Kennislacunes

Overall knowledge gaps

Creation of a National and Regional PC-AKI Registry in the Netherlands

While the number of patients with an impaired renal function CKD grade 4-5, eGFR <30 ml/min/1.73m²) is relatively limited, the nephrology care for these patients should be optimized. This requires an optimal database that is currently lacking. Data are needed on their nephrology status and co-morbidities, but also of their evolution of their renal function impairment, both before and after imaging with intravascular iodine-containing contrast media. A potential type of study design that may provide relevant information is a cluster randomization study where radiologists/cardiologists and nephrologists cooperate.

 

Such an effort would require data input from multiple hospitals (university and community), organized by a multidisciplinary team of medical specialists from different backgrounds as well as IT-specialists from Hospital Information Systems.

 

Improved data on CI-AKI from intra-arterial CM

The efforts made in the radiological community to separate CIN from PC-AKI by performing randomized controlled trials and, when possible, propensity score-matched studies with well-matched control populations should be extended to interventional radiology and cardiology. This would allow the evaluation of the epidemiology of “true” CI-AKI in catheter-based diagnostic and interventional studies, and the possible contributory, confounding effects of catheter or device manipulations. However, this is very complex since the definition of good control populations for interventional procedures is not straightforward as sham procedures are never performed. For some vascular territories, CO₂ angiography may be a suitable comparator.

 

Better stratification of the relative risks of interventional procedures

There is abundant literature about risk of PC-AKI and intra-arterial iodine-containing CM administration in (coronary) angiography including percutaneous (coronary) interventions. However, this is a very heterogeneous patient group, which could be much better stratified in procedures with low/medium/high relative risks depending on the patient characteristics, type and length of the procedure, and/or CM use. In the future, a well validated risk assessment model may become available.

 

Knowledge gaps per guideline chapter

Risk stratification and stratification tools

1. It is unclear which patient-related determinants can predict that intravenous hydration will decrease the risk of PC-AKI.
2. It is unclear whether patients with kidney transplantation have an increased risk of PC-AKI.
3. It is unclear which risk stratification tools should be used for the estimation of the risk of PC-AKI in patients undergoing either intravenous or intra-arterial iodine-containing contrast medium administration.

 

Estimation of Glomerular Filtration Rate

1. It is unclear what length of time a serum creatinine or eGFR measurement is valid, when estimating the risk of PC-AKI.
2. It is unclear what the optimal follow-up time is for a patient who has developed PC-AKI.

 

Prevention: hydration and complications

1. It is unclear whether the risk of PC-AKI is similar in patients who receive intravenous iodine-containing contrast-medium administration in combination with hydration versus no hydration.
2. It is unclear whether controlled hydration is more effective in reducing the risk of PC-AKI as compared to standard hydration in patients who receive intra-arterial iodine-containing contrast medium administration for a coronary angiography with or without intervention.
3. It is unclear whether the risk of PC-AKI is similar in patients who receive intravenous iodine-containing contrast medium administration in combination with oral hydration versus standard hydration.
4. It is unclear which schedule (of pre- and/or posthydration) is the most optimal hydration schedule to reduce the risk of PC-AKI, both in patients undergoing intravenous iodine-containing contrast medium administration and in patients undergoing intra-arterial iodine-containing contrast medium administration.

 

Other preventive measures: Statins

1. It is unclear which type of statin is optimal to reduce the risk of PC-AKI in patients undergoing intra-arterial iodine-containing contrast medium administration.
2. It is unclear which dosing scheme of statin before and/or after hydration is optimal to reduce the risk of PC-AKI.

 

Other preventive measures: N-acetylcysteine

1. It is unclear whether N-acetylcysteine reduces the risk of PC-AKI in patients undergoing intravenous or intra-arterial iodine-containing contrast medium administration.
2. It is unclear whether N-acetylcysteine should be administered orally or intravenously to reduce the risk of PC-AKI optimally.
3. It is unclear whether any positive effects of N-acetylcysteine on kidney function contribute to true kidney-sparing effects.

 

Other preventive measures: Vitamin C

1. It is unclear whether Vitamin C reduces the risk of PC-AKI in patients undergoing intravenous or intra-arterial iodine-containing contrast medium administration.
2. It is unclear which administration route (orally or intravenously) and dose of Vitamin C should be used to optimally reduce the risk of PC-AKI.

 

Other preventive measures: Discontinuation of nephrotoxic medication

1. It is unclear whether discontinuation of any type of nephrotoxic medication prior to intravascular iodine-containing contrast medium administration reduces the risk of PC-AKI in patients that chronically use this medication.

 

Other preventive measures: dialysis and hemo(dia)filtration

1. It is unclear whether hemodialysis or hemo(dia)filtration reduces the risk of PC-AKI in CKD 4-5 patients undergoing intravascular iodine-containing contrast medium administration.
2. It is unclear whether the potential beneficial effects of hemodialysis or hemodialfiltration outweigh the risks whether in CKD 4-5 patients undergoing intravascular iodine-containing contrast medium administration.

 

Contrast medium use in diabetic patients using metformin

1. It is unclear whether metformin is the cause of lactic acidosis in patients undergoing intravascular contrast administration.
2. It is unclear whether discontinuation of metformin in patients with type 2 diabetes reduces the risk of lactic acidosis in patients undergoing intravascular iodine-containing contrast medium administration.