Esophageal Chemical Clearance Protects Against Reflux

Mentore Ribolsi, MD, PhD

New research suggests esophageal chemical clearance could be a defense mechanisms against reflux in patients with gastroesophageal reflux disease (GERD).

A team, led by Mentore Ribolsi, MD, PhD, Department of Digestive Diseases, Campus Bio Medico University of Rome, identified the relationship between post-reflux swallow-induced peristaltic wave index (PSPW) and mean nocturnal baseline impendence (MNBI).

Impedance-pH monitoring enables the evaluation of esophageal chemical clearance, which is a response to reflux elicited by the esophago-salivary reflex, through the PSPW index. Mucosal integrity is often evaluated by means of MNBI, a GERD marker.

However, the relationship between the PSPW index and MNBI has not previously been fully investigated.

The New Investigation

In the study, the investigators examined impedance-pH tracings from 230 consecutive patients and evaluated the association between acid exposure time (AET), total refluxes (TRs), PSPW index, and MNBI using ROC analysis and multivariate regression models.

They also classified patients by means of AET thresholds and symptom-reflux association indexes into conclusive and inconclusive GERD, reflux hypersensitivity (RH), and functional heartburn (FH) and defined pathologic MNBI <2292 Ω according to published outcome studies.

The Data

The results show a significant direct correlation between PSPW index and MNBI (0.759; P <0.001). Using the ROC analysis, a PSPW index cut-off value of 53% was the best discriminator between normal from pathologic MNBI values (sensitivity 88%, specificity 86.4%).

They also found AET cut-off of 4% or 6%, a sensitivity of 80.7% and 46% and a specificity of 62.5% and 93.2%.

After conducting the multivariate analysis, AET >4% and PSPW index value <53% or <61% were significantly linked to pathologic MNBI values.

“Esophageal chemical clearance is a major defense mechanism against reflux and its impairment represents a major determinant of reflux-associated mucosal damage,” the authors wrote.

Guidance for Patients With GERD

Last year, the American College of Gastroenterology (ACG) updated the guidelines for diagnosing, treating, and managing patients with GERD for the first time since 2013.

Since the last update to GERD guidelines by the ACG there has been a number of advancements in surgical and endoscopic therapies for GERD.

Oner of the main changes in recent years is closer scrutiny of proton pump inhibitors (PPI), with questions about safety and overprescribing of the treatment prevalent in research.

For diagnosing GERD, patients with classic symptoms of heartburn and regurgitation with no alarm symptoms, the recommendation is for an 8-week trial of empiric PPIs once daily prior to a meal.

If the patient responds, the new reccomendations call for discontinuing the PPIs.

Another recommendation is diagnostic endoscopies after PPI is stopped for 2-4 weeks for patients whose classic symptoms do not respond adequately to the 8-week PPI trial or in patient whose symptoms return when PPIs are discontinued.

For patients with chest pain but not heartburn and adequate evaluation to exclude heart disease, the guidelines call for the objective testing for GERD.

The authors also do not recommend using barium swallow solely as a diagnostic test and endoscopies should be the first test for evaluating patients presenting with dysphagia or other alarm symptoms like weight loss and gastrointestinal bleeding, as well as for patients with multiple risk factors for Barrett’s esophagus.

For patients with suspected but unclear GERD, and no objective evidence of GERD from the endoscopy, the guidelines call for reflux monitoring off therapy to establish the diagnosis.

The study, “Association between post-reflux swallow-induced peristaltic wave index and esophageal mucosal integrity in patients with GERD symptoms,” was published online in Neurogastroenterology & Motility.