeshow test was performed to test model calibration (observed vs. expected mortality). ROC (receiver operator caracteristics) analysis was performed to evaluate model discrimination. 3) Adjusted mortality: to compare mortality to a standard population direct standardization was performed to obtain crude and adjusted mortality and the standarized mortality ratio (SMR). Results A total of 571 procedures were screened. 1) Population description: RACHS 1: 17.51%, RACHS 2 : 38.00%, RACHS 3: 31.17%, RACHS 4: 8.23%, RACHS 5: 0.18%, RACHS 6: 4.9%. 2) Model validation: Mortality by RACHS: Rachs 1: 0%; Rachs 2: 0.92%; Rachs 3: 3.37%; Rachs 4: 10.64; Rachs 5: 0%; Rachs 6: 32.14%. Test de Hosmer-Lemeshow p=0.50 p<0.001., ROC Area for the model was 0.84 p<0.001. 3) Crude mortality was 3.85%, expected mortality according to a reference distribution population was 3.05%, and the SMR was 0.47 (95% CI 0.27-0.67). Conclusions In our institution the RACHS method is a valid risk stratification tool in pediatric cardiovascular surgery patients. The risk distribution in our population is statistically similar to the original study. However, mortality was lower than expected according to a standard population.

Keywords : Congenital Heart Disease; Cardiovascular Surgery; Mortality; Risk.

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