Introduction
Materials and methods
Results
Question 5: Should questionnaires or scoring systems be used for risk stratification by clinicians when they request a contrast-enhanced imaging study?
Patient questionnaires
Risk stratification
|
In hospitals which use sCr measurements for all patients before intravascular CM administration there is no benefit in using questionnaires for PC-AKI risk stratification. |
In hospitals which use sCr measurements selectively, Choyke questionnaires may be used to identify patients with eGFR < 45 ml/min/1.73 m2 before intra-arterial CM administration with first pass renal exposure. |
Level of evidence D |
Risk prediction scores are only available for coronary angiography and/or percutaneous coronary intervention, and have only modest abilities, so cannot be recommended to stratify the risk of PC-AKI. |
Level of evidence A |
Nephrotoxic medication
|
In CKD patients receiving CM, optimal nephrologic care involves minimising the use of nephrotoxic drugs. |
Level of evidence D |
ACE inhibitors and angiotensin receptor blockers do not have to be stopped before CM administration. |
Level of evidence B |
There is insufficient evidence to recommend withholding nephrotoxic drugs such as NSAIDs, antimicrobial agents or chemotherapeutic agents before CM administration. |
Level of evidence C |
Risk prediction models
Question 6: Should nephrotoxic medication be withheld to reduce the risk of PC-AKI?
Question 7: What are the most cost- and time-effective protocols for oral and intravenous hydration to reduce the risk of PC-AKI?
Hydration as a preventive strategy for PC-AKI
Oral hydration versus intravenous saline hydration
Hydration
|
Preventive hydration should be used to reduce the incidence of PC-AKI in at-risk patients. |
Level of evidence B |
Intravenous saline and bicarbonate protocols have similar efficacy for hydration. |
Level of evidence A |
For intravenous and intra-arterial CM administration with second pass renal exposure hydrate the patient with either (a) 3 ml/kg/h bicarbonate 1.4% (or 154 mmol/l solution) for 1 h before CM or (b) 1 ml/kg/h saline 0.9% for 3–4 h before and 4–6 h after CM. |
Level of evidence D |
For intra-arterial CM administration with first pass renal exposure hydrate the patient with either (a) 3 ml/kg/h bicarbonate 1.4% (or 154 mmol/l solution) for 1 h before CM followed by 1 ml/kg/h bicarbonate 1.4% (or 154 mmol/l) for 4–6 h after CM |
or (b) 1 ml/kg/h saline 0.9% for 3–4 h before and 4–6 h after CM. |
Level of evidence D |
Oral hydration as the sole means of prevention is not recommended. |
Level of evidence D |
In patients with severe heart failure (NYHA grade 3–4) or patients with end-stage renal failure (CKD grade V) preventive IV hydration should be individualized by the clinician responsible for patient care. |
Level of evidence D |
Drugs
|
N-Acetylcysteine has not been conclusively shown to reduce the risk of PC-AKI in patients with eGFR < 45 ml/min/1.73 m2 receiving intravenous or intra-arterial CM, and its use is NOT recommended. |
Level of evidence A |
Giving short-term, high-dose statins to patients not already taking statins has not been shown to reduce the risk of PC-AKI in patients with eGFR < 45 ml/min/1.73 m2 receiving intravenous or intra-arterial CM, and its use is NOT recommended. |
Level of evidence B |
ACE inhibitors or angiotensin receptor blockers have not been shown conclusively to reduce the risk of PC-AKI in patients receiving intravenous or intra-arterial CM, and their use is NOT recommended. |
Level of evidence B |
Vitamin C has not been shown conclusively to reduce the risk of PC-AKI in patients receiving intravenous or intra-arterial CM, and its use is NOT recommended. |
Level of evidence B |
Renal replacement therapy
|
Renal replacement therapy has not been shown conclusively to reduce the risk of PC-AKI in patients receiving intravenous or intra-arterial CM, and its use is NOT recommended. |
Level of evidence B |
Intravenous hydration: saline versus bicarbonate
Forced diuresis versus conventional hydration
In which patients should the hydration protocol be individualized?
Question 8: Which other strategies (pharmaceutical, vitamin, renal replacement therapy) have been proved effective in preventing PC-AKI?
N-Acetylcysteine (NAc)
Statins
RAAS blockade: ACE inhibitors and angiotensin-II receptor blockers
Vitamin C
Renal replacement therapy (RRT)
Question 9: Should administration of metformin be adapted to reduce the risk of metformin-associated lactic acidosis in patients with type 2 diabetes mellitus scheduled to receive intravascular contrast media?
Metformin administration in patients at risk of PC-AKI
|
Note that these recommendations may deviate from current EMA/FDA recommendations.
|
Patients with eGFR > 30 ml/min/1.73 m2 and no evidence of AKI receiving either intravenous CM or intra-arterial CM with second pass renal exposure: continue taking metformin normally. |
Patients (a) with eGFR < 30 ml/min/1.73 m2 receiving either intravenous CM or intra-arterial CM with second pass renal exposure or (b) receiving intra-arterial CM with first pass renal exposure or (c) with AKI: stop taking metformin from the time of CM administration: measure eGFR within 48 hours and restart metformin if renal function has not changed significantly. |
Level of evidence D |
Dialysis schedules in relation to CM administration
|
It is not necessary to adapt the timing of intravascular CM administration in relation to the dialysis schedule in patients undergoing chronic dialysis or haemofiltration, but it may be done to minimise volume overload. |
Level of evidence D |
Question 10: Should the timing of CM administration be adapted to the schedule of haemodialysis or haemofiltration sessions in patients on renal replacement therapy?
Conclusion
Definitions
| |
Post-contrast acute kidney injury (PC-AKI) is defined as an increase in serum creatinine ≥ 0.3 mg/dl (or ≥ 26.5 μmol/l), or ≥ 1.5 times baseline, within 48–72 h of intravascular administration of a contrast medium. | |
Intra-arterial injection with first pass renal exposure indicates that contrast medium reaches the renal arteries in a relatively undiluted form, e.g. injection into the left heart, thoracic and suprarenal abdominal aorta or the renal arteries. | |
Intra-arterial injection with second pass renal exposure indicates that contrast medium reaches the renal arteries after dilution either in the pulmonary or peripheral circulation e.g. injection into the right heart, pulmonary artery, carotid, subclavian, coronary, mesenteric or infra-renal arteries. | |
Measurement of renal function
| |
• Estimated glomerular filtration rate (eGFR), calculated from the serum creatinine, is recommended to estimate renal function before administration of contrast medium. | |
• In adults ≥ 18 years, the CKD-EPI formula to estimate GFR is recommended.
| |
eGFR (ml/min/1.73 m2) = | |
Female sCr ≤ 62 μmol/l: 144 × (sCr/62)−0.329 × 0.993Age | |
Female sCr > 62 μmol/l: 144 × (sCr/62)−1.209 × 0.993Age | |
Male sCr ≤ 80 μmol/l: 141 × (sCr/80)−0.411 × 0.993Age | |
Male sCr > 80 μmol/l: 141 × (sCr/80)−1.209 × 0.993Age | |
(sCr in μmol/l; age in years) | |
All equations × 1.159 if African American race | |
• In children, the revised Schwartz formula to estimate GFR is recommended,
| |
eGFR (ml/min/1.73 m2) = 36.5 × Length/sCr (sCr in μmol/l; length in cm) | |
Note: Neither serum nor plasma creatinine is an ideal indicator of renal function and may miss decreased renal function. | |
Renal adverse reactions to iodine-based contrast media
| |
RISK FACTORS FOR PC-AKI
| |
Patient-related | • eGFR less than 45 ml/min/1.73 m2 before intra-arterial contrast medium administration with first pass renal exposure or in ICU patients |
• eGFR less than 30 ml/min/1.73 m2 before intravenous contrast medium or intra-arterial contrast medium administration with second pass renal exposure | |
• Known or suspected acute renal failure | |
Procedure-related | • Intra-arterial contrast medium administration with first pass renal exposure |
• Large doses of contrast medium given intra-arterially with first pass renal exposure | |
• High osmolality contrast media | |
• Multiple contrast medium injections within 48-72h | |
Time of referral
| |
ELECTIVE EXAMINATION
| |
MEASUREMENT OF RENAL FUNCTION
| |
• Measure eGFR before administering intravascular iodine-based contrast medium | |
either (a) In all patients | |
or (b) In patients who have a history of | |
- Renal disease (eGFR < 60 ml/min/1.73 m2) | |
- Kidney surgery | |
- Proteinuria | |
- Hypertension | |
- Hyperuricemia | |
- Diabetes mellitus | |
• Timing of eGFR measurement | |
- Within 7 days before contrast medium administration in patients with an acute disease, an acute deterioration of a chronic disease or who are hospital inpatients | |
- Within 3 months before contrast medium administration in all other patients | |
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 45 ml/min/1.73 m2 for intra-arterial administration with first pass renal exposure and eGFR less than 30 ml/min/1.73 m2 for intravenous and intra-arterial administration with second pass renal exposure as closely as clinical circumstances permit. | |
Before the examination
| |
ELECTIVE EXAMINATION
| |
At-risk patients (see above) | • Consider an alternative imaging method not using iodine-based contrast media |
• Intravenous saline and bicarbonate have similar efficacy for preventive hydration | |
• For intravenous contrast media administration and intra-arterial contrast media administration with second pass renal exposure hydrate the patient either with intravenous sodium bicarbonate 1.4% (or 154 mmol/l in dextrose 5% water): 3 ml/kg/h for 1 h before contrast medium or with intravenous saline 0.9%, 1 ml/kg/h for 3–4 h before and 4–6 h after contrast medium | |
• For intra-arterial contrast media administration with first renal exposure hydrate the patient either with intravenous sodium bicarbonate 1.4% (or 154 mmol/l in dextrose 5% water): 3 ml/kg/h for 1 h before and 1 ml/kg/h for 4–6 h after contrast medium or with intravenous saline 0.9%, 1 ml/kg/h for 3–4 h before and 4–6 h after contrast medium | |
• The clinician responsible for patient care should individualize preventive hydration in patients with severe congestive heart failure (NYHA grade 3–4) or patients with end-stage renal failure (eGFR < 15 ml/min/1.73 m2) | |
• Oral hydration is not recommended as the sole method of preventive hydration | |
EMERGENCY EXAMINATION
| |
At-risk patients (see above) | • Consider an alternative imaging method not using iodine-based contrast media |
• Use preventive hydration before contrast medium administration (see ‘Elective Examination’ for protocols) | |
Time of examination
| |
All patients | • Use low or iso-osmolar contrast media |
• Use the lowest dose of contrast medium consistent with a diagnostic result | |
• For intra-arterial contrast medium administration with first pass renal exposure keep either the ratio CM dose (in gram I)/absolute eGFR (in ml/min) < 1.1 or the ratio CM volume (in ml)/eGFR (in ml/min/1.73 m2) < 3.0 (assuming a contrast medium concentration of 350 mg iodine/ml) | |
After the examination
| |
At-risk patients | • Continue preventive hydration if appropriate (see protocols above) |
• Determine eGFR 48 h after administration of contrast medium | |
• If at 48 h there is a diagnosis of PC-AKI, monitor the patient clinically for at least 30 days and determine eGFR at regular intervals | |
Note: No pharmacological prophylaxis (with statins, renal vasodilators, receptor antagonists of endogenous vasoactive mediators or cytoprotective drugs) has been shown to offer consistent protection against PC-AKI. | |
Patients with diabetes mellitus taking metformin
| |
• Patients with eGFR > 30 ml/min/1.73 m2 and no evidence of AKI receiving either intravenous or intra-arterial iodine-based contrast medium with second pass renal exposure: Continue taking metformin normally. | |
• Patients (a) with eGFR < 30 ml/min/1.73 m2 receiving either intravenous or intra-arterial contrast medium with second pass renal exposure or (b) receiving intra-arterial contrast medium with first pass renal exposure or (c) with AKI: | |
Stop taking metformin from the time of contrast medium administration. Measure eGFR within 48 h and restart metformin if renal function has not changed significantly. | |
Dialysis and contrast medium administration
| |
• All iodine-based contrast media can be removed by haemodialysis or peritoneal dialysis. | |
• There is no evidence that haemodialysis protects patients with normal or impaired renal function from PC-AKI. | |
• In all patients, avoid osmotic and fluid overload. | |
PATIENTS ON DIALYSIS
| |
Patients on haemodialysis
| • Co-ordinating the time of the iodine-based contrast medium injection with the haemodialysis session is unnecessary |
• Extra haemodialysis session to remove iodine-based contrast medium is unnecessary | |
Patients on continuous ambulatory peritoneal dialysis
| Haemodialysis to remove iodine-based contrast medium is unnecessary |