Wet Heparin for Obtaining Liver Tissue for EUS Guided Liver Biopsy

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

Since its inception, endoscopic ultrasound with fine needle aspiration (EUS-FNA) has proven a valuable diagnostic and prognostic tool for evaluating a diverse number of pathologies. One such pathology is chronic liver disease (CLD), for which EUS-guided liver biopsy has become a well-accepted method for tissues acquisition. EUS-LB also been compared with percutaneous and transguluar routes showing at least comparable ability to obtain adequate tissue for CLD.

Though enhancements to EUS-FNA, such as dry suction, stylet pull have not proven to demonstrate increased diagnostic accuracy for EUS-FNA, the use of wet suction technique (WEST) has demonstrated the ability to obtain more cellular tissue samples with less blood contamination. In an attempt to obtain further improvement in tissue adequacy, with less blood contamination for EUS-LB, the use of wet heparinized needles will be investigated as compared with conventional EUS-LB for patients with CLD. To do this subjects shall be selected to undergo EUS-LB. As it is the standard to perform 3 needle passes during EUS-LB, subjects will undergo one pass with the following designations: pass 1: conventional EUS-LB [no flush], pass 2: dry heparin heparin [5 milliliters (mL) of heparin flushed and then flushed with air], and pass 3: wet heparin [5 milliliters (mL) of heparin flushed and retained in the needle]. It is predicted that specimens collected with heparinized needle shall show improved adequacy compared with conventional EUS-LB. It is also predicted that the heparin wash will lead to less blood contamination compared with conventional methods. Subjects shall also be monitored for adverse events (AE).

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

1. Proportion of cases for which a histologic diagnosis could be made based upon the amount of tissue obtained with the needle.
2. Number of portal tracts (PT) in the specimen
3. Aggregate specimen length (ASL), length of the longest piece (LLP), and degree of fragmentation Secondary End Points

1. Presence of a visible core specimen 2. Presence of visible clots in specimen 3. Adverse events (AE) and serious adverse events (SAE) 4 HYPOTHESIS AND SPECIFIC AIMS 4.1 Hypothesis It is predicted that EUS-LB with wet heparin will lead to less blood contamination and more adequate tissue acquisition, as compared with dry heparin and conventional EUS-LB 4. 2 Specific Aim 1 To determine the adequacy of EUS-LB using wet and dry heparin 4.3 Specific Aim 2 To determine the degree of blood contamination for EUS-LB using wet heparin and dry heparin 4.4 Specific Aim 3 To determine the adequacy for EUS-LB using wet heparin and dry heparin 5 PRELIMINARY DATA Heparin flush has been used previously in several patients undergoing EUS-guided liver biopsy, and cores of liver tissue can be obtained. It has been found that this needle preparation using heparin flush has led to the presence of less blood contamination of tissue and therefore improved diagnostic accuracy and ability to make the diagnosis.

6 STUDY DESIGN 6.1 Description This is an open-labeled, prospective trial comparing tissue acquisition adequacy and blood contamination for EUS-LB using wet heparin (Group A), dry heparin (Group B) and conventional EUS-LB (Group C).

Group A: Needle flushed with 5mL of heparin, left in the EUS-FNB needle Group B: Needle flushed with 5mL of heparin, then flushed with air to dry Group C: Needle not flushed with solution

Subjects shall then undergo EUS-LB (see below) with 3 trans-gastric passes total in the left lobe, as is the present standard of practice. Pass 1: Group C, Pass 2: Group B, Pass 3: Group A.

After EUS-LB, the tissue sample shall then be evaluated after each pass by the endosongrapher performing EUS-LB for tissue length. The tissue and fluid washed from the tissue specimens shall then be sent for processing, as described below, and evaluated for the primary and secondary outcomes by 2 expert pathologists, blinded to which arm each specimen had come from. Patients shall then receive a telephone call 7 days after EUS-LB to evaluate for adverse events.

Inclusion Criteria:

1. Patients undergoing EUS-LB
2. Platelet count > 50,000
3. International normalized ratio (INR) < 1.5
4. Age > 18 years
5. Non-pregnant patients

Exclusion Criteria:

1. Age < 18 years
2. Pregnant Patients
3. Inability to obtain consent
4. Anticoagulants or anti-platelet agents use (excluding aspirin) within the last 7-10 days
5. Platelet count < 50,000
6. INR > 1.5
7. Presence of ascites
8. Known liver cirrhosis
9. Patients with a heparin or porcine allergy
10. Patients with prior heparin induced thrombocytopenia (HIT)
11. Patient's with religious aversion to porcine-containing products