Effect of N-acetylcysteine on cystatin C-based renal function after elective coronary angiography (ENABLE Study): a prospective, randomized trial.

Background: Several studies have reported the role of N-acetylcysteine on the prevention of contrast induced nephropathy (CIN) with conflicting results. To date, the effect of acetylcysteine on cystatin C-based CIN has not been described. This study was designed to examine the incidence of cystatin C-based CIN and investigate the effect of N-acetylcysteine on the prevention of CIN after coronary angiography (CAG).

Methods: We conducted a prospective, randomized trial on 166 patients (80 patients in N-acetylcysteine group and 86 patients in control group) that underwent elective CAG with apparently normal renal function. Serum cystatin C and creatinine concentrations were measured before, and at 24 and 48 h after CAG.

Results: The overall incidence of cystatin C-based CIN among all study subjects was 10.2% (5.0% in N-acetylcysteine group and 15.1% in control group, p<0.05) and that of serum creatinine-based CIN was 6% (3.8% in N-acetylcysteine group and 8.1% in control group, p=NS). Kappa analysis between cystatin C-based CIN and serum creatinine-based CIN showed a substantial agreement (k=0.64). Multivariate logistic regression analysis showed that N-acetylcysteine administration was independently protective against the development of cystatin C-based CIN (Odd ratio[95% confidence interval] 0.255[0.066 to 0.994]) but there was a trend toward protection against that of serum creatinine-based CIN.

Conclusions: This study suggests that in patients with apparently normal renal function, prophylactic oral N-acetylcysteine administration is effective at preventing cystatin C-based CIN development after elective coronary angiography and/or intervention, and that serum cystatin C might be a more sensitive marker of the early CIN than serum creatinine.