N-acetylcysteine reduces contrast-associated nephropathy but not clinical events during long-term follow-up

Background Contrast-associated nephropathy (CAN) is associated with increased morbidity and mortality following percutaneous coronary intervention (PCI). N-acetylcysteine (NAC) has been shown to reduce the risk of nephropathy; however, the impact of NAC on long-term clinical outcomes has not been assessed. Methods This randomized, double-blind, placebo-controlled trial enrolled 180 patients with moderate renal dysfunction undergoing PCI or coronary angiography with a high likelihood of ad hoc PCI; 171 patients completed the clinical follow-up. Patients received oral NAC (2000 mg/dose, N = 95) or placebo (n = 85) twice a day for 3 doses if randomized the night prior to the procedure, and 2 doses if randomized the day of the procedure. The primary end point was the incidence of a ≥25% increase in serum creatinine level 48 to 72 hours after PCI. Secondary end points were the inhospital incidence of death, nonfatal myocardial infarction, or urgent dialysis, and the 9-month incidence of death, nonfatal myocardial infarction, need for dialysis, or repeat hospitalization for cardiac reasons. Results CAN occurred in 9.6% of patients assigned to NAC and 22.2% of patients assigned to placebo (P = .04); 1 patient receiving NAC required urgent dialysis. The inhospital composite end point occurred in 7 (7.4%) NAC-treated and 3 (3.5%) placebo-treated patients, P = NS. At 9 months, the composite end point occurred in 23 (24.2%) NAC-treated patients and 18 (21.2%) placebo-treated, P = NS. Conclusion Although high-dose NAC prevented periprocedural CAN, this benefit did not translate into a decrease in adverse outcomes over 9 months. Further studies to determine the clinical utility of this drug are required.