Liver biopsy

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Chapter 33 LIVER BIOPSY

• Liver biopsy is frequently performed to assist in the diagnosis and staging of liver disease.

• Since liver biopsy is an invasive procedure, the procedure requires appropriate precautions and informed consent.

• Safety warrants that patients should ideally have a normal (or close to normal) coagulation profile.

• Most biopsies are performed percutaneously with the assistance of hepatic ultrasound.

• The most serious complications include bleeding and haemobilia.

• Close monitoring of the blood pressure and pulse is required post procedure.

• For best histological interpretation the biopsy should ideally be at least 2 cm in length and contain at least six portal tracts.

INTRODUCTION

Liver biopsy remains an important tool in the investigation of hepatic dysfunction. It can obtain qualitative information regarding liver architecture, as well as type and degree of acute hepatic injury, and can both identify and qualify degree of fibrosis. A biopsy is usually performed after numerous non-invasive liver tests have been obtained.

It is also useful in evaluating and monitoring treatment of hepatic abnormalities and diseases, including post-transplant, and in guiding future management.

BIOPSY METHODS

Percutaneous

Most commonly used method, and safe when performed by an experienced operator. Use of ultrasound as a marker for needle entry improves safety.

Transjugular

A more invasive method, and most commonly used in patients with bleeding diatheses, or those with other conditions that would make percutaneous approach unsafe, such as morbid obesity or massive ascites, or after a failed attempt at percutaneous biopsy.

Laparoscopic

Invasive, and requires a surgical approach, and therefore general anaesthetic. Often performed in conjunction with another surgical procedure (e.g. cholecystectomy). Has an advantage over percutaneous biopsy in malignant hepatic lesions and in cirrhosis, and provides a higher diagnostic yield.

Ultrasound or CT-guided fine needle aspiration

Obtains only a small number of cells, and is used mainly to target specific liver lesions, rather than sample a homogeneous liver.

Indications

• Grading and staging of chronic hepatitis B.

• Grading and staging of chronic hepatitis C in genotype 1, or hepatitis B and C coinfection.

• Diagnosis of abnormal liver tests, usually after at least 6 months of inconclusive serological tests.

• Diagnosis of non-alcoholic steatohepatitis (NASH), autoimmune hepatitis and alcoholic liver disease.

• Diagnosis of haemochromatosis with ferritin >1000 μg/L and Wilson’s disease.

• Primary biliary cirrhosis and sclerosing cholangitis.

• Evaluation of liver function post-transplant, and to assess potential donor.

• Assessment of drug effects on the liver (e.g. long-term methotrexate therapy).

• Diagnosis of a liver lesion.

• Pyrexia of unknown origin.

Histology is not needed prior to therapy for hepatitis C in some centres, therefore biopsy is not always necessary. Biopsy may stage the disease satisfactorily, but is not good for predicting clinical response to treatment.

Percutaneous biopsy of a neoplastic lesion has the small potential for seeding, and is therefore not usually performed. A lesion >2 cm with a high alpha-fetoprotein (AFP) in serum is highly sensitive for malignancy.

Biopsy is the only method of assessing fibrosis in NASH (see Chapter 39). Patients with a BMI >30 kg/m², diabetes or age >45 years should be biopsied. Up to 20% of NASH patients will have severe fibrosis.

Diagnosis of viral hepatitis or NAFLD does not require biopsy.

At least six portal tracts are needed for accurate diagnosis. Specimen should be at least 2 cm in length.

Contraindications

Absolute

• Previous unexplained bleeding.

• Uncooperative patient.

• Suspected vascular lesion or echinococcal disease.

• Poor resuscitation facilities.

• Accurate biopsy site not identified by percussion or ultrasound.

Relative

• Non-steroidal antiinflammatory drug (NSAID) use in last 7 days.		May be corrected by appropriate methods prior to biopsy
• Platelets <60,000/mL.
• Prothrombin time >4 seconds.
• Prolonged bleeding time (>10 minutes).
• Haemophilia.
• Ascites.
• Obesity.
• Right-sided pleural or diaphragmatic infections.
• Acute renal failure.
• Skin infection at the potential biopsy site.

PATIENT PREPARATION

• Thorough history and examination.

• Fully informed consent, including:

– Indication for biopsy

– Alternatives

– Limitation of biopsy

– A full understanding of the risks and complications.

• Patient is fasted or has had a light breakfast prior to biopsy.

• Patient uses the bathroom prior to biopsy, and understands they need to lie still post procedure.

• Patient should be resting and feel comfortable. Low-dose benzodiazepine premedication is sometimes useful.

• An ultrasound has been performed, if required, to mark the biopsy site.

• Patient has not inadvertently used aspirin, NSAIDs, warfarin or other anticoagulant medications, including many herbal preparations e.g. Ginkgo biloba, fish oil.

• Administration of relevant factors that decrease risk of post-procedure bleeding, e.g. fresh frozen plasma (FFP), desmopressin acetate, platelets.

• Patient should be close to hospital in case of delayed complication.

EQUIPMENT

• Suction needle: more likely to cause fragmentation of specimen, which reduces accuracy and therefore avoided in suspected cirrhosis.

• Cutting needle: more likely to cause bleeding due to longer time within the liver.

• Spring-loaded cutting needle: most commonly used.

POST PROCEDURE

• Right lateral position for up to 2 hours.

• Supine for a further 1 hour.

• Monitor blood pressure and pulse every 15 minutes for first hour, then every 30 minutes until discharge.

• Patients should have a realistic expectation of post-procedure recovery. In surveys, 30% of patients would refuse a future repeat biopsy.

SUMMARY

Liver biopsy is a relatively safe investigation in experienced hands, and remains the gold standard for investigation of hepatic dysfunction or architectural abnormality. The percutaneous method is most commonly used, and can be done as an outpatient. Indications for biopsy include investigation of abnormal liver function tests, grading and staging of chronic hepatitis B or C, and monitoring treatment post liver transplant. Non-invasive serological and liver function tests should be obtained prior to biopsy. Major contraindications to percutaneous biopsy include bleeding tendencies, morbid obesity and ascites. Alternative methods of biopsy include laparoscopic or transjugular techniques. Informed consent is vital, with a full explanation of risks, possible complications and alternative investigations. Most patients will experience a small amount of pain at the biopsy site.

FURTHER READING

Bravo AA, Sheth SG, Chopra S. Liver biopsy. N Engl J Med. 2001;344:495-500.

Campbell MS, Reddy KR. Review article: the evolving role of liver biopsy. Aliment Pharmacol Ther. 2004;20:249-259.

de Ledinghen V, Combes M, Trouette H, et al. Should a liver biopsy be done in patients with subclinical chronically elevated transaminases? Eur J Gastroenterol Hepatol. 2004;16:879-883.

Firpi RJ, Soldevila-Pico C, Abdelmalek MF, et al. Short recovery time after percutaneous liver biopsy: Should we change our current practices? Clin Gastroenterol Hepatol. 2005;3:926-929.

van der Poorten D, Kwok A, Lam T, et al. Twenty-year audit of percutaneous liver biopsy in a major Australian teaching hospital. Int Med J. 2006;36:692-699.

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