Contrast nephropathy with a non-ionic iodide medium in patients with normal and mildly impaired renal function

Abstract

Effects of infusion of a non-ionic contrast medium(iopamidol, 370 mg l/ml) on renal function in a normovolemic state were examined in patients with normal and mildly affected renal function who underwent coronary angiography(CAG). The patients were divided into three groups: group I (n = 69) with serum creatinine(S-Cr) level < 1.0 mg/dl; group II (n = 50) with S-Cr level of 1.0 to 1.3 mg/dl and group III(n = 17) with S-Cr level of 1.3 to 2.0 mg/dl. Patients with S-Cr > or = 2.0 mg/dl were subjected to 3-h hemodialysis immediately after CAG(group HD, n = 11). Serum(S) and urine(U) values of Cr, Na, K, Cl, beta 2-microglobulin(beta 2MG), and U-N-acetyl-beta-D-glucosaminidase(NAG) were measured before and 24 h after CAG. U-NAG and U-beta 2MG were corrected for U-Cr, and fractional excretion of beta 2MG(FE beta 2MG) was determined. Basal U-NAG/Cr, U-beta 2MG/Cr and FE beta 2MG were increased in groups III and HD, suggesting the preexistence of tubular dysfunction. S-Cr was increased significantly only in group I, but there was no change in S-beta 2MG. U-NAG/Cr after CAG was elevated in all the groups, whereas U-beta 2MG/Cr(or FE beta 2MG) was increased only in group III. Greater than two-fold increases of U-NAG/Cr were noted equally in groups I through III. In contrast, the greater than two-fold increase of U-beta 2MG/Cr(or FE beta 2MG) occurred more frequently in group III as compared to the other groups. The incidences of such cases in group HD were similar to those of group III. The half life of serum iodide concentration was significantly shortened by 3-h HD(1.8 +/- 0.3 h vs. 15.9 +/- 3.8 h without HD). In conclusion, patients presenting S-Cr > or = 1.3 mg/dl were at high risk of renal tubular dysfunction even when contrast media was administered in the absence of significant increase in S-Cr. Whether an increase in U-NAG/Cr indicates tubular damage or is merely the result of tubular reabsorption of the agent remains to be clarified. Post-CAG hemodialysis efficiently eliminates contrast medium from the circulation.