Guidelines on the use of iodinated contrast media in patients with kidney disease 2012: digest version

Open image in new window What is the definition of CIN? Answer: CIN is defined as an increase in serum creatinine (SCr) levels by ≥0.5 mg/dL or ≥25 % from baseline within 72 h after a contrast radiography using iodinated contrast media. Open image in new window Because the risk for developing CIN increases as kidney function decreases, it is important to evaluate kidney function on the basis of the latest SCr levels prior to contrast radiography. According to the classification of the severity of CKD, which is based on the cause, GFR, and presence and severity of albuminuria (Table 1) [1], patients with a GFR of <60 mL/min/1.73 m2 (G3a–G5) are considered to have CKD in this guideline. In another words, CKD is also diagnosed in patients with a GFR of ≥60 mL/min/1.73 m2 and albuminuria, in the present guidelines only patients with a GFR of <60 mL/min/1.73 m2 are defined as having CKD. Table 1 Classification of severity of CKD (2012) Open image in new window Risks of ESKD requiring dialysis or transplantation, and risks for cardiovascular diseases such as stroke, myocardial infarction, and heart failure are coded with colors ranging from green (lowest), yellow, orange and red (highest) CKD chronic kidney disease, Cr creatinine, ESKD end-stage kidney disease, GFR glomerular filtration rate Adapted from KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Inter Suppl. 2013;3:19–62 [1], with permission from Nature Publishing Group., modified for Japanese patients The following formula is used to calculate estimated GFR (eGFR). Open image in new window CIN is a form of acute kidney injury (AKI) that occurs after exposure to iodinated contrast media, and is diagnosed on the basis of reducing kidney function after contrast radiography when other causes such as cholesterol embolism are ruled out. AKI due to CIN is generally reversible. Usually, SCr levels increase to a peak 3–5 days after onset, and return to normal in 7–14 days. However, kidney injury may worsen to the point that hemodialysis is required in some patients. The criteria for the diagnosis of CIN used in clinical research of this condition vary among studies. The minimum increment of SCr levels that defined CIN included 0.5 mg/dL, 1.0 mg/dL, and 25 % or 50 % from baseline, and the duration of monitoring for CIN included 24 h, 48 h, 72 h, 4 days, and 7 days after contrast radiography. The most commonly used criteria for CIN in clinical research is an increase in SCr levels by ≥0.5 mg/dL or ≥25 % from baseline within 72 h after contrast radiography. However, physicians in the clinical setting should not wait for 72 h, and should start close monitoring of SCr levels from an early stage when CIN is suspected. The incidence of CIN, and clinical characteristics such as patients’ baseline kidney function, vary depending on the criteria used for diagnosis. Standardized diagnostic criteria are necessary to promote clinical research of this condition and develop preventive procedures. Open image in new window Open image in new window