¹Nephrology Division, Acute Renal Failure Group, Heart Institute, University of São Paulo School of Medicine, São Paulo, Brazil

Correspondence: L Yu, Department of Nephrology, University of Sao Paulo School of Medicine, Av. Dr Arnaldo 455-3° A-S 3310, São Paulo, Brazil 01246-903. E-mail: luisyu@usp.br

Received 13 January 2007; Revised 11 April 2007; Accepted 15 May 2007; Published online 11 July 2007.

Abstract

Acute kidney injury (AKI) following cardiac surgery (AKICS) is associated with increased postoperative (post-op) morbidity and mortality. A prognostic score system for AKI would help anticipate patient (pt) treatment. To develop a predictive score (AKICS) for AKI following cardiac surgery, we used a broad definition of AKI, which included perioperative variables. Six hundred three pts undergoing cardiac surgery were prospectively evaluated for AKI defined as serum creatinine above 2.0 mg/dl or an increase of 50% above baseline value. Univariate and multivariate analyses were used to evaluate pre-, intra-, and post-op parameters associated with AKI. The AKICS scoring system was prospectively validated in a new data set of 215 pts with an incidence of AKI of 14% . Variables included in the AKICS score were age greater than 65, pre-op creatinine above 1.2 mg/dl, pre-op capillary glucose above 140 mg/dl, heart failure, combined surgeries, cardiopulmonary bypass time above 2 h, low cardiac output, and low central venous pressure. The AKICS score presented good calibration and discrimination in both the study group and validation data set. The AKICS system that we developed, which incorporates five risk categories, accurately predicts AKI following cardiac surgery.