Background/Aims: Acute kidney injury (AKI) following surgery is a major complication, but the prevalence and risk factors in the Asian population are unclear. Recently, a consensus definition of AKI (AKIN) was proposed. We studied a cohort of cardiac surgery patients and identified AKI by AKIN and associated risk factors. Methods: We retrospectively evaluated 1,056 consecutive patients undergoing cardiac surgery in Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China from January 1, 2004 to June 30, 2007. We recorded AKIN stage, clinical characteristics, perioperative variables and complications, as well as clinical outcomes. Univariate and multivariate regression as well as survival analysis was performed. Results: AKI occurred in 328 (31.1%) patients, stage 1 in 21.1%, stage 2 in 6.3% and stage 3 in 3.7%. Patients with AKI were older (65.8 vs. 53.5 years, p < 0.001), more often male (66.8 vs. 54.1%, p < 0.001), and had higher Charlson Comorbidity Index (CCI) (CCI >2: 22.6 vs. 7.8%, p < 0.001). In logistic regression, advanced age (OR 1.48 per decade, 95% CI 1.32–1.67), CCI >2 (OR 2.82, 95% CI 1.80–4.41), hypertension (OR 2.13, 95% CI 1.47–3.09), left ventricular ejection fraction (LVEF) <45% (OR 1.97, 95% CI 1.14–3.40), postoperative central venous pressure (CVP) <6 cm H2O (OR 13.28, 95% CI 8.72–20.14) and postoperative use of ACEI/ARB (OR 1.90, 95% CI 1.27–2.85) were risk factors of AKI. Mortality rose progressively with increased AKIN stage (non-AKI 0.7%, stage 1 4.9%, stage 2 12.1% and stage 3 48.7%). In ROC analysis, AKIN classification was identified to be associated with in-hospital mortality with an AUC of 0.865 (95% CI 0.801–0.929, sensitivity 0.884, specificity 0.714, p < 0.001). Finally, in a Cox proportional hazards model, AKIN stage (HR 2.40, p < 0.001), re-exploration (HR 6.30, p = 0.002) and multiple organ dysfunction syndrome (MODS) (HR 4.42, p = 0.001) were associated risk factors for in-hospital mortality. Conclusion: We evaluated AKIN as a marker of AKI and mortality risk in a large, unselected Chinese cohort of incident patients undergoing cardiac surgery. AKI following cardiac surgery was diagnosed by AKIN criteria in around one third of the patients, and AKI may be associated with outcome. The value of preventative strategies to reduce AKI and their effect on in-hospital mortality should be studied.

1.
Rosner MH, Okusa MD: Acute kidney injury associated with cardiac surgery. Clin J Am Soc Nephrol 2006;1:19–32.
2.
Kuitunen A, Vento A, Suojaranta-Ylinen R, et al: Acute renal failure after cardiac surgery: evaluation of the RIFLE classification. Ann Thorac Surg 2006;81:542–546.
3.
Siegel NJ, Shah SV: Acute renal failure: directions for the next decade. J Am Soc Nephrol 2003;14:2176–2177.
4.
Palomba H, de Castro I, Neto AL, et al: Acute kidney injury prediction following elective cardiac surgery: AKICS Score. Kidney Int 2007;72:624–631.
5.
Thakar CV, Arrigain S, Worley S, et al: A clinical score to predict acute renal failure after cardiac surgery. J Am Soc Nephrol 2005;16:162–168.
6.
Mehta RH, Grab JD, O’Brien SM, et al: Bedside tool for predicting the risk of postoperative dialysis in patients undergoing cardiac surgery. Circulation 2006;114:2208–2216.
7.
Lassnigg A, Schmidlin D, Mouhieddine M, et al: Minimal changes of serum creatinine predict prognosis in patients after cardiothoracic surgery: a prospective cohort study. J Am Soc Nephrol 2004;15:1597–1605.
8.
Mehta RL, Kellum JA, Shah SV, et al: Acute kidney injury network: report of an initiative to improve outcomes in acute kidney injury. Crit Care 2007;11:R31.
9.
Charlson ME, Pompei P, Ales KL, et al: A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chron Dis 1987;5:373–383.
10.
Marshall JC, Cook DJ, Christou NV, et al: Multiple organ dysfunction score: a reliable descriptor of a complex clinical outcome. Crit Care Med 1995;23:1638–1652.
11.
Wijeysundera DN, Karkouti K, Dupuis JY, et al: Derivation and validation of a simplified predictive index for renal replacement therapy after cardiac surgery. JAMA 2007;297:1801–1809.
12.
Chertow GM, Lazarus JM, Christiansen CL, et al: Preoperative renal risk stratification. Circulation 1997;95:878–884.
13.
Davison D, Junker C: Advances in critical care for the nephrologist: hemodynamic monitoring and volume management. Clin J Am Soc Nephrol 2008;3:554–561.
14.
Abuelo JG: Normotensive ischemic acute renal failure. N Engl J Med 2007;357:797–805.
15.
Kincaid EH, Ashburn DA, Hoyle JR, et al: Does the combination of aprotinin and angiotensin-converting enzyme inhibitor cause renal failure after cardiac surgery? Ann Thorac Surg 2005;80:1388–1393.
16.
Textor SC: Renal failure related to angiotensin-converting enzyme inhibitors. Semin Nephrol 1997;17:67–76.
17.
Thakar CV, Liangos O, Yared JP, et al: ARF after open-heart surgery: influence of gender and race. Am J Kidney Dis 2003;41:742–751.
18.
Xue JL, Daniels F, Star RA, et al: Incidence and mortality of acute renal failure in Medicare beneficiaries, 1992 to 2001. J Am Soc Nephrol 2006;17:1135–1142.
19.
Park KM, Kim JI, Ahn Y, et al. Testosterone is responsible for enhanced susceptibility of males to ischemic renal injury. J Biol Chem 2004;279:52282–52292.
20.
Takayama J, Takaoka M, Sugino Y, et al: Sex difference in ischemic acute renal failure in rats: approach by proteomic analysis. Biol Pharm Bull 2007;30:1905–1912.
21.
Cooper WA, O’Brien SM, Thourani VH, et al: Impact of renal dysfunction on outcomes of coronary artery bypass surgery: results from the Society of Thoracic Surgeons National Adult Cardiac Database. Circulation 2006;13:1063–1070.
22.
Howell NJ, Keogh BE, Bonser RS, et al: Mild renal dysfunction predicts in-hospital mortality and post-discharge survival following cardiac surgery. Eur J Cardiothorac Surg 2008;34:390–395.
23.
Bagshaw SM, Gibney RT: Conventional markers of kidney function. Crit Care Med 2008;36:S152–S158.
24.
Sánchez-Lozada LG, Tapia E, Santamaría J, et al: Mild hyperuricemia induces vasoconstriction and maintains glomerular hypertension in normal and remnant kidney rats. Kidney Int 2005;67:237–247.
25.
Khosla UM, Zharikov S, Finch JL, et al: Hyperuricemia induces endothelial dysfunction. Kidney Int 2005;67:1739–1742.
26.
Kang DH, Park SK, Lee IK, et al: Uric acid-induced C-reactive protein expression: implication on cell proliferation and nitric oxide production of human vascular cells. J Am Soc Nephrol 2005;16:3553–3562.
27.
Klatte K, Chaitman BR, Theroux P, et al: Increased mortality after coronary artery bypass graft surgery is associated with increased levels of postoperative creatine kinase-myocardial band isoenzyme release: results from the GUARDIAN trial. J Am Coll Cardiol 2001;38:1070–1077.
28.
Ejaz AA, Mu W, Kang DH, et al: Could uric acid have a role in acute renal failure? Clin J Am Soc Nephrol 2007;2:16–21.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.