Role of Esophageal Manometry and Conventional Ambulatory pH Monitoring in Patients with Laryngopharyangeal Reflux and Typical Reflux Symptoms

Gastroesophageal reflux disease (GERD) presents with typical esophageal symptoms in majority of patients.[1] Laryngopharyngeal reflux (LPR) is an uncommon extraesophageal manifestation of GERD and is diagnosed based on the presence of chronic cough, hoarseness, or throat clearing.[1] The present study was undertaken to determine the utility of endoscopy and esophageal physiological testing using high-resolution esophageal manometry (HREM) and conventional 24 h pH study in patients with suspected LPR and typical GERD symptoms. This is a retrospective analysis of data of adult patients (>18 years) who were evaluated for suspected LPR or typical reflux symptoms (heartburn, regurgitation with or without chest pain) between May 2019 and April 2024. All patients were nonresponsive to proton pump inhibitors (PPI) for >8 weeks. Upper gastrointestinal endoscopy was done for all patients and esophagitis was graded as per Los Angeles criteria.[2] HREM and conventional 24 h pH testing were done on the same day. Patients with history of foregut surgery, pregnancy, major motility disorders, combined LPR and typical reflux symptoms, and incomplete records were excluded from the study. Tests were done after discontinuing PPI for at least 2 weeks. HREM was done using 16 channel water perfusion system (GS Hebbard, Melbourne, Australia), reporting was done using Trace 1.3.3 software (GS Hebbard, Melbourne, Australia) and interpreted using Chicago Classification (CC) v4.0.[3] Recording of basal lower esophageal sphincter (LES) pressures, basal upper esophageal sphincter pressures (UES), integrated relaxation pressures (IRP), and esophagogastric junction (EGJ) morphology was done. UES pressures were calculated as per protocol in the sitting position with head in the neutral position. There is no established normal range for UES pressure measurement using water perfusion system used in the study. As per previous studies, the normal pressures range between 100 and 150 mm Hg.[4] EGJ morphology was classified as follow – type I when LES and crural diaphragm were superimposed, type II when separated <3 cm, and type III when separated ≥3 cm. EGJ-contractile integral (EGJ-CI) was noted and assessment of peristalsis was done using ten 5 mL water swallows in supine posture. Peristalsis was assessed using proximal CI [PCI, Figure 1] and distal CI. For tests done before 2021, re-interpretation of manometry records was done as per CC v 4.0. As per CC v 4.0, analysis of peristalsis requires both upright and supine swallows. Upright swallows were not done for all patients before 2021 and hence were not included for interpretation of the peristaltic pattern.Figure 1: (a) manometry measurements done in the study. (b) Representative image of manometry interpretation used in the studyTwenty-four pH test was done using a single-sensor probe (Sandhill Scientific, Highland Ranch, USA) and interpreted using computerized software (Sandhill Scientific, Highland Ranch, USA). Manual interpretation of computerized reports was done in all cases. Acid exposure time (AET) was interpreted as per Lyon Consensus[1] and Asian guidelines.[5] Patients were grouped into Group 1 (suspected LPR only) and Group 2 (typical GERD symptoms only). Statistical tests used included median, range, percentages, Chi-square test, and Mann–Whitney U-test. Analysis was performed using IBM Statistical Package for the Social Sciences (SPSS) version 20 (IBM, Armonk, NY, USA). P < 0.05 was considered statistically significant. A total of 116 patients formed the study cohort Group 1 (20, 17.2%) and Group 2 (96, 82.8%). Patients in Group 1 had lower basal UES pressures (P = 0.04) and lower proximal CI (P = 0.02). AET >6% was noted in 30% of patients in gGroup 1 and 48% of patients in Group 2 (P = 0.14). On using Asian cutoff (AET >4%), the detection of acid exposure was significantly higher in Group 2 (55.2% vs. 30%, P = 0.04). Symptom index >50% was noted in only one-third of cases in Group 1 and 52.1% of patients in Group 2 (P = 0.16) [Table 1].Table 1: Comparison of demographic details, endoscopy findings, manometry findings and 24 h pH study findings in the two groupsThe present study included patients who did not respond to PPI therapy for 8 weeks. Such patients are more likely to have functional phenotype or esophageal hypersensitivity. In addition, esophageal or gastric dysmotility, weakly acid reflux, bile reflux, and psychological stressors may be responsible for symptoms. This needs to be diagnosed with additional tests such as manometry and 24 h pH testing.[6] The results highlight that patients with LPR have reduced UES pressures and PCI. The findings of impaired proximal esophageal contractility and UES dysfunction are similar to earlier studies.[7] A recent study studied 89 patients with LPR using high-resolution impedance manometry and compared the findings of these patients with 63 healthy volunteers. The authors were noted that LPR patients had significantly shorter UES and LES. Age, LES IRP, and the UES length were independent risk factors for LPR symptoms. In patients with moderate LPR symptoms, lower IRP (P = 0.049) and failed peristalsis (P = 0.004) were significantly more common than those with mild LPR symptoms.[8] These parameters could not be assessed in the present study due to retrospective design. However, they provide directions for future, prospective research. Conventional pH testing is insufficient to detect acid reflux in patients with LPR. The present study underscores this observation. Earlier studies have noted that reflux symptom index and reflux findings score are reliable tools to diagnose LPR. Empirical trial with PPI for >8 weeks can improve symptoms and laryngoscopic findings in patients with LPR.[9] Using dual probe esophageal pH study, proximal acid exposure is noted in only 10% of patients with voice disorders and has no significant association with above scores.[10] Prolonged duration of pH study, use of wireless pH probe, pharyngeal placement of probe, and use of pH impedance testing improve detection of acid reflux in LPR patients.[11-14] The present study is limited by the small sample size, retrospective nature of the study, use of conventional pH testing instead of pH impedance testing which is gold standard for LPR testing, and lack of comparison with healthy controls. UES data are limited due to lack of normative Indian data on UES function using the Hebbard system. Moreover, in our setting, most patients undergo conventional pH test due to monetary constraints. Thus, we have tried to analyze the role of conventional pH testing in patients with LPR. To conclude, water perfusion HREM may provide additional information on UES function and proximal esophageal motility in patients with LPR. Conventional pH study is not useful to detect acid reflux in patients with LPR. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.