title: Assessment of perioperative mortality risk in patients with infective endocarditis undergoing cardiac surgery: performance of the EuroSCORE I and II logistic models.
abstract: OBJECTIVE
  The European System for Cardiac Operative Risk Evaluation (EuroSCORE) has been established as a tool for assisting decision-making in surgical patients and as a benchmark for quality assessment. Infective endocarditis often requires surgical treatment and is associated with high mortality. This study was undertaken to (i) validate both versions of the EuroSCORE, the older logistic EuroSCORE I and the recently developed EuroSCORE II and to compare their performances; (ii) identify predictors other than those included in the EuroSCORE models that might further improve their performance.
  
  
  METHODS
  We retrospectively studied 128 patients from a single-centre registry who underwent heart surgery for active infective endocarditis between January 2007 and November 2014. Binary logistic regression was used to find independent predictors of mortality and to create a new prediction model. Discrimination and calibration of models were assessed by receiver-operating characteristic curve analysis, calibration curves and the Hosmer-Lemeshow test.
  
  
  RESULTS
  The observed perioperative mortality was 16.4% (n = 21). The median EuroSCORE I and EuroSCORE II were 13.9% interquartile range (IQ) (7.0-35.0) and 6.6% IQ (3.5-18.2), respectively. Discriminative power was numerically higher for EuroSCORE II {area under the curve (AUC) of 0.83 [95% confidence interval (CI), 0.75-0.91]} than for EuroSCORE I [0.75 (95% CI, 0.66-0.85), P = 0.09]. The Hosmer-Lemeshow test showed good calibration for EuroSCORE II (P = 0.08) but not for EuroSCORE I (P = 0.04). EuroSCORE I tended to over-predict and EuroSCORE II to under-predict mortality. Among the variables known to be associated with greater infective endocarditis severity, only prosthetic valve infective endocarditis remained an independent predictor of mortality [odds ratio (OR) 6.6; 95% CI, 1.1-39.5; P = 0.04]. The new model including the EuroSCORE II variables and variables known to be associated with greater infective endocarditis severity showed an AUC of 0.87 (95% CI, 0.79-0.94) and differed significantly from EuroSCORE I (P = 0.03) but not from EuroSCORE II (P = 0.4).
  
  
  CONCLUSIONS
  Both EuroSCORE I and II satisfactorily stratify risk in active infective endocarditis; however, EuroSCORE II performed better in the overall comparison. Specific endocarditis features will increase model complexity without an unequivocal improvement in predictive ability.
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal serg.lou.madeira@gmail.com.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Madeira
authors.affiliation: Department of Cardiology, Hospital Central do Funchal, Funchal, Madeira, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Rodrigues
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: António
authors.initials: A
authors.lastname: Tralhão
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Santos
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Almeida
authors.affiliation: Department of Cardiothoracic Surgery, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Marques
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Ferreira
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Raposo
authors.affiliation: Department of Cardiothoracic Surgery, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: José
authors.initials: J
authors.lastname: Neves
authors.affiliation: Department of Cardiology, Hospital de Santa Cruz, Lisbon, Portugal.
authors.forename: Miguel
authors.initials: M
authors.lastname: Mendes
mesh_terms: D000368:Aged; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D004696:Endocarditis / Q000401:mortality* / Q000601:surgery; D004697:Endocarditis, Bacterial; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011174:Portugal / Q000453:epidemiology; D011183:Postoperative Complications / Q000401:mortality*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends
keywords: Heart surgery; Infective endocarditis; Risk stratification