Written by Clay Smith
CTA is likely underutilized to identify the source of GI bleeding in select patients, especially those with lower GI bleeding (LGIB).
Why does this matter?
Options to diagnose GI bleeding are endoscopy, capsule endoscopy, nuclear scintigraphy, traditional angiography, CT enterography, or CTA. I often forget CTA is an option. Remember, a CTA is not the same as a CT with contrast. So, should we utilize CTA more often?
Dabbling in the occult
This was a retrospective review of 1,493 patients at a single center with GI bleeding. CTA was used in just 0.7%. Compare this with endoscopy, which was used in 75.7%. CTA can identify not only active bleeding but underlying structural changes to aid in planning targeted endoscopy or embolization procedures. CTA has been shown to have 85.2% sensitivity and 92.1% specificity for acute GI bleeds and can detect bleeding rates as low as 0.3mL/min. Accuracy is even better in LGIB, with sensitivity 90% and specificity 92% in a 2017 meta-analysis. CTA is recommended for LGIB by the British Society of Gastroenterology: “We recommend that if a patient is haemodynamically unstable or has a shock index (heart rate/systolic BP) of >1 after initial resuscitation and/or active bleeding is suspected, CT angiography provides the fastest and least invasive means to localise the site of blood loss before planning endoscopic or radiological therapy (strong recommendation, low quality evidence).” Which bleeding patients are ideal candidates for CTA? Obviously, a patient with known cirrhosis and bright red hematemesis would have little mystery as to the source of bleeding. This article advocates for more CTA use for acute GI bleeding in general. Personally, I plan to use it more often in cases in which the cause of bleeding is not clear and definitely in active LGIBs.
The utilization of CTA in management of gastrointestinal bleeding in a tertiary care center ED. Are we using it enough? Am J Emerg Med. 2021 Jan;39:60-64. doi: 10.1016/j.ajem.2020.01.015. Epub 2020 Jan 11.