[Prevention of contrast-induced acute kidney injury]

Contrast-induced nephropathy (CIN) is one of the most frequent causes of acute kidney injury in hospitalized patients. Its incidence depends on patient risk factors (chronic kidney disease, diabetes, cardiovascular diseases and older age) and procedure-related factors (high contrast dose, intraarterial administration). Chronic kidney disease, especially if associated with diabetes, is the main risk factor for CIN. Hydration before and after contrast administration is the only preventive therapy that is strongly recommended by guidelines in patients at risk. CIN prevention studies have focused mainly on cardiac patients with a moderate renal risk (GFR 60-40 mL/min) who underwent intraarterial contrast administration. Many clinical trials have evaluated the efficacy of hydration associated with sodium bicarbonate and of N-acetylcysteine (NAC) in CIN prevention. Sodium bicarbonate infusion has shown better efficacy than saline infusion, particularly when short infusion times are needed, such as in emergency procedures. NAC has not shown any clear effect, and some positive study results have not been confirmed in other trials. The discussion is still open on the efficacy of renal replacement therapies for the prevention of CIN in individuals at high renal risk (GFR <30 mL/min), in whom CIN could mark the entrance to chronic dialysis.