B. Renal adverse reactions

B. RENAL ADVERSE REACTIONS (CONTRAST INDUCED NEPHROPATHY, CIN)

B.1. Measurement of Renal Function

B.2. Renal Adverse Reactions to Iodine-based Contrast Media

B.2.1. Time of Referral

B.2.2. Before the Examination

B.2.3. Time of Examination

B.2.4. After the Examination

B.2.5. Multiple Myeloma Patients

B.3. Renal Adverse Reactions to Gadolinium-based Contrast Media

B.4. Patients taking Metformin

B.4.1. Iodine-based Contrast Media

B.4.2. Gadolinium-based Contrast Media

B.5. Dialysis and Contrast Medium Administration

 

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B. RENAL ADVERSE REACTIONS (CONTRAST INDUCED NEPHROPATHY, CIN)

 

Definition: Contrast induced nephropathy (CIN) is a condition in which a decrease in renal function occurs within 3 days of the intravascular administration of a contrast medium in the absence of an alternative etiology. An increase in serum creatinine by more than 25% or 44 µmol/l (0.5 mg/dl) indicates CIN.

 

B.1. Measurement of Renal Function

 

• Renal function is best assessed by the glomerular filtration rate (GFR), determined from the inulin clearance or by isotope methods, but these are not suitable for routine use before contrast medium administration.
• Serum creatinine is not an ideal indicator of renal function and may miss decreased renal function.
• Estimated glomerular filtration rate (eGFR), calculated from the serum creatinine, is the best method of estimating renal function before contrast medium administration.
• The CKD-EPI formula gives the most accurate eGFR:

eGFR = 141 x min(SCr/k,1)a x max(SCr/k,1)-1.209 x 0.993Age x [1.018 if Female] x [1.159 if Black]

where SCr is serum creatinine (mg/dL), k is 0.7 for females and 0.9 for males, a is -0.329 for females and -0.411 for males, min indicates the minimum of SCr/k or 1, and max indicates the maximum of SCr/k or 1. If serum creatinine is measured in µmol/l, divide the creatinine value obtained by 88.

 

 

B.2. Renal Adverse Reactions to Iodine-based Contrast Media

 

RISK FACTORS FOR CONTRAST INDUCED NEPHROPATHY
Patient-related	eGFR less than 60 ml/min/1.73 m2 before intra-arterial administration eGFR less than 45 ml/min/1.73 m2 before intravenous administration In particular in combination with Diabetic nephropathy Dehydration Congestive heart failure (NYHA grade 3-4) and low LVEF Recent myocardial infarction (< 24 h) Intra-aortic balloon pump Peri-procedural hypotension Low hematocrit level Age over 70 Concurrent administration of nephrotoxic drugs Known or suspected acute renal failure
Procedure-related	Intra-arterial administration of contrast medium High-osmolality agents Large doses of contrast medium Multiple contrast medium administrations within a few days

 

 

B.2.1. Time of Referral

 

ELECTIVE EXAMINATION

IDENTIFY AT-RISK PATIENTS who require measurement of renal function
Patients with known eGFR less than 60 ml/min/1.73 m2 Patients who will receive intra-arterial contrast medium Age over 70 Patients with a history of: Renal disease Renal surgery Proteinuria Diabetes mellitus Hypertension Gout Recent nephrotoxic drugs	Determine eGFR (or SCr) within 7 days of contrast medium administration.

 

EMERGENCY EXAMINATION

Identify at-risk patients (see above) if possible:

• Determine eGFR if the procedure can be deferred until the result is available without harm to the patient.
• If eGFR cannot be obtained, follow the protocols for patients with eGFR less than 60 ml/min/1.73 m² forintra-arterial administration and eGFRless than 45 ml/min/1.73 m² for intravenous administration as closely as clinical circumstances permit.

 

B.2.2. Before the Examination

ELECTIVE EXAMINATION
At-risk patients (see above)	Consider an alternative imaging method not using iodine-based contrast media. Discuss the need to stop nephrotoxic drugs with the referring physician. Start volume expansion. A suitable protocol is intravenous normal saline, 1.0-1.5 ml/kg/h, for at least 6 h before and after contrast medium. An alternative protocol is intravenous sodium bicarbonate (154 mEq/l in dextrose 5% water): 3 ml/kg/h for 1 h before contrast medium and 1 ml/kg/h for 6 h after contrast medium.
EMERGENCY EXAMINATION
At-risk patients (see above)	Consider an alternative imaging method not using iodine-based contrast media. Start volume expansion as early as possible before contrast medium administration (see elective examination).

 

B.2.3. Time of Examination

At-risk patients (see above)	Use low- or iso-osmolar contrast media. Use the lowest dose of contrast medium consistent with a diagnostic result.
Patients not at increased risk	Use the lowest dose of contrast medium consistent with a diagnostic result.

B.2.4. After the Examination

At-risk patients

Continue volume expansion. Determine eGFR 48-72 h after contrast medium.

 

Note: No pharmacological prophylaxis (with renal vasodilators, receptor antagonists of endogenous vasoactive mediators or cytoprotective drugs) has yet been shown to offer consistent protection against contrast induced nephropathy.

 

 

B.2.5. Multiple Myeloma Patients

 

• Multiple myeloma patients with normal renal function are not at increased risk of CIN provided that they are well hydrated and that low- or iso-osmolar iodine-based contrast agents are used.
• Multiple myeloma patients often have reduced renal function, and such patients are at increased risk of CIN.

 

 

B.3. Renal Adverse Reactions to Gadolinium-based Contrast Media

 

MR-EXAMINATIONS

• The risk of nephrotoxicity is very low when gadolinium-based contrast media are used in approved doses.
• In patients with reduced renal function refer to ESUR guidelines on NSF (A.3.2.).

RADIOGRAPHIC EXAMINATIONS

• Gadolinium-based contrast media should not be used for radiographic examinations in patients with renal impairment.
• Gadolinium-based contrast media are more nephrotoxic than iodine-based contrast media in equivalent X-ray attenuating doses.

 

 

B.4. Patients taking Metformin

 

B.4.1. Iodine-based Contrast Media

 

1) Patients with eGFR equal to or greater than 60 ml/min/1.73 m² (CKD 1 and 2) can continue to take metformin normally.

 

2) Patients with eGFR 30-59 ml/min/1.73 m² (CKD 3)

a) Patients receiving intravenous contrast medium with eGFR equal to or greater than 45ml/min/1.73 m² can continue to take metformin normally.

 

b) Patients receiving intra-arterial contrast medium, and those receiving intravenous contrast medium with an eGFR between 30 and 44 ml/min/1.73 m², should stop metformin 48 h before contrast medium and should only restart metformin 48 h after contrast medium if renal function has not deteriorated.

 

3) Patients with eGFR less than 30 ml/min/1.73 m² (CKD 4 and 5), or with an intercurrent illness causing reduced liver function or hypoxia. Metformin is contraindicated and iodine-based contrast media should be avoided.

 

4) Emergency patients. Metformin should be stopped from the time of contrast medium administration. After the procedure, the patient should be monitored for signs of lactic acidosis. Metformin should be restarted 48 h after contrast medium if serum creatinine/eGFR is unchanged from the pre-imaging level.

                                           

B.4.2. Gadolinium-based Contrast Media

No special precautions are necessary when diabetic patients on metformin are given gadolinium-based contrast medium.

 

 

B.5. Dialysis and Contrast Medium Administration

All iodine and gadolinium-based contrast media can be removed by hemodialysis or peritoneal dialysis. However, there is no evidence that hemodialysis protects patients with impaired renal function from contrast medium induced nephropathy or nephrogenic systemic fibrosis.

In all patients, avoid osmotic and fluid overload.

To avoid the risk of NSF refer to A.3.2.

 

Patients on dialysis
Patients on hemodialysis	Iodine-based contrast medium Correlation of time of the contrast medium injection with the hemodialysis session is unnecessary. Extra hemodialysis session to remove contrast medium is unnecessary. Gadolinium-based contrast medium Correlation of time of the contrast medium injection with the hemodialysis session is recommended. Extra hemodialysis session to remove contrast medium as soon as possible after it has been administered is recommended.
Patients on continuous ambulatory peritoneal dialysis	Iodine-based contrast medium Hemodialysis to remove the contrast medium is unnecessary. Gadolinium-based contrast medium The need for hemodialysis should be discussed with the referring physician.