SAGE-Hindawi Access to Research Cardiology Research and Practice Volume 2010, Article ID 649164, 12 pages doi:10.4061/2010/649164 Review Article Contrast-Induced Nephropathy in Patients Undergoing Percutaneous Coronary Intervention Sana Shoukat,1 Saqib A. Gowani,1 Asif Jafferani,2 and Sajid H. Dhakam1 1 Cardiology Section, Department of Medicine, The Aga Khan University, Stadium Road, P.O. Box 3500, Karachi 74800, Pakistan 2 MBBS Program, The Aga Khan University, B-4, Al-Qahir Apt., Violet Street, Garden East, Karachi 74550, Pakistan Correspondence should be addressed to Asif Jaﬀerani, asifahsan ali@yahoo.co.uk Received 29 March 2010; Revised 21 July 2010; Accepted 25 August 2010 Academic Editor: Christian Wilhelm Hamm Copyright © 2010 Sana Shoukat et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Contrast Induced Nephropathy (CIN) is a feared complication of numerous radiological procedures that expose patients to contrast media. The most notorious of these procedures is percutaneous coronary intervention (PCI). Not only is this a leading cause of morbidity and mortality, but it also adds to increased costs in high risk patients undergoing PCI. It is thought to result from direct cytotoxicity and hemodynamic challenge to renal tissue. CIN is deﬁned as an increase in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the ﬁrst 2-3 days after contrast administration, after other causes of renal impairment have been excluded. The incidence is considerably higher in diabetics, elderly and patients with pre-existing renal disease when compared to the general population. The nephrotoxic potential of various contrast agents must be evaluated completely, with prevention as the mainstay of focus as no eﬀective treatment exists. The purpose of this article is to examine the pathophysiology, risk factors, and clinical course of CIN, as well as the most recent studies dealing with its prevention and potential therapeutic interventions, especially during PCI. The role of gadolinium as an alternative to iodinated contrast is also discussed. 1. Introduction There is a high prevalence of Chronic Kidney Disease (CKD) in Patients with Coronary Artery Disease (CAD), ranging from 23%–46% in diﬀerent studies [1–3]. Patients with CKD also have a higher risk of cardiovascular events than the general population [4–6]. Also, cardiovascular disease accounts for more than half of end-stage renal disease (ESRD) deaths [7]. Reduced renal function has been seen to be independently associated with risk of death, cardiovas- cular events, and hospitalization in large, community-based populations [6, 8]. The incidence of renal insuﬃciency in this high-risk group of population undergoing coronary intervention is on the rise due to the use of radiographic contrast in increasingly complex cardiac interventional procedures [9]. This has a direct consequence on mortality as seen by Brown et al. who showed that a transient as well as persistent postprocedural renal dysfunction was prognostically signif- icant for mortality during extended followup [10]. Renal function is directly related to mortality in patients with acute myocardial infarction undergoing Primary Percutaneous Coronary Intervention (PCI)-lower the Creatinine Clearance (CrCl); lesser is the survival after Primary PCI [11]. This paper covers the latest update on contrast-induced nephropathy among patients undergoing PCI. 2. Deﬁnition Contrast-induced nephropathy (CIN) after PCI has multiple deﬁnitions in the medical literature [12, 13]. Due to these diﬀerent deﬁnitions used across literature, existing data on this clinical entity is inconsistent. Harjai et al. attempted to identify the optimal deﬁnition of CIN by assessing the prognostic signiﬁcance of 4 commonly used contemporary deﬁnitions of CIN (increases in serum creatinine after PCI [Cr] >1.0 mg/dL, >0.5 mg/dL, and >25% after PCI; and the American College of Cardiology National Cardiovas- cular Data Registry deﬁnition which deﬁnes it as a 2-fold increase in serum creatinine to >2.0 mg/dL or a need for dialysis after PCI [14]) with respect to 6-month major adverse cardiovascular events and all-cause mortality. Only