The European Society of Urogenital Radiology (ESUR) has updated its gadolinium guidelines. Its version 10 contains four key changes that will simplify patient management significantly, according to Dr. Henrik Thomsen, chair of the ESUR's Contrast Media Safety Committee (CSMC).
"We have reduced the GFR (glomerular filtration rate) level for patients we believe are at risk of postcontrast acute kidney injury (PC-AKI)," he told AuntMinnieEurope.com. "A large number of patients have GFR of between 30 and 45 mL/min, whereas only 2% of patients have GFR below 30 mL/min -- and these are usually already known to the nephrology department."
Lowering the GFR cutoff will reduce the number of patients needing this careful monitoring, and this will make patient management -- and daily routine -- easier both for patients and doctors, added Thomsen, who is a professor of radiology at the University of Copenhagen. "It means we will be managing a smaller group of patients than before for prophylactic hydration or alternative examinations, as well as for the issue of stopping Metformin intake ahead of contrast-enhanced exams."
The main updates are as follows:
- The minimum GFR that determines hydration or not of patients prior to contrast administration has been lowered from 45 mL/min to 30 mL/min. Moreover, departing from version 9 guidance, multiple myeloma patients have been determined to no longer be at increased risk of PC-AKI if they are well hydrated, as outlined in section B 2.5.
- Diabetes patients on Metformin whose GFR is above 30 mL/min can continue taking the drug, whereas in the previous guidance, those with GFR under 45 mL/min needed to stop taking it two days before contrast agent administration, and underwent kidney function testing 48 hours later.
- CMSC officially endorses the decision by the European Medicines Agency (EMA) to suspend linear gadolinium agents except for liver imaging.
- The guidelines now include a new element in the form of an appendix of letter templates for contacting other specialists connected to the patient's management such as allergologists, as well as changes in the adverse reactions section, which now focuses on moderate and serious reactions, as mild reactions can be seen in patients undergoing studies even without contrast, according to Thomsen.
Version 10 also states that for patients who should be hydrated before and after infusion of contrast medium, for example, those with GFR of 20 mL/min, bicarbonate is just as good as sodium chloride and requires less time.
He noted that important changes in guidance take years to formulate. The decision to lower GFR for hydration and Metformin was taken after an extensive literature review, discussion, and peer-reviewed write-up, but the committee will also be following the results of prospective studies currently underway in the U.S. to factor into the next update (version 11) of the guidelines.
Various sections of the guidance answer questions submitted on a weekly basis to ESUR by specialists over the past four years. Such questions include how long between two contrast injections, as covered in section B 7, with the answer ranging between four hours and 48 hours, depending on the patient. In addition, radiologists asked what effect warming up contrast media may have on patients, which the committee covered in section A 13.
Other questions will be answered in version 11 of the guidelines.
Thomsen pointed to the large readership that ESUR's guidelines usually generate across the U.S. and Asia, as well as Europe, and hopes departments will update their protocols quickly after reading version 10. Available for the moment only in English, the guidelines will be translated into French, German, Italian, and Spanish this year.