Liver biopsies play a crucial role in the diagnosis and treatment of hepatic diseases in pets. While fine-needle aspirates of the liver are commonly performed, they have shown poor diagnostic accuracy—as low as 30% when compared with histopathology in some studies. This significant discrepancy highlights why surgical biopsies are often the recommended approach for comprehensive liver evaluation.
Understanding the Risks
Veterinarians must carefully weigh the benefits of obtaining diagnostic samples against potential complications. Dr. Rachel Williams, a board-certified small animal surgeon, notes in a recent article in DVM360 that "patients may be systemically ill, with prolonged clotting times, ascites, or significant cirrhosis of the liver, which can make surgical biopsies more challenging and at a higher risk for complications."
The most significant concern during liver biopsy procedures is bleeding, given the liver's crucial role in blood clotting. Therefore, checking a patient's clotting times prior to obtaining biopsies is generally recommended as a precautionary measure.
Best Practices for Liver Biopsies
According to the American College of Veterinary Internal Medicine's 2019 consensus statement on diagnosing and treating chronic hepatitis in dogs, several key recommendations should be followed:
- Obtain samples large enough to include 12 to 15 portal triads
- Sample different liver lobes, as there may be variation between them
- Submit samples for aerobic and anaerobic culture
- Include tissue for copper quantification (requiring 20-40 mg of liver tissue)
For comprehensive assessment, veterinarians should collect a minimum of three surgical biopsy specimens from at least two liver lobes for histopathology, plus additional samples for culture and copper quantification.
Biopsy Techniques
Ultrasound-guided biopsy: This minimally invasive option uses a Tru-Cut biopsy device under ultrasound guidance. While less invasive than surgical approaches, diagnostic accuracy ranges from 48% to 83% when compared with surgical biopsies. If using this method, more than four specimens are recommended to ensure adequate sampling.
Open surgical techniques: These include the guillotine technique (where a portion of the liver lobe periphery is ligated and transected), biopsy punch methods (creating samples from anywhere in the liver), and the use of vessel sealing devices. Each technique has specific advantages and considerations regarding sample quality and potential bleeding.
Laparoscopic liver biopsy: This approach offers a balance between minimally invasive techniques and high-quality samples. "The magnification and illumination associated with laparoscopic surgery may also aid in targeted biopsy of lesions, and the use of laparoscopy can result in reduced pain and a faster recovery," explains Dr. Williams. Multiple techniques exist for obtaining the sample, with the twisting technique reported to have the fewest artifacts.
Postoperative Care
Following liver biopsies, careful monitoring is essential. Vital signs should be regularly recorded, and many surgeons recommend checking packed cell volume/total solids and blood pressure 2-4 hours after surgery to detect potential bleeding complications. Most patients can be discharged the same day with appropriate pain management.
Importantly, antibiotics and steroids are generally not needed immediately after the procedure. These medications should be prescribed only after biopsy results are available and indicate a specific need for such treatments.
By understanding and following these guidelines, veterinary professionals can maximize the diagnostic value of liver biopsies while minimizing risks to patients with suspected hepatic disease.
References:
Source: https://www.dvm360.com/view/performing-a-liver-biopsy
