Patients undergoing cardiac catheterization with receipt of contrast media should receive adequate preparatory hydration.164,165 (Level of Evidence: B) 2011 recommendation remains current. 3. Calculation of the contrast volume to creatinine clearance ratio is useful to predict the maximum volume of contrast media that can be given without significantly increasing the risk of contrast-associated nephropathy.166,167 (Level of Evidence: B) 2011 recommendation remains current. Class IIa 1. An invasive strategy is reasonable in patients with mild (stage 2) and moderate (stage 3) CKD.162,163,168,169 (Level of Evidence: B) (There are insufficient data on benefit/risk of invasive strategy in UA/NSTEMI patients with advanced CKD 2011 recommendation remains current. CKD indicates chronic kidney disease; and UA/NSTEMI, unstable angina/non ST-elevation myocardial infarction. Jneid et al 2012 UA/NSTEMI Focused Update 893 were consistent regardless of ancillary preventive therapies (hydration, acetylcysteine), route of administration (IV or intra-arterial), age, sex, dose, or preexisting CKD or diabetes. Of further interest, findings were similar in the 8 studies (n 1793 patients) performed in the setting of coronary angiography.174 A more recent study comparing iodixanol versus iopamidol provides additional supportive evidence.176 However, even these clinical inferences must be tempered by the relative paucity of head-to-head trials comparing CIN rates among the various contrast media and the variability in results (eg, for iohexol versus other low-osmolar compara- tors).177 180 Furthermore, the assumption that a transient rise in serum creatinine after 24 to 48 hours is a reliable predictor of the more serious but somewhat delayed development of renal failure requiring hospitalization or dialysis has been challenged. A nationwide Swedish survey181 of hospitaliza- tions for renal failure after coronary procedures in 57 925 patients found that this risk was paradoxically higher with iodixanol (1.7%) than ioxaglate (0.8%) or iohexol (0.9%; P 0.001). 