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Reducing Nephrotoxicity with Iso-Osmolar Contrast

Iodixanol could be part of the solution for high-risk patients who undergo coronary angiography.

Nephropathy, a serious complication of contrast angiography, is common in diabetes patients with preexisting renal impairment. In this double-blind, multicenter, European trial, 129 diabetes patients with a stable serum creatinine level (1.5 mg/dL in men, 1.3 mg/dL in women, 3.5 mg/dL in both) were randomized to iohexol or iodixanol before coronary (126) or aortofemoral (3) angiography. Iohexol is a nonionic, monomeric contrast medium with relatively low osmolarity (780 mOsm/kg water); iodixanol is a nonionic, dimeric contrast medium that is iso-osmolar to blood (290 mOsm/kg water). The study was supported by a company that makes both agents.

The iodixanol and iohexol groups had similar baseline characteristics, including mean serum creatinine level (about 1.5-1.6 mg/dL), creatinine clearance (about 50 mL/min), and contrast volume received (about 162 mL). All patients also received about 1 L of intravenous hydration.

Three days after angiography, the mean increase in peak serum creatinine level was lower in iodixanol recipients than in iohexol recipients (0.13 vs. 0.55 mg/dL, P=0.001). A 0.5-mg/dL increase in creatinine level occurred in 3% and 26%, respectively (P=0.002). The odds of nephropathy were 11 times higher with iohexol than with iodixanol. All 6 incidents of acute renal failure occurred with iohexol; 2 resulted in death, 1 in persistent renal failure.

Comment: In diabetes patients with renal dysfunction undergoing mostly coronary angiography, less nephrotoxicity occurred with the iso-osmolar contrast agent iodixanol than with the somewhat higher-osmolarity agent iohexol. For both agents, contrast volumes were high; use of less contrast might have diminished the difference in nephrotoxicity between the 2 groups. Acetylcysteine, which has been shown in some studies to reduce nephrotoxicity (Journal Watch Cardiology Mar 7 2003), was used in only a few patients in this study and did not affect the findings. High-risk patients undergoing angiography should receive intravenous hydration and a minimal volume of contrast; these patients may benefit further from acetylcysteine and an iso-osmolar contrast agent.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology March 7, 2003

Citation(s):

Aspelin P et al. for the NEPHRIC Study Investigators. Nephrotoxic effects in high-risk patients undergoing angiography. N Engl J Med 2003 Feb 6; 348:491-9.

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Sandler CM. Contrast-agent-induced acute renal dysfunction -- Is iodixanol the answer? N Engl J Med 2003 Feb 6; 348:551-3.

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• Medline abstract (Free)