Contrast induced-nephropathy is a complication that is underestimated in clinical practice after cardiac catheterization. During the last 30 years, because of the increasing use of contrast medium for diagnostic and therapeutic procedures, this has become the third in-hospital cause of acute renal failure (12%). That's why, it is necessary to establish an earlier marker of renal dysfunction that can help us in the diagnosis and allow us to initiate the appropriate therapeutics, because depending on the severity of the renal damage, it can increase the cardiovascular risk and morbidity.

The risk of contrast medium nephropathy is still present even with the use of low osmolarity contrast media, and many patients increase their in-hospital days, costs and hemodialysis requirement. Cystatin C is a non glucosylated protein produced in nucleated cells in a constant rate, and because of its low molecular weight it's filtered through the glomerular membrane without restriction and it's fully reabsorbed in the proximal tubule, that's why it's considered an excellent marker evaluating the glomerular filtration rate in patients with acute renal failure during the first 24-48 hours.

We propose that Cystatin C can be useful as an earlier and superior marker of contrast-induced nephropathy in high and intermedium cardiac catheterization patients.