Ionic low-osmolar versus nonionic iso-osmolar contrast media to obviate worsening nephropathy after angioplasty in chronic renal failure patients: the ICON (Ionic versus non-ionic Contrast to Obviate worsening Nephropathy after angioplasty in chronic renal failure patients) study

This randomized, prospective, double-blind, multicenter study compared nephrotoxicity of the nonionic iso-osmolar contrast media (CM) iodixanol versus the ionic low-osmolar CM ioxaglate in patients with chronic renal insufficiency undergoing coronary angiography. The properties of iodinated CM might contribute to the incidence of contrast-induced nephropathy (CIN). Patients with renal impairment undergoing coronary angiography were randomly assigned to iodixanol (n = 72) or ioxaglate (n = 74). Baseline characteristics were well-matched between the 2 groups. The predicted risk score for CIN was similar in the iodixanol and in the ioxaglate groups (11.9 +/- 4.1 vs. 11.8 +/- 4.1), as was the use of N-acetylcysteine (70% vs. 73%). The primary end point of the study, median peak increase of serum creatinine from day 0 through day 3 after angiography, did not differ between the iodixanol (0.09 mg/dl; interquartile range 0.00 to 0.30 mg/dl) and the ioxaglate (0.15 mg/dl; interquartile range 0.00 to 0.40 mg/dl; p = 0.07) groups. The percentages of patients with a peak increase of serum creatinine >or=0.5 mg/dl (15.9% in iodixanol vs. 18.2% in ioxaglate), >or=1.0 mg/dl (1.4% vs. 4.5%), and >or=25% or >or=0.5 mg/dl (15.9% vs. 24.2%, respectively) also did not differ significantly between the 2 groups. In high-risk patients undergoing coronary angiographic procedures, use of the nonionic iso-osmolar CM iodixanol does not reduce renal deterioration in patients with renal impairment, compared with the ionic low-osmolar CM ioxaglate. Given that the study was underpowered to compare nephrotoxicity of the 2 groups under the active medical protection of CIN, a larger randomized study is warranted that will enroll patients with higher risks of CIN under a strict control of hydration regimens and adjunctive medications.