B0205 - Relationship Between Upper Esophageal Sphincter (UES) and Distal Acid Exposure in Patients With GERD: Evaluation of pH Impedance and High Resolution Manometry (HRM)

Introduction: Gastroesophageal reflux disease (GERD) is the most common disorder of the gastrointestinal tract in the United States. The UES is essential by sustaining basal pressure (normal = 34-104mmHg) to prevent laryngopharyngeal reflux (LGR) and also relaxation pressure (normal = < 15mmHg) for the passage of food boluses during ingestion. Unlike the lower esophageal sphincter (LES), the physiology of the UES in GERD is not well established. The aim of this large retrospective study is to evaluate both pH Impedance and HRM to assess whether GERD is associated with a high pressure UES.

Methods: This cohort consists of patients that underwent both pH Impedance and HRM at an esophageal motility laboratory between 09/2018 and 01/2022. Patients less than 18 years old, on PPI therapy at time of testing, or with exams further than one month apart were excluded from the study. Patients with uninterpretable or inconclusive exams were also omitted. All data from pH Impedance and HRM reports were recorded for each subject. Primary variable of interest was total acid exposure time (AET) which was further categorized into GERD or normal according to both Demeester (AET >4.2%) and Lyons criteria (AET >6%). All variables were compared to corresponding basal and residual pressure on HRM.

Results: There were 727 adults with both pH Impedance and HRM performed over the 40-month span with our sample including 318 patients after implementation of exclusion criteria (mean age = 53.5, 76.1% female). The diagnosis of GERD was found in 191 subjects (60%) per Demeester Criteria and 146 patients (46%) per Lyons criteria. Subjects diagnosed with GERD per Demeester criteria were found to have a higher mean UES basal pressure (72.8 mmHg) compared to those without GERD (64.3 mmHg) (p=0.04). This was also true in Lyons criteria (69.3 mmHg vs 65.0 mmHg) (p=0.33). Further comparative analysis between pH impedance variables and UES pressure are summarized in Table 1.

Discussion: Our results suggest that patients with elevated total AET secondary to GERD may have elevated basal UES pressures. This is likely due to a chronic compensatory mechanism to prevent micro aspirations and damage to the larynx. These results are further supported by a recent smaller retrospective study demonstrating an association of elevated residual UES pressure in patients with more episodes of proximal reflux. The findings of this study propose that UES pressure may be a novel measurement to assist with classifying and diagnosing GERD.