Proposed Preoperative Risk Score for Patients Candidate to Cardiac Valve Surgery

Background: To establish a risk score for heart surgery allows the assessment of preoperative risk, informing the patient and defining care during the intervention. Objective: To assess preoperative risk factors for death in cardiac valve surgery and construct a simple risk model (score) for in-hospital mortality of patients candidate to surgery at Hospital Sao Lucas of Pontificia Universidade Catolica do Rio Grande do Sul (HSL-PUCRS). Methods: The study sample included 1,086 adult patients that underwent cardiac valve surgery between January 1996 and December 2007 at HSL-PUCRS. Logistic regression was used to identify risk and in-hospital mortality factors. The model was developed in 699 patients and its performance was tested in the remaining data (n = 387). The final model was created using the total study sample (n = 7,086). Results: Global mortality was 11.8%; 8.8% of elective cases and 63.8% of emergency cases. At the multivariate analysis, 9 variables remained independent predictors for the outcome: advanced age, surgical priority, female sex, ejection fraction <= 45%, concomitant myocardial revascularization (CABG), pulmonary hypertension, NYHA functional class III or IV, creatinine levels (1.5 to 2.49 mg/dl and > 2.5 mg/dl or undergoing dialysis). The area under the ROC curve was 0.83 (95% Cl: 0.78-0.86). The risk model showed good capacity for observed/predicted mortality: the Hosmer-Lemeshow test was x(2) = 5.67; p = 0.691 and r = 0.98 (Pearson's coefficient). Conclusion: The variables predictive of in-hospital mortality allowed the construction of a simplified risk score for daily practice, which classifies the patient as having low, moderate, high, very high and extremely high preoperative risk. (Arq Bras Cardiol 2010;94(4): 507-514)