The first Latin-American risk stratification system for cardiac surgery: can be used as a graphic pocket-card score

a Instituto de Cardiología, Hospital Español de Buenos Aires, 2975 Belgrano Avenue, Ciudad autónoma de Buenos Aires, C1209AQK, Buenos Aires, Argentina b Instituto FLENI, 2325 Montañeses, Ciudad autónoma de Buenos Aires, C1428AQK, Buenos Aires, Argentina c Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA d Clínica Suizo-Argentina, 1461 Pueyrredón Avenue, Ciudad autónoma de Buenos Aires, C1118AQK, Buenos Aires, Argentina e Sanatorio de la Trinidad, 4720 Cerviño Avenue, Ciudad autónoma de Buenos Aires, C1425AQK, Buenos Aires, Argentina *Corresponding author. Department of Cardiovascular Surgery, Instituto FLENI, 2325 Montañeses C1428AQK, Belgrano, Buenos Aires, Argentina. Tel.: +54 11-5777-3200; fax: +54 11-5777-3209. E-mail address : drcarosella{at}yahoo.com (V.C. Carosella). This study aims to develop the first Latin-American risk model that can be used as a simple, pocket-card graphic score at bedside. The risk model was developed on 2903 patients who underwent cardiac surgery at the Spanish Hospital of Buenos Aires, Argentina, between June 1994 and December 1999. Internal validation was performed on 708 patients between January 2000 and June 2001 at the same center. External validation was performed on 1087 patients between February 2000 and January 2007 at three other centers in Argentina. In the development dataset the area under receiver operating characteristics (ROC) curve was 0.73 and the Hosmer–Lemeshow (HL) test was P =0.88. In the internal validation ROC curve was 0.77. In the external validation ROC curve was 0.81, but imperfect calibration was detected because the observed in-hospital mortality (3.96%) was significantly lower than the development dataset (8.20%) ( P