Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Endosc. Jun 25, 2015; 7(7): 728-735
Published online Jun 25, 2015. doi: 10.4253/wjge.v7.i7.728
Feasibility and safety of endoscopic cryoablation at the duodenal papilla: Porcine model
Dennis Yang, Mary K Reinhard, Mihir S Wagh
Dennis Yang, Mihir S Wagh, Division of Gastroenterology, University of Florida, Gainesville, FL 32608, United States
Mary K Reinhard, Animal Care Services, Infectious Disease and Pathology, University of Florida, Gainesville, FL 32608, United States
Author contributions: Yang D performed the literature search, statistical analysis, and wrote the first draft of manuscript; Wagh MS provided the concept of the manuscript and contributed new articles to the literature search and critical appraisal; Reinhard MK was involved in histopathology review and tissue analysis; all the authors were involved with the acquisition of data, analysis, interpretation, and critical revision of the final manuscript.
Ethics approval: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee at the University of Florida (IACUC protocol number).
Conflict-of-interest: None of the authors have relevant disclosures or conflict of interest to declare related to this study.
Data sharing: Technical appendix, statistical code, and dataset available from the corresponding author at mihir.wagh@medicine.ufl.edu. No additional data is available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Mihir S Wagh, MD, FASGE, Division of Gastroenterology, University of Florida, 1329 SW 16th Street, Room 5251, Gainesville, FL 32608, United States. mihir.wagh@medicine.ufl.edu
Telephone: +1-352-2739474 Fax: +1-352-6279002
Received: September 4, 2014
Peer-review started: September 4, 2014
First decision: January 8, 2015
Revised: January 27, 2015
Accepted: March 30, 2015
Article in press: April 2, 2015
Published online: June 25, 2015
Abstract

AIM: To assess the feasibility and safety of liquid nitrogen spray cryoablation at the duodenal papilla in a porcine model.

METHODS: This prospective study protocol was approved by the University of Florida Institutional Animal Care and Use Committee. Six pigs underwent liquid nitrogen spray cryotherapy at the duodenal papilla. Freeze time of 20-s was applied per cycle (4 cycles/session). Survival animals (n = 4) were monitored for adverse events. Hemoglobin, white blood count, liver tests, and lipase were obtained at baseline and post-treatment. EGD was performed on day#7 to evaluate the papilla and for histology. All animals were euthanized and necropsy was performed at the end of the one-week survival period. Feasibility was defined as successful placement of the decompression tube in the duodenum, followed by delivery of spray cryotherapy to the duodenal papilla. Safety was determined by monitoring post-treatment blood tests and clinical course. Treatment effect was defined as endoscopic and histologic changes after cryotherapy. This was established by comparing endoscopic and histologic findings from mucosal biopsies prior to cryotherapy and on post-operative day (POD)#7. Full-thickness specimen was obtained post-mortem to assess depth of injury.

RESULTS: Spray cryotherapy was feasible and successfully performed in all 6/6 (100%) animals. Cryospray with liquid nitrogen (four 20-s freeze-thaw cycles) at the duodenal papilla resulted in white frost formation at and around the target region. The mean procedural time was 54.5 min (range 50-58 min). All six animals studied had stable blood pressure, heart rate, and pulse oximetry measurements during the procedure. There were no significant intra-procedural adverse events. There were no significant differences in hemoglobin, white cell count, liver tests or lipase from baseline to post-cryotherapy. Survival animals were monitored daily post-operatively without any clinical ill effects from the cryotherapy. There was no bleeding, infection, or perforation on necropsy. Endoscopic on POD#7 showed edema and ulceration at the duodenal papilla. On histology, there was loss of crypt architecture with moderate to severe necrosis and acute mixed inflammatory infiltration in each specimen following cryotherapy. The extent of cryogen-induced tissue necrosis (depth of injury) was limited to the mucosa on full-thickness specimen evaluation.

CONCLUSION: Endoscopic liquid nitrogen spray cryotherapy is feasible and safe for ablation at the duodenal papilla in a porcine model.

Keywords: Liquid-nitrogen cryotherapy, Cryoablation, Duodenal adenoma, Ampullectomy, Papillectomy

Core tip: With advances in therapeutic endoscopy, endoscopic resection is commonly performed for the management of ampullary adenomas. However, endoscopic papillectomy can still carry significant morbidity, especially in elderly patients with comorbidities. Hence, less invasive effective endoscopic ablative modalities would be desirable. In this study, we demonstrate that endoscopic liquid nitrogen spray cryotherapy is feasible and safe for ablation at the duodenal papilla in a porcine model. These preliminary findings suggest a potential role of cryotherapy as an adjunct endoscopic treatment for residual/recurrent ampullary lesions or as a primary modality in patients who are not optimal candidates for surgery or endoscopic resection.