The rhythm and rate of distension‐induced esophageal contractility: A physiomarker of esophageal function

Abstract

Background Distention of the esophagus elicits a unique pattern of repetitive contractions in healthy controls. We aimed to assess the rhythm and rate of distension‐induced contractile patterns between achalasia and controls and identify factors that distinguish the normal contractile response to distension. Methods Twenty asymptomatic controls and 140 adult patients with treatment‐naïve achalasia defined by HRM (29 type I, 81 type II, 30 type III) were prospectively evaluated with functional luminal imaging probe (FLIP) during sedated endoscopy. 16‐cm FLIP balloons were positioned within the distal esophagus during stepwise balloon distension. Functional luminal imaging probe panometry studies were retrospectively analyzed using a customized program. Key results All controls had contractility in a repetitive antegrade contraction (RAC) pattern with a rate of mean (10‐90th) 6 (4‐8) contractions per minute. 19/20 controls had > 6 consecutive antegrade contractions (ACs), that is, duration > 6 ACs, >6 cm in length, at a rate of 6 ± 3 contractions per minute (met the “Rule‐of‐6s”). 50 achalasia patients had repetitive contractions that occurred at a rates of 11 (7 ‐ 15) ACs per minute; P < .001 compared with controls, or 12 (8‐15) repetitive retrograde contractions per minute. Only 1/140 achalasia patients had a contractile response that met the “Rule‐of‐6s.” Conclusion The normal contractile response to sustained distention is associated with > 6 RACs with a consistent rate of 6 ± 3 per minute, which was exceptionally rare in achalasia. These findings support that the RAC pattern is disrupted in achalasia and the faster rate may be a manifestation of abnormal inhibition and/or a reduced refractory period.

The use of impedance planimetry (Endoscopic Functional Lumen Imaging Probe, EndoFLIP®) in the gastrointestinal tract: A systematic review

“…The body of the esophagus was studied in 6 reports in healthy volunteers (n = 2‐20) using 54‐56 the classical 8 cm probe or a more recent 16‐cm probe (EF322‐N) 38,57,58 . These publications introduced the concept of distension plateau (DP) , which was defined as the reflection of the fixed luminal diameter that would fail to expand despite increasing intraballoon pressures 38,57 .…”

“…These publications introduced the concept of distension plateau (DP) , which was defined as the reflection of the fixed luminal diameter that would fail to expand despite increasing intraballoon pressures 38,57 . Moreover, the contractility response of the esophagus to distension (ie, secondary peristalsis) could be identified in these studies, with the introduction of new parameters: 1/esophageal body contractions (transient decrease of ≥5 mm in the luminal diameter in ≥3 adjacent impedance planimetry channels); 2/repetitive anterograde contractions (RACs; ≥3 antegrade contractions consecutively); and 3/repetitive retrograde contractions (RRCs; ≥3 retrograde contractions consecutively) 38,57‐59 . The RAC pattern, occurring every 6‐10 seconds, was found to be the normal contractile response to sustained volume distension in 95% of HV (LE 3) 58,59 mostly at 40 and 50 mL fill volume and was assimilated to secondary peristalsis (Figure 3).…”

“…The body of the esophagus was also investigated in patients with achalasia in six reports (ie, panometry) 37‐39,58,59,64 . Contrary to 95% (19/20) of HV, less than 1% (1/140) of patients with achalasia exhibited the RAC pattern as response to distension in a large cohort of patients 58 (LE 3).…”

“…The body of the esophagus was also investigated in patients with achalasia in six reports (ie, panometry) 37‐39,58,59,64 . Contrary to 95% (19/20) of HV, less than 1% (1/140) of patients with achalasia exhibited the RAC pattern as response to distension in a large cohort of patients 58 (LE 3). Moreover, type I and type II achalasia patients demonstrated absent contractility or non‐RAC contractility pattern, whereas patients with type III achalasia showed RRC pattern, which was not observed in HV 38,59,64 (LE 3).…”

Achalasia subtypes can be identified with functional luminal imaging probe (FLIP) panometry using a supervised machine learning process

“…this cohort has been previously described. 10 A cohort of 40 patients with achalasia evaluated between October 2017 and October 2018 was utilized as a "test cohort. "…”