EUS-guided liver biopsy has moved to the fore, with this procedure becoming more widespread and, at many centers, replacing liver biopsy performed via transabdominal or transjugular routes. With the introduction of EUS-guided portal pressure measurement procedures (most of which include a liver biopsy as well), this trend is only likely to increase with time. EUS-guided liver biopsy is not as simple or as straightforward as it may seem at first glance, so it seems fitting to have Dr David Diehl provide his personal insights into this topic. Perhaps no other physician in North America has performed as many EUS-guided liver biopsies as Dr Diehl, nor has any other physician written and spoken so much on this topic; his is literally the final word on the procedure. Douglas G. Adler, MD, FASGE GIE Senior Associate Editor Co-Director, Center for Advanced Therapeutic Endoscopy Porter Adventist Hospital, PEAK Gastroenterology Denver, Colorado1.Talk to your hepatologists and other referring physicians to inform them that you are doing EUS-guided liver biopsy (EUS-LB). We found that our gastroenterology and hepatology colleagues who were not doing percutaneous liver biopsies any more were agreeable with transferring the liver biopsy workload to the EUS team. Be sure to inform the hepatologists that portal pressure gradient measurements can be made during the same EUS session, avoiding the more invasive transjugular technique.There are several advantages to the EUS-LB technique, including these:A.Clinical care of the patient remains in the gastroenterology/hepatology department.B.Real-time US needle guidance appears to be safer than other approaches to liver biopsy.C.The sedated procedure decreases patient anxiety and can result in increased patient satisfaction.D.Bilobar biopsy is easily accomplished, decreasing the potential for sampling error.E.Additional endoscopic procedures, including EGD, EUS, or colonoscopy can be done during the same endoscopic session, resulting in time, effort, and money savings for the patient, physician, and healthcare system.Talk to your pediatric gastroenterologists as well, to let them know that this procedure is available, inasmuch as it is likely to be less anxiety provoking for the younger patient to have a sedated procedure.1Johal A.S. Khara H.S. Maksimak M.G. et al.Endoscopic ultrasound-guided liver biopsy in pediatric patients.Endosc Ultrasound. 2014; 3: 191-194Crossref PubMed Scopus (14) Google Scholar2.Talk to your pathologists to let them know that you will be doing EUS-guided liver biopsies. EUS-LB specimens meet accepted benchmarks for adequacy in terms of specimen length and complete portal triad count.2Pineda J.J. Diehl D.L. Miao C.L. et al.EUS-guided liver biopsy provides diagnostic samples comparable with those via the percutaneous or transjugular route.Gastrointest Endosc. 2016; 83: 360-365Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar They are comparable with or even better than specimens obtained by percutaneous or transjugular liver biopsy. Our pathologists independently noted an improvement in sample quality when we started using EUS-LB, particularly when using the core needle (see tip 5). The core needle can provide excellent long cores, even in the presence of cirrhosis (Fig. 1).3.Check procedure indication and need for additional procedures during the same EUS-LB session. It is common for a patient undergoing a liver biopsy to have an indication for another endoscopic evaluation. For example, a patient may require an EGD to rule out varices, to investigate dyspepsia, to rule out Barrett’s esophagus, and others. A colonoscopy may be required for screening or surveillance reasons.There may be a need for EUS assessment of pancreatic abnormalities seen on imaging. The EUS may be required in the evaluation of biliary disease such as bile duct dilatation, to rule out gallbladder stones/sludge, or for the evaluation of suspected biliary pain. In some clinical scenarios, portal pressure measurement may be necessary, and this can be done immediately before the liver biopsy.4.Check procedure contraindications. In general, we require an international normalized ratio (INR) of <1.5 and a platelet count of 50,000 before liver biopsy. The patient should not be taking anticoagulation or antiplatelet agents for an appropriate length of time before the procedure. If that is not possible, a transjugular approach may be required.Large-volume ascites is thought to be a contraindication to liver biopsy. Previous gastric surgery (eg, Roux-en-Y gastric bypass) is not a contraindication because a left lobe liver biopsy can be readily done even in patients with partial gastric resection. Known liver cirrhosis is not strictly a contraindication, but it is uncommon for a patient with cirrhosis to need a liver biopsy.5.Select the biopsy needle. Usually, 19-gauge EUS needles are used for EUS-LB; 22-gauge needles produce specimens that are subject to fragmentation during specimen processing and are not preferred. A 19-gauge “core needle” (fine-needle biopsy) is preferred over a 19-gauge FNA needle, with better LB specimens.3Ching-Companioni R.A. Diehl D.L. Johal A.S. et al.19 G aspiration needle versus 19 G core biopsy needle for endoscopic ultrasound-guided liver biopsy: a prospective randomized trial.Endoscopy. 2019; 51: 1059-1065Crossref PubMed Scopus (29) Google Scholar If a 19-gauge FNB needle is not available, a 19-gauge FNA needle should be adequate, although it works best if used with the “wet suction” method (see tip 6).6.Prepare the biopsy needle. We have found that “wet suction” provides higher tissue yields compared with dry suction.4Mok S.R. Diehl D.L. Johal A.S. et al.A prospective pilot comparison of wet and dry heparinized suction for EUS-guided liver biopsy (with videos).Gastrointest Endosc. 2018; 88: 919-925Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar For wet suction, the needle stylet is removed. The needle is then flushed with a small amount of a standard heparin flush. The suction syringe is filled with 1 to 2 mL of water, the stopcock is turned to off, and then the suction syringe is set at a full suction setting (Fig. 2). This is then mounted on the primed needle.Figure 2Setup for doing wet suction, which has been found to be superior to dry suction for EUS-guided liver biopsy. The needle is primed with dilute heparin to prevent clot formation in the needle, although saline solution priming is also acceptableView Large Image Figure ViewerDownload Hi-res image Download (PPT)A stylet slow-pull technique is preferred by some endosonographers, but it is still advantageous to flush the needle with heparin first (and then reinsert the stylet) to prevent blood clotting in the needle (Fig. 3).Figure 3View from proximal part of stomach with a radial echoendoscope, the spleen (on the right) may present a very large target and can have very similar echotexture to that of the liver (on the left). It is important to positively identify the liver and distinguish it from the spleen with the linear echoendoscope before fine-needle biopsy to prevent inadvertent splenic puncture.View Large Image Figure ViewerDownload Hi-res image Download (PPT)7.Assess the biopsy target in the liver and avoid inadvertent splenic biopsy. Be certain to distinguish the left lobe of the liver from the spleen, which is in a similar location in the proximal stomach, can be enlarged in chronic liver disease, and may have a similar US echotexture to that of the liver (Fig. 3).5Diehl D.L. Mehta M. Shafqet M.A. et al.Splenic biopsy as an unintended consequence of EUS-guided liver biopsy: a cautionary tale.Gastrointest Endosc. 2020; 91: 195-196Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar The left lobe can be positively identified by known landmarks (hepatic veins, portal venous structures), although portal structures may be obscured in livers with significant fat. Inadvertent splenic puncture can result in possible bleeding adverse effect, particularly if splenic hilar vessels are in the path of needle insertion.The right hepatic lobe target is easily found with the echoendoscope tip placed in the duodenal bulb and torqued counterclockwise (Fig. 4).Figure 4Right hepatic lobe is identified, and biopsy is performed with the echoendoscope placed in the duodenal bulb.View Large Image Figure ViewerDownload Hi-res image Download (PPT)8.Use an optimal and safe needle biopsy technique. Find a trajectory for needle travel into the liver that avoids sizable vessels. This may be 2 to 3 cm, or in some cases could be longer than 3.5 cm (Figs. 5 A and B). It is important to realize that in some cases a very long needle throw will not be possible.Figure 5Different lengths of needle travel may be possible in different patients. A, The estimated trajectory of needle travel is less than in a different patient (B). However, excellent liver cores can be obtained with either of these depths of needle insertion.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Both endoscope knobs are locked, and the echoendoscope elevator is used to deflect the needle. It may be advantageous add to some endoscope, pull the big wheel back, and have the assistant hold the endoscope at the bite block to prevent recoiling with initial needle puncture. The needle is introduced about 1 cm into the liver parenchyma with a short rapid movement. The initial needle stroke needs to be “high velocity” to get the needle through the gastric (or duodenal) wall, but the initial stroke should not be too deep. The gastric wall can be a little hard to puncture on occasion, and the echoendoscope adjustments described above allow the needle to enter the liver in as nearly a perpendicular approach as possible.Once the needle is in the liver, the suction is applied by turning the stopcock to “open,” and the needle is advanced with slow and steady movements to and fro 3 to 4 times in the liver. A 3-cm course of needle travel is excellent and sufficient; but it can be longer if no vessels are seen beyond this point.After the biopsy, and before the needle is removed from the liver, the suction is turned off. The needle is removed from the echoendoscope in preparation for sample collection (see tip 9).We usually do bilobar liver biopsy. This seems to be advantageous in biopsies done for nonalcoholic steatohepatitis. Unilobar biopsy may be sufficient for other indications for liver biopsy. If the sample that is obtained appears inadequate in terms of specimen length or excessive fragmentation, then a second pass could be done.9.Retrieve specimen without introducing fragmentation, and assess adequacy of biopsy. Excessive handling of the specimen should be avoided. It is common that the specimen will be admixed with blood. If the needle was primed with heparin, then the blood is less likely to form a “noodle-like” clot. A collection sieve allows blood to be washed from the specimen and rapid adequacy review is possible. A purpose-made device has been developed for liver biopsy sample collection (Fig. 6) (CoreCatcher, Kite Endoscopic Innovations, Concord Township, Ohio, USA). This device has a peel-off mesh that catches the liver cores and can be transferred directly to formalin. In addition, immediate review of the amount of tissue obtained is possible.Figure 6A microsieve can be used to collect the specimen without excessive handling and allows immediate assessment of biopsy adequacy (Core Catcher, Kite Endosopic Innovations).View Large Image Figure ViewerDownload Hi-res image Download (PPT)Alternatively, the contents of the needle can be expressed straight into the jar of formalin. Assessment of the adequacy of the specimen may be more difficult because admixed blood can obscure the view of the liver cores in the jar (Fig. 7).Figure 7Difference between using a microsieve versus simply expressing the specimen directly into formalin. Assessment of specimen adequacy is harder without filtering out the blood first.View Large Image Figure ViewerDownload Hi-res image Download (PPT)10.Assess the patient after biopsy. One hour of recovery time is sufficient for EUS-LB, even if bilobar biopsy is done. About 30% to 40% of patients experience abdominal pain after EUS-LB. It is likely that the cause of pain after liver biopsy is local peritoneal irritation by a small amount of blood that may be coming from the puncture sites. Pain after EUS-LB is typically self limited, although some patients require a single dose of opiates. We typically use 1 mg hydromorphone hydrochloride, although 50 to 75 μg of fentanyl is also effective. Patients are typically discharged after 1 hour of observation and return to a normal diet.Pain that is persistent is first managed with a second dose of opiate analgesia. If this is not effective, we usually perform contrast-enhanced liver CT to determine whether a bleeding adverse event has occurred. Even if there is evidence of bleeding or intrahepatic hematoma (Fig. 8), it is usually self limited and does not usually require interventional radiologic management by vascular embolization, although we do admit the patients for at least overnight observation.Figure 8CT view, obtained after EUS-LB because of what was thought to be excessive pain after the procedure, showing a hematoma in the left hepatic lobe. The patient was observed overnight but did not require transfusion or angiographic embolization.View Large Image Figure ViewerDownload Hi-res image Download (PPT)