Written by Sam Parnell
Contrast-associated acute kidney injury (CA-AKI) is a controversial subject. The available evidence is reassuring that significant acute kidney injury, death, and need for renal replacement therapy are rare after IV contrast administration.
Why does this matter?
Several studies have shown an association between contrast administration and acute kidney injury. Listen to the deep dive Rob Orman and Clay Smith did on contrast nephropathy on ERcast. That podcast was based on these two posts: Contrast Nephropathy Is Real and Contrast Nephropathy Is a Myth. Does intravenous contrast truly cause acute kidney injury? If so, what patients are at risk and what can we do to prevent this from happening?
The Kidney and IV Contrast Relationship: “It’s Complicated”
CA-AKI may be an indicator of an increased risk of adverse renal outcomes rather than a mediator of such outcomes.
Confounding and indication bias are major limitations of many CA-AKI studies.
Changes in creatinine are sensitive for AKI but have low specificity. This may also be due to hemodynamic instability, fluid shifts, and medication effects.
Significant AKI, death, and the need for renal replacement therapy are very rare after IV contrast administration.
There are no adequately powered clinical trials showing that prevention of CA-AKI results in a survival benefit.
History of chronic kidney disease, high-osmolality contrast agents, large contrast volume (>350 ml or 4 ml/kg), or repeat contrast dosing within 72 hours have all been shown to increase the risk of CA-AKI.
The unintended consequence of excessive concern about CA-AKI is clinicians are more hesitant to order contrasted studies for patients who may benefit from them.
IV fluid may be beneficial in preventing CA-AKI, but the optimal rate and volume is unknown.
In summary, further investigation is needed to determine if a causal relationship exists between IV contrast and kidney injury, but the available evidence is reassuring that significant AKI, death, and the need for renal replacement therapy are rare after IV contrast administration.
Don’t miss REBEL EM on this topic.
And don’t forget about Rob O and Clay on ERcast – a look at both sides and practical pearls.
Contrast-Associated Acute Kidney Injury. N Engl J Med. 2019 May 30;380(22):2146-2155. doi: 10.1056/NEJMra1805256.
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Reviewed by Clay Smith