Renal Insufficiency Following Radiocontrast Exposure Trial (REINFORCE): a randomized comparison of sodium bicarbonate versus sodium chloride hydration for the prevention of contrast-induced nephropathy

INTRODUCTION: For the prevention of contrast-induced nephropathy (CIN) after coronary angiography, hydration by 0.9% sodium chloride solution and N-acetylcysteine is currently recommended. However, it is unclear whether volume supplementation with sodium bicarbonate is better than with sodium chloride when used in conjunction with nonionic, low-osmolar iopamidol. The aim of this study was to analyze and compare the effects of sodium bicarbonate and sodium chloride on renal function in 145 patients exposed to nonionic iso-osmolar contrast medium iodixanol in a randomized study. PATIENTS AND METHODS: Renal Insufficiency Following Radiocontrast Exposure is a prospective, randomized, single-center, double-blinded trial of 145 patients (age 72.6+/-6.7 years) with elevated baseline serum creatinine levels (mean 132.6+/-29.3 micromol/l). Eligible patients were randomized to either a 154 mEq/l infusion of sodium bicarbonate (n=71, group I) or sodium chloride 0.9% solution (n=74, group II). The primary endpoint was serum creatinine elevation beyond 25% or 44 micromol/l on the first or second day following exposure to the contrast medium. Serum creatinine, serum cystatin C, plasma viscosity, urinary enzymes alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase, and alpha1-microglobulin were measured at baseline and on days 1 and 2 after contrast medium administration. RESULTS: An overall proportion of five CIN (3.4%) was observed with equal distribution among the groups (4.2% in sodium bicarbonate group vs. 2.7% in sodium chloride group; P=0.614). Parameters of renal function demonstrated no differences between the two hydration regimens on day 1 after angiography; even on day 2 most parameters were similar in groups I and II. CONCLUSION: Renal Insufficiency Following Radiocontrast Exposure demonstrates a homogeneously low rate of CIN after exposure to nonionic, iso-osmolar iodixanol regardless of the use of either bicarbonate sodium or sodium chloride solution for volume supplementation. Low-toxicity contrast media and any hydration may offset potential antioxidant effects of sodium bicarbonate.