Canadian Association of Radiologists: consensus guidelines for the prevention of contrast-induced nephropathy.

The development of acute renal failure significantly complicates intravascular contrast medium (CM) use and is linked with high morbidity and mortality. The increasing use of CM, an aging population, and an increase in chronic kidney disease (CKD) will result in an increased incidence of contrast-induced nephropathy (CIN)-unless preventive measures are used. The Canadian Association of Radiologists has developed these guidelines as a practical approach to risk stratification and prevention of CIN. The major risk factor predicting CIN is preexisting CKD, which can be predicted from the glomerular filtration rate (GFR). In terms of being an absolute measure, serum creatinine (SCr) is an unreliable measure of renal function. Patients with GFR >60 mL/min have a very low risk of CIN, and preventive measures are generally unnecessary. When GFR is <60 mL/min, preventive measures should be instituted. The risk of CIN is greatest in patients with GFR <30 mL/min. Preventive measures: Alternative imaging that does not require CM should be considered. Fluid volume loading is the single most important protective measure. Nephrotoxic medications should be discontinued 48 hours prior to the study. CM volume and frequency of administration should be minimized, but satisfactory image quality should still be maintained. High-osmolar contrast should be avoided in patients with renal impairment. There is some evidence to suggest that iso-osmolar contrast reduces the risk of CIN among patients with renal impairment, but further study is necessary to determine whether iso-osmolar contrast is superior to low-osmolar contrast. Acetylcysteine (AC) has been advocated to reduce the incidence of CIN; however, not all studies have shown a benefit, and it is difficult to formulate evidence-based recommendations at this time. Its use may be considered in high-risk patients but is not considered mandatory.