Current concepts of contrast-induced nephropathy: A brief review

Contrast-induced nephropathy (CIN) is a common hospital-acquired acute kidney injury. Published studies on this condition have dramatically increased in recent years. This article aims to provide a brief literature review. English articles published from 1983 to 2012 were retrieved from PubMed by searching using the term "contrast-induced nephropathy." Patients with CIN were associated with increased resource utilization, prolonged hospital stay, and increased long-term mortality. CIN is defined as a ≥0.5mg/dL rise in serum creatinine or a 25% increase, assessed within 48-72 hours after administration of contrast medium (CM). All patients receiving CM should be evaluated for their CIN risk, especially preexisting kidney disease. The CM should be prewarmed to 37°C and injected at the lowest possible dose. Repeat injection within 72 hours should be avoided. Either iso-osmolar CM or low-osmolar CM, except ioxaglate or iohexol, can be used in all patients. Iso-osmolar CM iodixanol may be a better choice for high-risk patients with chronic kidney disease requiring intra-arterial administration. Nephrotoxic drugs should be stopped 2 days prior to when the patient undergoes a procedure. All patients receiving CM should be at an optimal volume status. Parenteral isotonic saline without any diuretic should be started 12 hours prior to CM at a rate of 1mL/kg/h and continued for 24 hours if there is no contraindication. In patients who require shorter volume supplement periods or are at a higher risk, bicarbonate infusion (154 mEq/L, 3mL/kg/h for 1 hour bolus prior to CM, followed by 1mL/kg/h for 6 hours) may be used as an alternative to isotonic saline. Oral N-acetylcysteine (600mg bid, starting on the day prior to the procedure) together with parenteral hydration is suggested for patients at risk. Hemodialysis/hemofiltration is only considered in chronic kidney disease stage 4/5 patients when an access is available. The other medications or techniques for reducing CIN risk are still unclear. CIN is a potentially preventable clinical condition. A careful review of published reports gives us a deeper understanding of CIN and a greater chance of decreasing its risk.