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Clearance of gadolinium chelates by hemodialysis: an in vitro study
P L Choyke1, M E Girton, E M Vaughan
1Department of Radiology, Henry M. Jackson Foundation, Bethesda, MD, USA.
Insights
Gadolinium (Gd)-chelates are not readily cleared by dialysis, with clearance rates significantly lower than urea and creatinine. Over 12 hours of dialysis may be needed to remove 97% of Gd-chelates.
Area of Science:
- Nephrology
- Radiology
- Pharmacology
Background:
- Gadolinium (Gd)-chelates are used as contrast agents in medical imaging.
- Current clinical use considers Gd-chelates as readily dialyzable.
- Published data on actual Gd-chelate dialysis clearance rates are lacking.
Purpose of the Study:
- To determine in vitro dialysis clearance rates for commonly used Gd-chelates.
- To inform rational strategies for enhancing Gd-chelate removal via dialysis.
- To compare Gd-chelate clearance with established dialysis efficiency benchmarks.
Main Methods:
- Three Gd-chelates (Gd-DTPA, Gd-HP-DO3A, Gd-DTPA-BMA) were diluted in plasma and saline.
- Dialysis was performed using a clinical dialyzer unit with a capillary filter at varying flow rates (0-300 cc/min).
- Predialyzer and postdialyzer concentrations were measured using atomic emission photometry; urea and creatinine clearances were also determined.
Main Results:
- Gd-chelate clearance rates were substantially lower than those of urea and creatinine.
- At 300 cc/min, Gd-DTPA clearance was 74 cc/min, while Gd-HP-DO3A and Gd-DTPA-BMA were 67 cc/min.
- No significant difference in clearance was observed between saline and plasma, indicating minimal protein binding.
Conclusions:
- Gd-chelates exhibit low dialysis clearance rates, challenging the assumption of ready dialyzability.
- Efficient removal of Gd-chelates requires prolonged dialysis times, estimated at 12.2 to 14.7 hours for 97% removal.
- These findings necessitate a re-evaluation of dialysis protocols for patients administered Gd-chelates.
Abstract:
Although the gadolinium (Gd)-chelates currently approved for clinical use in the United States are considered "readily dialyzable," the actual clearance rates have not been published. The purpose of this study was to establish in vitro dialysis clearance rates of Gd-chelates to develop rational strategies for removing the agents with dialysis. Three agents, Gd-diethylenetriaminopentaacetic acid (Gd-DTPA), Gd-HP-DO3A and Gd-DTPA-BMA were diluted separately in plasma and saline and were dialyzed by using a clinical dialyzer unit with a commercially available capillary filter at rates of 0-300 cc/min. Predialyzer and postdialyzer concentrations were determined by inductively coupled atomic emission photometry. Urea and creatinine clearance rates also were determined. The clearance rate for Gd-chelates were considerably lower than that of urea and creatinine, which are generally considered benchmarks of dialysis efficiency. At 300 cc/min flow rates, the clearances were (clearance in cubic centimeters per minute with 95% confidence interval): Gd-DTPA-74 cc/min (68-80 cc/min) delta-HP-DO3A 67 cc/min (63-71cc/min); and Gd-DTPA-BMA 67 cc/min (63-71cc/min). In comparison, urea and creatinine were 180 cc/min (178-181 cc/min) and 142 cc/min (124-131 cc/min), respectively. There was no difference between clearance rates of Gd-chelates in saline and plasma, implying there was no protein binding. By using a first order kinetic model of dialysis time, more than 12.2 to 14.7 hours of dialysis would be necessary to remove 97% of the injected dose of Gd-chelate.(ABSTRACT TRUNCATED AT 250 WORDS)