Application of the data to the case
The patient presented with abdominal pain potentially attributable to acute mesenteric ischemia, where a delayed or missed diagnosis can be potentially fatal. He was counseled about the comparatively small risk of CA-AKI with IV contrast and underwent contrast-enhanced CT scanning without incident. The diagnosis of acute mesenteric ischemia was confirmed, and he was referred for urgent laparotomy.
Bottom line
The absolute risk of CA-AKI varies according to baseline renal function and is not clearly linked to the receipt of IV contrast. The risks of withholding contrast may be greater than the risk of CA-AKI. Clinicians should counsel patients accordingly.
Dr. Anderson is national lead, VHA Hospital Medicine, and associate professor of medicine at the Minneapolis VA Health Care System. Dr. Yamanaka is a hospitalist at the Minneapolis VA Medical Center and an assistant professor of medicine at the University of Minnesota.
References
1. Nash K et al. Hospital-acquired renal insufficiency. Am J Kidney Dis. 2002;39(5):930-6. doi: 10.1053/ajkd.2002.32766.
2. Section 4: Contrast-induced AKI. Kidney Int Suppl. 2012;2(1):69-88. doi: 10.1038/kisup.2011.34.
3. Wilmot A et al. The adoption of low-osmolar contrast agents in the United States: Historical analysis of health policy and clinical practice. AJR Am J Roentgenol. 2012;199(5):1049-53. doi: 10.2214/AJR.11.8426.
4. Newhouse JH et al. Frequency of serum creatinine changes in the absence of iodinated contrast material: Implications for studies of contrast nephrotoxicity. AJR Am J Roentgenol. 2008;191(2):376-82. doi: 10.2214/AJR.07.3280.
5. Davenport MS et al. Contrast material-induced nephrotoxicity and intravenous low-osmolality iodinated contrast material: Risk stratification by using estimated glomerular filtration rate. Radiology. 2013;268(3):719-28. doi: 10.1148/radiol.13122276.
6. McDonald JS et al. Risk of intravenous contrast material-mediated acute kidney injury: A propensity score–matched study stratified by baseline-estimated glomerular filtration rate. Radiology. 2014;271(1):65-73. doi: 10.1148/radiol.13130775.
7. Hinson JS et al. Risk of acute kidney injury after intravenous contrast media administration. Ann Emerg Med. 2017;69(5):577-86. doi: 10.1016/j.annemergmed.2016.11.021.
Key points
- Early studies suggesting an association between IV contrast and AKI used an older formulation of contrast media not routinely used today. Importantly, these studies did not use control groups.
- Results from multiple recent large trials comparing IV contrast patients with controls suggest that AKI is not clearly linked to the receipt of IV contrast and that it varies according to baseline renal function.
- Randomized controlled trials of prophylactic normal saline or sodium bicarbonate to prevent CA-AKI show mixed results. Clinical trials comparing N-acetylcysteine with placebo showed no difference in the rates of AKI, dialysis initiation, or mortality.
Quiz
Which of the following is not clearly associated with acute kidney injury in hospitalized patients?
A. Decreased baseline glomerular filtration rate
B. Angiotensin-converting enzyme (ACE) inhibitor use
C. Hemodynamic instability
D. Intravenous contrast administration
Answer: D
While decreased baseline renal function, ACE inhibitors, and hemodynamic instability are known risk factors for hospital-associated renal injury, a growing body of literature suggests that intravenous contrast used in computed tomography studies does not precipitate acute kidney injury.
Further reading
McDonald JS et al. Frequency of acute kidney injury following intravenous contrast medium administration: a systematic review and meta-analysis. Radiology. 2013;267(1):119-128. doi: 10.1148/radiol.12121460.
McDonald RJ et al. Behind the numbers: Propensity score analysis – a primer for the diagnostic radiologist. Radiology. 2013;269(3):640-5. doi: 10.1148/radiol.13131465.
Luk L et al. Intravenous contrast-induced nephropathy – the rise and fall of a threatening idea. Adv Chronic Kidney Dis. 2017;24(3):169-75. doi: 10.1053/j.ackd.2017.03.001.
Mehran R et al. Contrast-associated acute kidney injury. N Engl J Med. 2019;380(22):2146-55. doi: 10.1056/NEJMra1805256.
