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Preventive measures were associated with a lower incidence of contrast-induced nephropathy in high-risk patients who underwent contrast-enhanced multidetector CT angiography.

Patients with diabetes were significantly more likely to develop contrast-induced nephropathy (CIN), but even in those patients the CIN was not severe, according to a report in the August issue of the American Journal of Cardiology.

The improved outcomes were associated with three methods designed to prevent CIN: 600 mg N-acetylcysteine given orally twice daily starting the day before multidetector CT angiography (MDCTA), intravenous sodium bicarbonate (150 mEq/L infused at 3 mL/kg per hour) for 45 minutes before and 45 minutes after MDCTA, and iodixanol use for MDCTA.

All patients had underlying chronic renal insufficiency and moderately elevated baseline creatinine levels. Those with baseline creatinine levels that were above normal (1.5 mg/dL or greater), but below severe (2.5 mg/dL or less) who underwent multidetector CT angiography (MDCTA) between December 2005 and November 2007 were included in the study. The mean age of the 400 consecutive patients was 76 years and 314 (nearly 79%) of the patients were men; 165 (41%) were diabetic.

The majority (83%) of the patients had peripheral MDCTA; the remainder had coronary MDCTA. Their mean baseline creatinine level was 1.8 mg/dL. The mean creatinine level 3-5 days post procedure was 1.75 mg/dL. The average contrast received was 101 cc, according to Dr. Mohammad El-Hajjar and colleagues at Albany (N.Y.) Medical College and Cornell University, New York.

Only 7 of the 400 subjects (1.75%) developed a creatinine increase of at least 0.5 mg/dL, indicative of CIN; and 2 of these had creatinine increases greater than 1 mg/dL. None of these patients required hemodialysis and neither baseline creatinine levels nor creatinine clearance values were predictive of CIN (Am. J. Cardiol. 2008;102:353-6).

Of the seven patients who developed CIN, five had diabetes and were aged older than 80 years. Multivariate analysis, however, showed that diabetes was the only significant predictor of CIN (odds ratio 5.9).

"This cohort represents the largest registry to date of outpatients with underlying [chronic renal insufficiency] undergoing contrast-enhanced MDCTA to document the incidence of CIN in this setting," the researchers stated.

"Of note, however, is that of 165 patients with diabetes included for analysis in our cohort, only 5 developed CIN, and none required hemodialysis. These results support the notion that a simple, easy-to-employ CIN-preventive strategy may be efficacious in individuals with diabetes requiring MDCTA," they concluded.

One limitation of the study was the lack of a control arm, but the researchers indicated that "withholding of potentially efficacious therapies in patients with [chronic renal insufficiency] requiring MDCTA is neither medically feasible nor ethical," Dr. El-Hajjar and his colleagues added.

The researchers stated that they had nothing to disclose.

When asked to comment on this article, Dr. Ronald M. Fairman, professor of Surgery and chief, Division of Vascular Surgery and Endovascular Therapy at the Hospital of the University of Pennsylvania, stated: "Certainly the oral administration of mucomyst is easy enough in the outpatient setting, however the same cannot be said of bicarb drips which can present challenges in an outpatient radiology practice. Furthermore, the recently published PREDICT study which randomized patients who had moderate to severe renal impairment and diabetes to either low-osmolar or iso-osmolar contrast agents, demonstrated an overall low incidence of CIN (about 5%) which was comparable between both study groups.

"Given the widespread use of CT angiography in the outpatient setting, this data mandates the development of guidelines and clinical pathways to minimize the risk of CIN," he concluded