Ambulatory high-resolution manometry, lower esophageal sphincter lift and transient lower esophageal sphincter relaxation.
ABSTRACT Lower esophageal sphincter (LES) lift seen on high-resolution manometry (HRM) is a possible surrogate marker of the longitudinal muscle contraction of the esophagus. Recent studies suggest that longitudinal muscle contraction of the esophagus induces LES relaxation.
Our goal was to determine: (i) the feasibility of prolonged ambulatory HRM and (ii) to detect LES lift with LES relaxation using ambulatory HRM color isobaric contour plots.
In vitro validation studies were performed to determine the accuracy of HRM technique in detecting axial movement of the LES. Eight healthy normal volunteers were studied using a custom designed HRM catheter and a 16 channel data recorder, in the ambulatory setting of subject's home environment. Color HRM plots were analyzed to determine the LES lift during swallow-induced LES relaxation as well as during complete and incomplete transient LES relaxations (TLESR).
Satisfactory recordings were obtained for 16 h in all subjects. LES lift was small (2 mm) in association with swallow-induced LES relaxation. LES lift could not be measured during complete TLESR as the LES is not identified on the HRM color isobaric contour plot once it is fully relaxed. On the other hand, LES lift, mean 8.4 ± 0.6 mm, range: 4-18 mm was seen with incomplete TLESRs (n = 80).
Our study demonstrates the feasibility of prolonged ambulatory HRM recordings. Similar to a complete TLESR, longitudinal muscle contraction of the distal esophagus occurs during incomplete TLESRs, which can be detected by the HRM. Using prolonged ambulatory HRM, future studies may investigate the temporal correlation between abnormal longitudinal muscle contraction and esophageal symptoms.
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ABSTRACT: Whereas it is well documented that fundoplication reduces acid reflux, the effects of the procedure on non-acid and gas reflux and the mechanisms through which this is achieved have not been fully elucidated. In 14 patients, reflux was measured with impedance-pH monitoring during a postprandial 90 min stationary recording period before and 3 months after fundoplication. Concomitantly, the occurrence of transient lower oesophageal sphincter relaxations (TLOSRs) and morphology of the oesophagogastric junction were studied with high-resolution manometry. This was followed by 24 h ambulatory impedance-pH monitoring. Before fundoplication, two separate high-pressure zones (hernia profile) were detected during 24.9% of total time, during which there was a large increase in reflux rate. After fundoplication, the hernia profile did not occur. Fundoplication decreased the number of TLOSRs (from 10.5 (SEM 1.2) to 4.5 (0.7), p<0.01) and also the percentage of TLOSRs associated with acidic or weakly acidic reflux (from 72.7% to 4.1%, p<0.01). Nadir pressure during TLOSRs increased after surgery (from 0 (0-0) to 1.0 (1-2) kPa, p<0.05). In the ambulatory study, there was a large decrease in prevalence of both acid (-96%, from 47.0 (5.9) to 1.8 (0.5), p<0.01) and weakly acidic reflux (-92%, from 25.0 (9.7) to 2.3 (0.9), p<0.01). The decrease in gas reflux was less pronounced (-53%, from 24.2 (4.9) to 11.3 (3.0), p<0.01). Fundoplication greatly reduces both acid and weakly acidic liquid reflux; gas reflux is reduced to a lesser extent. Three mechanisms play a role: (1) abolition of the double high-pressure zone profile (hiatal hernia); (2) reduced incidence of TLOSRs; and (3) decreased percentage of TLOSRs associated with reflux.Gut 02/2008; 57(2):161-6. · 10.73 Impact Factor
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ABSTRACT: Swallow and esophageal distension-induced relaxations of the lower esophageal sphincter (LES) are associated with an orad movement of the LES because of a concurrent esophageal longitudinal muscle contraction. We hypothesized that the esophageal longitudinal muscle contraction induces a cranially directed mechanical stretch on the LES and therefore studied the effects of a mechanical stretch on the LES pressure. In adult opossums, a silicon tube was placed via mouth into the esophagus and laparotomy was performed. Two needles with silk sutures were passed, 90 degrees apart, through the esophageal walls and silicon tube, 2 cm above the LES. The tube was withdrawn, and one end of each of the four sutures was anchored to the esophageal wall and the other end exited through the mouth to exert graded cranially directed stretch on the LES by using pulley and weights. A cranially directed stretch caused LES relaxation, and with the cessation of stretch there was recovery of the LES pressure. The degree an d duration of LES relaxation increased with the weight and the duration of stretch, respectively. The mean LES relaxation in all animals was 77.7 +/- 4.7%. The required weight to induce maximal LES relaxation differed in animals (714 +/- 348 g). N(G)-nitro-L-arginine, a nitric oxide inhibitor, blocked the axial stretch-induced LES relaxation almost completely (from 78 to 19%). Our data support the presence of an axial stretch-activated inhibitory mechanism in the LES. The role of axial stretch in the LES relaxation induced by swallow and esophageal distension requires further investigation.AJP Gastrointestinal and Liver Physiology 02/2007; 292(1):G329-34. · 3.65 Impact Factor
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ABSTRACT: Esophageal shortening accompanies peristalsis in laboratory animals and is attributed to longitudinally oriented fibers in esophageal muscle layers. To evaluate this phenomenon in humans, esophageal shortening during suspended respiration in response to swallows was measured in five normal volunteers (median age, 23 yr). Metal mucosal clips were endoscopically placed at and 10 cm above the gastroesophageal junction, and their movement was recorded by videotaped fluoroscopy. All subjects demonstrated esophageal shortening with each swallow in a characteristic pattern with small interswallow variance. Early, minimal shortening of the proximal segment (6.0 +/- 2.4 mm) was followed by delayed, prominent distal segment shortening (18.9 +/- 9.3 mm) that principally accounted for overall change in total esophageal length (18.0 +/- 8.1 mm). The degree of esophageal shortening did not correlate with circular muscle contraction wave parameters that were obtained with intraluminal manometrics in a separate study (P greater than 0.2 for each correlation), and distal segment shortening uniformly preceded the onset of contraction waves in the same region. These findings indicate that patterned esophageal shortening with swallows occurs in humans, most prominently in the distal esophagus. The technique may be useful in determining the participation of axial esophageal movement in esophageal motility disorders.The American journal of physiology 04/1991; 260(3 Pt 1):G512-6. · 3.28 Impact Factor