Abstract
Background and study aims Endoscopic ultrasound (EUS) has been used for portal vein sampling in patients with
pancreaticobiliary cancers for enumerating circulating tumor cells but is not yet
a standard procedure. Further evaluation is needed to refine the methodology. Therefore,
we evaluated the feasibility and safety of 19-gauge (19G) versus a 22-gauge (22 G)
EUS fine-needle aspiration needles for portal vein sampling in a swine model.
Methods Celiotomy was performed on two farm pigs. Portal vein sampling occurred transhepatically.
We compared 19 G and 22 G needles coated interiorly with saline, heparin or ethylenediaminetetraacetic
acid (EDTA). Small- (10 mL) and large- (25 mL) volume blood collections were evaluated.
Two different collection methods were tested: direct-to-vial and suction syringe.
A bleeding risk trial for saline-coated 19 G and 22 G needles was performed by puncturing
the portal vein 20 times. Persistent bleeding after 3 minutes was considered significant.
Results All small-volume collection trials were successful except for 22 G saline-coated
needles with direct-to-vial method. All large-volume collection trials were successful
when using suction syringe; direct-to-vial method for both 19 G and 22 G needles were
unsuccessful. Collection times were shorter for 19 G vs. 22 G needles for both small
and large-volume collections (P < 0.05). Collection times for saline-coated 22 G needles were longer compared to
heparin/EDTA-coated (P < 0.05). Bleeding occurred in 10 % punctures with 19 G needles compared to 0 % with
22 G needles.
Conclusion The results of this animal study demonstrate the feasibility and the safety of using
22 G needles for portal vein sampling and can form the basis for a pilot study in
patients.
