Esophageal body adaptation to Nissen fundoplication: Increased esophagogastric outflow resistance yields delayed and sustained peristaltic contractions without increased amplitude

BACKGROUND

Improvement in lower esophageal sphincter (LES) competency after laparoscopic Nissen fundoplication (LNF) is well established, yet esophageal body physiology data are limited. We aimed to describe the impact of LNF on whole esophagus physiology using standard and novel manometric characteristics.

METHODS

A cohort of patients with an intact fundoplication without herniation and no postoperative dysphagia were selected and underwent esophageal manometry at one-year after surgery. Pre- and post-operative manometry files were reanalyzed using standard and novel manometric characteristics and compared.

KEY RESULTS

A total of 95 patients were included in this study. At 16.1 (8.7) months LNF increased LES overall and abdominal length and resting pressure (p < 0.0001). Outflow resistance (IRP) increased [5.8 (3-11) to 11.1 (9-15), p < 0.0001] with a 95th percentile of 20 mmHg in this cohort of dysphagia-free patients. Distal contractile integral (DCI) also increased [1177.0 (667-2139) to 1321.1 (783-2895), p = 0.002], yet contractile amplitude was unchanged (p = 0.158). There were direct correlations between pre- and post-operative DCI [R: 0.727 (0.62-0.81), p < 0.0001] and postoperative DCI and postoperative IRP [R: 0.347 (0.16-0.51), p = 0.0006]. Contractile front velocity [3.5 (3-4) to 3.2 (3-4), p = 0.0013] was slower, while distal latency [6.7 (6-8) to 7.4 (7-9), p < 0.0001], the interval from swallow onset to proximal smooth muscle initiation [4.0 (4-5) to 4.4 (4-5), p = 0.0002], and the interval from swallow onset to point when the peristaltic wave meets the LES [9.4 (8-10) to 10.3 (9-12), p < 0.0001] were longer. Esophageal length [21.9 (19-24) to 23.2 (21-25), p < 0.0001] and transition zone (TZ) length [2.2 (1-3) to 2.5 (1-4), p = 0.004] were longer. Bolus clearance was inversely correlated with TZ length (p = 0.0002) and time from swallow onset to proximal smooth muscle initiation (p < 0.0001). Bolus clearance and UES characteristics were unchanged (p > 0.05).

CONCLUSIONS & INFERENCES

Increased outflow resistance after LNF required an increased DCI. However, this increased contractile vigor was achieved through sustained, not stronger, peristaltic contractions. Increased esophageal length was associated with increased TZ and delayed initiation of smooth muscle contractions.

Esophagogastric junction distensibility measurements during Heller myotomy and POEM for achalasia predict postoperative symptomatic outcomes

BACKGROUND

The functional lumen imaging probe (FLIP) is a novel diagnostic tool that can be used to measure esophagogastric junction (EGJ) distensibility. In this study, we performed intraoperative FLIP measurements during laparoscopic Heller myotomy (LHM) and peroral esophageal myotomy (POEM) for treatment of achalasia and evaluated the relationship between EGJ distensibility and postoperative symptoms.

METHODS

Distensibility index (DI) (defined as the minimum cross-sectional area at the EGJ divided by distensive pressure) was measured with FLIP at two time points during LHM and POEM: (1) at baseline after induction of anesthesia, and (2) after operation completion.

RESULTS

Measurements were performed in 20 patients undergoing LHM and 36 undergoing POEM. Both operations resulted in an increase in DI, although this increase was larger with POEM (7 ± 3.1 vs. 5.1 ± 3.4 mm(2)/mmHg, p < .05). The two patients (both LHM) with the smallest increases in DI (1 and 1.6 mm(2)/mmHg) both had persistent symptoms postoperatively and, overall, LHM patients with larger increases in DI had lower postoperative Eckardt scores. In the POEM group, there was no correlation between change in DI and symptoms; however, all POEM patients experienced an increase in DI of >3 mm(2)/mmHg. When all patients were divided into thirds based on final DI, none in the lowest DI group (<6 mm(2)/mmHg) had symptoms suggestive of reflux (i.e., GerdQ score >7), as compared with 20 % in the middle third (6-9 mm(2)/mmHg) and 36 % in the highest third (>9 mm(2)/mmHg). Patients within an "ideal" final DI range (4.5-8.5 mm(2)/mmHg) had optimal symptomatic outcomes (i.e., Eckardt ≤ 1 and GerdQ ≤ 7) in 88 % of cases, compared with 47 % in those with a final DI above or below that range (p < .05).

CONCLUSIONS

Intraoperative EGJ distensibility measurements with FLIP were predictive of postoperative symptomatic outcomes. These results provide initial evidence that FLIP has the potential to act as a useful calibration tool during operations for achalasia.

The acoustic cough monitoring and manometric profile of cough and throat clearing

Cough and throat clearing might be difficult to differentiate when trying to detect them acoustically or manometrically. The aim of this study was to assess the accuracy of acoustic monitoring for detecting cough and throat clearing, and to also determine whether these two symptoms present with different manometric profiles on esophageal pressure topography. Ten asymptomatic volunteers (seven females, mean age 31.1) were trained to simulate cough and throat clearing in a randomized order every 6 minutes during simultaneous acoustic monitoring and high-resolution manometry. The accuracy of automated acoustic analysis and two blinded reviewers were compared. The pattern of the events and the duration of the pressure changes were assessed using the 30 mmHg isobaric contour. There were 50 cough and 50 throat-clearing events according to the protocol. The sensitivity and specificity of automated acoustic analysis was 84% and 50% for cough, while the blinded analysis using sound revealed a sensitivity and specificity of 94% and 92%. The manometric profile of both cough and throat clearing was similar in terms of qualitative findings; however, cough was associated with a greater number of repetitive pressurizations and a more vigorous upper esophageal sphincter contraction compared with throat clearing. The acoustic analysis software has a moderate sensitivity and poor specificity to detect cough. The profile of cough and throat clearing in pressure topography revealed a similar qualitative pattern of pressurization with more vigorous pressure changes and a greater rate of repetitive pressurizations in cough.

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.

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.

Interferon alpha treatment of patients with impaired interferon gamma signaling

Patients with deficiency in the interferon gamma receptor (IFN-γR) are unable to respond properly to IFN-γ and develop severe infections with nontuberculous mycobacteria (NTM). IFN-γ and IFN-α are known to signal through STAT1 and activate many downstream effector genes in common. Therefore, we added IFN-α for treatment of patients with disseminated mycobacterial disease in an effort to complement their IFN-γ signaling defect. We treated four patients with IFN-γR deficiency with adjunctive IFN-α therapy in addition to best available antimicrobial therapy, with or without IFN-γ, depending on the defect. During IFN-α treatment, ex vivo induction of IFN target genes was detected. In addition, IFN-α driven gene expression in patients' cells and mycobacteria induced cytokine response were observed in vitro. Clinical responses varied in these patients. IFN-α therapy was associated with either improvement or stabilization of disease. In no case was disease exacerbated. In patients with profoundly impaired IFN-γ signaling who have refractory infections, IFN-α may have adjunctive anti-mycobacterial effects.

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.

Increased risk for persistent intestinal metaplasia in patients with Barrett's esophagus and uncontrolled reflux exposure before radiofrequency ablation

BACKGROUND & AIMS

Radiofrequency ablation (RFA) is a safe alternative to esophagectomy for patients with dysplastic Barrett's esophagus (BE). Although some studies have indicated that RFA is effective at eradicating dysplasia, most have found that RFA is not as effective in eradicating intestinal metaplasia. We investigated whether uncontrolled reflux is associated with persistent intestinal metaplasia after RFA.

METHODS

Thirty-seven patients with BE underwent RFA, high-resolution manometry, and 24-hour impedance-pH testing; they received proton pump inhibitors twice daily. Patients returned every 2 months for repeat treatment or standard surveillance. Patients were classified as complete responders (CRs) if all intestinal metaplasia was eradicated in fewer than 3 ablation sessions. We analyzed clinical parameters to identify factors associated with a CR or incomplete responder (ICR).

RESULTS

Among the 37 patients, 22 had a CR and 15 had an ICR. Mann-Whitney U tests revealed that length of BE, size of hiatal hernia, and frequency of reflux, but not acid reflux, differed between CRs and ICRs. CRs had fewer weakly acidic events than ICRs (29.5 vs 52; P < .05) and total reflux events (33.5 vs 60; P < .05), and a trend toward fewer weakly alkaline events (1.0 vs 5.0; P = .06). No other clinical or manometric features differed between groups.

CONCLUSIONS

Uncontrolled, predominantly weakly acidic reflux despite twice-daily proton pump inhibitor therapy before RFA increases the incidence of persistent intestinal metaplasia after ablation in patients with BE. Length of BE and size of hiatal hernia also were associated with persistent intestinal metaplasia after RFA.

Refining the criterion for an abnormal Integrated Relaxation Pressure in esophageal pressure topography based on the pattern of esophageal contractility using a classification and regression tree model

BACKGROUND

The Integrated Relaxation Pressure (IRP) is the esophageal pressure topography (EPT) metric used for assessing the adequacy of esophagogastric junction (EGJ) relaxation in the Chicago Classification of motility disorders. However, because the IRP value is also influenced by distal esophageal contractility, we hypothesized that its normal limits should vary with different patterns of contractility.

METHODS

Five hundred and twenty two selected EPT studies were used to compare the accuracy of alternative analysis paradigms to that of a motility expert (the 'gold standard'). Chicago Classification metrics were scored manually and used as inputs for MATLAB™ programs that utilized either strict algorithm-based interpretation (fixed abnormal IRP threshold of 15 mmHg) or a classification and regression tree (CART) model that selected variable IRP thresholds depending on the associated esophageal contractility.

KEY RESULTS

The sensitivity of the CART model for achalasia (93%) was better than that of the algorithm-based approach (85%) on account of using variable IRP thresholds that ranged from a low value of >10 mmHg to distinguish type I achalasia from absent peristalsis to a high value of >17 mmHg to distinguish type III achalasia from distal esophageal spasm. Additionally, type II achalasia was diagnosed solely by panesophageal pressurization without the IRP entering the algorithm.

CONCLUSIONS & INFERENCES

Automated interpretation of EPT studies more closely mimics that of a motility expert when IRP thresholds for impaired EGJ relaxation are adjusted depending on the pattern of associated esophageal contractility. The range of IRP cutoffs suggested by the CART model ranged from 10 to 17 mmHg.

Many patients continue using proton pump inhibitors after negative results from tests for reflux disease

BACKGROUND & AIMS

Ambulatory reflux testing is used to evaluate symptoms of gastroesophageal reflux disease (GERD) refractory to protein pump inhibitors (PPIs). We investigated the prevalence of PPI use in patients with negative results from Bravo pH or multichannel intraluminal impedance-pH (MII-pH) tests and factors that might predict the use of PPIs.

METHODS

We analyzed data from patients who had undergone Bravo pH monitoring or MII-pH testing at Northwestern University, without evidence of reflux disease. Demographics, endoscopy findings, pathology results, and provider recommendations were obtained via chart review. Eligible patients (n = 90) were contacted by telephone, and a cross-sectional survey was administered with questions about symptom severity, demographics, medication use, and health behaviors. Patients were compared by current PPI use, and statistical analyses were performed by using SAS version 9.2 software.

RESULTS

Thirty-eight patients (42.2%) reported current PPI use despite a negative result from a pH study. Only 17 patients (18.9%) recalled being instructed to stop taking PPIs; chart review showed documented instructions to stop PPI therapy for 15 patients (16.7%). There were no significant differences in demographic or clinical characteristics among patients compared by current PPI use. Patients taking a PPI were more likely than those not taking a PPI to report troublesome symptoms that affected their daily life, as measured by a questionnaire for the diagnosis of GERD (the GerdQ).

CONCLUSIONS

More than 42% of patients with negative results from pH monitoring studies continue PPI therapy despite physiological data that they do not have GERD.

Phenotypes and clinical context of hypercontractility in high-resolution esophageal pressure topography (EPT)

OBJECTIVES

This study aimed to refine the criteria for esophageal hypercontractility in high-resolution esophageal pressure topography (EPT) and to examine the clinical context in which it occurs.

METHODS

A total of 72 control subjects were used to define the threshold for hypercontractility as a distal contractile integral (DCI) greater than observed in normals. In all, 2,000 consecutive EPT studies were reviewed to find patients exceeding this threshold. Concomitant EPT and clinical variables were explored.

RESULTS

The greatest DCI value observed in any swallow among the control subjects was 7,732 mm Hg-s-cm; the threshold for hypercontractility was established as a swallow with DCI >8,000 mm Hg-s-cm. A total of 44 patients were identified with a median maximal DCI of 11,077 mm Hg-s-cm, all with normal contractile propagation and normal distal contractile latency, thereby excluding achalasia and distal esophageal spasm. Hypercontractility was associated with multipeaked contractions in 82% of instances, leading to the name "Jackhammer Esophagus." Dysphagia was the dominant symptom, although subsets of patients had hypercontractility in the context of esophagogastric junction (EGJ) outflow obstruction, reflux disease, or as an apparent primary motility disorder.

CONCLUSIONS

We describe an extreme phenotype of hypercontractility characterized in EPT by the occurrence of at least a single contraction with DCI >8,000 mm Hg-s-cm, a value not encountered in control subjects. This phenomenon, branded "Jackhammer Esophagus," was usually accompanied by dysphagia and occurred both in association with other esophageal pathology (EGJ outflow obstruction, reflux disease) or as an isolated motility disturbance. Further studies are required to define the pathophysiology and treatment of this disorder.