Proposta de escore de risco cirúrgico em pacientes com estenose aórtica submetidos à cirurgia de troca valvar

Abstract

Background: Due to population aging, prevalence of aortic stenosis and limited number of scores in the literature, it is essential to develop risk scores adapted to our reality and created in the specific context of this disease. Objective: To construct a clinical death risk score from the data of patients with aortic stenosis submitted to valve replacement surgery. Methods: Observational study of historical cohort. Data collected from 802 patients with aortic stenosis who underwent valve replacement at the São Lucas Hospital of PUCRS between January 1996 and July 2018 were analyzed. Through the aid of multiple logistic regression in a forward stepwise process, a weighted risk score was built based on the magnitude of the coefficients ß of the logistic equation. When they were transformed (exp [ß]) into odds ratios (odds ratios), the values have been rounded up to the whole number using the truncation process to compose the final score. Two performance statistics were obtained: statistic c (area under the ROC curve) and the Hosmer-Lemeshow chi-square of goodness-of-fit with the Pearson correlation coefficient between the observed events and those predicted by the model. Results: The risk predictors that made up the score were: valve replacement surgery combined with coronary artery bypass graft, prior renal failure, presence of NYHA III/IV class heart failure, age greater than 70 years and ejection fraction less than 50%. The area under the ROC curve was 0.77 (CI: 95%, 0.72-0.82). The risk model showed good ability for observed / predicted mortality: Hosmer-Lemeshow test was c2 = 3.70 (p = 0.594) and Pearson's coefficient was r = 0.98 (p < 0.001). Conclusion: We propose a risk score for hospital death in patients undergoing aortic valve replacement using five variables: valve replacement surgery combined with coronary artery bypass graft, previous renal failure, presence of NYHA class III/IV heart failure, age > 70 years and ejection fraction < 50 %, being a simple score, with good performance and adapted to the Brazilian reality.