Vascular viewpoint

Question: Does oral acetylcysteine prevent acute contrast nephropathy in patients with moderate renal impairment who undergo elective coronary angiography? Population: Patients with moderate stable renal insufficiency (creatinine clearance,60 ml/min or serum creatinine .1.2 mg/dl [106 mmol/l]) who were scheduled to undergo elective coronary angiography with or without intervention. Design and methods: Randomized placebo-controlled trial. A total of 200 patients were randomized to either oral acetylcysteine 600 mg BID (n = 102) or matching placebo (n = 98). Treatment was given for a total of four doses, starting the day before angiography and continuing on the day of the procedure. All patients received intravenous normal saline for 12 hours before and 6 hours after contrast exposure, and low osmolality contrast agents. Primary outcome was the occurrence of more than a 25% increase in serum creatinine level within 48 hours after contrast exposure. Coprimary outcomes were a change in creatinine clearance and serum creatinine level. Secondary outcomes were major adverse cardiac events, need for dialysis, and length of hospitalization. Patients, caregivers, and outcome assessors were blinded to group assignment. Analysis was by intention-to-treat. Results: Within 48 hours after contrast administration 12/98 (12%) control patients and 4/102 (4%) acetylcysteine patients developed a more than 25% increase in serum creatinine level. Relative risk = 0.32 (95% CI: 0.10--0.96; p = 0.03). Serum creatinine was lower in the acetylcysteine group than in the control group during the first 48 hours after angiography (1.22 mg/dl [108 mmol/l] vs 1.38 mg/dl [122.9 mmol/l]; p = 0.006), but this difference was no longer significant at seven days. Creatinine clearance increased significantly more in the acetylcysteine group than in the placebo group at day two [+30% vs +5%; p < 0.001] and at day seven [+23% vs +15%; p = 0.045]. The average length of stay was half a day shorter in the group receiving acetylcysteine(p = 0.02). No patients in either group required dialysis. There were no treatment-related adverse events. Conclusions: Acetylcysteine safely and effectively reduces the incidence of contrast-induced nephropathy in patients with moderate renal insufficiency undergoing coronary angiography.