CHICAGO—Iso-osmolar and low-osmolar contrast agents showed similar nephrotoxicity in a study of patients with impaired renal function undergoing percutaneous coronary intervention (PCI), according to findings presented here at the American College of Cardiology annual meeting.


In this prospective, randomized, double-blind trial, iodixanol, an iso-osmolar agent, and iomeprol, a low-osmolar agent, were randomly administered to 324 patients undergoing PCI.

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The agents were administered following appropriate IV hydration with saline solution. The proportion of patients who developed contrast-induced nephropathy (CIN) was similar in the iodixanol and iomeprol groups (22.2% and 27.7%, respectively).


The researchers defined CIN as a change of 0.5 mg/dL or greater in serum creatinine or a 25% or greater change in serum creatinine. The maximal rise in serum creatinine after PCI was 0.19 mg/dL for iodixanol and 0.21 mg/dL for iomeprol.


Severe CIN occurred more frequently in the iodixanol group than than the iomeprol group (6.2% vs. 3.7%), but the difference was not statistically significant. The need for dialysis was low in both groups (1.9% vs. 0.6 %, respectively). The average number of days in the hospital were similar (6.3 vs. 6.5).


However, a subgroup analysis revealed that patients with mildly impaired renal function had significantly lower impairment of renal function when they received iodixanol.


The findings come from the CONTRAST (Contrast media and Nephrotoxicity following coronary Revascularization by Angioplasty) trial. The study population included subjects at least 18 years old with impaired renal function undergoing PCI for symptomatic coronary artery disease (CAD).


To be in the study, each patient had to have an estimated glomerular filtration rate of 60 mL/min per 1.73 m2 or less or a serum creatinine level of 1.5 mg/dL or higher. The cohort represents patients at increased risk for CIN, which is associated with adverse outcomes, researchers say.


CONTRAST is the first randomized trial to look exclusively at high-risk patients exposed to high amounts of contrast medium during PCI. According to lead author and study presenter Rainer Wessely, MD, PhD, of the Deutsches Herzzentrum at Technische Universitaet, Munich, Germany, patients with chronic renal insufficiency have a high need of coronary procedures, which involve the use of contrast media.


Some previous studies have shown that iodixanol reduces the risk of kidney damage when moderate doses are used during diagnostic angiography whereas other studies have shown no difference between CIN rates in low-risk patients for iso-osmolar and low osmolar contrast agents.


At 90 days, patients who received iodixanol had a 3.7% rate of MI compared with 4.3% for iomeprol; their death rates were 1.2% and 1.8%, respectively. A subgroup analysis of diabetic patients revealed no significant between the two groups.