Joint Contrast Policy Proposed at THR

 

Renal Function and IV Contrast Administration

 

–Stop screening Outpatients for Renal Function prior to Iodinated Contrast administration

–Remove thresholds on Inpatients for Iodinated contrast use

a) No need for immediate dialysis

b) No premedication required (e.g. Sodium Bicarb or N-acetylcysteine)

c) Metformin should only be held for AKI patients

–Gadolinium – Macrocyclic agents (Group 2)

a) Stop GFR screening for outpatients

b) Adjust inpatient GFR threshold requiring MD decision to GFR < 40

–Still required to screen patients for contrast Allergy

–No need to wait 24 hours for second contrast dose unless the total exceeds 250ml.

 

 

TRA standard committee policy:

Gadolinium and Iodine

The latest edition of the ACR Contrast Manual v10.3 2018 differentiates the risk of NSF among the different gadolinium agents on the market. For class II agents (Multihance/Gadavist/Dotarem/ProHance), the ACR does not recommend routine screening or labs prior to gadolinium injection in single doses. Class II agents are also felt to be safe for patients with end stage renal disease on hemodialysis. This assumes that there is a reasonable indication for gadolinium use in the first place and consideration must be given to patients with AKI. However, class I agents (Omniscan/Magnevist/OptiMark) and Group III agents (Eovist), should be avoided in patients with GFR below 30, those on hemodialysis or those patients with known or suspected AKI. Despite the latest recommendations from the ACR, the FDA does not differentiate between the different classes of gadolinium and continues to recommend avoidance of all gadolinium in patients with GFR below 30. Therefore, the committee recommends that a GFR of 30 be used as a general cutoff for all classes of gadolinium. This is a conservative cutoff that is within the both the ACR and FDA guidelines.

Regarding iodinated contrast injection, the ACR Contrast Manual states that “At the current time, there is very little evidence that IV iodinated contrast material is an independent risk factor for AKI in patients with eGFR ≥30 mL / min/1.73m2. Therefore, if a threshold for CIN risk is used at all, 30 mL / min/1.73m2 seems to be the one with the greatest level of evidence [3].” Please review the ACR Contrast Manual for detailed discussion of these recommendations, particularly pages 35-42 and 84-90.

So, in summary, the committee recommends that a GFR of 30 be used as a general cutoff for IV administration of all gadolinium agents and iodinated contrast, with special consideration for patients with AKI or other contraindications such as pregnancy or allergy. This is not an absolute cutoff. Keep in mind that group II gadolinium agents are generally safe for patients with GFR below 30 based upon current ACR recommendations, so don’t be afraid to use them if the situation is appropriate.

 

Metformin Policy

Metformin ACR Guidelines
a. Category I: GFR > 30 – continue Metformin
b. Category II: GFR <30, AKI IV/V: Stop at time of procedure and hold for 48hr and then recheck GFR and start only when renal function shown to be normal
c. Gd: No need to stop if giving normal doses in range of 0.1-0.3mmol/kg

 

Dialysis patient can get IV iodinated contrast material if dialysis is performed within 24 hours to reduce volume overload. (Special concern should be paid to patient with acute renal failure or patient who is oliguric. Dialysis does not protect patient receiving MR contrast from developing NSF.

Time interval between iodinated contrast dosing

ACR Contrast Manual v10.3 2018 states, “We do not believe that there is sufficient evidence to specifically endorse the decision to withhold a repeat contrast medium injection until more than 24 hours have passed since the prior injection, nor to recommend a specific threshold of contrast medium volume beyond which additional contrast media should not be given within a 24-hour period.” (page 38).

As such we believe that as stated in the ACR Contrast Manual that “the decision to administer closely spaced contrast-enhanced studies is clinical and subjective, with high-risk patients (e.g., Stage IV and Stage V chronic kidney disease, AKI) treated with greater caution than the general population.” As such repeat doses of IV contrast should not be withheld from patients within a 24-hour period if clinically warranted. Also as stated in the Contrast Manual, volume expansion with 0.9% NS or Sodium Bicarbonate may be of benefit in preventing Post Contrast AKI.

 

Breast Feeding and Lactating Patients

ACR guidelines suggest that it is safe for patients to continue breast feeding after receiving iodinated or Gadolinium based contrast agents. Due to the extremely small amount of either contrast agent that is excreted in breast milk, and subsequently absorbed by the infant’s GI tract, there is no clear indication for cessation of breast feeding or for “pump and dump” recommendations. However, if the patient is still concerned about the risks of contrast a period of pumping and discarding breast milk for 12-24 hours may be considered.