A75-29 Gastroesophageal Refluxate Impedance and Aspiration Risk in Lung Transplant Recipients

Rationale

Swallowing impairment and aspiration is identified in a majority (54-84%) of lung transplant recipients and may result in increased morbidity and mortality. Fundoplication surgery may re-establish lower esophageal sphincter (LES) tone and reduce aspiration risk; uncontrolled studies suggest benefit for some recipients (Leiva-Juarez Ann Thor Surg 2022; 113:1801-10). However increased morbidity and mortality may occur in patients sixty or older, near average lung transplant recipient age. Identifying patients with a lower aspiration risk may eliminate unnecessary fundoplication. Intra-esophageal pH and impedance testing evaluates reflux risk and distinguishes refluxate phase (gas, liquid or mixed), however correlation between refluxate phase and aspiration is unclear. Therefore, pH impedance testing was compared with lung transplant recipient histopathology to determine correlation between aspiration and refluxate phase.

Methods

Between January 1, 2023 and December 31, 2025, 41 lung transplant recipients in whom esophageal pH and impedance testing was performed were retrospectively identified. Esophageal pH and impedance catheters were placed transnasally and data collected for 24hours. pH probes were positioned 5 cm above the LES; 6 impedance sensors positioned 1,3,5,9,11 and 13 cm above the LES. In 21 patients, reflux character was available; defined as either liquid, gas or a mixture. Liquid reflux was a retrograde 50% decrease in impedance from baseline in the 2 distal impedance sites. Gas reflux was a simultaneous impedance increase greater than 3,000 Ohm in any 2 consecutive sites with absolute value greater than 7,000 Ω in one site. (Sifrim Gut.2004; 53:1024-31) Mixed liquid gas reflux is gas reflux occurring during or immediately before liquid reflux. Patient Demeester scores (Johnson LF Am. J.Gastrol 62: 325-32) were calculated; scores greater than 14.7 define pathologic reflux. Lung tissue obtained at surveillance bronchoscopy via biopsy was reviewed by a pulmonary pathologist, recording the presence or absence of aspiration. Impedance data and Demeester scores were compared in all patients.

Results

Evidence of aspiration was identified in 5 patients and absence of aspiration in 16 patients. DeMeester Scores in patients with or without aspiration were not different (20.6 vs 15.1, respectively, p= .33). Similarly, total reflux events, gas only and mixed reflux events were not different. Liquid only reflux events were not different between those with or without aspiration (39 vs 33.9, p =.09)

Conclusion

A difference between pathologic reflux and refluxate event character was not identified when comparing lung transplant recipients with or without aspiration. Examination in a larger cohort may prove beneficial.

This abstract is funded by: None