Modelo Probabilístico Regional para Avaliação Prognóstica da Cirurgia de Revascularização Miocárdica / Probabilistic Model for Prediction of Prognostics in Myocardial Revascularization: Complications in Coronary Surgery

Fundamento: Escores de risco avaliam risco pré-operatório e permitem definir cuidados durante a intervenção, porém a performance destes instrumentos em amostras distintas das originais é pouco investigada. Objetivos: Testar a validade externa de escores de risco cirúrgico cardíaco (STS e Euroscore) e investigar o poder preditivo de características clínicas da amostra. Métodos: Estudo de coorte retrospectivo realizado entre outubro de 2010 e abril de 2015. Fatores de risco para morbidade hospitalar foram identificados através de regressão logística. A amostra foi separada para validação cruzada, com 2/3 dos pacientes usados no ajuste do modelo e 1/3 para predições. A performance do STS, do Euroscore e de variáveis clínicas na amostra foi avaliada através de estatística-C (área sob a curva ROC) e calibração através do pelo de Hosmer-Lemeshow (H-L). Resultados: 72 pacientes foram operados de doença arterial coronariana no Hospital Santa Izabel da Santa Casa, BA. A idade média foi 62,8 anos e 32,5% eram mulheres. Os escores de risco não apresentaram poder discriminativo significativo para amostra. Os fatores identificados como preditores independentes para o desfecho foram: idade, revascularização prévia e creatinina prévia. O modelo ajustado apresentou valores de discriminação e calibração semelhantes no ajuste (AUROC = 0,72; IC 95% 0,59-0,84; H-L valor p: 0,410) e na validação cruzada (AUROC = 0,70; IC 95% 0,55 - 0,84; H-L valor p: 0,197). Conclusão: Escores de risco apresentaram desempenho insatisfatório. Variáveis clínicas permitiram a construção de um modelo com boa performance para predição de morbidade nos pacientes operados de revascularização

Introduction: Risk scores evaluate pre-operatory risk and present support for clinical decisions, however the performance of these tools in samples different from the original ones remains unclear. Objectives: Investigate the external validity of risk scores (STS and Euroscore) in cardiac surgery and the predictive performance of clinical features derived from the sample. Methods: Retrospective Cohort study conducted between October,2010, and April, 2015. We used logistic regression to identify risk factors for hospital morbidity. The sample was divided for cross-validation, with 2/3 of the patients selected for model fitting and 1/3 for prediction testing. The performance of risk scores and clinical features was evaluated through AUROC and calibraton the Hosmer-Lemeshow test (H-L). Results: Data was retrieved from 472 patients who underwent coronary cardiac surgery in Hospital Santa Izabel da Santa Casa, BA. Mean age was 62.8 years old and 32.5% of the sample were women. Traditional surgical risk scores did not present significant discriminative performance for this sample. Factors associated with the outcome after adjusting for covariates were: age, previous myocardial revascularization and presurgical creatinine levels. The adjusted model presented similar discrimination and calibration values during training (AUROC = 0,72; IC 95% 0,59-0,84; H-L valor p: 0,41) and validation (AUROC = 0,70; IC 95% 0,55 - 0,84; H-L valor p: 0,197) Conclusion: Traditional scores may be inaccurate when applied to different environments. New risk scores with good predictive power can be developed using local clinical variables

Predicting outcomes in partial nephrectomy: is the renal score useful?

ABSTRACT Introduction and Objective The R.E.N.A.L. nephrometry system (RNS) has been validated in multiple open, laparoscopic and robotic partial nephrectomy series. The aim of this study was to test the accuracy of R.E.N.A.L. nephrometry system in predicting perioperative outcomes in surgical treatment of kidney tumors <7.0cm in a prospective model. Materials and Methods Seventy-one patients were selected and included in this prospective study. We evaluate the accuracy of RNS in predicting perioperative outcomes (WIT, OT, EBL, LOS, conversion, complications and surgical margins) in partial nephrectomy using ROC curves, univariate and multivariate analyses. R.E.N.A.L. was divided in 3 groups: low complexity (LC), medium complexity (MC) and high complexity (HC). Results No patients in LC group had WIT >20 min, versus 41.4% and 64.3% MC and HC groups respectively (p=0.03); AUC=0.643 (p=0.07). RNS was associated with convertion rate (LC:28.6% ; MC:47.6%; HC:77.3%, p=0.02). Patients with RNS <8 were most often subjected to partial nephrectomy (93% x 72%, p=0.03) and laparoscopic partial nephrectomy (56.8% x 28%, p=0.02), AUC=0.715 (p=0.002). The RNS was also associated with operative time. Patients with a score >8 had 6.06 times greater chance of having a surgery duration >180 min. (p=0.017), AUC=0.63 (p=0.059). R.E.N.A.L. score did not correlate with EBL, complications (Clavien >3), LOS or positive surgical margin. Conclusion R.E.N.A.L. score was a good method in predicting surgical access route and type of nephrectomy. Also was associated with OT and WIT, but with weak accuracy. Although, RNS was not associated with Clavien >3, EBL, LOS or positive surgical margin.