Multiple rapid swallow responses segregate achalasia subtypes on high-resolution manometry

Area of Science:

• Gastroenterology
• Esophageal Physiology
• High-Resolution Manometry

Background:

• Multiple rapid swallows (MRS) elicit complex esophageal responses, including inhibition of peristalsis and lower esophageal sphincter (LES) tone, followed by a rebound excitation.
• These MRS responses are mediated by intact neural pathways and may vary across different subtypes of achalasia spectrum disorders.

Purpose of the Study:

• To investigate the utility of multiple rapid swallows (MRS) in differentiating subtypes of achalasia spectrum disorders.
• To assess esophageal peristaltic performance and LES function in response to MRS in patients with achalasia and healthy controls.

Main Methods:

• Prospective identification of consecutive subjects with incomplete LES relaxation on high-resolution manometry (HRM) without mechanical obstruction.
• Classification of achalasia spectrum disorders according to Chicago criteria and review of HRM plots.
• Assessment of esophageal and LES function during 10 wet swallows and MRS (five 2 mL water swallows 2-3 s apart), compared with 18 healthy controls.

Main Results:

• Complete failure of peristalsis with MRS occurred in achalasia subtypes 1 and 2.
• Eighty percent of achalasia subtype 3 and patients with EGJ outflow obstruction showed a contractile response to MRS, significantly different from subtypes 1 and 2 (P < 0.001).
• The percent decrease in LES residual pressure during MRS differentiated achalasia subtypes, with aperistaltic subtypes showing a lesser decline compared to those with preserved peristalsis and controls (P < 0.001).

Conclusions:

• Multiple rapid swallow responses effectively segregate achalasia spectrum disorders into two distinct patterns based on esophageal body contraction.
• These findings support the current subtyping of achalasia and highlight significant pathophysiologic differences among subtypes.