In this Italian study, the effect of N-acetylcysteine in preventing subclinical nephropathy was striking.
Studies on use of the antioxidant N-acetylcysteine to prevent contrast-induced nephropathy have yielded mixed results in patients undergoing coronary angiography. In this new study, Italian researchers examined the effect of N-acetylcysteine in 354 patients with acute myocardial infarction who underwent angiography plus primary angioplasty.
Patients were randomized to receive standard-dose N-acetylcysteine (600 mg intravenously before the procedure, followed by 600 mg orally twice daily for 2 days); high-dose N-acetylcysteine (1200 mg IV and orally); or placebo. All patients were hydrated with intravenous saline. At baseline, median serum creatinine level was 1.0 mg/dL.
Contrast nephropathy (defined as a 25% increase in serum creatinine level during the 72 hours after angioplasty) occurred significantly more often in placebo recipients than in standard- or high-dose N-acetylcysteine recipients (33% vs. 15% and 8%). In-hospital mortality was also significantly higher in the placebo group than in the N-acetylcysteine groups (11% vs. 4% and 3%). A composite endpoint (death, acute renal failure requiring renal replacement therapy, or need for mechanical ventilation) followed the same pattern (18% vs. 7% and 5%).
In this trial, the protective effect of N-acetylcysteine was striking: It resulted not only in a lower incidence of subclinical nephropathy, but also in better clinical outcomes. The authors speculate that extrarenal effects of N-acetylcysteine (e.g., favorable antioxidant effects on the heart) might have contributed to the drug's clinical benefit. Because this study was conducted at a single hospital, these promising results should be confirmed in other centers.
Reference:
Marenzi G et al. N-acetylcysteine and contrast-induced nephropathy in primary angioplasty. N Engl J Med 2006 Jun 29; 354:2773-82.