Background: Contrast-induced nephropathy (CIN) after coronary angiography is associated with increased morbidity and mortality rates. Preliminary studies with N-acetylcysteine (NAC) have found conflicting results in the prevention of CIN in patients undergoing coronary angiography. This study was designed to evaluate the efficacy and safety of NAC in the prevention of CIN in patients undergoing coronary angiography.
Methods: This study was prospective, randomized, double-blind, and placebo-controlled. Patients referred for elective coronary angiography with a baseline creatinine clearance level <50 mL/min and serum creatinine >1.2 mg/dL were randomly assigned to 1500 mg NAC or placebo, starting the evening before angiography and given every 12 hours for 4 doses. The primary study end point was the development of CIN, which was defined as an increase of >0.5 mg/dL or an increase of > or =25% in serum creatinine over baseline within 48 hours of angiography. Secondary end points included changes in serum creatinine and blood urea nitrogen, requirement of dialysis, side effects of study medication, hospital length of stay, and hospital charges.
Results: CIN occurred in 8.2% (4/49) of patients taking NAC and 6.4% (3/47) of patients taking placebo. Changes in BUN and serum creatinine from baseline were not significantly different in the two treatment groups. Baseline BUN and volume of contrast were the only independent predictors of CIN. More patients with diabetes had development of CIN (5/43; 12%) compared with nondiabetic patients (2/52; 4%), but the difference was not significant (P =.15). The incidence of CIN in diabetic patients was not different in the two treatment groups. No patient with development of CIN required dialysis. Side effects (mostly gastrointestinal) occurred in 16% of patients taking NAC and in none of the patients taking placebo. Length of stay and hospital charges were not different between the treatment groups.
Conclusions: In patients with reduced renal function undergoing elective coronary angiography, NAC does not reduce the risk of CIN.