Urinary 8-Hydroxy-2′-Deoxyguanosine: A Biomarker for Radiation-Induced Oxidative DNA Damage in Pediatric Cardiac Catheterization

Abstract

To determine the utility of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) as a sensitive biomarker for radiation-induced cellular DNA damage in children undergoing cardiac catheterization. We enrolled pediatric patients with congenital heart diseases requiring cardiac catheterization in conjunction with healthy children and children under sedation as control. Demographic, clinical, laboratory and invasive hemodynamic data, urinary 8-OHdG levels, and radiation exposure measurements were collected prospectively. Nineteen patients, 10 healthy children and 9 children under sedation, were studied. In 19 patients who underwent cardiac catheterization, the median level of 8-OHdG in urine obtained at 24-48 hours after the procedure was significantly higher than at baseline (44.0 vs 17.3 ng/mg creatinine, P = .0001). Furthermore, the urinary 8-OHdG level after the procedure increased in 18 of the 19 study subjects. In contrast, there was no significant difference in 8-OHdG levels between the 2 spot urine samples obtained at arbitrary intervals of 24-48 hours in 10 healthy children (P = .7213), and at baseline and 24-48 hours following echocardiography in 9 children under sedation (P = .1097). Stepwise multiple regression analysis revealed that the cumulative air kerma during the cardiac catheterization was the variable which was strongly and significantly associated with the ratio of post- to precardiac catheterization urinary 8-OHdG levels among the evaluated variables (R(2) = 0.7179, F = 11.0256, P = .0007). Urinary 8-OHdG could be a useful biomarker for radiation-induced cellular DNA damage in children undergoing diagnostic cardiac catheterization.