Wet Heparinized Suction: A Novel Technique to Enhance Tissue Acquisition for Endoscopic Ultrasound Guided Liver Biopsy (EUS-LB): A Prospective Trial

3 BACKGROUND AND SIGNIFICANCE Since its inception in 1992, endoscopic ultrasound with fine needle aspiration (EUS-FNA) has continued to be an evolving method for obtaining diagnostically accuracy for gastrointestinal, and extra-luminal pathology. Present society guidelines by both the European Society of Gastrointestinal Endoscopy (ESGE) and American Society of Gastrointestinal Endoscopy (ASGE) have estimated an overall 60-90% diagnostic accuracy of EUS-FNA. However, this accuracy is dependent upon determination of adequacy by expert gastrointestinal pathologists, which may not be available at all centers.

To enhance the diagnostic accuracy of EUS-FNA, several techniques have been described including, acquisition of a core specimen by fine needle biopsy (FNB), the use of a stylet, and suction. Regarding FNB, this technique allows for acquisition of a tissue specimen with intact tissue architecture and therefore more ability for immunohistochemical staining (IHC). The original generations of FNB needles have been studies, demonstrating no noticeable advantage of convention FNA. More recent evolutions of these FNB needles have led to promising preliminary results. For obtaining EUS-guided liver biopsy (EUS-LB), the technical success was 100% and over 91% diagnostic accuracy. Furthermore, EUS-LB appears to have a higher diagnostic accuracy for chronic liver disease (CLD) compared with percutaneous (PLB) and transgulular (TLB) routes. Overall, EUS-FNB appears to be a promising additional to EUS guided tissue acquisition, which shall lead to improved diagnostic accuracy.

In addition to EUS-FNB, both EUS-FNA with stylet use and suction, have gained some notoriety. It is important to note that there is no definitive evidence of improved diagnostic accuracy of EUS-FNA with these methods. One caveat to these supplemental methods for EUS-FNA, would be the use of "wet suction" technique (WEST) for EUS-FNA. The wet suction technique involved the use of 5 milliliters (mL) of 0.9% normal saline (NS) to supplant the traditional column of air present in the FNA needle. When compared to traditional EUS-FNA, the WEST demonstrated an increase in cellularity of the cellblock, improved specimen accuracy and no difference in the blood contamination compared with standard EUS-FNA. Though not specifically an EUS technique, using heparinized needles for PLB of liver lesions, has been described as well. Despite these promising results, this technique has never been employed as an enhancement to EUS-FNA.

Therefore in this study a heparinized solution (wet heparin) shall be employed for the acquisition of tissue in EUS-LB compared with dry heparin and convention EUS-LB. It is predicted that EUS-LB wet heparin will lead to less blood contamination and more adequate tissue acquisition, as compared with dry heparin and conventional EUS-LB.

Primary End Points