Postreflux swallow-induced peristaltic wave index and nocturnal baseline impedance can link PPI-responsive heartburn to reflux better than acid exposure time

BACKGROUND

Acid exposure time (AET) is considered the most useful parameter to predict response of reflux-related heartburn to medical or surgical treatment. However, recent studies showed high rates of heartburn response to proton pump inhibitor (PPI) therapy in patients with normal AET. We aimed to compare the efficacy of postreflux swallow-induced peristaltic wave (PSPW) index and mean nocturnal baseline impedance (MNBI) with AET in linking PPI-responsive heartburn to reflux.

METHODS

Off-therapy impedance-pH tracings from 425 patients, 317 with PPI-responsive and 108 with PPI-refractory heartburn were blindly re-analyzed. Demographic and endoscopic characteristics, conventional impedance-pH variables, PSPW index, and MNBI were assessed with multivariate logistic regression to identify factors independently associated with PPI responsiveness. Prediction models were developed to assess the strength of reflux linkage with factors independently associated with PPI responsiveness by calculating the area under the curve (AUC) at receiver-operating-characteristic (ROC) analysis.

KEY RESULTS

At multivariate logistic regression analysis, AET, MNBI, and PSPW index were the only factors independently associated with PPI responsiveness, abnormal values found in 60%, 76%, and 92% of PPI-responsive cases (P<.017). At ROC analysis, PSPW index (AUC:.794, P=.002) and MNBI (AUC: 0.742, P=.003), both separately and combined (AUC: 0.811, P<.001) linked reflux with PPI-responsiveness better than AET (AUC: 0.687).

CONCLUSIONS & INFERENCES

AET, PSPW index, and MNBI are independently associated with PPI-responsive heartburn. PSPW index and MNBI can link PPI-responsive heartburn to reflux better than AET and should become part of the standard analysis of impedance-pH tracings.

Effect of methylnaltrexone and naloxone on esophageal motor function in man

BACKGROUND

Endogenous opioids (EO) acting on μ-opiod receptors in central and enteric nervous system (ENS) control gastrointestinal motility but it is still unclear whether EO in ENS may control esophageal function in man, thus we will study the effects of methylnaltrexone (MNTX), a peripherally selective, and naloxone (NA), a non-selective μ-opiod receptor antagonist, on esophageal motility in healthy subjects.

METHODS

Fifteen HV (6 M; 34.1 ± 0.6 years; BMI: 22.1 ± 0.1 kg/m² ) underwent three esophageal high-resolution manometry impedance (HRiM) studies with 10 saline swallows administered every 30 minutes: drug was administered after 30 minutes (MNTX subcutaneously/NA or saline intravenously), a solid meal after 90 minutes; measurements continued for 120 minutes postprandially.

KEY RESULTS

Methylnaltrexone did not significantly decrease the upper esophageal sphincter (UES) percentage of relaxation preprandially (72.5 ± 5 vs 66.9 ± 4.6 and 73 ± 3.8%, ANOVA between placebo, MNTX and NA, P=NS) and postprandially (60 minutes: 68.2 ± 5.6 vs 61 ± 5.5 and 67.1 ± 5.6%; 120 minutes: 68 ± 5.9 vs 59.3 ± 5.2 and 67.7 ± 4.7%; ANOVA between placebo, MNTX and NA, P=NS). MNTX and NA did not significantly alter preprandial and postprandial LES resting pressures and integrated relaxation pressure (ANOVA between placebo, MNTX and NA, all P=NS). Peak front velocity and distal contractile integral were not altered pre- and postprandially by MNTX and NA (ANOVA between placebo, MNTX and NA, P=NS). Transient lower esophageal sphincter relaxations (TLESRs') number was not altered by MNTX and NA (ANOVA between placebo, MNTX and NA, all P=NS).

CONCLUSIONS AND INFERENCES

The peripheral selective and non-selective μ-opioid receptor antagonists MNTX and NA, respectively, do not alter TLESRs occurrence and esophageal peristalsis.

Prolonged measurement improves the assessment of the barrier function of the esophago-gastric junction by high-resolution manometry

BACKGROUND

Etiology of gastro-esophageal reflux disease (GERD) is multifactorial, but incompetence of the esophago-gastric junction (EGJ) appears to be of crucial importance. Established manometric parameters for assessment of EGJ barrier function are sub-optimal, potentially because they reflect only a very brief (up to 30 seconds), not necessarily representative period. This prospective, case-control study tested the performance of novel, high-resolution manometry (HRM) parameters of EGJ function in the assessment of GERD.

METHODS

Patients with reflux symptoms and healthy controls (HC) underwent standard HRM and 24-hour pH±impedance measurements. EGJ morphology, lower esophageal sphincter pressure integral (LES-PI), EGJ contractile integral (EGJ-CI) were compared with total-EGJ-CI, a novel parameter summarizing EGJ barrier function during the entire HRM protocol. Esophageal acid exposure ≥4.2%/24 h (A-Reflux-pos) or ≥73 reflux episodes in 24 hours (V-Reflux-pos) were considered pathological.

KEY RESULTS

Sixty five HC and 452 patients completed HRM, 380 (84%) patients underwent ambulatory reflux-monitoring. LES-PI, EGJ-CI and total-EGJ-CI correlated with EGJ morphology subtypes (all P<.00001). Only total-EGJ-CI was consistently lower in A-Reflux-pos and V-Reflux-pos subjects compared with HC and patients without GERD. Total-EGJ-CI was also the single best parameter for prediction of pathological reflux (optimal cut-off 47 mmHg cm, AUC 0.746, P<.0001). This cut-off value, approximately 1 SD below the mean normal value, showed modest sensitivity 54% and positive predictive value 46%, but good specificity 85% and negative predictive value 89% for GERD diagnosis.

CONCLUSION & INFERENCES

Total EGJ-CI, a new metric that summarizes EGJ contractility over time, allows an improved assessment of EGJ barrier function. Pathological reflux is unlikely if this metric is within the upper two-thirds of the normal range.