Phenotyping patients with borderline elevated esophageal acid exposure

Area of Science:

• Gastroenterology
• Esophageal Physiology
• Diagnostic Medicine

Background:

• Ambulatory reflux monitoring defines pathologic gastroesophageal acid reflux based on acid exposure time (AET).
• Lyon Consensus criteria classify AET <4% as normal, >6% as pathologic, and 4-6% as borderline.
• Differentiating borderline AET cases requires further investigation into associated metrics.

Purpose of the Study:

• To investigate the characteristics of patients with borderline acid exposure time (AET).
• To identify metrics, including mean nocturnal baseline impedance (MNBI) and high-resolution manometry (HRM) findings, that differentiate borderline AET.
• To assess the clinical significance of borderline AET in conjunction with other diagnostic parameters.

Main Methods:

• Retrospective review of 89 patients with normal (<4%), borderline (4-6%), and abnormal (>6%) AET from pH-impedance monitoring (2015-2019).
• Analysis included demographic data, MNBI, and HRM parameters (Chicago classification v3.0).
• Exclusion criteria included prior foregut surgery, major esophageal motility disorders, or unreliable impedance testing.

Main Results:

• Borderline AET patients exhibited significantly lower MNBI compared to normal AET (1607.7 vs. 2524.0 ohms) and higher MNBI than abnormal AET (951.5 ohms).
• A higher frequency of ineffective esophageal motility (IEM) was observed in borderline AET patients (42.1%) compared to normal AET (8.0%).
• The prevalence of IEM in borderline AET patients was similar to those with abnormal AET (34.6%).

Conclusions:

• Patients with borderline AET have intermediate MNBI values between normal and abnormal AET groups.
• Borderline AET is frequently associated with IEM, similar to abnormal AET.
• Low MNBI and IEM in patients with borderline AET may warrant increased clinical significance.