Nephrotoxicity of ioxaglate and ioversol assessed by glomerular filtration rate: a pilot study.

OBJECTIVE

To determine the effect of ioxaglate and ioversol on glomerular filtration rate (GFR) in a heterogeneous inpatient group to allow calculation of the necessary sample size for a randomized trial.

PATIENTS AND METHODS

The study group consisted of 36 men and 12 women, ranging in age from 25 to 79 (mean 63) years. Fourteen of the patients, those undergoing abdominal aortography with or without renal arteriography, received ioxaglate (Hexabrix 320; 40 to 240 [mean 141] mL), and the remaining 34, those receiving intravenous injections and those undergoing computed tomography with arterioportography or carotid arteriography, received ioversol (Optiray 320; 20 to 180 [mean 87] mL). GFR was measured by determining the clearance of diethyl-enetriaminepenta-acetic acid labelled with technetium-99m up to 72 hours before and 24 hours after administration of the contrast medium. Risk factors for nephrotoxicity included diabetes (7 patients) and pre-existing renal impairment (mild in 11 and severe in 6).

RESULTS

GFR decreased by 20% to 34% in six patients (13%); in only one of these was the serum level of creatinine increased at 24 hours. One of these six patients had received 120 mL of ioversol for carotid arteriography and had no risk factors for nephrotoxicity. The other five had received 40 to 187 (mean 115) mL of ioxaglate, three for abdominal aortography and two for selective renal arteriography. The risk factors in these patients included diabetes (two patients) and severe pre-existing renal impairment (two patients). Renal failure necessitating treatment did not develop in any of the patients.

CONCLUSIONS

A decrease in GFR occurred more often with ioxaglate than with ioversol and usually occurred in patients with additional risk factors. Injection of contrast medium into the abdominal aorta or the renal artery may increase the risk of nephrotoxicity. Changes in serum level of creatinine at 24 hours were not reliable in identifying patients with decreased GFR. On the basis of these data, the authors estimate that a group of 194 patients would be necessary for a randomized trial comparing the nephrotoxicity of ioxaglate and ioversol for abdominal aortography.