Pre-Operative Serum Brain Natriuretic Peptide and Risk of Acute Kidney Injury after Cardiac Surgery.

Circulation. 2012 Feb 9;

Authors: Patel UD, Garg AX, Krumholz HM, Shlipak MG, Coca SG, Sint K, Thiessen-Philbrook H, Koyner JL, Swaminathan M, Passik CS, Parikh CR

Abstract
BACKGROUND: Acute kidney injury (AKI) following cardiac surgery is associated with poor outcomes and is difficult to predict. We conducted a prospective study to evaluate whether pre-operative brain natriuretic peptide (BNP) levels predict postoperative AKI among patients undergoing cardiac surgery. METHODS AND RESULTS: The TRIBE-AKI Consortium enrolled 1,139 adults undergoing cardiac surgery at six hospitals from 2007-2009, who were selected for high AKI risk. Pre-operative BNP was categorized into quintiles. AKI was common using Acute Kidney Injury Network definitions; at least mild AKI was a ?0.3mg/dL or 50% rise in creatinine, n=407 (36%), and severe AKI was either a doubling of creatinine or the requirement of acute renal replacement therapy, n=58 (5.1%). In analyses adjusted for pre-operative characteristics, pre-operative BNP was a strong and independent predictor of mild and severe AKI. Compared with the lowest BNP quintile the highest quintile had significantly higher risk of at least mild AKI (risk ratio [RR] 1.87; 1.40-2.49) and severe AKI (RR 3.17; 1.06-9.48). After adjustment for clinical predictors, addition of BNP improved the area under the curve to predict at least mild AKI (0.67 to 0.69, p=0.02) and severe AKI (0.73 to 0.75, p=0.11). Compared with clinical parameters alone, BNP modestly improved risk prediction of AKI cases into lower and higher risk (continuous net reclassification index at least mild AKI 0.183; 0.061, 0.314; severe AKI 0.231; 0.067, 0.506). CONCLUSIONS: Pre-operative BNP level is associated with post-operative AKI in high-risk patients undergoing cardiac surgery. If confirmed in other types of patients and surgeries, pre-operative BNP may be a valuable component of future efforts to improve pre-operative risk stratification and discrimination among surgical candidates. CLINICAL TRIAL REGISTRATION INFORMATION: clinicaltrials.gov; NCT00774137.

PMID: 22322531 [PubMed - as supplied by publisher]

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