Impact of Preoperative Functional Capacity on Postoperative Outcomes in Congenital Heart Surgery: An Observational and Prospective Study

Abstract

Background

Despite advances in surgical technique and postoperative care in congenital heart disease, cardiovascular morbidity is still high.

Objective

To evaluate the association between preoperative cardiovascular fitness of children and adolescents, measured by the 6-minute walk test (6MWT) and Heart Rate Variability (HRV), and the occurrence of cardiogenic, septic shock and death in the postoperative period.

Methods

Prospective, observational clinic study including 81 patients aged from 8 to 18 years. In the preoperative period, the 6MWT (distance walked and SpO₂) and HRV were performed. The adjusted risk score for surgeries for congenital heart disease (RACHS-1) was applied to predict the surgical risk factor for mortality. The occurrence of at least one of the listed complications was considered as a combined event. P values < 0.05 were considered as significant.

Results

Of the patients, 59% were male, with mean age of 12 years; 33% were cyanotic; and 72% had undergone previous cardiac surgery. Cardiogenic shock was the most common complication, and 31% had a combined event. Prior to surgery, type of current heart disease, RACHS-1, SpO₂at rest, during the 6MWT and recovery were selected for the multivariate analysis. The SpO₂at recovery by the 6MWT remained as an independent risk factor (OR 0.93, 95%CI [0.88 - 0.99], p=0.02) for the increasing occurrence of combined events.

Conclusion

SpO₂after the application of the 6MWT in the preoperative period was an independent predictor of prognosis in children and adolescents undergoing surgical correction; the walked distance and the HRV did not present this association.

Heart Defects, Congenital; Walk Test; Heart Rate; Physical Functional Performance; Postoperative Complications