Esophagogastric junction distensibility assessed with an endoscopic functional luminal imaging probe (EndoFLIP)

Achalasia

Achalasia is a rare motility disorder of the oesophagus characterised by loss of enteric neurons leading to absence of peristalsis and impaired relaxation of the lower oesophageal sphincter. Although its cause remains largely unknown, ganglionitis resulting from an aberrant immune response triggered by a viral infection has been proposed to underlie the loss of oesophageal neurons, particularly in genetically susceptible individuals. The subsequent stasis of ingested food not only leads to symptoms of dysphagia, regurgitation, chest pain, and weight loss, but also results in an increased risk of oesophageal carcinoma. At present, pneumatic dilatation and Heller myotomy combined with an anti-reflux procedure are the treatments of choice and have comparable success rates. Per-oral endoscopic myotomy has recently been introduced as a new minimally invasive treatment for achalasia, but there have not yet been any randomised clinical trials comparing this option with pneumatic dilatation and Heller myotomy.

Acta from the EndoFLIP® Symposium

Laparoscopic fundoplication (LF) is a surgical treatment for gastroesophageal reflux disease (GERD) that has been performed for more than 20 years. High-volume centers of excellence report long-term success rates greater than 90% with LF. On the other hand, general population-based outcomes are reported to be markedly worse, leading to a nihilistic perception of the procedure on the part of the medical referral population. The lack of standardization of the technique and the lack of tools to calibrate objectively the repairs are probably among the causes of variability in the outcomes and may explain the decline in the number of LF procedures in recent years. The functional lumen imaging probe (EndoFLIP(®)) device is essentially a "smart bougie" in the form of a balloon catheter that measures shape and compliance of the gastroesophageal junction (GEJ) during surgery using impedance planimetry. With approximately 3 years of international experience gained with this tool, a symposium was convened in October 2012 in Strasbourg, France, with the aim of determining if intraoperative EndoFLIP use could provide standardization of surgical treatment of GERD through the understanding of physiological changes occurring to the GEJ during fundoplication. This article provides a brief history of the EndoFLIP system and reviews data previously published on the use of EndoFLIP to characterize the GEJ in normal subjects. It then summarizes the data from the 5 high-volume international sites with expert surgeons performing LF presented in Strasbourg to objectively profile the characteristics of a normal postoperative GEJ.

Measurement of esophago-gastric junction cross-sectional area and distensibility by an endolumenal functional lumen imaging probe for the diagnosis of gastro-esophageal reflux disease

BACKGROUND

Measurement of esophago-gastric junction (EGJ) cross-sectional area (CSA) and distensibility by an Endolumenal Functional Lumen Imaging Probe (EndoFLIP®) may distinguish between gastro-esophageal reflux disease (GERD) patients and healthy volunteers (HV). We aimed to assess the agreement of EndoFLIP® measurements with clinical and physiologic diagnosis of GERD.

METHODS

Twenty-one HV and 18 patients with typical GERD symptoms were studied. After gastroscopy, EGJ CSA, and distensibility were measured by EndoFLIP®. Forty-eight hour esophageal pH monitoring was then performed by a wireless system. The ability of EndoFLIP® to discriminate GERD patient and HVs was assessed. Planned secondary analysis then assessed whether EGJ CSA and distensibility were increased in individuals with pathologic acid exposure.

KEY RESULTS

Healthy volunteers were younger and had lower body mass index (BMI; both p < 0.001). Pathologic acid exposure was present in 3/21 (14%) HVs and 9/18 (50%) patients (p = 0.126). At 30 mL EndoFLIP® bag volume, EGJ CSA was higher (p = 0.058) and EGJ distensibility was lower (p = 0.020) in HVs than patients. Secondary analysis showed that EGJ measurements were similar in participants with and without pathologic acid exposure (CSA 98 mm² vs 107 mm²; p = 0.789, distensibility; p = 0.704). An inverse association between BMI and CSA (R² = 0.2758, p = 0.001) and distensibility (R² = 0.2005, p = 0.005) was present.

CONCLUSIONS & INFERENCES

Endolumenal Functional Lumen Imaging Probe is not useful for GERD diagnosis because EGJ CSA and distensibility do not distinguish between HVs and GERD patients defined by clinical presentation or pH measurement. This unexpected result may be due to an important, confounding interaction of obesity.

Regional variation in distal esophagus distensibility assessed using the functional luminal imaging probe (FLIP)

BACKGROUND

This study aimed to evaluate the spatial variation in esophageal distensibility in normal subjects using a novel multichannel functional luminal imaging probe (FLIP).

METHODS

Ten healthy subjects (four men, age 21-49 years) were evaluated during endoscopy with a high-resolution impedance planimetry probe (FLIP) positioned through the esophagogastric junction (EGJ) and distal 10 cm of the esophageal body. Stepwise bag distensions using 5-mL increments from 0 to 60 mL were conducted, and simultaneous measurements of cross-sectional area (CSA) and the associated intrabag pressure from each subject were analyzed using a customized MATLAB™ program. The distensibility along the esophagus was determined and compared between the EGJ and interval locations at 2-5 cm and 6-10 cm above the EGJ.

KEY RESULTS

The pressure-CSA relationship was nearly linear among sites at lower pressures (0 to 7.5 mmHg) and reached a distension plateau at pressures ranging from 8 to 24 mmHg. The location of greatest distensibility was 4 cm above the EGJ. Although the CSAs of individual recording loci were not significantly different, there was a significant difference between the mean CSAs when comparing the region 2 to 5 cm proximal to EGJ with that 6 to 10 cm proximal to the EGJ.

CONCLUSIONS & INFERENCES

There were significant regional differences in distensibility along the distal esophagus with lower values in the proximal part compared with more distal part. The greatest distensibility was noted to occur at about 4 cm above the EGJ in close proximity to the location of the contractile deceleration point and phrenic ampulla.

Effect of transoral incisionless fundoplication on reflux mechanisms

OBJECTIVES

Transoral incisionless fundoplication (TIF) is a new endoscopic treatment option for gastroesophageal reflux disease (GERD). The mechanisms underlying the anti-reflux effect of this new procedure have not been studied. We therefore conducted this explorative study to evaluate the effect of TIF on reflux mechanisms, focusing on transient lower esophageal sphincter relaxations (TLESRs) and esophagogastric junction (EGJ) distensibility.

METHODS

GERD patients (N = 15; 11 males, mean age 41 years, range 23-66), dissatisfied with medical treatment were studied before and 6 months after TIF. We performed 90-min postprandial combined high-resolution manometry and impedance-pH monitoring and an ambulatory 24-h pH-impedance monitoring. EGJ distensibility was evaluated using an endoscopic functional luminal imaging probe before and directly after the procedure.

RESULTS

TIF reduced the number of postprandial TLESRs (16.8 ± 1.5 vs. 9.2 ± 1.3; p < 0.01) and the number of postprandial TLESRs associated with reflux (11.1 ± 1.6 vs. 5.6 ± 0.6; p < 0.01), but the proportion of TLESRs associated with reflux was unaltered (67.6 ± 6.9 vs. 69.9 ± 6.3 %). TIF also led to a decrease in the number and proximal extent of reflux episodes and an improvement of acid exposure in the upright position; conversely, TIF had no effect on the number of gas reflux episodes. EGJ distensibility was reduced after the procedure (2.4 ± 0.3 vs. 1.6 ± 0.2 mm(2)/mmHg; p < 0.05).

CONCLUSIONS

TIF reduced the number of postprandial TLESRs, the number of TLESRs associated with reflux and EGJ distensibility. This resulted in a reduction of the number and proximal extent of reflux episodes and improvement of acid exposure in the upright position. The anti-reflux effect of TIF showed to be selective for liquid-containing reflux only, thereby preserving the ability of venting gastric air.

Review on novel concepts of columnar lined esophagus

BACKGROUND

Columnar lined esophagus (CLE) is a marker for gastroesophageal reflux and associates with an increased cancer risk among those with Barrett's esophagus. Recent studies fostered the development of integrated CLE concepts.

METHODS

Using PubMed, we conducted a review of studies on novel histopathological concepts of nondysplastic CLE.

RESULTS

Two histopathological concepts-the squamo-oxyntic gap (SOG) and the dilated distal esophagus (DDE), currently model our novel understanding of CLE. As a consequence of reflux, SOG interposes between the squamous lined esophagus and the oxyntic mucosa of the proximal stomach. Thus the SOG describes the histopathology of CLE within the tubular esophagus and the DDE, which is known to develop at the cost of a shortened lower esophageal sphincter and foster increased acid gastric reflux. Histopathological studies of the lower end of the esophagus indicate, that the DDE is reflux damaged, dilated, gastric type folds forming esophagus and cannot be differentiated from proximal stomach by endoscopy. While the endoscopically visible squamocolumnar junction (SCJ) defines the proximal limit of the SOG, the assessment of the distal limit requires the histopathology of measured multilevel biopsies. Within the SOG, CLE types distribute along a distinct zonation with intestinal metaplasia (IM; Barrett's esophagus) and/or cardiac mucosa (CM) at the SCJ and oxyntocardiac mucosa (OCM) within the distal portion of the SOG. The zonation follows the pH-gradient across the distal esophagus. Diagnosis of SOG and DDE includes endoscopy, histopathology of measured multi-level biopsies from the distal esophagus, function, and radiologic tests. CM and OCM do not require treatment and are surveilled in 5 year intervals, unless they associate with life quality impairing symptoms, which demand medical or surgical therapy. In the presence of an increased cancer risk profile, it is justified to consider radiofrequency ablation (RFA) of IM within clinical studies in order to prevent the progression to dysplasia and cancer. Dysplasia justifies RFA ± endoscopic resection.

CONCLUSIONS

SOG and DDE represent novel concepts fusing the morphological and functional aspects of CLE. Future studies should examine the impact of SOG and DDE for monitoring and management of gastroesophageal reflux disease (GERD).

Comparison of esophagogastric junction distensibility changes during POEM and Heller myotomy using intraoperative FLIP

BACKGROUND

Peroral endoscopic myotomy (POEM) is a novel endoscopic surgical procedure for the treatment of achalasia. The comparative effects of POEM and laparoscopic Heller myotomy (LHM) on esophagogastric junction (EGJ) physiology are unknown. A novel measurement catheter, the functional lumen imaging probe (FLIP), allows for intraoperative evaluation of EGJ compliance by measuring luminal geometry and pressure during volume-controlled distensions.

METHODS

Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by pressure) was measured with FLIP intraoperatively in patients undergoing LHM and POEM. Separate measurements were taken after each operative step. During LHM, measurements were performed after: (1) induction of anesthesia, (2) insufflation of pneumoperitoneum, (3) hiatal dissection and esophageal mobilization, (4) myotomy, (5) partial fundoplication, and (6) deinsufflation. During POEM, they were performed after: (1) induction of anesthesia, (2) submucosal tunnel creation, and (3) myotomy.

RESULTS

Eleven LHM and 14 POEM patients underwent intraoperative FLIP. Baseline DI was similar between groups. LHM resulted in an overall increase in mean DI (pre 1.4 vs. post 7.6 mm(2)/mmHg, using a 40-ml distension volume; p < 0.001). Insufflation of pneumoperitoneum and hiatal dissection did not affect DI. Myotomy caused an increase in DI. Partial fundoplication (6 Toupet, 5 Dor) caused a decrease in DI, and deinsufflation caused an increase in DI. POEM also resulted in an overall increase in mean DI (pre 1.4 vs. post 7.9 mm(2)/mmHg; p < 0.001). Measured individually, both submucosal tunnel creation and myotomy caused increases in DI. When overall changes were compared, there were no differences in the amount of DI increase between LHM and POEM.

CONCLUSIONS

POEM and LHM result in a similar improvement in EGJ distensibility intraoperatively. Further study is needed to correlate intraoperative FLIP measurements with postoperative symptomatic and physiologic outcomes.

Esophageal distensibility as a measure of disease severity in patients with eosinophilic esophagitis

BACKGROUND & AIMS

The aim of this study was to assess whether measurements of esophageal distensibility, made by high-resolution impedance planimetry, correlated with important clinical outcomes in patients with eosinophilic esophagitis.

METHODS

Seventy patients with eosinophilic esophagitis (50 men; age, 18-68 y) underwent endoscopy with esophageal biopsy collection and high-resolution impedance planimetry using the functional lumen-imaging probe. The patients were followed up prospectively for an average of 9.2 months (range, 3-14 mo), and the risk of food impaction, requirement for dilation, and symptom severity during the follow-up period was determined from medical records. Esophageal distensibility metrics and the severity of mucosal eosinophilia at baseline were compared between patients presenting with and without food impaction and those requiring or not requiring esophageal dilation. Logistic regression and stratification assessments were used to assess the predictive value of esophageal distensibility metrics in assessing risk of food impaction, the need for dilation, and continued symptoms.

RESULTS

Patients with prior food impactions had significantly lower distensibility plateau (DP) values than those with solid food dysphagia alone. In addition, patients sustaining food impaction and requiring esophageal dilation during the follow-up period had significantly lower DP values than those who did not. The severity of mucosal eosinophilia did not correlate with risk for food impaction, the requirement for dilation during follow-up evaluation, or DP values.

CONCLUSIONS

Reduced esophageal distensibility predicts risk for food impaction and the requirement for esophageal dilation in patients with eosinophilic esophagitis. The severity of mucosal eosinophilia was not predictive of these outcomes and had a poor correlation with esophageal distensibility.

Feasibility of esophagogastric junction distensibility measurement during Nissen fundoplication

Increased esophagogastric junction distensibility has been implicated in the development of gastroesophageal reflux disease (GERD). Previous authors have demonstrated a reduction in distensibility following anti-reflux surgery, but the changes during the operation are not clear. Our study aimed to ascertain the feasibility of measuring intraoperative distensibility changes and to assess if this would have potential to modify the operation. Seventeen patients with GERD were managed in a standardized manner consisting of preoperative assessment with symptom scoring, endoscopy, 24 hours pH studies, and manometry. Patients then underwent laparoscopic Nissen fundoplication with intraoperative distensibility measurement using an EndoFLIP EF-325 functional luminal imaging probe (Crospon Ltd, Galway, Ireland). This device utilizes impedance planimetry technology to measure cross-sectional area and distensibility within a balloon-tipped catheter. This is inflated at the esophagogastric junction to fixed distension volumes. Thirty-second median cross-sectional area and intraballoon pressure measurements were recorded at 30 and 40 mL balloon distensions. Measurement time points were initially after induction of anesthesia, after pneumoperitoneum, after hiatal mobilization, after hiatal repair, after fundoplication, and finally pre-extubation. Postoperatively, patients continued on protocol and were discharged after a two-night stay tolerating a sloppy diet. Patients with a hiatus hernia on high-resolution manometry had a significantly higher initial esophagogastric junction distensibility index (DI) than those without. Hiatus repair and fundoplication resulted in a significant overall reduction in the median DI from the initial to final recordings (30 mL balloon distension reduction of 3.26 mm(2) /mmHg (P = 0.0087), 40 mL balloon distension reduction of 2.39 mm(2) /mmHg [P = 0.0039]). There was also a significant reduction in the DI after pneumoperitoneum, hiatus repair, and fundoplication at 40 mL balloon distension. Two individual cases in the series highlight the utility of the system in potentially changing the operation. After fundoplication, patient 7 recorded a DI of 0.47 mm(2) /mmHg, the lowest in our series, and subsequently required reoperation because of significant symptoms of dysphagia. Patient 12 had a fundoplication that appeared visually too tight and was converted intraoperatively to a Lind 270° wrap resulting in a change in the DI from 0.65 to 0.89 mm(2) /mmHg. Laparoscopic Nissen fundoplication results in a significant reduction in the distensibility of the esophagogastric junction. The EndoFLIP system is able to demonstrate significant changes during the operation and may help guide intraoperative modification. Larger multicenter studies with long-term follow up would be beneficial to develop a target range of distensibility associated with good outcome.

Advances in motility testing--current and novel approaches

Disorders of gastrointestinal motility are frequently seen in clinical practice. Apart from motility disorders, factors leading to lowered visceroperception thresholds are recognized as commonly involved in the pathogenesis of functional gastrointestinal disorders. The wide array of gastrointestinal motility and viscerosensitivity tests available is in contrast with the relatively limited number of tests used universally in clinical practice. The main reason for this discrepancy is that the outcome of a test only becomes truly important when it carries clinical consequences. The main goal of this Review is to assess the place of the presently available gastrointestinal motility and sensitivity tests in the clinical armamentarium of the gastroenterologist.

A study of pathophysiological factors associated with gastro-esophageal reflux disease in twins discordant for gastro-esophageal reflux symptoms

BACKGROUND

Differences in lower esophageal sphincter (LES) and peristaltic function and in transient LES relaxations (TLESR) have been described in patients with gastro-esophageal reflux disease (GERD). However, some of these differences may be the result of chronic GERD rather than being an underlying contributory factor.

METHODS

Twins discordant for GERD symptoms, i.e., only one twin had GERD symptoms, underwent standard LES and esophageal body manometry, and then using a sleeve sensor prolonged LES and pH monitoring, 30 min before and 60 min after a 250 mL 1200 kcal lipid meal.

KEY RESULTS

Eight monozygotic and 24 dizygotic female twins were studied. Although there was no difference in preprandial LES pressure (symptomatic 13.2 ± 7.1 mmHg vs asymptomatic 15.1 ± 6.2 mmHg, P = 0.4), LES pressure fell further postprandially in symptomatic twins (LES pressure area under the curve 465 ± 126 vs 331 ± 141 mmHg h, P < 0.01). 12/37 (32%) of acid reflux episodes in symptomatic twins occurred due to low LES pressure or deep inspiration/strain and 0/17 in asymptomatic twins (P = 0.01). There was no difference between symptomatic and asymptomatic twins in: peristaltic amplitude, ineffective esophageal body motility, hiatus hernia prevalence, or LES length. There was also no difference in TLESR frequency preprandially (symptomatic median 1(range 0-2) vs asymptomatic 0(0-2), P = 0.08) or postprandially (2.5(1-8) vs 3(1-6), P = 0.81).

CONCLUSIONS & INFERENCES

Twins with GERD symptoms had lower postprandial LES pressure and given the close genetic link between the twins, it is possible that such differences are caused by GERD. Acid reflux episodes associated with a hypotensive LES were seen in symptomatic, but not in asymptomatic twins.

Effect of peroral endoscopic myotomy on esophagogastric junction physiology in patients with achalasia

BACKGROUND

Pneumatic dilation and laparoscopic Heller myotomy improve parameters of esophageal function such as lower esophageal sphincter (LES) pressure, esophageal emptying, and esophagogastric junction (EGJ) distensibility.

OBJECTIVE

To evaluate the effect of peroral endoscopic myotomy (POEM) on esophagogastric function.

DESIGN

Prospective trial.

SETTING

Endoscopy department at a university hospital.

PATIENTS

All consecutive patients aged >17 years with achalasia and an Eckardt score of ≥3.

INTERVENTION

Before and 3 months after POEM, 10 consecutive patients underwent esophageal manometry, timed barium esophagograms, and EndoFLIP as well as an EGD.

MAIN OUTCOME MEASUREMENTS

Eckardt symptom score, LES resting pressure, centimeters of barium stasis, EGJ distensibility, and reflux esophagitis.

RESULTS

Compared with scores before POEM, patient symptom scores were significantly reduced (1, interquartile range [IQR 0-1] vs 8 [IQR 4-8]; P = .005). LES pressure decreased significantly (6.0 mm Hg [IQR 2.6-7.4] vs 19.0 mm Hg [IQR 13.0-28.0]; P = .008). Esophageal emptying increased significantly, and a 5-minute barium column measured 2.3 cm (IQR 0-3.2 cm) versus 10.1 cm (IQR 5.7-10.8 cm; P = .005). EGJ distensibility increased significantly (6.7 mm(2)/mm Hg [IQR 3.8-16.6] vs 1.0 mm(2)/mm Hg [IQR 0.4-2.3]; P = .02) at 50 mL. In 6 of 10 patients, reflux esophagitis was seen. Of these patients, 3 reported reflux symptoms.

LIMITATIONS

Small number of patients, short-term follow-up.

CONCLUSION

POEM improves esophagogastric function and suggests favorable long-term results based on Eckardt score, esophageal manometry, esophageal emptying, and EGJ distensibility. Long-term follow-up of larger series will determine whether the high rate of reflux esophagitis affects the clinical application of POEM.

Distensibility of the esophagogastric junction assessed with the functional lumen imaging probe (FLIP™) in achalasia patients

BACKGROUND

The functional lumen imaging probe (FLIP), measures esophagogastric junction (EGJ) distensibility (cross-sectional area/luminal pressure) during volume-controlled distension. The aim of this study is to apply this tool to the assessment of the EGJ in untreated and treated achalasia patients and to compare EGJ distensibility with other diagnostic tools utilized in managing achalasia.

METHODS

Findings from FLIP, high-resolution manometry (HRM), timed barium esophagram, and symptom assessment by Eckardt Score (ES) were compared in 54 achalasia patients (23 untreated, 31 treated). Twenty healthy volunteers underwent FLIP as a comparator group. The EGJ distensibility index (EGJ-DI) was defined at the 'waist' of the FLIP bag during volumetric distension, expressed in mm(2)  mmHg(-1) . The ES was used to gauge treatment outcome: good response < 3 or poor response ≥ 3.

KEY RESULTS

Of the 31 treated patients, 17 had good and 14 poor treatment response. The EGJ-DI was significantly different among groups, greatest in the control subjects and least in the untreated patients; patients with good treatment response had significantly greater EGJ-DI than untreated or patients with poor response. The correlations between EGJ-DI and ES and integrated relaxation pressure on HRM were significant.

CONCLUSIONS & INFERENCES

The FLIP provided a useful measure of EGJ distensibility in achalasia patients that correlated with symptom severity. The measurement of EGJ distensibility was complementary to existing tests suggesting a potentially important role in the clinical management of achalasia.

Esophageal dilation with integrated balloon imaging: initial evaluation in a porcine model

BACKGROUND

When treating achalasia, balloon dilation is often combined with fluoroscopy to allow the lower esophageal sphincter to be visualized as it is being dilated. We sought to evaluate a new balloon dilation technology, EsoFLIP, which allows the shape of the balloon to be visualized in a nonradiographic manner by using impedance planimetry electrodes located within the dilation balloon.

METHODS

Two pigs weighing 35 kg were used. The EsoFLIP balloon dilator was introduced under endoscopic visualization. Successive injections of 50, 60, 70 and 85 mL into the dilation balloon permitted dilations at increasing diameters to be achieved. Following each dilation fluid was withdrawn to leave 30 mL in the balloon and an EsoFLIP image was captured to track progressive dilation of the gastroesophageal junction (GEJ).

RESULTS

The EsoFLIP catheter was safely deployed in the two pigs and no complications were noted. For pig 1, during dilation, the measured balloon diameter at the waist was 24.1, 28.9, 29.2 and 30.0 mm for balloon dilation volumes of 50, 60, 70 and 85 mL respectively. For pig 2 the corresponding diameter at the waist was 22.8, 27.1, 28.5 and 29.4 mm. The GEJ diameter increased from 12.5 and 12.4 mm to 17.4 and 17.5mm for pigs 1 and 2 respectively. Distensibility of the GEJ in pig 1 increased from 2.3 mm(2)/mmHg before to 4.4 mm(2)/mmHg after dilation and in pig 2 from 4.4 to 9.6 mm(2)/mmHg. The GEJ substantively achieved its final diameter after the dilation using just 50 mL in the balloon.

CONCLUSIONS

We demonstrated technical feasibility and safety of the EsoFLIP dilator in a porcine model. Further studies in humans with achalasia remain to be conducted, which, besides demonstrating technical feasibility, should also evaluate the use of distensibility measurements taken during dilation to predict outcomes.

Endoscopic approaches to treatment of achalasia

Endoscopic therapy for achalasia is directed at disrupting or weakening the lower esophageal sphincter (LES). The two most commonly utilized endoscopic interventions are large balloon pneumatic dilation (PD) and botulinum toxin injection (BTI). These interventions have been extensively scrutinized and compared with each other as well as with surgical disruption (myotomy) of the LES. PD is generally more effective in improving dysphagia in achalasia than BTI, with the latter reserved for infirm older people, and PD may approach treatment results attained with myotomy. However, PD may need to be repeated. Small balloon dilation and endoscopic stent placement for achalasia have only been used in select centers. Per oral endoscopic myotomy is a newer endoscopic modality that will likely change the treatment paradigm for achalasia. It arose from the field of natural orifice transluminal endoscopic surgery and represents a scarless endoscopic approach to Heller myotomy. This is a technique that requires extensive training and preparation and thus there should be rigorous accreditation and monitoring of outcomes to ensure safety and efficacy.

Intraoperative assessment of esophagogastric junction distensibility during per oral endoscopic myotomy (POEM) for esophageal motility disorders

BACKGROUND

Per oral endoscopic myotomy (POEM) is a novel treatment for esophageal motility disorders such as achalasia. To date, the extent of the myotomy has been determined based on the subjective assessment of the endoscopist. We hypothesized that the real-time measurement of esophagogastric junction (EGJ) distensibility using a novel functional lumen-imaging probe would enable objective evaluation of POEM.

METHODS

Patients diagnosed with achalasia disorders electively underwent POEM. Using impedance planimetry with a transorally inserted functional lumen-imaging probe (EndoFLIP), cross-sectional areas (CSA) and distensibilities at the EGJ were measured intraoperatively immediately before and after the transoral myotomy (n = 4). All patients completed their 6-month follow-up and two patients had repeat distensibility tests at this time. Four healthy volunteers served as a control group.

RESULTS

POEM was successfully performed in all patients (4/4). Premyotomy measurements (40-ml fill mode) showed a median diameter of 6.5 mm (range = 5.2-7.9 mm) at the narrowest location of the EGJ and was 10.1 mm (7.3-13.2 mm) following POEM. CSA increased from 41.5 mm(2) (20-49 mm(2)) to 86 mm(2) (41-137 mm(2)) at a similar median intraballoon pressure (40.3 vs. 38.6 mmHg). The increased EGJ distensibility (DI, 1.0 vs. 2.4 mm(2)/mmHg) was comparable to that of healthy volunteers (2.7 mm(2)/mmHg).

CONCLUSION

Functional lumen distensibility measures show that POEM can result in an immediate correction of the nonrelaxing lower esophageal sphincter, which appears similar to that of healthy controls. Intraoperative EGJ profiling may be an important tool to objectively guide the needed extent and completeness of the myotomy during POEM.

Intraoperative assessment of esophagogastric junction distensibility during per oral endoscopic myotomy (POEM) for esophageal motility disorders

BACKGROUND

Per oral endoscopic myotomy (POEM) is a novel treatment for esophageal motility disorders such as achalasia. To date, the extent of the myotomy has been determined based on the subjective assessment of the endoscopist. We hypothesized that the real-time measurement of esophagogastric junction (EGJ) distensibility using a novel functional lumen-imaging probe would enable objective evaluation of POEM.

METHODS

Patients diagnosed with achalasia disorders electively underwent POEM. Using impedance planimetry with a transorally inserted functional lumen-imaging probe (EndoFLIP), cross-sectional areas (CSA) and distensibilities at the EGJ were measured intraoperatively immediately before and after the transoral myotomy (n = 4). All patients completed their 6-month follow-up and two patients had repeat distensibility tests at this time. Four healthy volunteers served as a control group.

RESULTS

POEM was successfully performed in all patients (4/4). Premyotomy measurements (40-ml fill mode) showed a median diameter of 6.5 mm (range = 5.2-7.9 mm) at the narrowest location of the EGJ and was 10.1 mm (7.3-13.2 mm) following POEM. CSA increased from 41.5 mm(2) (20-49 mm(2)) to 86 mm(2) (41-137 mm(2)) at a similar median intraballoon pressure (40.3 vs. 38.6 mmHg). The increased EGJ distensibility (DI, 1.0 vs. 2.4 mm(2)/mmHg) was comparable to that of healthy volunteers (2.7 mm(2)/mmHg).

CONCLUSION

Functional lumen distensibility measures show that POEM can result in an immediate correction of the nonrelaxing lower esophageal sphincter, which appears similar to that of healthy controls. Intraoperative EGJ profiling may be an important tool to objectively guide the needed extent and completeness of the myotomy during POEM.

Functional luminal imaging probe: a new technique for dynamic evaluation of mechanical properties of the anal canal

BACKGROUND

The muscle structures surrounding the anal canal are of major importance in maintaining continence but their anatomy and function vary along its length. Standard manometry does not provide detailed information about mechanical properties of the anal canal. A new functional luminal imaging probe (FLIP) has been developed for this purpose. The aim of our study was to investigate whether FLIP allows detailed evaluation of dynamic biomechanical properties along the length of the anal canal.

METHODS

The in vitro validity and reproducibility of the FLIP system were tested. Fifteen healthy volunteers (age 32-65 years, mean 51 years), of whom 12 were females, were investigated. The integrity and dimensions of the anal sphincter apparatus were evaluated with endoanal ultrasonography and standard anal manometry. During standardized distensions with the FLIP, 16 cross-sectional areas of the anal canal were measured at 5-mm intervals. Distensibility of the following three segments was evaluated: upper anal canal (surrounded by the internal anal sphincter and the puborectalis muscle), mid-anal canal (surrounded by the internal anal sphincter and the external anal sphincter) and lower anal canal (surrounded by the external anal sphincter). Color contour plots were generated from the FLIP-based dynamic recordings of serial cross-sections.

RESULTS

In vitro tests confirmed the validity and reproducibility of the FLIP system. The luminal geometry during distension and the biomechanical properties of the anal canal differed at the three levels. Both at rest and during squeeze the mid-anal canal was significantly less distensible than the upper (p < 0.01) and the lower (p < 0.05) anal canal.

CONCLUSIONS

FLIP is a promising method for evaluation of the nonhomogeneous biomechanical properties along the length of the anal canal.

Efficacy of treatment for patients with achalasia depends on the distensibility of the esophagogastric junction

BACKGROUND & AIMS

Many patients with persistent dysphagia and regurgitation after therapy have low or no lower esophageal sphincter (LES) pressure. Distensibility of the esophagogastric junction (EGJ) largely determines esophageal emptying. We investigated whether assessment of the distensibility of the EGJ is a better and more integrated parameter than LES pressure for determining efficacy of treatment for patients with achalasia.

METHODS

We measured distensibility of the EGJ using an endoscopic functional luminal imaging probe (EndoFLIP) in 15 healthy volunteers (controls; 8 male; age, 40 ± 4.1 years) and 30 patients with achalasia (16 male; age, 51 ± 3.1 years). Patients were also assessed by esophageal manometry and a timed barium esophagogram. Symptom scores were assessed using the Eckardt score, with a score <4 indicating treatment success. The effect of initial and additional treatment on distensibility and symptoms was evaluated in 7 and 5 patients, respectively.

RESULTS

EGJ distensibility was significantly reduced in untreated patients with achalasia compared with controls (0.7 ± 0.9 vs 6.3 ± 0.7 mm(2)/mm Hg; P < .001). In patients with achalasia, EGJ distensibility correlated with esophageal emptying (r = -0.72; P < .01) and symptoms (r = 0.61; P < .01) and was significantly increased with treatment. EGJ distensibility was significantly higher in patients successfully treated (Eckardt score <3) compared with those with an Eckardt score >3 (1.6 ± 0.3 vs 4.4 ± 0.5 mm(2)/mm Hg; P = .001). Even when LES pressure was low, EGJ distensibility could be reduced, which was associated with impaired emptying and recurrent symptoms.

CONCLUSIONS

EGJ distensibility is impaired in patients with achalasia and, in contrast to LES pressure, is associated with esophageal emptying and clinical response. Assessment of EGJ distensibility by EndoFLIP is a better parameter than LES pressure for evaluating efficacy of treatment for achalasia.

Esophageal motor disorders: how to bridge the gap between advanced diagnostic tools and paucity of therapeutic modalities?

High-resolution manometry has added significantly to our current understanding of esophageal motor function by providing improved detail and a data analysis paradigm that is more akin to an imaging format. Esophageal pressure topography provides a seamless dynamic representation of the pressure profile through the entire esophagus and thus, is able to eliminate movement artifact and also assess intrabolus pressure patterns as a surrogate for bolus transit mechanics. This has led to improved identification of anatomic landmarks and measurement of important physiological parameters (esophagogastric junction relaxation, distal latency, and contractile integrity). This research has bridged the gap into clinical practice by defining physiologically relevant phenotypes that may have prognostic significance and improve treatment decisions in achalasia, spasm, and hypercontractile disorders. However, more work is needed in determining the etiology of symptom generation in the context of normal or trivial motor dysfunction. This research will require new techniques to assess visceral hypersensitivity and alterations in central modulation of pain and discomfort.

Impaired postoperative EGJ relaxation as a determinant of post laparoscopic fundoplication dysphagia: a study with high-resolution manometry before and after surgery

BACKGROUND

Laparoscopic fundoplication (FP) reduces gastroesophageal reflux (GER) efficiently. Dysphagia is its main complication, but no clear data have been published in literature to evaluate risk factors associated with it. The goal of this retrospective study was to identify factors associated with dysphagia occurring after FP for GER disease, with high-resolution manometry (HRM) performed before and after surgery.

METHODS

Twenty patients (11 women; mean age, 49 (range, 19-68 years) underwent HRM before and 2-3 months after laparoscopic Nissen-Rossetti FP. Analysis was performed with esophageal pressure topography according to the Chicago Classification.

RESULTS

Before FP, ten patients had a manometric hiatal hernia (none after FP). Esophagogastric junction (EGJ) pressures increased after surgery (p < 0.01). Bolus pressurization was present in 2% of all swallows before FP and in 22% after (p = 0.01). Postoperative bolus pressurization percentage was significantly correlated with EGJ relaxation as measured with integrated relaxation pressure (IRP) (r = 0.79, p < 0.01). Eight patients reported dysphagia after FP. The only pre- or post-operative parameter significantly associated with dysphagia was postoperative IRP (5.1 mmHg without vs. 10.3 with dysphagia, p < 0.02).

CONCLUSIONS

FP establishes an efficient antireflux mechanism by correcting hiatal hernia and increasing EGJ pressures. EGJ relaxation as measured by IRP is significantly altered after surgery, leading to more frequent motility disorders, and bolus pressurization. Postoperative dysphagia was associated with higher values of IRP.

Physiology of the LES

The purpose of this review is to consider the neuromuscular mechanism of LES contractility both by itself and in relation to the esophagogastric junction (EGJ) complex in order to appreciate the intricacies of EGJ valvular function.

Upper esophageal sphincter impedance as a marker of sphincter opening diameter

The measurement of the physical extent of opening of the upper esophageal sphincter (UES) during bolus swallowing has to date relied on videofluoroscopy. Theoretically luminal impedance measured during bolus flow should be influenced by luminal diameter. In this study, we measured the UES nadir impedance (lowest value of impedance) during bolus swallowing and assessed it as a potential correlate of UES diameter that can be determined nonradiologically. In 40 patients with dysphagia, bolus swallowing of liquids, semisolids, and solids was recorded with manometry, impedance, and videofluoroscopy. During swallows, the UES opening diameter (in the lateral fluoroscopic view) was measured and compared with automated impedance manometry (AIM)-derived swallow function variables and UES nadir impedance as well as high-resolution manometry-derived UES relaxation pressure variables. Of all measured variables, UES nadir impedance was the most strongly correlated with UES opening diameter. Narrower diameter correlated with higher impedance (r = -0.478, P < 0.001). Patients with <10 mm, 10-14 mm (normal), and ≥ 15 mm UES diameter had average UES nadir impedances of 498 ± 39 Ohms, 369 ± 31 Ohms, and 293 ± 17 Ohms, respectively (ANOVA P = 0.005). A higher swallow risk index, indicative of poor pharyngeal swallow function, was associated with narrower UES diameter and higher UES nadir impedance during swallowing. In contrast, UES relaxation pressure variables were not significantly altered in relation to UES diameter. We concluded that the UES nadir impedance correlates with opening diameter of the UES during bolus flow. This variable, when combined with other pharyngeal AIM analysis variables, may allow characterization of the pathophysiology of swallowing dysfunction.

The LINX® reflux management system: confirmed safety and efficacy now at 4 years

BACKGROUND

Sphincter augmentation with the LINX® Reflux Management System is a surgical option for patients with chronic gastroesophageal disease (GERD) and an inadequate response to proton pump inhibitors (PPIs). Clinical experience with sphincter augmentation is now available out to 4 years.

METHODS

In a multicenter, prospective, single-arm study, 44 patients underwent a laparoscopic surgical procedure for placement of the LINX System around the gastroesophageal junction (GEJ). Each patient's baseline GERD status served as the control for evaluations post implant. Long-term efficacy measures included esophageal acid exposure, GERD quality-of-life measures, and use of PPIs. Adverse events and long-term complications were closely monitored.

RESULTS

For esophageal acid exposure, the mean total % time pH < 4 was reduced from 11.9 % at baseline to 3.8 % at 3 years (p < 0.001), with 80 % (18/20) of patients achieving pH normalization (≤ 5.3 %). At ≥ 4 years, 100 % (23/23) of the patients had improved quality-of-life measures for GERD, and 80 % (20/25) had complete cessation of the use of PPIs. There have been no reports of death or long-term device-related complications such as migration or erosion.

CONCLUSIONS

Sphincter augmentation with the LINX Reflux Management System provided long-term clinical benefits with no safety issues, as demonstrated by reduced esophageal acid exposure, improved GERD-related quality of life, and cessation of dependence on PPIs, with minimal side effects and no safety issues. Patients with inadequate symptom control with acid suppression therapy may benefit from treatment with sphincter augmentation.

Distensibility testing of the esophagus

The following contains commentaries on distensibility testing using the functional lumen imaging probe (FLIP); the use of the distention test of the esophageal body in the clinic diagnosis of noncardiac chest pain; the functional lumen imaging in gastroesophageal reflux disease-impaired esophagogastric junction; a multimodal pain model for the esophagus; the rationale for distensibility testing; and further developments in standardized distension protocols.

Adult esophagogastric junction distensibility during general anesthesia assessed with an endoscopic functional luminal imaging probe (EndoFLIP®)

BACKGROUND

Increased esophagogastric junction distensibility occurs with esophageal reflux. The EndoFLIP(®) is now available as a clinical tool to measure this. Control data for patients without reflux has to date only been available for a handful of patients evaluated under sedation during endoscopy. This study explores the baseline data for patients who undergo laparoscopy using general anesthesia with pneumoperitoneum.

METHODS

Patients who require surgery in the absence of a history of esophageal reflux underwent EndoFLIP(®) evaluation of pressure, cross-sectional area, and distensibility with bag fills of 30 and 40 ml. This was performed after induction of anesthesia, during pneumoperitoneum, and just before extubation.

RESULTS

Baseline levels were established and were noted to be significantly affected by the impact of pneumoperitoneum, with negligible effects from general anesthesia, patient gender, age, body mass index, or muscle relaxation.

CONCLUSIONS

These data provide a guide for more accurate intraoperative EndoFLIP(®) calibration of crural hiatal repair during surgery.

The lower esophageal sphincter

The lower esophageal sphincters (LES) together with the crural diaphragm are the major antireflux barriers protecting the esophagus from reflux of gastric content. However, reflux of gastric contents into the esophagus is a normal phenomenon in healthy individuals occurring primarily during episodes of transient lower esophageal sphincter relaxation (TLESR), defined as LES relaxation in the absence of a swallow. Transient lower esophageal sphincter relaxation is also the dominant mechanism of pathologic reflux in gastroesophageal reflux disorder (GERD) patients. Frequency of TLESR does not differ significantly between healthy individuals and those with GERD, but TLESRs are more likely to be associated with acid reflux in GERD patients. Understanding the mechanisms responsible for elicitation of a TLESR, using recently introduced novel technology is an area of intense interest. Pharmacologic and non-pharmacologic manipulation of receptors involved in the control of TLESR has recently emerged as a potential target for GERD therapy.

Functional lumen imaging probe to assess geometric changes in the esophagogastric junction following endolumenal fundoplication

BACKGROUND

The functional lumen imaging probe (FLIP) uses impedance planimetry to measure the geometry of a distensible organ. The purpose of this study was to evaluate FLIP as a method to determine structural changes at the gastroesophageal junction (GEJ) following transoral incisionless fundoplication (TIF) and compare these findings with the accepted methods of esophageal testing.

METHODS

Two different approaches (TIF1.0 and 2.0) using the EsophyX™ device were performed in six and five animals, respectively. Three dogs underwent a sham procedure. FLIP measurements were performed pre- and post-procedure and at 2-week follow-up. Upper endoscopy, manometry, and 48-h pH testing were also performed at each time point. FLIP was performed in ten patients before and 3 months after TIF.

RESULTS

Following TIF procedures, there was a significant decrease in cross-sectional area (CSA) of GEJ compared to baseline; however, the CSA of both groups returned to baseline at 2-week follow-up. The FLIP results were supported with pH testing and correlated highly with both measures of GEJ structural integrity (LES and cardia circumference). Following TIF in humans, there was a decrease in GEJ distensibility compared to baseline that persisted to the 3-month evaluation.

CONCLUSION

FLIP is able to measure and display changes in tissue distensibility at the GEJ, and results correlate with established methods of testing. FLIP may represent a single testing modality by which to diagnose GERD and evaluate the outcome after antireflux surgery.

An alginate-antacid formulation (Gaviscon Double Action Liquid) can eliminate or displace the postprandial 'acid pocket' in symptomatic GERD patients

BACKGROUND

Recently, an 'acid pocket' has been described in the proximal stomach, particularly evident postprandially in GERD patients, when heartburn is common. By creating a low density gel 'raft' that floats on top of gastric contents, alginate-antacid formulations may neutralise the 'acid pocket'.

AIM

To assess the ability of a commercial high-concentration alginate-antacid formulation to neutralize and/or displace the acid pocket in GERD patients.

METHODS

The 'acid pocket' was studied in ten symptomatic GERD patients. Measurements were made using concurrent stepwise pH pull-throughs, high resolution manometry and fluoroscopy in a semi-recumbent posture. Each subject was studied in three conditions: fasted, 20 min after consuming a high-fat meal and 20 min later after a 20 mL oral dose of an alginate-antacid formulation (Gaviscon Double Action Liquid, Reckitt Benckiser Healthcare, Hull, UK). The relative position of pH transition points (pH >4) to the EGJ high-pressure zone was analysed.

RESULTS

Most patients (8/10) exhibited an acidified segment extending from the proximal stomach into the EGJ when fasted that persisted postprandially. Gaviscon neutralised the acidified segment in six of the eight subjects shifting the pH transition point significantly away from the EGJ. The length and pressure of the EGJ high-pressure zone were minimally affected.

CONCLUSIONS

Gaviscon can eliminate or displace the 'acid pocket' in GERD patients. Considering that EGJ length was unchanged throughout, this effect was likely attributable to the alginate 'raft' displacing gastric contents away from the EGJ. These findings suggest the alginate-antacid formulation to be an appropriately targeted postprandial GERD therapy.

Review article: the clinical relevance of transient lower oesophageal sphincter relaxations in gastro-oesophageal reflux disease

BACKGROUND

Transient lower oesophageal sphincter relaxations (TLOSR) are considered the physiological mechanism that enables venting of gas from the stomach and appear as sphincter relaxations that are not induced by swallowing. It has become increasingly clear that most reflux episodes occur during TLOSRs and therefore play a key role in gastro-oesophageal reflux disease (GERD).

AIM

To describe the current knowledge about TLOSRs and its clinical implications.

METHODS

Search of the literature published in English using the PubMed database and relevant abstracts presented at international conventions.

RESULTS

Several factors influence the rate of TLOSRs including anti-reflux surgery, meal, body position, nutrition, lifestyle and a wide array of neurotransmitters. Ongoing insights in the neurotransmitters responsible for the modulation of TLOSRs, as well as the neural pathways involved in TLOSR induction, have lead to novel therapeutic targets. These therapeutic targets can serve as an add-on therapy in patients with an unsatisfactory response to proton pump inhibitor by inhibiting TLOSRs and its associated reflux events. However, the TLOSR-inhibiting drugs that are currently available still have significant side effects.

CONCLUSION

It is likely that in the future, selected GERD patients may benefit from transient lower oesophageal sphincter relaxation inhibition when compounds are found without significant side effects.

Mechanical properties of the esophagus in eosinophilic esophagitis

BACKGROUND & AIMS

This study aimed to analyze the mechanical properties of the esophagus in eosinophilic esophagitis (EoE) using the functional luminal imaging probe (EndoFLIP; Crospon Medical Devices, Galway, Ireland).

METHODS

Thirty-three EoE patients (22 male; age range, 23-67 years) and 15 controls (6 male; age range, 21-68 years) were included. Subjects were evaluated during endoscopy with the EndoFLIP probe, comprised of a compliant cylindrical bag (maximal diameter 25 mm) with 16 impedance planimetry segments. Stepwise bag distensions from 2 to 40 mL were conducted and the associated intrabag pressure and intraluminal geometry were analyzed.

RESULTS

The EndoFLIP clearly displayed the tubular esophageal geometry and detected esophageal narrowing and localized strictures. Stepwise distension progressively opened the esophageal lumen until a distension plateau was reached such that the narrowest cross-sectional area (CSA) of the esophagus maximized despite further increases in intra-bag pressure. The esophageal distensibility (CSA vs pressure) was reduced in EoE patients (P = .02) with the distension plateau of EoE patients substantially lower than that of controls (median: CSA 267 mm(2) vs 438 mm(2); P < .01). Mucosal eosinophil count, age, sex, and current proton pump inhibitor treatment did not predict this limiting caliber of the esophagus (P ≥ 0.20).

CONCLUSIONS

Esophageal distensibility, defined by the change in the narrowest measurable CSA within the distal esophagus vs intraluminal pressure was significantly reduced in EoE patients compared with controls. Measuring esophageal distensibility may be an important adjunct to the management of EoE, as it is capable of providing an objective means to measure the outcomes of medical or dilation therapy.