Risk of contrast-induced kidney injury is expected to be strongly correlated with exposure time. Studies on the excretion of iodinated contrast material are few and have mostly been carried out in patients with normal renal function. Although case wise reports of persistent renograms have been published, it is not known how long contrast is retained before excretion in patients with eGFR \<30 mL/min/1.73m2, nor which of these patients are most susceptible to contrast retention. The current observational study aims to compare contrast elimination time and % contrast excretion in patients with eGFR \<30 mL/min/1.73m2, to matched patients (for age, sex and contrast procedure type) with eGFR 30-59 and eGFR \>=60 mL/min/1.73m2.
The primary aim of the current study is to determine contrast elimination time and % in three groups of patients, (with severely reduced, moderate, and mildly reduced to normal renal function). Secondary aims are to explore whether specific situations/characteristics result in higher probability of delayed elimination of contrast, and whether there is a link between elimination time and adverse post-contrast outcomes (post-contrast incidences of acute kidney injury; post-contrast changes in eGFR within 5 days from baseline; 1-month post-contrast change in eGFR; 1-month post-contrast incidences of eGFR decline \>=5 mL/min/1.73m2; 1-month dialysis and mortality).
Study Type
OBSERVATIONAL
Iodinated contrast content of urine samples, collected post-contrast over a period of 5 days at all times of natural excretion within that period, will be assayed. Serum creatinine will be measured daily before (day 0) and during 5 days post-contrast, and again at 1 month post-contrast.
Maastricht UMC
Maastricht, Netherlands
time to contrast-free urine.
time to the first contrast-free urine sample from the time of intravascular iodinated contrast administration. Time to contrast-free urine will be compared between three groups of patients (with eGFR \<30 mL/min/1.73m2, eGFR 30-59 mL/min/1.73m2, and eGFR \>=60 mL/min/1.73m2).
Time frame: 5 days
% contrast elimination.
percentage of total contrast administered excreted in urine within 5 days. Percentage contrast elimination will be compared between three groups of patients (with eGFR \<30 mL/min/1.73m2, eGFR 30-59 mL/min/1.73m2, and eGFR \>=60 mL/min/1.73m2).
Time frame: 5 days
contrast elimination versus adverse post-contrast outcomes.
The underlying hypothesis is that delayed elimination increases contrast toxicity which increases adverse event risk. This will be explored by comparing percentages with post-contrast adverse events (acute kidney injury; changes in eGFR; eGFR decline ≥5mL/min/1.73m2; dialysis; mortality; up to 1-month) in groups with and without delayed elimination, stratified by eGFR (\<30, 30-59, ≥60). Relevant patient and procedural characteristics will also be compared to identify potential predictors of delayed elimination. Contrast elimination times are unknown, therefore 'delayed' is defined as time to contrast-free urine exceeding patient group median value. In clinical practice, normal contrast elimination is assumed to be ≥24h. Therefore, 1. Normal (≤24h); 2. Delayed (24-48h); 3. Severely delayed (\>48h) elimination subgroups will also be compared. Subgroup cut-off values may be added at a later stage (e.g., in the event of many or no patients with elimination \>48h).
Time frame: 1 month
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