Use and efficacy of saline hydration and N-acetyl cysteine to prevent contrast-induced nephropathy in low-risk populations undergoing coronary artery angiography.

Contrast-induced nephropathy (CIN) is most commonly defined as acute renal failure occurring within 48-72 h of exposure to an intravascular radiographic contrast medium that is not attributable to other causes. In the international literature, a 25% increase in serum creatinine levels or an increase in absolute values of 0.5 mg/dl from baseline has been suggested to define CIN. The reported incidence of CIN varies widely, ranging from 2 to 50%. This variability results from differences in the presence or absence of risk factors. With a retrospective analysis we evaluated the use of saline hydration plus N-acetyl cysteine (NAC) to prevent CIN in a low-risk population of patients undergoing coronary artery angiography compared with an historic low risk group not treated. From January 2009 to December 2009, 152 consecutive patients who underwent coronary artery angiography with a low osmolarity contrast agent were enrolled in our study, and compared with an historic control group consisting of 172 low-risk patients. Nephrotoxic drugs such as diuretics, ACE-I and ARBs were stopped at least 24 h before the procedure. Inclusion criteria to define low-risk population were the absence of: diabetes, age >65 years, or baseline creatinine >1.4 mg/dl. We have treated group A (152 patients, 47.3%) with a saline hydration (1 ml/kg/h) plus N-acetyl cysteine 600 mg 12 h before and 12 h after the procedure; group B (group control of 170 patients, 52.7%) were not treated. The overall incidence of CIN was 7.1% (23 patients). In particular, the incidence of CIN was 2.6% (4 patients) in the group A and 11.2% (19 patients) in the group B (p = 0.002). In the multivariate analysis, including risk factor such as age, hypertension, hypercholesterolemia, current smoking habit baseline creatinine level, contrast index and hydration, the last variable was the only one inversely correlated independently with the incidence of CIN (p = 0.001). In conclusion, intravenous hydration with saline and NAC is an effective and low cost tool in preventing CIN in patients undergoing coronary artery angiography, and, according to the current guidelines, should be used in all high-risk patients for CIN. Our results show that even in patients at low risk, hydration with saline 0.9% plus NAC is useful and significantly reduces the incidence of CIN.