Use of NaCl saline hydration and N-Acetyl Cysteine to prevent contrast induced nephropathy in different populations of patients at high and low risk undergoing coronary artery angiography

AIM

Contrast-induced nephropathy (CIN) is most commonly defined as acute renal failure occurring within 48-72 h of exposure to intravascular radiographic contrast medium that is not attributable to other causes. In 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 authors evaluated the use of NaCl saline hydration and N-acetyl cysteine (NAC) to prevent CIN in different populations of patients at high and low risk undergoing coronary artery angiography.

METHODS

From January 2007 to December 2008, 597 patients underwent coronary artery angiography with a low osmolarity contrast agent. Nephrotoxic drugs such as diuretics, metformin, ACE-I and ARBs were stopped at least 24 h before the procedure. The population was divided into two groups: group A (high risk 342 patients, 57.2%) identified for the presence of at least one risk factor such as diabetes, age >65 years, baseline creatinine >1.4 mg/dL and group B (low risk 255 patients, 42.8%) for the absence of any of the risk mentioned above. Only group A was treated with a saline hydration (1 mL/kg/h) plus NAC 600 mg 12 h before and 12 h after the procedure.

RESULTS

The overall incidence of CIN was 6.7% (40 patients). In particular, the incidence of CIN was 4.4% (15 patients) in the group A and 9.8% (25 patients) in the group B respectively (P=0.017). Interestingly, the Contrast Index (volume administrated/theoretical maximum volume) was significantly lower in group B (P<0.005). In the multivariate analysis, including risk factors such as age, diabetes, hypertension, hypercholesterol-mia, current smoke, 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).

CONCLUSIONS

The 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. Present results show that even in patients at low risk for CIN, hydration could be useful: in fact, despite the Contrast Index was significantly lower in this population, the incidence of CIN was greater, thus suggesting a potential role for hydration also in the low-risk population.