Renal failure is more common in iso-osmolar than low-osmolar contrast media
CHICAGO—Iso-osmolar contrast media is not the solution to solve the major problem of renal failure after injection, according to a retrospective study presented Tuesday at the 94th annual meeting of the Radiological Society of North America (RSNA).

Per Liss, MD, PhD, from the department of radiology at Uppsala University in Uppsala, Sweden, who presented the results, explained that the beneficial effect of using iso-osmolar iodinated contrast media (CM) compared with low-osmolar CM to reduce contrast induced nephropathy (CIN) has been under debate due to conflicting results.

In 2003, a NEPHRIC study on contrast nephropathy, published by Aspelin et al, compared outcomes in 129 renally impaired angiography patients with diabetes randomized to iodixanol or to the nonionic monomer agent iohexol. In this study, the rate of CIN was 26 percent with the nonionic monomer and 3 percent with iodixanol. In addition, six patients in the iohexol group developed acute renal failure, while none did in the iodixanol group.  

Liss explained he and colleagues previous published a study in Kidney International in 2006, which suggested no beneficial effect, but rather the opposite.

To further evaluate the incidence of CM-induced renal failure in clinical practice, the researchers analyzed retrospective data of more than 23,000 patients in 18 Swedish hospitals. The providers principally used a single CM for percutaneous coronary interventions (PCI) and coronary angiography during the years 2005-2006. Iso-osmolar iodixanol was used in 18,517 patients, low-osmolar ioxaglate in 4,707 subjects.

Patients were evaluated from SCAAR (Swedish Coronary Angiography and Angioplasty Registry) and rehospitalizations with a diagnosis of renal failure and/or treated for dialysis in the Swedish all-national “Hospital Discharge Register.”

Liss and colleagues found that the incidence of the diagnosis renal failure within 12 months after PCI/angiography was greatest for patients receiving iodixanol (1.4 percent) compared to ioxaglate (0.9 percent).

When adjusted for gender, age, diabetes, injected volume of CM, previous PCI and previous renal insufficiency and the hazard ratio for iodixanol, Liss said that the treated patients remained significantly higher than that for ioxaglate. The average volume of injected CM was significantly higher in the patients receiving ioxaglate (202.4 ml) compared to those receiving iodixanol (188.1 ml).

He noted that the calculated creatinine clearance before the injection was similar in the two groups (ioxaglate 82.7 ml/min; iodixanol 83.7 ml/min).

Liss concluded that based on their findings, they confirmed that within one year after injection, renal failure was found more often after use of the iso-osmolar CM iodixanol than for the low-osmolar CM ioxaglate.

However, he said that further clinical studies are needed, adding that he and his colleagues have begun another study to assess the conflicting outcomes.