DETERMINATION OF GLOMERULAR-FILTRATION RATE WITH VISIPAQUE IN PATIENTS WITH SEVERELY REDUCED RENAL-FUNCTION

Iodixanol (Visipaque, Nycomed Imaging AS, Oslo, Norway), an isotonic, dimeric and non-ionic contrast medium (CM), and iohexol (Omnipaque, Ny comed Imaging AS, Oslo, Norway), a low-osmolar, monomeric and non-ioni c contrast medium, were used as glomerular filtration rate (GFR) marke rs in patients with severely impaired renal function. Different method s for determining GFR were compared. A total of 16 patients with s-cre atinine > 400 mu mol/l were enrolled in the study; 8 in each CM group. Serum-iodine was measured, and plasma CM clearance was determined usi ng the Brochner-Mortensen method, the single-sample method and convent ional method. The ratios between the results obtained from the convent ional method and each of the two other methods were calculated. these data were plotted against the mean of the pairs compared, and the uppe r and lower limits of agreement were calculated as the mean ratio +/- 2SD. The comparison showed a high degree of agreement between methods, and the two simpler methods seem to be good alternatives to the conve ntional method, which gave good estimates of GFR (vs that determined b y means of renal I-125-iothalamate clearance) when 24-h blood samples were included. However, slight overestimations of GFR, due to extraren al excretion of the CM, were observed. In summary, serum clearance of iodixanol, as determined by the Brochner-Mortensen method or single-sa mple method seems to be a simple and accurate marker of GFR in patient s with severely reduced renal function. The findings obtained with iod ixanol were similar to those obtained with iohexol.