IJCS | Volume 33, Nº2, March / April 2020

165 (p = 0.986) was obtained, indicating good performance of the model. The only POAF prediction score that had a similar discriminationwas reported byMathew et al., 26 in which an area under the ROC curve of 0.77 was obtained after the definition of 10 pre-, intra- and postoperative predictor variables. 26 Previously reported prediction scores had lower discrimination values compared with our risk score. 11,12,26,33-35 The absence of a perfect discrimination can be explained by the multifactorial origin of the POAF, pathophysiological mechanisms that have not been fully characterized to date, and heterogeneity of heart diseases. Our risk model was developed and validated in one center, and several studies have suggested that the scores have a lower efficacy when applied in different patients from those used to construct the model. Therefore, external validation is fundamental to determine the clinical relevance of this risk model. However, as with any risk stratification score, this tool should be reassessed in the long term regarding existing variables and incorporation of new variables. It is important to highlight that, since these results were obtained from a clinical database, caution is needed when extrapolating them to the general population. This is the first clinical predictive score for POAF developed in a Brazilian population. Conclusion In summary, we detected four risk variables for the development of POAF during the postoperative period of heart valve surgery and/or revascularization in a Brazilian sample. Using these risk variables, it was possible to construct a score that had a good predictive ability for the outcome occurrence. In addition, thismodel enables the appropriate classification of patients with a low, medium, high or very high risk of developing POAF. Author contributions Conception and design of the research: Ronsoni RM, Leiria TLL, Pires LM, KruseML, Pereira E, Silva RG, Lima GG. Acquisition of data: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Analysis and interpretation of the data: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Statistical analysis: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Obtaining financing: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Writing of the manuscript: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Critical revision of the manuscript for intellectual content: Ronsoni RM, Leiria TLL, Pires LM, Kruse ML, Pereira E, Silva RG, Lima GG. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the dissertation of master submitted by Rafael de March Ronsoni, from Instituto de Cardiologia – Fundação Universitária de Cardiologia – RS. Ethics approval and consent to participate This study was approved by the Ethics Committee of the ICIFUC under the protocol number 2345902. All the procedures in this studywere in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 1. Villareal RP, Hariharan R, Liu BC, Kar B, Lee VV, Elayda M, et al. Postoperative atrial fibrillation andmortality after coronary artery bypass surgery. J Am Coll Cardiol. 2004;43(5):742–8. 2. Mariscalco G, EngströmKG.Atrial fibrillation after cardiac surgery: Risk factors and their temporal relationship in prophylactic drug strategy decision. Int J Cardiol. 2008;129(3):354–62. 3. Echahidi N, Pibarot P, O’Hara G, Mathieu P. Mechanisms, Prevention, and Treatment of Atrial Fibrillation After Cardiac Surgery. J Am Coll Cardiol. 2008;51(8):793-801. 4. Aranki SF, Shaw DP, Adams DH, Rizzo RJ, Couper GS, VanderVliet M, et al. Predictors of Atrial Fibrillation After Coronary Artery Surgery. Circulation. 1996;94(3):39-46. 5. Creswell LL, Schuessler RB, Rosenbloom M, Cox JL. Hazards of postoperative atrial arrhythmias. Ann Thorac Surg. 1993;56(3):539–49. 6. Hogue CW, Creswell LL, Gutterman DD, Fleisher LA. American College of Chest Physicians. Epidemiology, mechanisms, and risks: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery. Chest. 2005;128(2):9S–16S. References Ronsoni et al. POAF risk score Int J Cardiovasc Sci. 2020; 33(2):158-166 Original Article