Measuring EGJ opening patterns using high resolution intraluminal impedance

Type II achalasia with focal elevated pressures: A distinct manometric and clinical sub-group

BACKGROUND

Type II achalasia (Ach2) is distinguished from other achalasia sub-types by the presence of panesophageal pressurization (PEP) of ≥30 mmHg in ≥20% swallows on high-resolution manometry (HRM). Variable manometric features in Ach2 have been observed, characterized by focal elevated pressures (FEPs) (focal/segmental pressures ≥70 mmHg within the PEP band) and/or high compression pressures (PEP ≥70 mmHg). This study aimed to examine clinical and physiologic variables among sub-groups of Ach2.

METHODS

This retrospective single center study performed over 3 years (1/2019-1/2022) included adults with Ach2 on HRM who underwent endoscopic ultrasound (EUS), functional lumen imaging probe (FLIP), and/or barium esophagram (BE) prior to therapy. Patients were categorized into two overarching sub-groups: Ach2 without FEPs and Ach2 with FEPs. Demographic, clinical, and physiologic data were compared between these sub-groups utilizing unpaired univariate analyses.

KEY RESULTS

Of 53 patients with Ach2, 40 (75%) were without FEPs and 13 (25%) had FEPs. Compared with the Ach2 sub-group without FEPs, the Ach2 sub-group with FEPs demonstrated a significantly thickened distal esophageal circular muscle on EUS (1.4 mm [SD 0.9] vs. 2.1 [0.7]; p = 0.02), higher prevalence of tertiary contractions on BE (46% vs. 100%; p = 0.0006), lower esophagogastric junction distensibility index (2.2mm2 /mmHg [0.9] vs 0.9 [0.4]; p = 0.0008) as well as higher distensive pressure (31.0 mmHg [9.8] vs. 55.4 [18.8]; p = 0.01) at 60 cc fill on FLIP, and higher prevalence of chest pain on Eckardt score (p = 0.03).

CONCLUSIONS AND INFERENCES

We identified a distinct sub-group of type II achalasia on HRM, defined as type II achalasia with focal elevated pressures. This sub-group uniquely exhibits spastic features and may benefit from personalized treatment approaches.

Normative values of intra-bolus pressure and esophageal compliance based on 4D high-resolution impedance manometry

BACKGROUND

This study aimed to quantify normative values of phase-specific intra-bolus pressure (IBP) and esophageal distensibility using 4D analysis of high-resolution-impedance manometry (HRIM).

METHODS

HRIM studies of supine swallows from 34 normal controls were analyzed with respect to the four phases of bolus transit: (1) accommodation, (2) compartmentalization, (3) peristalsis/esophageal emptying, and (4) ampullary emptying. Phase-specific IBP, bolus volume, and distensibility index (DI) in the esophageal body and esophagogastric junction (EGJ) during phases 1-3 were extracted.

RESULTS

The median (5-95th/IQR) IBP values were as follows: phase 1: 4.0 (-2.0-10.4/1.9-5.8) mmHg, phase 2: 5.7 (0.2-14.1/3.6-8.9) mmHg, and phase 3: 11.2 (2.9-19.4/7.7-15.1) mmHg. The median bolus volume calculated by integrating impedance planimetry cross-sectional areas was 4.1 ml during the compartmentalization phase. The EGJ-DI at max EGJ diameter during phase 2 and 3 was 2.8 (1.1-9.5/1.8-3.7) mm² /mmHg and 6.0 (3.2-20.3/5.1-7.8) mm² /mmHg, respectively. The phase 3 EGJ-DI values (6.0 (3.2-20.3/5.1-7.8) mm² /mmHg) were similar to those calculated using functional lumen imaging probe (FLIP) at the 60 ml volume on the same subjects (5.8 [3.5-7.2/5.0-6.4] mm² /mmHg).

CONCLUSIONS AND INFERENCES

4D-HRIM provides a standardized methodology to track the nadir impedance and provide measurements of IBP during maximal distention across phases 1-3 of bolus transit. Median IBP and delta IBP were different across the phases, supporting the need to define IBP by phase. Additionally, the EGJ-DI calculated during phase 3 was similar to the 60-ml EGJ-DI from FLIP in the same subjects suggesting that 4D-HRIM can quantify EGJ opening during primary peristalsis.

Kyoto international consensus report on anatomy, pathophysiology and clinical significance of the gastro-oesophageal junction

OBJECTIVE

An international meeting was organised to develop consensus on (1) the landmarks to define the gastro-oesophageal junction (GOJ), (2) the occurrence and pathophysiological significance of the cardiac gland, (3) the definition of the gastro-oesophageal junctional zone (GOJZ) and (4) the causes of inflammation, metaplasia and neoplasia occurring in the GOJZ.

DESIGN

Clinical questions relevant to the afore-mentioned major issues were drafted for which expert panels formulated relevant statements and textural explanations.A Delphi method using an anonymous system was employed to develop the consensus, the level of which was predefined as ≥80% of agreement. Two rounds of voting and amendments were completed before the meeting at which clinical questions and consensus were finalised.

RESULTS

Twenty eight clinical questions and statements were finalised after extensive amendments. Critical consensus was achieved: (1) definition for the GOJ, (2) definition of the GOJZ spanning 1 cm proximal and distal to the GOJ as defined by the end of palisade vessels was accepted based on the anatomical distribution of cardiac type gland, (3) chemical and bacterial (Helicobacter pylori) factors as the primary causes of inflammation, metaplasia and neoplasia occurring in the GOJZ, (4) a new definition of Barrett's oesophagus (BO).

CONCLUSIONS

This international consensus on the new definitions of BO, GOJ and the GOJZ will be instrumental in future studies aiming to resolve many issues on this important anatomic area and hopefully will lead to better classification and management of the diseases surrounding the GOJ.

Novel gel bolus to improve impedance-based measurements of esophageal cross-sectional area during primary peristalsis

INTRODUCTION

Intraluminal esophageal impedance (ILEE) has the potential to measure esophageal luminal distension during swallow-induced peristalsis in the esophagus. A potential cause of inaccuracy in the ILEE measurement is the swallow-induced air in the bolus.

AIM

Compare a novel gel bolus to the current alternatives for the measurement of impedance-based luminal distension (cross-sectional area, CSA) during primary peristalsis.

METHODS

12 healthy subjects were studied using high-resolution impedance manometry (HRMZ) and concurrently performed intraluminal ultrasound (US) imaging of the esophagus. Three test bolus materials were used: 1) novel gel, 2) 0.5 N saline, and 3) commercially available Diversatek EFTV viscous. Testing was performed in the supine and Trendelenburg (-15°) positions. US imaging assessed air in the bolus and luminal CSA. The Nadir impedance values were correlated to the US measured CSA. A custom Matlab software was used to assess the bolus travel times and impedance-based luminal CSA.

RESULTS

The novel gel bolus had the least amount of air in the bolus during its passage through the esophagus, as assessed by US image analysis. The novel gel bolus in the supine and Trendelenburg positions had the best linear fit between the US measured CSA and nadir impedance value (R²  = 0.88 & R²  = 0.90). The impedance-based calculation of the CSA correlated best with the US measured CSA with the use of the novel gel bolus.

CONCLUSION

We suggest the use of novel gel to assess distension along with contraction during routine clinical HRM testing.

Detecting Oropharyngeal and Esophageal Emptying by Submental Ultrasonography and High-Resolution Impedance Manometry: Intubated vs. Non-Intubated Video-Assisted Thoracoscopic Surgery

Postoperative swallowing, affected by general anesthesia and intubation, plays an important part in airway and oral intake safety regarding effective oropharyngeal and esophageal emptying. However, objective evidence is limited. This study aimed to determine the time required from emergence to effective oropharyngeal and esophageal emptying in patients undergoing non-intubated (N) or tracheal-intubated (I) video-assisted thoracoscopic surgery (VATS). Hyoid bone displacement (HBD) by submental ultrasonography and high-resolution impedance manometry (HRIM) measurements were used to assess oropharyngeal and esophageal emptying. HRIM was performed every 10 min after emergence, up to 10 times. The primary outcome was to determine whether intubation affects the time required from effective oropharyngeal to esophageal emptying. The secondary outcome was to verify if HBD is comparable to preoperative data indicating effective oropharyngeal emptying. Thirty-two patients suitable for non-intubated VATS were recruited. Our results showed that comparable HBDs were achieved in all patients after emergence. Effective esophageal emptying was achieved at the first HRIM measurement in 11 N group patients and 2 I group patients (p = 0.002) and was achieved in all N (100%) and 13 I group patients (81%) within 100 min (p = 0.23). HBD and HRIM are warranted for detecting postoperative oropharyngeal and esophageal emptying.

High-resolution impedance manometry measurement of bolus flow time in achalasia and its correlation with dysphagia

BACKGROUND

We assessed whether a high-resolution impedance manometry (HRIM) metric, bolus flow time (BFT) across the esophagogastric junction (EGJ), was abnormal in achalasia patients subtyped by the Chicago Classification and compared BFT to other HRM metrics.

METHODS

HRIM studies were performed in 60 achalasia patients (14 type I, 36 type II and 10 type III) and 15 healthy controls. Studies were analyzed with a MATLAB program to calculate BFT using a virtual HRIM sleeve. Integrated relaxation pressure (IRP) and basal end-expiratory EGJ pressure were also calculated. The relationship between BFT and dysphagia symptom scores was assessed using the impaction dysphagia questionnaire (IDQ).

KEY RESULTS

Median BFT was significantly lower in achalasia patients (0.5 s, range 0.0-3.5 s) compared to controls (3.5 s, range 2.0-5.0 s; p < 0.05). BFT was significantly lower in types I and II than in type III achalasia in both the supine and upright positions (p < 0.0001). BFT was the only HRIM metric significantly associated with IDQ score in both the supine (R(2)  = 0.20, p = 0.0046) and upright positions (R(2)  = 0.27, p = 0.0002).

CONCLUSIONS & INFERENCES

BFT was significantly reduced in all subtypes of achalasia and complementary to the IRP as a diagnostic discriminant in equivocal achalasia cases. Additionally, BFT had a more robust correlation with dysphagia severity compared to other metrics of EGJ function.

Flow time through esophagogastric junction derived during high-resolution impedance-manometry studies: a novel parameter for assessing esophageal bolus transit

This study aimed to develop and validate a method to measure bolus flow time (BFT) through the esophagogastric junction (EGJ) using a high-resolution impedance-manometry (HRIM) sleeve. Ten healthy subjects were studied with concurrent HRIM and videofluoroscopy; another 15 controls were studied with HRIM alone. HRIM studies were performed using a 4.2-mm-outer diameter assembly with 36 pressure sensors at 1-cm intervals and 18 impedance segments at 2-cm intervals (Given Imaging, Los Angeles, CA). HRIM and fluoroscopic data from four barium swallows, two in the supine and two in the upright position, were analyzed to create a customized MATLAB program to calculate BFT using a HRIM sleeve comprising three sensors positioned at the crural diaphragm. Bolus transit through the EGJ measured during blinded review of fluoroscopy was almost identical to BFT calculated with the HRIM sleeve, with the nadir impedance deflection point used as the signature of bolus presence. Good correlation existed between videofluoroscopy for measurement of upper sphincter relaxation to beginning of flow [R = 0.97, P < 0.001 (supine) and R = 0.77, P < 0.01 (upright)] and time to end of flow [R = 0.95, P < 0.001 (supine) and R = 0.82, P < 0.01 (upright)]. The medians and interquartile ranges (IQR) of flow time though the EGJ in 15 healthy subjects calculated using the virtual sleeve were 3.5 s (IQR 2.3-3.9 s) in the supine position and 3.2 s (IQR 2.3-3.6 s) in the upright position. BFT is a new metric that provides important information about bolus transit through the EGJ. An assessment of BFT will determine when the EGJ is open and will also provide a useful method to accurately assess trans-EGJ pressure gradients during flow.

Distension of the esophagogastric junction augments triggering of transient lower esophageal sphincter relaxation

Patients with gastroesophageal reflux disease show an increase in esophagogastric junction (EGJ) distensibility and in frequency of transient lower esophageal sphincter relaxations (TLESR) induced by gastric distension. The objective was to study the effect of localized EGJ distension on triggering of TLESR in healthy volunteers. An esophageal manometric catheter incorporating an 8-cm internal balloon adjacent to a sleeve sensor was developed to enable continuous recording of EGJ pressure during distension of the EGJ. Inflation of the balloon doubled the cross-section of the trans-sphincteric portion of the catheter from 5 mm OD (round) to 5 × 11 mm (oval). Ten healthy subjects were included. After catheter placement and a 30-min adaptation period, the EGJ was randomly distended or not, followed by a 45-min baseline recording. Subjects consumed a refluxogenic meal, and recordings were made for 3 h postprandially. A repeat study was performed on another day with EGJ distension status reversed. Additionally, in one subject MRI was performed to establish the exact position of the balloon in the inflated state. The number of TLESR increased during periods of EGJ distension with the effect being greater after a meal [baseline: 2.0(0.0-4.0) vs. 4.0(1.0-11.0), P=0.04; postprandial: 15.5(10.0-33.0) vs. 22.0(17.0-58.0), P=0.007 for undistended and distended, respectively]. EGJ distension augments meal-induced triggering of TLESR in healthy volunteers. Our data suggest the existence of a population of vagal afferents located at sites in/around the EGJ that may influence triggering of TLESR.

Factors influencing lower esophageal sphincter relaxation after deglutition

AIM

To study the relationship between upper esophageal sphincter (UES) relaxation, peristaltic pressure and lower esophageal sphincter (LES) relaxation following deglutition in non-dysphagic subjects.

METHODS

Ten non-dysphagic adult subjects had a high-resolution manometry probe passed transnasally and positioned to cover the UES, the esophageal body and the LES. Ten water swallows in each subject were analyzed for time lag between UES relaxation and LES relaxation, LES pressure at time of UES relaxation, duration of LES relaxation, the distance between the transition level (TL) and the LES, time in seconds that the peristaltic wave was before (negative value) or after the TL when the LES became relaxed, and the maximal peristaltic pressure in the body of the esophagus.

RESULTS

Relaxation of the LES occurred on average 3.5 s after the bolus had passed the UES and in most cases when the peristaltic wave front had reached the TL. The LES remained relaxed until the peristaltic wave faded away above the LES.

CONCLUSION

LES relaxation seemed to be caused by the peristaltic wave pushing the bolus from behind against the LES gate.

Detection of gastroesophageal reflux disease: advances in methodology

The incidence of gastroesophageal reflux disease (GERD) is increasing year by year. Currently, many methods are available for detection of GERD. Traditional detection methods, such as the reflux disease questionnaire and proton pump inhibitor test, are convenient and effective and can be used for primary screening of GERD. Endoscopy, chromoendoscopy, and magnification endoscopy have also been used widely in clinical detection of GERD. The usage of narrow-band imaging endoscopy, light-induced fluorescence endoscopy and confocal endoscopy offers new insight into the esophageal appearance of Barrett's esophagus and non-erosive reflux disease. Endoscopic optical coherence tomography and frequency-domain angle-resolved low-coherence interferometry are optical biopsy techniques that will be used gradually in clinical practice. The 24-hour esophageal pH monitoring, bile reflux monitoring, and esophageal manometry are the most commonly used method for monitoring gastroesophageal reflux but can not be used to monitor all reflux events. The 24-hour multichannel intraluminal impedance measurement and high-resolution manometry can redeem the shortage of the above detections and have been used gradually in clinical diagnosis. In this paper, we review the advances in methodology for detection of GERD.

Pediatric esophageal high-resolution manometry: utility of a standardized protocol and size-adjusted pressure topography parameters

OBJECTIVES

Esophageal high-resolution manometry (EHRM) has evolved rapidly from a research tool to a routine investigation in adult clinical practice. This study proposes and evaluates a standardized EHRM protocol for use in pediatric clinical practice.

METHODS

Thirty pediatric patients underwent unsedated EHRM. Indications for EHRM were dysphagia, feeding difficulty, or pre-fundoplication assessment. Two 20-channel customized water-perfused silicone catheters, with an outside diameter of 3.8 mm (MuiScientific, Ontario, CA), were used. The catheters had one distal gastric channel, five channels 0.5 cm apart for the e-sleeve, and 14 proximal channels either 1 cm (for children <5 years) or 2 cm apart (for children >5 years). Single wet swallows, multiple rapid swallows (MRS), and solid swallows were systematically studied.

RESULTS

The median age was 10 years (range 6 months-15 years). The esophageal motor findings were normal peristalsis (n=15), peristaltic dysfunction (n=12), achalasia (n=3), and spasm on consumption of solid food (n=2). The distal contractile integral adjusted for esophageal length (DCIa) of patients with peristaltic dysfunction was significantly lower than that of patients without peristaltic dysfunction (P<0.001). On MRS, aperistalsis with lack of esophagogastric junction (EGJ) relaxation was observed in patients with achalasia, and aperistalsis with complete EGJ relaxation was observed in patients with severe peristaltic dysfunction. On consumption of solid food, esophageal spasm associated with bolus impaction was observed in two patients.

CONCLUSIONS

This study provides objective information with regard to topography pressure parameters in esophageal motility disorders of childhood while using a standardized EHRM protocol. The new DCIa variable may be useful for the assessment of patients with peristaltic dysfunction.

Subcardial 24-h wireless pH monitoring in gastroesophageal reflux disease patients with and without hiatal hernia compared with healthy subjects

OBJECTIVES

After meals, highly acidic gastric juice is present in the subcardial region, the so-called acid pocket. Patients with gastroesophageal reflux disease (GERD) have a higher frequency of acidic reflux. Our aim was to investigate the possible differences in subcardial pH in GERD over 24 h and the role of hiatal hernia (HH), using a wireless capsule.

METHODS

A total of 14 healthy volunteers (4 men, 24-60 years), 10 GERD patients without HH (4 men, 25-68 years), and 11 GERD patients with HH >or=3 cm (2 men, 46-74 years) underwent 24-h wireless pH monitoring 2 cm below the squamocolumnar junction. All patients had increased 24-h acid reflux. A standardized lunch was given to all study subjects.

RESULTS

No capsule detached during the 24-h recording. Median 24-h pH was similar in healthy subjects, and in patients without and with HH, median: 1.4 (interquartile range: 1.2 -1.9), 1.5 (1.3 -1.7), and 1.4 (1.3 -1.7), respectively. Similar results were seen in the supine period. Median pH after the standardized meal was often highly acidic, 2.7 (1.5 - 3.2), 1.9 (1.6 - 2.3), and 2.5 (1.6 - 3.2), respectively. The first minute with a median pH <2 occurred 14 min (4 - 49), 14 min (6 - 25), and 20 min (4 - 43), respectively, P=NS, after the end of the meal. Similar data were observed on pooling all meals together.

CONCLUSIONS

Subcardial pH is confirmed to be highly acidic early after meals, but it is similar over 24 h in healthy subjects and GERD patients independent of the presence of HH.

Impaired air-liquid settling during swallowing in gastroesophageal reflux disease. A digital videofluoroscopic study

We hypothesize that the surface of the zone of air-liquid mixture in the esophagus after swallowing is the result of the esophageal gastric junction (EGJ) function or dysfunction. The aim of this study was to quantify the air-liquid components of the bolus in the esophagus and across the EGJ by means of digital videofluoroscopy sequences recorded in patients with gastroesophageal reflux disease (GERD). The patients were allocated to a Normo or a Hypo group, according to basal lower esophageal sphincter (LES) pressure. Two types of analysis were undertaken from the video sequences. For static analysis, maximal opening diameter of the LES and surfaces of air, air-barium mixture, and barium suspension were measured on two images extracted from each sequence. For dynamic analysis, transit times across the EGJ of the total bolus, air, mixture, and barium suspension were evaluated on a video sequence. For static analysis, the maximal opening diameter of the LES, air, and mixture surfaces were higher in the Hypo group. For dynamic analysis, transit time of total bolus, air, and mixture were longer in the Hypo group. The increase in mixture can be attributed to a defect in settling of both air and liquid phases in the esophagus in patients with low LES pressure and/or esophageal hypotonicity. Thus, these evaluations should provide information on the passage modalities of the bolus in esophagus and across the EGJ to assess differential diagnosis of GERD and hence to better select the most appropriate antireflux surgical procedure.

New technologies for the evaluation of esophageal motility disorders: impedance, high-resolution manometry, and intraluminal ultrasound

New technologies have been introduced for studying esophageal function, including intraluminal impedance and ultrasound, whereas conventional techniques, such as manometry, have undergone substantial upgrades because of advances in transducer technology, computerization, and graphic data presentation. Although these techniques provide both novel and more detailed information regarding esophageal function, it is still unclear whether they have improved the ability to diagnose and treat patients more effectively. Regardless, they are innovative research tools and they have added substantially to the understanding of the pathophysiology of dysphagia and esophageal motor dysfunction. This article describes the technical aspects of each of these technologies and the potential benefits they offer over conventional techniques for the evaluation of esophageal motor diseases.

Recent developments in esophageal motor disorders

PURPOSE OF REVIEW

Every year more insight into the pathogenesis and treatment of esophageal motor disorders is obtained. This review highlights some interesting literature published in this area during the last year.

RECENT FINDINGS

Longitudinal and circular muscle contractions act in a well coordinated fashion to allow normal peristalsis. Techniques such as intraluminal impedance, high-resolution manometry and intraluminal ultrasound provide useful additional information on esophageal function both in the normal and abnormal situation. The dynamics of the gastroesophageal junction can be studied with a newly developed probe, and the mechanism behind transient lower esophageal sphincter relaxations is still being unravelled. New manometric criteria for nutcracker esophagus have been proposed, whereas further evidence is reported supporting an association between diabetes mellitus and cardiovascular disease and esophageal dysmotility and spasm, respectively. Finally, several long-term follow-up results of surgical myotomy and pneumodilatation have been reported.

SUMMARY

Due to the perfection of esophageal measuring techniques, our knowledge of esophageal function continues to increase. The studies reviewed here provide interesting information on the pathogenesis and treatment of several esophageal motor disorders.

Transient lower esophageal sphincter relaxations and reflux: mechanistic analysis using concurrent fluoroscopy and high-resolution manometry

BACKGROUND & AIMS

The aim of this study was to perform a detailed analysis of the mechanics leading to esophagogastric junction (EGJ) opening during transient lower esophageal sphincter relaxations (tLESRs) using high-resolution manometry coupled with simultaneous fluoroscopy.

METHODS

Six subjects without hiatus hernia had endoclips placed at the squamocolumnar junction and 10 cm proximal. A 36-channel solid-state manometric assembly was placed spanning from stomach to pharynx, and subjects were studied for 2 hours after a high-fat meal. An esophageal pH electrode also was placed and fluoroscopy was initiated at the onset of a tLESR. Axial clip movement was measured during replay of the videotaped fluoroscopy and was correlated with manometric data.

RESULTS

Ninety-three tLESRs were recorded, 62 tLESRs of which had good fluoroscopic visualization. Seventy-eight tLESRs had manometric evidence of flow and the majority had evidence of a common cavity (88%), but few were detected by the pH electrode. Esophageal shortening and crural diaphragm inhibition always preceded EGJ opening and common cavity. A positive pressure gradient between the stomach and the EGJ lumen of 7.1 mm Hg (interquartile range, 4.1-9.1 mm Hg) preceded the EGJ opening.

CONCLUSIONS

Key events leading to the EGJ opening during tLESRs were LES relaxation, crural diaphragm inhibition, esophageal shortening, and a positive pressure gradient between the stomach and the EGJ lumen. The manometric signature of opening was pressure equalization within the EGJ, but this only occasionally was associated with pH evidence of reflux. Future investigations will need to analyze how this delicately balanced anatomic-physiologic system is perturbed in subjects with reflux disease.

Technological insights: Combined impedance manometry for esophageal motility testing-current results and further implications

This review focuses on current aspects of the novel technology of combined impedance manometry for esophageal motility testing. It presents methodological features, summarizes current results and discusses implications for further research. The combined technique assesses simultaneously bolus transport and associated peristalsis, thus allowing detailed analysis of the relationships between bolus transit and esophageal motility. Recent studies demonstrate that combined impedance manometry provides important additional information about esophageal motility as compared to conventional manometry: (1) monitoring of bolus transport patterns, (2) calculation of bolus transit parameters, (3) evaluation of bolus clearance, (4) monitoring of swallow associated events such as air movement and reflux, and (5) investigation of the relationships between bolus transit and LES relaxation. Studies with healthy subjects have identified several useful parameters for comprehensive assessment of eosphageal function. These parameters were found to be pathological in patients with classical achalasia, mild GERD, and ineffective esophageal motility. The technology of combined impedance manometry provides an important new tool for esophageal function testing, advancing both clinical and basic research. However, several important issues remain to be standardized to make the technique suitable for widely clinical use.

Functional oesophago-gastric junction imaging

Despite its role in disease there is still no definitive method to assess oesophago-gastric junction competence (OGJ). Traditionally the OGJ has been assessed using manometry with lower oesophageal sphincter pressure as the indicator. More recently this has been shown not to be a very reliable marker of sphincter function and competence against reflux. Disorders such as gastro-oesophageal reflux disease and to a lesser extend achalasia still effects a significant number of patients. This review looks at using a new technique known as impedance planimetry to profile the geometry and pressure in the OGJ during distension of a bag. The data gathered can be reconstructed into a dynamic representation of OGJ action. This has been shown to provide a useful representation of the OGJ and to show changes to the competence of the OGJ in terms of compliance and distensibility as a result of endoluminal therapy.

Technology Insight: the role of impedance testing for esophageal disorders

Classic techniques like videofluoroscopy, stationary manometry, and ambulatory 24 h pH-metry are routinely used in the clinic to study patients with dysphagia, chest pain and reflux-related symptoms. Although these techniques have been very useful over the years, both for diagnosis and for therapeutic guidance, there are still many patients with dysphagia or chest pain who remain undiagnosed even after testing, and patients with typical and atypical symptoms of gastroesophageal reflux disease, with normal pH-metry findings, who do not respond adequately to antisecretory therapy. Esophageal impedance monitoring is a new technique that can be used alone and in combination with pH-metry and manometry to evaluate bolus transport and all types of gastroesophageal reflux (acid and nonacid). This review describes the esophageal impedance monitoring technique and summarizes the published validation studies that compare impedance monitoring with other methods, as well as normal values and reproducibility of impedance patterns and their association with symptoms.

Transient lower esophageal sphincter relaxations do not result from passive opening of the cardia by gastric distention

BACKGROUND & AIMS

Transient lower esophageal sphincter relaxation is the main mechanism for gastroesophageal reflux. Although there is evidence that transient lower esophageal sphincter relaxations are neurally mediated, another school of thought is that transient lower esophageal sphincter relaxations result from gastric distention, which shortens the sphincter to the point where it opens and the pressure decreases. We assessed the relationship of transient lower esophageal sphincter relaxation to gastroesophageal junction opening in an unsedated human model.

METHODS

Seven healthy volunteers (6 men and 1 woman, aged 18-53 years) were studied while they were sitting. Manometry was performed by using a sleeve catheter passed through 1 nostril. A 5.3-mm endoscope was placed through the other nostril to obtain a retroflexed view of the cardia. The biopsy channel was connected to a barostat to distend the stomach with air at 15 mm Hg for 30 minutes. Manometric and endoscopic video-recording times were synchronized but scored independently.

RESULTS

The transient lower esophageal sphincter relaxation onset invariably preceded gastroesophageal junction opening (median, 5.0 seconds; range, 0.5-20.7 seconds; P < .001). The transient lower esophageal sphincter relaxation nadir also typically occurred before gastroesophageal junction opening (median, 2.1 seconds; range, -4.2 to +19.5 seconds; P < .001). Once open, the gastroesophageal junction moved proximally for the duration of the transient lower esophageal sphincter relaxation. Termination of transient lower esophageal sphincter relaxations occurred about the time the time of gastroesophageal junction closure.

CONCLUSIONS

These data refute the hypothesis that transient lower esophageal sphincter relaxations result from passive mechanical distraction of the gastroesophageal junction. Rather, transient lower esophageal sphincter relaxations must occur before the gastroesophageal junction can open.