ABSRTACT
Background: Increasing numbers of patients are exposed to contrast medium (CM) during Cardiac Catheterization procedures. Radiocontrast use in all branches of medicine is reported to be the third most common cause of new onset renal failure in hospital patients. Objectives: To assess renal dysfunction induced by use of contrast media (CM) in infants and children with congenital heart diseases (CHD) undergoing Cardiac Catheterization. Methods: Serum creatinine (Cr), corrected creatinine clearance (c.Cr.Cl.), serum Beta 2 microglobulin (β2MG), urinary retinol binding protein (uRBP), fractional excretion of sodium (FENa), and urine to serum osmolality ratio (u/sOSM) were measured in 19 patients with congenital cyanotic heart diseases (CCHD) and 26 patients with congenital cyanotic heart diseases (CCHD) 24 hours before and 72 hours after cardiac Catheterization using low osmolar nonionic CM. Patients were compared to 31 healthy controls of matched age and sex. Results: Before Cardiac Catheterization, there was no significant difference in the studied parameters between CCHD and CAHD patients when compared either to each other or to the healthy controls. Only u/s OSM ratio was significantly reduced in CCHD patients when compared to CAHD (P=0.02) or controls (P=0.01). After cardiac Catheterization, all patients showed significant reduction of their c.Cr.Cl, u/s OSM (P <0.001& 0.002 respectively) and a significant increase of β2MG, uRBP & FENa (p <0.001, 0.002 and 0.003 respectively) and a non-significant change of Cr (p=0.23).  Both before and after cardiac Catheterization; c.Cr.Cl correlated more significantly with β2MG (r=-0.65 & -0.79, p=0.001& 0.005 respectively) rather than with Cr (r=-0.41& -0.52, p=0.02 & 0.01 respectively). Out of the studied 45 patients; only 3patients matched the definition of CM nephropathy despite the significant change in different renal parameters. Conclusions: Children with CHD develop significant defects in glomerular and tubular parameters after CM use despite that their Cr may not increase. Revision of the currently used definition of CM nephropathy may be required.