[Contrast nephropathy in cardiac procedures: no advantages with prophylactic use of N-acetylcysteine (NAC)].

Background: Acute renal failure induced by contrast agents represents the third cause of acute nephropathy in hospitalized patients. Some mediators are potentially involved in this process: recent data underscored the role of oxidising agents and prophylactic administration of NAC showed a lower incidence of acute renal damage after using contrast agents.
Methods: We analyzed 100 patients consecutively undergoing coronary angiography and/or transluminal angioplasty: the study group was given NAC orally at a dose of 600 mg twice daily, on the day before and on the day of administration of the contrast agent, together with hydration, while the control group was given only the hydration protocol with hypotonic saline.
Results: Twenty patients had baseline serum creatinine concentrations > 1.2 mg/dL (mild renal insufficiency group). The mean dose of contrast agent (Iodixanol; Visipaque 320, Nycomed) was 203 mL/procedure, with no statistical difference between groups. Among the patients with normal renal function, 5.7% in the NAC group and 8.8% in the control group had baseline serum creatinine concentrations above 0.3 mg/dL after 48 hours (p=NS). In patients with mild renal failure, 16.6% in the NAC group and 0% in the control group had serum creatinine concentrations > 0.5 mg/dL at 48 h (p=NS). We found no significant differences in serum creatinine values at 48 hours vs. baseline in anyone (NAC group with normal renal function or mild renal insufficiency, control group with normal renal function or mild renal insufficiency). Similarly, serum creatinine values at either baseline or after 48 hours were not significantly different in patients with normal renal function (NAC vs. control group) and with mild renal failure.
Conclusions: Our study showed no potential advantage in the prevention of acute nephropathy, induced by high volumes of contrast agent, through the administration of NAC in patients with normal renal function and mild renal failure. However, the NAC dose used in our study might not be sufficient in balancing the contrast agent volume employed in these procedures.