Neurons or Nephrons – Creatinine Screening for Stroke Imaging

November 20, 2020

Written by Aaron Lacy

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Elimination of creatinine pre-screening before IV contrast in patients with suspected stroke did not change rates of contrast induced nephropathy (CIN), hemodialysis, or mortality.

Why does this matter?
Millions of neurons die each minute a stroke goes unrecognized or untreated. A critical component of modern stroke treatment is neuroimaging with IV contrast. Traditional teaching is that those with underlying kidney disease should not receive IV contrast; therefore, kidney function screening before IV contrast is currently recommended. If there are no clinically significant adverse events in patients who receive IV contrast regardless of underlying kidney disease, why waste valuable minutes screening for it?

Would you sacrifice nephrons for neurons? You may not have to do either.
This retrospective study of 382 ED patients with suspected stroke included patients during (n = 186) a period with mandatory creatinine screening and those in a period without  (n = 196) screening before administration of IV contrast for CTA/CTP studies. There was no statistically significant difference in odds ratios observed for CIN (7.0% vs 7.1%), renal impairment at 30 days (8.4% vs 7.5%) or 90 days post-contrast (6.7% vs 4.0%), or mortality (4.8% vs 2.6%). No patients underwent hemodialysis.

There is a mounting body of evidence that AKI after administration of IV contrast is overstated. This study’s observed rates of post-contrast AKI are consistent with prior reported levels in the literature, and patients had low rates of mortality and none needed dialysis. At this point, I see no need to delay IV contrast in patients with such a time critical diagnosis for creatinine screening. The phrase “Neurons over Nephrons” implies that it may be worth the sacrifice of kidney function in order to save the brain – but if the kidneys don’t suffer regardless of our screening practices, are we really sacrificing them? Our hospital currently forgoes point-of-care creatinine screening in our acute stroke patients, and I don’t see a reason to start.

Source
Impact of creatinine screening on contrast-induced nephropathy following computerized tomography for stroke. Am J Emerg Med. 2020 Sep 20;S0735-6757(20)30840-8. doi: 10.1016/j.ajem.2020.09.044. Online ahead of print.

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