Background: N-acetylcysteine (NAC) is an antioxidant drug largely tested in different clinical situations. Recently, NAC has been employed with variable success in the prevention of radiocontrast nephropathy. Since aortic aneurysm surgical repair is a condition that is frequently accompanied by acute renal failure (ARF), we sought to investigate whether NAC has any role in preventing ARF in this scenario.
Methods: A randomized, placebo-controlled, double-blind trial with the following inclusion criteria: elective aortic aneurysm repair in patients with stable renal function. The groups were randomly matched for age, gender, presence of diabetes and pre-existent renal failure. NAC or placebo (control) was administered p.o. for 24 h before operation and maintained i.v. for 48 h after operation. The dose of NAC was 1200 mg b.i.d. the day before surgery and 600 mg b.i.d. after. The primary endpoint was the development of ARF up to the third post-operative day, defined as an increase in SCr > or = 25% from baseline. Secondary endpoints were: ICU mortality and ICU length of stay.
Results: Forty-two patients (n = 18 for NAC group and n = 24 for control) were studied. The baseline SCr and calculated GFR did not differ between the groups (1.19 +/- 0.33 vs 1.37 +/- 0.49 mg/dl; and 64.6 +/- 26.22 vs 65.7 +/- 28.32 ml/min, NAC vs control, respectively, P = 0.17 and P = 0.90). Need for suprarenal aortic cross-clamping and its duration, occurrence of major bleeding, intra-operative hypotension and the post-operative peak of CPK did not differ between NAC and control groups. The overall incidence of ARF in the study was 36% (13/36), but it was not significantly different between groups (7/14, 50% in NAC vs 6/22, 27.3% in control, P = 0.16). The overall mortality was 23% (10/42) and was not different (P = 0.209) in NAC group (33.3%) when compared with control (16.7%), the same occurring with the length of ICU stay (2.93 +/- 1.53 vs 2.52 +/- 1.36 days, P = 0.40).
Conclusion: This study suggests that the putative beneficial effects of NAC on radiocontrast nephropathy might not be applicable to other situations, such as ARF associated with elective aortic aneurysm repair.