Author of 1 Presentation
SS 9.5 - CT angiography for overt GI bleeding: extravasation volume correlates with prognosis and bleeding rate (ID 467)
Abstract
Purpose
To measure the extravasation volume of first-pass CTA in patients with overt GI bleeding (GIB) and to correlate volume with clinical outcomes.
Material and methods
In this retrospective, IRB-approved and HIPAA-compliant study, we reviewed all patients from 1/2014 to 7/2019 who presented with overt GIB and had active extravasation on CTA. Extravasation volume (EV) was calculated using 3D segmentation software. Imaging data were correlated with clinical data, including if further workup was pursued, active bleeding was identified, and blood transfusions were required following CTA.
Results
50 consecutive patients met inclusion criteria, corresponding to 6 (12%) upper, 18 (36%) small bowel, and 26 (52%) lower GIB. 42 patients underwent further workup with catheter angiography, endoscopy, or surgery, with a median elapsed time of 9 hours between CTA and further workup. Of 42, 16 (38%) had active bleeding intra-operatively and all underwent intervention with successful hemostasis. Arterial extravasation volume was 2.72±2.97 mL for those with active bleeding and 0.76±1.01 mL for those without (p=0.0009). Using a threshold volume of 0.80 mL, the odds ratio of requiring massive transfusion was 7.0 (95% confidence interval 1.9-26; p=0.004), identifying active bleeding was 11.8 (2.6-54; p=0.002), and therapeutic yield was 6.8 (1.5-30; p=0.01). Using a previously described mathematical model, bleeding rate can be estimated from extravasation volume and attenuation, and the lower limit of detected bleeding rate was calculated to be < 0.1 mL/minute.
Conclusion
Larger extravasation volumes may be used to triage patients who require additional management and improve therapeutic yield. Current CTAs can detect bleeding rates lower than 0.1 mL/minute.