QUARTERLY BEAT
JULY 2026
and starfish prep exist (Liffman 2017). The needle should be held close to the slide when expelling the specimen to avoid missing the slide or drying the sample prior to spreading. For the FN-NA technique, it may be helpful to attach a syringe containing air already pulled back to the 1-3 mL position. This technique speeds spreading the sample onto the slides while also avoiding premature expulsion of the sample while connecting a syringe to the hub of the needle.
systematic review (Klopfleisch 2011) of both veterinary and human literature concluded that the risk of neoplastic seeding is low and there is no evidence of increased risk of distant site metastasis with needle procedures. The author, numerous colleagues, and yet another recent review article (Liffman 2017) share the opinion that the benefit of an immediate diagnosis appears to outweigh the low risk, as long as risk is appropriately discussed with the owner. When neoplastic seeding occurs, it is usually with highly aggressive tumors that fail to respond to chemotherapy or have already metastasized. Finally, the author has observed that urinary obstruction from the primary mass is almost always more of a problem clinically than peritoneal or abdominal wall masses that result from seeding. Still, it is reasonable to pursue less invasive testing (e.g., BRAF testing or traumatic catheterization) if the patient is stable and can await results and/or the clinician or client are unwilling to assume the low risk of neoplastic seeding. The incidence of infection or septic peritonitis is rare following routine aspiration procedures. Certainly, that risk theoretically increases if the aspirated tissue is infected (e.g., abscess or infected urine/bile). If a patient is immunocompromised, extra precautions may be taken such as a more thorough sterile preparation, the wearing of sterile gloves, and prophylactic antibiotics. Increased vagal tone is similarly rare. The author only recalls a handful of instances of vagal induced bradycardia or hypotension in his career, all involving cystocentesis of the urinary bladder in healthy cats and one dog. Fortunately, all were self-limiting or responsive to atropine.
SAFETY
Aspiration techniques are incredibly safe when performed properly with ultrasound guidance. Although not often discussed as such, inconclusive or misleading results are perhaps the most common complication since the procedure costs money to both perform and send to a clinical pathologist for interpretation. With regard to patient harm, hemorrhage is the most frequently encountered complication, but it is often self-limiting. Rare complications include infection, neoplastic seeding, increased vagal tone, or death. In a large study (Livraghi 1983) of 11,700 humans, the overall complication rate was 0.55%. Major complications were rare (0.05%) and included biliary peritonitis (n=2, 0.017%), tumor seeding (2, 0.017%), intrahepatic hematoma (1, 0.008%), peritonitis (1, 0.008%), and necrotizing pancreatitis leading to death (1, 0.008%). Two older veterinary abstracts (Menard & Papageorges 1996 and Papageorges 1996) reported two deaths each among 600 (0.33%) canine liver aspirates and 307 (0.65%) feline aspirates. More recent studies report no deaths and a complication rate of 0 – 5.6% (Flemming 2019, Hager 1985, O’Keefe 1987), Bonfanti 2004, and Liffman 2017). Higher complication rates (e.g., 5.6%) often get reported with studies that use larger gauge needle biopsies. Logically, risk for hemorrhage increases with needles larger than 18G and diseases that cause significant thrombocytopenia, platelet dysfunction, or hypocoagulability. However, diseases that increase risk for bleeding are not an absolute contraindication for aspiration procedures. For example, one study reported no complications when splenic aspirates were performed in patients with thrombocytopenia (O’Keefe 1987). If the need for a diagnosis outweighs the risk, the FN-NA technique and a smaller gauge needle (e.g., 25G or 27G) may be used. The concern for neoplastic seeding when aspirating tumors is commonly cited as a reason not to aspirate tumors such as urothelial cell carcinoma (formerly transitional cell carcinoma). However, the evidence does not support that this is a common complication. In humans, the estimated frequency of neoplastic seeding is 0.009%, most commonly seen with pancreatic neoplasia (Smith 1991). This complication seems equally rare in veterinary species with only sparse reports in the literature involving highly aggressive forms of pulmonary adenocarcinoma,
CONCLUSION
Overall, ultrasound-guided abdominal organ FNA is a practical, minimally invasive diagnostic tool that can offer valuable clinical information when performed thoughtfully and with good technique. By understanding the basics of patient preparation, equipment selection, sampling method, and procedural safety, clinicians can improve diagnostic yield while helping reduce the risk of complications. In Part 2, we’ll take a deeper look at the unique organ-specific considerations that shape why, when, and how we sample different abdominal tissues.
ABBREVIATIONS
•
BRAF: B-Raf proto-oncogene
•
FN-NA: fine needle non-aspiration
•
FNA: fine needle aspirate
•
G: gauge
renal cell carcinoma, pancreatic carcinoma, and urothelial cell carcinoma (Warrne-Smith 2011, Livet 2016, Nyland 2002, Vignoli 2007, Wilson 2007, Higuchi 2013, and Jegatheeson 2020). In fact, a recent
WEBINAR HIGHLIGHTS
VETGIRLONTHERUN.COM
VETGIRL BEAT EMAGAZINE 21
Made with FlippingBook - Online Brochure Maker