Percutaneous Liver Biopsy

Indications

Percutaneous liver biopsy indications encompass those of liver biopsy in general. A liver biopsy has three major roles: (1) establishing a diagnosis, (2) for assessment of prognosis or disease staging, and (3) assisting with treatment options and clinical management.[3][4][5]

Liver biopsy plays a major role in diagnosing numerous liver pathologies and can add additional information where blood testing may not. For example, a biopsy can assist with evaluating abnormal liver function tests if another workup is unremarkable.[6] Non-alcoholic fatty liver disease (NAFLD) affects up to 100 million Americans, and biopsy is the only procedure that can definitively differentiate non-alcoholic fatty liver disease from non-alcoholic steatohepatitis (NASH).[7] In those affected with a fever of unknown origin (FUO), liver biopsy led to the diagnosis of histoplasmosis and tuberculosis in some cases.[8] In patients in whom autoimmune hepatitis (AIH) is strongly suspected despite negative autoantibodies and/or normal IgG levels, liver biopsy helps confirm diagnosis and guide treatment. A biopsy can also elucidate those who have an “overlap” syndrome comprising primary biliary cirrhosis (PBC) with AIH.[9] Biopsy aids in diagnosing drug-induced liver injury (DILI), acute or chronic rejection in post-liver transplant patients, and infiltrative and/or storage disease, among others.

Liver biopsy findings can have prognostic significance in the evaluation of liver disease. It can be useful in determining the stage of fibrosis and grade of inflammation for those affected with chronic hepatitis B (HBV) and/or hepatitis C (HCV). However, there are increasing biochemical and virological measurements that are assisting with prognostication in these diseases.[10] In patients with chronic HCV infection, comorbidities such as chronic alcohol use and/or hepatic steatosis have correlated with more rapid liver fibrosis progression.[11] Also, in patients with hemochromatosis, those evaluated with biopsy revealing advanced fibrosis were at increased risk of developing hepatocellular cancer (HCC) compared to those without fibrosis.[12]

Liver biopsy aiding the diagnosis of AIH can lead to the initiation of steroid therapy and guide with tapering and/or discontinuation of immunosuppressive therapy. Treatment plans for those with PBC can be guided based on the severity of fibrosis.[4]

Contraindications

Contraindications to percutaneous liver biopsy divide into absolute and relative contraindications.[13]

Absolute Contraindications

• The inability of a patient to fully cooperate with the procedure
• Significant coagulopathy or thrombocytopenia (unless corrected before the liver biopsy)
• NSAID use (including aspirin) within the last 5 to 7 days
• Patient refusal to accept blood transfusion or inability to provide blood transfusion support
• Suspected hemangioma, vascular tumor, or echinococcal cyst
• Inability to identify an adequate biopsy site by percussion and/or ultrasound
• Extrahepatic biliary obstruction 
• Massive ascites

Relative Contraindications

• Morbid obesity
• Mild ascites
• Hemophilia
• Infection within the right pleural cavity
• Infection below the right hemidiaphragm
• Amyloidosis

Equipment

For a percutaneous liver biopsy, there are varying needle sizes and types, with three main categories.[13]

• Suction needles (Menghini needle, Klatskin needle, Jamshidi needle)
• Cutting needles (Vim-Silverman needle, Trucut needle)
• Spring-loaded cutting needles with triggering mechanisms

The choice of needle is primarily based upon operator preference, instrumental availability, and clinical picture.[10] For example, if there is a high suspicion for cirrhosis, a cutting needle may be preferred over a suction needle, given the fact that fibrotic tissue tends to become fragmented with the use of suction needles.[14]

Preparation

Before performing a percutaneous liver biopsy, patients should understand the risks, benefits, and alternatives to the procedure, along with why it is clinically indicated. Informed consent should then be obtained. Most liver biopsies take place in the outpatient setting. The clinician conducts history and physical, and routine laboratory studies, including a complete blood count, platelet count, and prothrombin time (PT)/international normalized ratio (INR), are checked. Some practices also choose to obtain an activated partial thromboplastin time, bleeding time, and/or blood type. Guidelines from the Society of Interventional Radiology recommend platelet transfusion if the platelet count is less than 50000 platelets per microliter and correcting an elevated INR to less than 1.5 before the biopsy.[4] Of particular importance centers around the timing of cessation and reinitiation of patients taking antiplatelet and anticoagulant medications. There is no clear timeline for termination, but most choose to discontinue these medications anywhere from 24 hours to 10 days before the biopsy. Warfarin is generally stopped at least five days before biopsy and restarted the day following a liver biopsy. Antiplatelet therapy is typically restarted 48 to 72 hours after the biopsy. These decisions should be made on a case-by-case basis and with risk-benefit analysis. There is no clear indication for fasting before the biopsy, but some have allowed patients to eat a light breakfast. The performance of percutaneous liver biopsy typically is without sedation, but those with anxiety may benefit from premedication with a benzodiazepine.[15]

Technique or Treatment

A percutaneous liver biopsy is performable using three different techniques: (1) palpation/percussion guided, (2) image-guided, (3) real-time image-guided. The palpation/percussion technique is based on physical examination and is the most common practice. The image-guided technique involves using ultrasound (US) to mark the biopsy site before needle insertion. The real-time image-guided technique involves using the US simultaneously with tissue sampling.

The patient is positioned supine on the bed, with his or her right side near the edge of the bed. The patient’s right arm is then placed above the head, and the lower extremities should be moved away from the body to best allow for intercostal space expansion. The skin is exposed, and percussion over the right upper quadrant is performed. The biopsy site is typically between the seventh and eighth intercostal space at the mid-axillary line, which is the point of maximal dullness. After marking the site, a bedside ultrasound can confirm the appropriateness of the site and eliminate the chances of bowel overlying the biopsy tract. The skin is then prepped and draped in a sterile fashion. Lidocaine solution (1% or 2% solution are options) is injected along the upper border of the rib to avoid neurovasculature that crosses along the lower border of each rib. A small incision with a surgical blade is made at the biopsy site. The biopsy needle of choice is then passed through the skin incision in the direction of the xiphoid process and parallel to the ground. The tissue sample is taken during the expiratory phase of respiration. After removing the needle, pressure is applied to the biopsy site for a few minutes, and a bandage is applied. The patient is then placed in the right lateral decubitus position, presumably to limit bleeding by allowing the liver to have pressure placed against the abdominal wall.

Following the procedure, the patient’s blood pressure, heart rate, and pain level are measured every 15 minutes for the first hour, 30 minutes for the next hour, and every hour thereafter until ready for discharge. Patients are typically observed between 2 to 4 hours post-procedure, according to the American Association for the Study of Liver Diseases (AASLD). Postoperative instructions include telling the patients to avoid lifting more than 10 to 15 pounds (4.5 to 7 kg) for one week.

There is also a method called a plugged biopsy, which is a variation of the percutaneous biopsy. It is an option in patients deemed high risk for bleeding (i.e., those with coagulopathy and/or thrombocytopenia or a small cirrhotic liver).[4] The approach is similar to the percutaneous liver biopsy except that the biopsy tract is plugged with collagen or thrombin as the needle is removed.

Complications

Complications following percutaneous liver biopsy are rare. Approximately 60 percent occur within the first 2 hours and 96 percent within 24 hours post-procedure.[13] Overall mortality risk was estimated to be roughly 0.2 percent in a study of over 61000 patients.[16] The most common complication is pain located at the biopsy site or referred to the right shoulder.[17] Other complications include:

• Transient hypotension (as a result of vasovagal response and/or hemorrhage)
• Hemorrhage (subscapular, intrahepatic, intraperitoneal, hemobilia, hemothorax)
• Pneumothorax
• Biliary peritonitis
• Transient bacteremia
• Portal vein thrombosis
• Subphrenic abscess
• Carcinoid crisis
• Death

Although the exact mechanism for pain following a biopsy is uncertain, it is believed to be a result of subcapsular swelling and/or bleeding. Anti-inflammatory medication is given for relief, but if there is no resolution, then inpatient hospitalization and radiographical imaging may be warranted.

Intrahepatic and/or subscapular hematomas can be painful or asymptomatic. These typically do not require radiographic imaging or surgical intervention.

Intraperitoneal hemorrhage, albeit rare, is the most serious bleeding complication. Patients typically report severe pain, and vital signs may reveal hypotension with tachycardia. The etiology may stem from a severe laceration during the biopsy or injury to the hepatic arterial system. An urgent consultation is necessary with the surgeons and interventional radiologists, along with radiographic imaging.

Hemobilia is a rare complication that is reflected by a triad of gastrointestinal bleeding, biliary pain, and jaundice (can be referred to as Quincke’s triad). This condition may resolve with supportive care, but continual bleeding would require angiographic embolization or surgical intervention.

Reports also exist of cases of transient bacteremia, hemothorax, pneumothorax, biliary peritonitis, portal vein thrombosis, subphrenic abscess, and carcinoid crisis.

Clinical Significance

Percutaneous liver biopsy provides a method for proper histological evaluation of a multitude of liver pathologies. It continues to play a crucial role in the diagnosis, prognosis, and treatment/management of those affected with liver disorders. The procedure remains a relatively safe one with great diagnostic yield.

Enhancing Healthcare Team Outcomes

Percutaneous liver biopsies may be performed by radiologists, gastroenterologists, hepatologists, or surgeons. Albeit rare, bleeding complications, among others, may arise. Increased knowledge among the interprofessional team, including nursing and technicians with regards to a patient’s symptoms and physical examination, will provide patient-centered care and help to reduce complications. [Level V]