- Early binding agents used were iodine based with high osmolality agents , osmolalility often exceeding 1500 mosm/kg H20 approaching 5 - 8 times that of normal human serum. By mid 1990S these agents were changed low osmolality or iso osmolar agents.
Contrast Induced Nephropathy
Criteria
- Serum creatinine increase by 0.3 mg/dl
- Increase in serum creatinine by 50%
- Urine output of less than 0.5ml/kg/hr for atleast 6 hours.
Risk factors
- eGFR >45 ml/min/1.73m : Normal Risk
- eGFR 30 -45 ml/min/1.73m2 : Borderline risk
- eGFR < 30 : Higher Risk
The Evidence
- Most literature evidence of CA-AKI is focused on contrast administration in the setting of PCI, where the dose is substantially higher. The dose of iodinated contrast for CT ranges from 60 -100 ml whereas in PCI is 200-600ml. Also the retrospective studies had confounding factors were the disease itself would have caused AKI.
- Mehran et al did a study to assess the relationship between dose of iodinated contrast and the risk of AKI or increase in creatinine by 25% or 0.5mg/dl. The study demonstrated a relationship wherein the odds of AKI were 1.46 for 200 – 400 mL, 1.98 for 400 – 600 mL, and 4.88 for above 600 mL of contrast.
- Hinson et al (j.annemergmed. 2016)published a propensity-matched retrospective study over a 5-year period comparing the development of AKI in patients who received contrast-enhanced CT (n = 7201), non-contrast enhanced CT (n = 5499), and patients who did not receive a CT (n = 5234). Defining AKI according to the Kidney Disease Improving Global Out comes guidelines, they discovered that 6.7%, 8.9%, and 8.1% of patients in these groups developed AKI respectively, with no significant differences between groups. All contrast patients received either iohexol or iodixanol intravenously with a maximum dose of 120 mL. There was no difference in subsequent development of chronic kidney disease, need for dialysis, or renal transplantation.
- Ehmann et al (Intensive Care Med.2023). published a retrospective entropy-balanced and propensity-balanced observational cohort study of 14,449 hospitalized patients already meeting criteria for AKI at the time of emergency department visit who did or did not receive contrast media. All patients received 70 - 120 mL of iohexol or iodixanol intravenously. They found no association between contrast administration and persis tent AKI or need for dialysis.
Conclusion
- The present literature shows that there is no evidence to suggest CA-AKI may be caused by 60 - 120ml of contrast.
Reference
- Rogers DC, Tadi P. Intravenous Contrast Media in Medical Imaging. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557794/
