CONTRAST: Iso-Osmolar Contrast Medium Fails to Show Benefit in PCI Patients

April 10, 2008

April 10, 2008 (Chicago, IL) – The iso-osmolar contrast medium iodixanol (Visipaque, GE Healthcare) did not prevent renal injury in patients undergoing PCI in the CONTRAST study, reported at last week's American College of Cardiology 57th Annual Scientific Session/i2 Summit-SCAI Annual Meeting.

Presenting the study, Dr Rainer Wessely (Deutsches Herzzentrum, Munich, Germany) explained that some earlier studies have shown that iodixanol reduces the risk of kidney damage when moderate doses of contrast medium are used, mainly during diagnostic angiography, but this is the first randomized trial to look exclusively at PCI, which involves far higher doses of contrast medium.

"Patients with chronic renal insufficiency have a high need for coronary procedures; however, these procedures involve the use of contrast medium, which may lead to contrast-induced nephropathy [CIN] or further kidney damage," Wessely noted. "In addition, since chronic renal failure is associated with a higher incidence of diffuse and complex coronary artery disease, invasive procedures often require the use of elevated contrast volumes." In fact, although the risk of CIN in patients with normal kidney function is very low (well below 1%), it can rise to 20% to 30% in patients with chronic kidney disease, he added. Iodixanol, a contrast agent that has approximately the same osmolarity as blood, was designed to reduce the risk of CIN when compared with a contrast medium with a higher osmolarity.

In the CONTRAST study, 324 patients with renal insufficiency (serum creatinine >1.5 mg/dL or an estimated glomerular filtration rate <60 mL/min per 1.73 m2) undergoing PCI were randomized to receive either iso-osmolar iodixanol (290 mOsm/L) or low-osmolar iomeprol (Iomeron, Bracco Diagnostics) (618 mOsm/L) contrast medium. All patients received intravenous hydration with a saline solution both before and after the procedure.

Results showed that there was no significant difference between the two groups in the proportion of patients who developed CIN or severe CIN. The need for dialysis was low and not significantly different in both groups, and there was also no difference in length of hospital stay.

Incidence of contrast-induced nephropathy (CIN)

Measure Iodixanol Iomeprol p
CIN (% of patients) 22.2 27.7 0.25
Severe CIN (% of patients) 6.2 3.7 0.30
Dialysis (% of patients) 1.9 0.6 0.31
Hospital stay (d) 6.3 6.5 0.59

In addition, there was no significant difference in individual and combined rates of MI, death, and repeat coronary procedures at 90 days.

During the discussion, it was pointed out that the rate of CIN in this study was actually very high, and this may have been due to the high doses of contrast media used and the lack of any preventive strategies such as N-acetyl cysteine or bicarbonate.

The complete contents of Heartwire , a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.



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