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ROLE OF MUCOSAL IMPEDANCE IN ASSESSMENT OF THE REFLUX BARRIER AFTER NISSEN FUNDOPLICATION
Inanc Sarici
*1,3, Sven Eriksson
1,3, Johnathan Nguyen
1, Ping Zheng
1, Shahin Ayazi
1,2,31Foregut Division, Surgical Institute, Allegheny Health Network, Pittsburgh, PA; 2Department of Surgery, Drexel University, Pittsburgh, PA; 3Chevalier Jackson Research Fellowship, Esophageal Institute, Western Pennsylvania Hospital, Allegheny Health Network, Pittsburgh, PA
Introduction: Mucosal impedance (MI) is a novel test that directly measures the conductivity of the mucosa, a marker of changes in paracellular permeability characteristic of chronic reflux. The probability of GERD is determined based on the measured impedance values (?) in the distal esophagus and its distal-to-proximal change (?/cm), with low distal ? and a high increase, characteristic of GERD. The role of MI after antireflux surgery or in the assessment of failure has not been evaluated. The aim of this study was to characterize and compare MI in patients with and without failure after Nissen fundoplication.
Methods:A cohort of GERD patients who underwent Nissen fundoplication and were found to have an anatomical failure (disrupted/herniated fundoplication) on endoscopy at ?1 year after surgery were invited to undergo mucosal impedance (MI) testing and 48-hour pH monitoring. A control group of patients with intact fundoplication confirmed on endoscopy at ?1 year underwent similar assessments. MI was measured at 1 cm intervals above the squamocolumnar junction (SCJ), with GERD probability calculated at 2, 5, and 10 cm above the SCJ using a validated model. Demographic, clinical, pH, and MI data were compared between groups.
Results: The final study population consisted of 25 patients (60.0% female) with a mean (SD) age of 61.3 (13.7) years and BMI of 28.2 (4.7). Of these, 14 patients (56%) had anatomical failure, and 11 (44%) were intact. Patients with failure had a higher median (IQR) GERD-HRQL score (35.0 [22.0–51.0] vs. 8.0 [4.0–40.0], p = 0.0153), but DeMeester score (p=0.738) and its individual pH-monitoring components (all p>0.05) were similar. Age, sex and BMI were also similar (p > 0.05).
On MI analysis, patients with failure had lower MI measurements at 2 cm (3.0k ? [1.7k–3.9k] vs. 4.6k ? [4.0k–5.5k], p = 0.020) and 5 cm above SCJ (3.7k ? [3.2k–4.5k] vs. 5.6k ? [3.9k–6.1k], p = 0.043)
(Figure 1). Patients with failure also had a pattern consistent with GERD (low ? intercept; high ?/cm) (
Figure 2) with a higher calculated probability of GERD (50% [40–60] vs. 30% [20–40], p = 0.0009). Intact patients had a normal pattern (high ? intercept and ?/cm).
Conclusion: Mucosal impedance measurements are associated with successful resolution of reflux following antireflux surgery. Intact Nissen fundoplication displays high mucosal impedance and MI patterns indicative of low permeability to intraluminal materials due to restoration of the integrity of cell membranes and tight junctions of the esophageal mucosa. By contrast disrupted or herniated fundoplications exhibited patterns suggestive of persistent GERD. These results highlight the potential of MI as a tool for assessing the effectiveness of ARS and monitoring esophageal mucosal recovery.
Figure 1. A topographic heatmap shows lower mucosal impedance (MI) values (red and yellow) at the distal esophagus in patients with anatomical failure after Nissen fundoplication (Figure 1A), while a separate heatmap for a patient with an intact fundoplication displays normal MI values (blue) (Figure 1B).
Figure 2. Trend lines show the distal esophageal ?-intercept and the distal to proximal change ?/cm. Anatomical failure has low ?-intercept and high ?/cm, indicative of GERD. Intact fundoplication has high ?-intercept indicative of normal integrity of the mucosa.
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