RESUMEN
BACKGROUND: Gadolinium is an alternative angiographic contrast agent in patients with impaired renal function and high risk for iodinated contrast adverse reaction. We report two cases of acute renal failure caused by gadolinium (0.6 and 0.9 mmol/kg of body weight) after the execution of digital subtraction angiography (DSA) to produce diagnostic-quality images in two elderly diabetic patients with pre-existing renal insufficiency. Both patients needed dialysis treatments for as long as a few weeks until their renal function improved. In our opinion, and according to the guidelines of European Society of Urogenital Radiology, gadolinium has not been assessed as less nephrotoxic than iodinated contrast agents. In fact, 1.8 to 4.8 g of iodine, equally attenuated with a relatively high dose (0.2 to 0.4 mmol) of a gadolinium chelate, is a low iodine dose and could hardly have any important nephrotoxic effects. CONCLUSIONS: The maximum dose of gadolinium-based contrast agents should never exceed 0.2 to 0.4 mmol/kg in azotemic patients who are undergoing DSA, even though these doses of gadolinium may not provide images of suitable quality for diagnosis and intervention.