N-acetylcysteine and contrast-induced nephropathy in primary angioplasty

BACKGROUND: Patients with acute myocardial infarction undergoing primary angioplasty are at high risk for contrast-medium-induced nephropathy because of hemodynamic instability, the need for a high volume of contrast medium, and the lack of effective prophylaxis. We investigated the antioxidant N-acetylcysteine for the prevention of contrast-medium-induced nephropathy in patients undergoing primary angioplasty. METHODS: We randomly assigned 354 consecutive patients undergoing primary angioplasty to one of three groups: 116 patients were assigned to a standard dose of N-acetylcysteine (a 600-mg intravenous bolus before primary angioplasty and 600 mg orally twice daily for the 48 hours after angioplasty), 119 patients to a double dose of N-acetylcysteine (a 1200-mg intravenous bolus and 1200 mg orally twice daily for the 48 hours after intervention), and 119 patients to placebo. RESULTS: The serum creatinine concentration increased 25 percent or more from baseline after primary angioplasty in 39 of the control patients (33 percent), 17 of the patients receiving standard-dose N-acetylcysteine (15 percent), and 10 patients receiving high-dose N-acetylcysteine (8 percent, P<0.001). Overall in-hospital mortality was higher in patients with contrast-medium-induced nephropathy than in those without such nephropathy (26 percent vs. 1 percent, P<0.001). Thirteen patients (11 percent) in the control group died, as did five (4 percent) in the standard-dose N-acetylcysteine group and three (3 percent) in the high-dose N-acetylcysteine group (P=0.02). The rate for the composite end point of death, acute renal failure requiring temporary renal-replacement therapy, or the need for mechanical ventilation was 21 (18 percent), 8 (7 percent), and 6 (5 percent) in the three groups, respectively (P=0.002). CONCLUSIONS: Intravenous and oral N-acetylcysteine may prevent contrast-medium-induced nephropathy with a dose-dependent effect in patients treated with primary angioplasty and may improve hospital outcome.