A unique longitudinal muscle contraction pattern associated with transient lower esophageal sphincter relaxation.
ABSTRACT Contraction of the longitudinal muscle of the esophagus may play a role in the relaxation and opening of the lower esophageal sphincter (LES). The goal of our study was to determine the pattern and precise temporal correlation between local longitudinal muscle contraction (LMC) of the esophagus during peristalsis and transient LES relaxation (TLESR).
Esophageal pressures and high-frequency intraluminal ultrasound imaging of the esophagus were recorded in 24 healthy subjects during swallow-induced peristalsis and spontaneous TLESR. Intraluminal multiple impedance recordings were obtained to determine the relationship between "common cavity pressure" and gastroesophageal reflux (GER).
During swallow-induced peristalsis, there is simultaneous contraction of circular and longitudinal muscles of the esophagus. On the other hand, TLESR is associated with a distinct pattern of LMC in the esophagus that has the following characteristics: (1) it is restricted to the distal esophagus; (2) it begins before the onset of TLESR and spreads in a retrograde manner; (3) it is generally stronger than the swallow-induced contraction; and (4) it is sustained during the entire duration of TLESR. The increase in esophageal pressure during TLESR is temporally correlated with the contraction of the LM of the distal esophagus, rather than with the impedance recorded GER.
We propose that the LMC of the distal esophagus may play an important role in the relaxation of LES and induction of GER.
Article: The position of the acid pocket as a major risk factor for acidic reflux in healthy subjects and patients with GORD.[show abstract] [hide abstract]
ABSTRACT: Gastro-oesophageal reflux occurs twice as much during transient lower oesophageal sphincter relaxations (TLOSRs) in patients with gastro-oesophageal reflux disease (GORD) compared to healthy volunteers (HVs). Our aim was to assess whether the localisation of the postprandial acid pocket and its interaction with a hiatal hernia (HH) play a role in the occurrence of acidic reflux during TLOSRs. Ten HVs and 22 patients with GORD (12 with HH<3 cm (s-HH), 10 with HH > or =3 cm (l-HH)) were studied. The squamocolumnar junction and diaphragmatic impression were marked with a radioactively labelled clip. To visualise the acid pocket, (99m)Tc-pertechnetate was injected intravenously and images were acquired up to 2 h postprandial. Concurrently, combined manometry/impedance and four-channel pH-metry were performed, with pH pull-through at multiple time-points. The rate of TLOSRs and the per cent associated with reflux was comparable between all groups. However, acidic reflux was significantly increased in patients, especially in patients with l-HH. Acid pocket length was significantly enlarged in patients. Moreover, immediately before a TLOSR, the acid pocket was more frequently located within the hiatus or above the diaphragm in patients with GORD (s-HH, 54%; l-HH, 77%) compared to HVs (22% of TLOSRs). Acidic reflux was significantly increased when the acid pocket was located above the diaphragm in all groups compared to a sub-diaphragmatic localisation. The position of the acid pocket is largely determined by the presence of a HH. Entrapment of the pocket above the diaphragm, especially in patients with l-HH, is a major risk factor underlying the increased occurrence of acidic reflux during a TLOSR in patients with GORD.Gut 09/2009; 59(4):441-51. · 10.11 Impact Factor
Article: Oesophageal shortening: in vivo validation of high-frequency ultrasound measurements of oesophageal muscle wall thickness.[show abstract] [hide abstract]
ABSTRACT: Assessment of oesophageal muscle wall thickness with high-frequency intraluminal ultrasound (HFIUS) is proposed as a method to evaluate longitudinal muscle contraction and oesophageal shortening in patients with oesophageal symptoms. Studies using this technique suggested that prolonged oesophageal wall thickening can be associated with chest pain and heartburn. Validation studies comparing HFIUS measurements against fluoroscopic investigations of oesophageal shortening are not available. The aim of this study was to evaluate the relationship between oesophageal muscle wall thickening and oesophageal shortening in vivo. Oesophageal shortening and muscle wall thickness were assessed simultaneously in lightly sedated cats, using fluoroscopic tracking of endoscopically attached metal clips and HFIUS, respectively. Oesophageal shortening was studied during secondary peristalsis and oesophageal mucosal acidification. Video fluoroscopy and HFIUS images were recorded simultaneously and the magnitude and timing of changes in distance between clips and muscle wall thickness were compared. During peristalsis, the distance between the clips was maximally reduced to 33% and the muscle wall thickness was increased to 218% above baseline. Maximal shortening and wall thickening correlated significantly and occurred simultaneously. Likewise, mucosal acidification provoked simultaneous oesophageal shortening (20%) and increased basal muscle wall thickness (40%). Secondary peristalsis during mucosal acidification was associated with strong and prolonged oesophageal shortening. Oesophageal muscle wall thickening, measured with HFIUS is a good predictor of oesophageal shortening and longitudinal muscle contraction during swallowing and oesophageal mucosal acidification.Gut 04/2010; 59(4):433-40. · 10.11 Impact Factor
Article: Arbaclofen placarbil decreases reflux with good tolerability in patients with gastroesophageal reflux disease (am j gastroenterol 2010;105:1266-1275).Journal of neurogastroenterology and motility 10/2010; 16(4):444-5.