Introduction
Gastroesophageal reflux is responsible for various extresophageal symptoms that are commonly labelled as laryngopharyngeal reflux (LPR). These mostly include cough, throat clearing, globus sensation and hoarseness. The pathophysiological link between reflux and symptoms likely includes direct effect of the refluxate on the upper airways epithelium and reflex that is initiated by stimulation of the afferent nociceptive fibres in the distal esophagus by acidic gastroesophageal reflux. Arguably, the relationship between reflux and laryngopharyngeal symptoms might involve other, yet not well explored mechanisms. In our previous research we found that LPR patients have impaired mucociliary clearance of the respiratory epithelium of the upper airways. This could contribute to the inflammation persistence and the presence of symptoms. We therefore aimed to determine whether any parameter of the reflux burden as detected by 24-hour pH/impedance correlates with ciliary beat frequency (CBF), the major quantifiable aspect of mucociliary clearance.
Aims & Methods
Consecutive patients with LPR confirmed by off PPI 24-hour pH/impedance had a sample of the ciliated epithelium obtained from the nose using a cytology brush. Nasal CBF was analysed using a digital high‐speed video microscope and the dedicated software application Ciliary Analysis (NI LabVIEW). Healthy volunteers without either esophageal or extraesophageal reflux symptoms served as a control group. Both patients’ and healthy volunteers’ group were without any airway inflammation at least 3 months prior to the evaluation and were at least 10 days of PPI therapy. Maximal, minimal, and the median value of the CBF (Hz) was obtained. We performed correlation analyses between the acid exposure time (AET), number of reflux episodes, mean nocturnal baseline impedance (MNBI) in all impedance segments (Z1-Z6) and CBF values.
Results
32 patients with LPR confirmed by 24-hour pH/impedance that had positive reflux symptom index (RSI>13) were included in the final analysis. Of them, 12 patients had confirmed by positive acid exposure time (AET>6%) and/or abnormal number of reflux episodes (>80). Firstly, we confirmed our previous observations that LPR patients had lower CB frequency (median value) compared to the healthy individuals (6,37±2,17 vs. 10,9±1,9; p<0.0001). Separate analysis of patients with proven GERD showed no CBF difference from the remaining (pH negative patients) (6,26±2,53 vs. 6,43±1,94; p=0,42). Secondly, we performed correlation analysis between AET/number of reflux episodes and CBF. We found no significant correlation between reflux burden and median value of CBF (N=32, R=-0.18, p=NS and R=0.05, p=NS for AET and number of refluxes, resp.). Thirdly, we performed correlation analyses between CBF and MNBI values of all impedance segments. Indeed, correlation analysis between median CBF and MNBI Z1-Z6 showed no significant correlations (N=32, R=-0.16, 0.09, 0.28, 0.01, 0.14 for Z1, Z2, Z3, Z4, Z5, Z6, resp., resulting in p=NS in all segments).
Conclusion
pH positive LPR patients had no difference in CBF values from the remaining (pH negative) patients. Reflux burden in the esophagus as determined by pH recording does not seem to be related to ciliary beat frequency. We observed no significant correlation between the MNBI values in any impedance segment and the median CBF value. Further research should be performed to determine the putative mechanism between the impairment of CBF and reflux.
Supported by: VEGA 1/0060/23