Acetylcysteine for Prevention of Renal Outcomes in Patients Undergoing Coronary and Peripheral Vascular Angiography: Main Results From the Randomized Acetylcysteine for Contrast-Induced Nephropathy Trial (ACT)

Study Questions:

What is the safety and efficacy of N-acetylcysteine (NAC) for prevention of contrast-induced nephropathy (CIN)?


The authors performed a randomized evaluation of NAC in 2,308 patients undergoing an intravascular angiographic procedure with at least one of the following risk factors for contrast-induced acute kidney injury (age >70 years, renal failure, diabetes mellitus, heart failure, or hypotension). Patients were randomized to NAC 1200 mg twice daily for 2 doses before and 2 doses after the procedure or similar dose of placebo. The primary endpoint was contrast-induced acute kidney injury, defined as a 25% elevation of serum creatinine above baseline between 48 and 96 hours after angiography.


There was no difference in the incidence of contrast-induced acute kidney injury between the two arms (12.7% vs. 12.7%; relative risk, 1.00; 95% confidence interval [CI], 0.81-1.25; p = 0.97). There was no difference in the secondary endpoint of dialysis (0.3% vs. 0.3%) or a composite of mortality or need for dialysis at 30 days (2.2% vs. 2.3%; HR, 0.97; 95% CI, 0.56-1.69; p = 0.92). No subgroup could be identified where NAC was beneficial.


The authors concluded that NAC does not reduce the risk of CIN or other major adverse events among patients undergoing contrast-based vascular procedures.


CIN is a major complication associated with coronary and peripheral angiography/intervention, and the only proven prophylactic strategies remain adequate hydration, minimization of contrast volume, and use of iso-osmolar or certain low-osmolar contrast media. The benefit of NAC was first reported nearly a decade ago in a small study, and this was followed by a number of small studies with mixed results. Despite the lack of definitive data, the drug has been widely prescribed for prophylaxis of CIN in part secondary to the low cost and assumption of no side effects. This is the first adequately powered study to test this strategy and clearly establishes the lack of benefit of NAC for this purpose, and this practice should be dropped.

Clinical Topics: Heart Failure and Cardiomyopathies, Acute Heart Failure

Keywords: Triiodobenzoic Acids, Acute Kidney Injury, Hypotension, Creatinine, Renal Dialysis, Renal Insufficiency, Free Radical Scavengers, Kidney Diseases, Cardiology, Heart Failure, Confidence Intervals, Diabetes Mellitus

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