02/10/2009Contrast Nephrology

Joel Topf, MD

I have heard that getting a dye for a cardiac catheterization or CAT scan can damage my kidneys. Is that true?

Yes. X-ray dye is usually made with iodine and is sometimes called iodinated contrast. The dye allows doctors to see the blood vessels and used when using x-rays to diagnose a number of medical problems. The dye that can damage the kidneys is always given intravenously. Another type of dye is given as a oral liquid. This oral contrast is not harmful to the kidneys.

If you have healthy kidneys the IV dye is almost never harmful; however if you have weak kidneys (chronic kidney disease stage 3, 4 or 5) and especially if you also have diabetes or are also over the age of 65 you are at risk of kidney damage from the contrast.

The kidney damage is called radiocontrast nephropathy. The damage is usually temporary (7-10 days) but sometimes it can cause permanent renal failure requiring dialysis.

There are ways to reduce the risk of developing radiocontrast nephropathy, though even in expert haqnds the risk cannot be eliminated. Protective strategies include:
1. Stopping diuretics
2. Hydrating the patient with saline solution
3. Taking an anti-oxidant called N-acetyl cysteine
4. Reducing the dose of contrast
5. Using a contrast agent with less toxicity

It is important, that if you are at risk of radiocontrast nephropathy and are going to get IV contrast that you notify your nephrologist beforehand so she can coordinate the protective strategy to spare your kidneys.

<< Back to List