Measuring the burden of gastroesophageal reflux after per-oral endoscopic myotomy

Summary

Investigating post-POEM gastroesophageal reflux is a challenge still unsolved. Here we discuss the main limitations of each diagnostic test for reflux in achalasia patients.

Pham et al. ¹ presented their per-oral endoscopic myotomy (POEM) long-term outcomes, showing good dysphagia relief. However, another important long-term finding of this study was that POEM induced reflux in almost half of the patients.

The authors’ main endpoint for assessing post-POEM gastroesophageal reflux (PGER) was the acid exposure in pH monitoring. However, investigating PGER is a challenge still unsolved.

Achalasia patients may manifest severe reflux even with few or no symptoms because achalasia is a mechanical and sensitive disorder.2 Achalasia patients have a lower impaired visceral sensation due to nerve degeneration, enlarged esophageal diameter, and other hypothetical mechanisms. ² Consequently, patients may present PGER and not use proton pump inhibitors.

Endoscopy also has limitations for detecting PGER. Mucosa damage, such as erosions, may be either a consequence of the reflux or of the chemical irritation due to food stasis. ³

The pH testing is usually accepted as the gold standard for detecting reflux in non-achalasia populations. However, pH testing in achalasia presents difficult to interpret findings. ⁴ The change in pH in the esophageal lumen is quite variable in these patients. Food stasis and bacteria activity may promote acidification, even with no reflux. Impedance-pH metry also has limitations. The food bolus retrograde moving along the esophagus may be misinterpreted as gastroesophageal reflux.

Videoesophagography is an old test for detecting reflux, but currently, it is rarely used due to low sensitivity. ⁵ However, in the setting of lack of high-quality diagnostic tests for PGER, the reflux detected in a prone position may be used in long-term follow-up after endoscopic therapy.

Due to the lack of a distinct diagnostic test for PGER, a combination of clinical, endoscopic, and imaging findings should be considered during the patients’ follow-up. Only future diagnostic tests will determine the real impact of POEM on reflux development.