J Appl Biomed 22:221-227, 2024 | DOI: 10.32725/jab.2024.026

Endoscopic luminal impedance planimetry of the lower oesophageal sphincter and pylorus in experimental pigs: a pilot study

Jan Bureš^{1, 2, 3, *}, Věra Radochová⁴, Darina Kohoutová^{3, 5}, Miroslav Zavoral^{1, 2}, Kristina Hugová^{6, 7}, Štěpán Suchánek^{1, 2}, Ondřej Soukup³, Jan Martínek^{6, 8}

¹ Military University Hospital Prague, Institute of Gastrointestinal Oncology, Prague, Czech Republic

² Charles University, First Faculty of Medicine and Military University Hospital Prague, Department of Medicine, Prague, Czech Republic

³ University Hospital Hradec Králové, Biomedical Research Centre, Hradec Králové, Czech Republic

⁴ University of Defence, Military Faculty of Medicine, Animal Laboratory, Hradec Králové, Czech Republic

⁵ The Royal Marsden NHS Foundation Trust, London, United Kingdom

⁶ Institute for Clinical and Experimental Medicine, Department of Hepatogastroenterology, Prague, Czech Republic

⁷ Charles University, First Faculty of Medicine, Institute of Physiology, Prague, Czech Republic

⁸ University of Ostrava, Faculty of Medicine, Academic Department of Internal Medicine, Ostrava, Czech Republic

Background/Aims: The functional lumen imaging probe (FLIP) relies on the principle of impedance planimetry that enables direct measurement of intraluminal pressure, cross-sectional areas, and wall biomechanical properties. The aim of our pilot project was to introduce this method to assess function of the lower oesophageal sphincter and pyloric muscle in experimental pigs.

Methods: All measurements were accomplished in one session in six adult female pigs (mean weight 34.2 ± 3.6 kg), using the EndoFLIP 1.0 System with EndoFLIP catheters. Five major parameters were evaluated: balloon pressure (mm Hg), estimated diameter (mm), cross-sectional area (mm2), distensibility (mm2/mm Hg), and zone compliance (mm3/mm Hg).

Results: In total, 180 readings were successfully accomplished. Most of the measured values were nearing lower average figures for the lower oesophageal sphincter, and upper average figures for the pylorus in healthy humans. The porcine pyloric sphincter is composed of the Torus pyloricus. It serves as a study "gatekeeper" between the stomach and D1 duodenum, thus explaining higher pyloric readings. There was a clear trend for increasing values of CSA (cross-sectional area), diameter, and balloon pressure with increased filling balloon volumes. However, the sphincter distensibility did not change with increasing filling volumes, either for the lower oesophageal sphincter or pylorus.

Conclusion: Endoscopic functional luminal planimetry in experimental pigs is feasible, both for the lower oesophageal sphincter and the pylorus. This is an important starting point for future experimental endoscopic trials and pharmacology studies.

Keywords: Endoscopic luminal impedance planimetry; Experimental pigs; Lower oesophageal sphincter; Pylorus

Grants and funding:

This work was supported by the research projects DZVRO MO1012 and MH CZ-DRO (UHHK, 00179906). The financial support was used to cover material costs (experimental animals, drugs, EndoFLIP catheters, endoscopic accessories). Neither the sponsors nor the financial support influenced the study design, collection, analysis and interpretation of data, manuscript writing, or the decision to submit the article for publication.

Conflicts of interest:

The authors have no conflict of interest to declare.

Received: June 28, 2024; Revised: September 19, 2024; Accepted: November 29, 2024; Prepublished online: December 11, 2024; Published: December 18, 2024  Show citation