Lack of efficacy of N-acetylcysteine in attenuating contrast induced nephropathy in patients with severe systolic heart failure

Abstract

Patients with severe left ventricular systolic (LVS) dysfunction frequently have concommitant renal dysfunction compared to similar patients with normal LVS function. We hypothesized that N-acetylcysteine (NAC) treatment prior to coronary angiography would reduce radiographic contrast-induced nephropathy (RCIN) in patients with severe LVS dysfunction. Retrospective chart analysis was performed at a single medical center on consecutive patients with ejection fractions <30% (25%±8%, n = 143) who required a left heart catheterization (LHC). Baseline characteristics were analyzed including; etiology of heart failure (HF), New York Heart Association (NYHA) Class, diabetes mellitus (DM), hypertension (HTN), pulmonary hypertension, previous bypass surgery, chronic renal insufficiency (CRI), and degree of coronary disease, if present. All patients received similar hydration prior to catheterization. Of the records reviewed, 24.5% of patients received NAC at the clinician's discretion, while the other patients were pretreated with hydration alone (control group). The NAC dose was 600 mg bid orally for two days peri-LHC. Low-osmolar nonionic contrast medium was used in all patients. There was a significant difference in some of the baseline characteristics between those who received NAC pretreatment and the control group; more patients who received NAC had baseline CRI, a history of previous bypass surgery, or a previous diagnosis of ischemic cardiomyopathy (P <0.05). Notably, there was no significant difference in ejection fraction, DM, HTN, or NYHA class between the groups (P > 0.4). RCIN was defined in this study as an increase in a patient's creatinine of ≥0.5 (mg/dl) 48 hours subsequent to their LHC. Analysis did not reveal any difference in RCIN between those who received NAC and the control group. The change in the creatinine for the two groups (mg/dl) was 0.16±0.47 and 0.05 ±0.33 (NAC, Control respectively, P value of 0.11). BUN was analyzed and was not changed in either group after LHC. NAC: 30.05 ±16.66 to 29.78 ±19.06 vs. Control: 21.81 ±12.63 to 21.99 ±13.69, (P = NS). Multivariate analysis showed that post-catheterization changes in serum creatinine was most closely associated with baseline creatinine (P<0.01). Surprisingly, DM, HTN or NYHA class were not predictive of who would develop RCIN in this group of heart failure patients. A prospective randomized trial should be performed to further elucidate the role of NAC as protective agent against RCIN in patients with severe LVS dysfunction.