RESUMO
In the present study we evaluated two commonly used iodinated contrast agents, iohexol and iodixanol, as potential markers of impaired renal function. A reversed phase LC-MS method has been developed in order to separate and quantify the two substances. The assay was linear between 0.02 and 9.7 micromol/L for iohexol and between 0.4 and 49.3 micromol/L for iodixanol (r(2) > 0.998). The recovery during sample preparation ranged from 89.1 to 112.4%. The intra- and inter-assay RSD values were 3.06-13.6% for iohexol and 4.32-12.7% for iodixanol. The validated method was subsequently applied to 17 patients scheduled for angiographic procedure displaying normal and impaired renal function. A mixture of iohexol and iodixanol was intra-arterially injected and their corresponding plasma levels were determined periodically over a 24h period following administration. The elimination of both contrast agents followed by the LC-MS approach allowed us to discriminate between patients with normal and impaired renal function at 4, 8 and 24h after administration. Our preliminary results support the predictive value of iohexol and/or iodixanol clearance in a clinical environment to screen and identify patients at risk of developing CIN.