RESUMO
BACKGROUND: Acetylcysteine may provide prophylaxis against contrast nephropathy (CN) in some patients. Its benefit may vary according to the characteristics of patients and contrast used. The objective is to evaluate the effectiveness of oral acetylcysteine in preventing CN after coronary procedures in our practice. METHODS: We prospectively studied 397 patients with a creatinine level equal to or above 1.3 mg/dl, diabetes mellitus, or 70+ years of age who underwent a coronary procedure. Patients were randomly assigned to receive either acetylcysteine or placebo and 0.9% saline before and after the contrast agent. High- or low-osmolality contrast was used according to the discretion of the interventional cardiologist. Serum creatinine was measured before and 24 to 48 hours after the procedure. RESULTS: An increase of greater than or equal to 25% in the baseline creatinine level 24 to 48 hours after the procedure occurred in 14 (7.1%) of 196 acetylcysteine patients and in 17 (8.4%) of 201 placebo patients (p=0.62). In the acetylcysteine group, the mean baseline serum creatinine concentration was 1.30+/-0.56 mg/dl and increased 0.076+/-0.21 mg/dl 24 to 48 hours after administration of contrast, whereas in the placebo group, it was 1.27+/-0.51 mg/dl and increased 0.101+/-0.28 mg/dl (p=0.33). In the subgroup with estimated baseline creatinine clearance <60 ml/minute, no difference was found in the incidence of CN (9.1% in the acetylcysteine group; 11.7% in the placebo; p=0.66). By multivariate analysis, left ventricular ejection fraction less than or equal to 40%, volume of contrast >200 ml, and estimated creatinine clearance (but not acetylcysteine) were related to CN. CONCLUSIONS: Oral acetylcysteine was not effective as a prophylactic treatment against CN for patients with a potential risk and submitted to coronary angiographic procedures with predominantly high-osmolality contrast.