Measurement of outflow resistance imposed by magnetic sphincter augmentation: defining normal values and clinical implication

Introduction No manometric criteria have been defined to select patients for magnetic sphincter augmentation (MSA). The first step to establish such criteria is to measure the outflow resistance at esophagogastric junction (EGJ) imposed by MSA. This resistance needs to be overcome by the esophageal contraction in order for the esophagus to empty and to avoid postoperative dysphagia. This study was designed to measure the outflow resistance caused by MSA in patients free of postoperative dysphagia. Methods Records of the patients who underwent MSA in our institution were reviewed. A group of MSA patients with excellent functional outcome, who were free of clinically significant postoperative dysphagia, were selected. These patients then underwent high-resolution impedance manometry (HRIM) at a target date of 1 year after surgery. The outflow resistance was measured by the esophageal intrabolus pressure (iBP) recorded 2 cm proximal to the lower esophageal sphincter (LES). Results The study population consisted of 43 patients. HRIM was performed at mean of 20.4 (10.4) months after surgery. The mean (SD) amplitude of the iBP was 13.5 (4.3) before surgery and increased to 19.1 (5.6) after MSA (p < 0.0001). Patients with a smaller size LINX device (≤ 14 beads) had a similar iBP when compared to those with a larger device (> 15 beads) [19.7 (4.5) vs. 18.4 (5.9), p = 0.35]. There was a significant correlation between the iBP and % incomplete bolus clearance [Spearman R: 0.44 (95% CI 0.15–0.66), p = 0.0032]. The 95th percentile value for iBP after MSA was 30.4 mmHg. Conclusion The EGJ outflow resistance measured by iBP is increased after MSA. The upper limit of normal for iBP is 30 mmHg in this cohort of patients who were free of dysphagia after MSA. This degree of resistance needs to be overcome by distal esophageal contraction and will likely be requisite to prevent persistent postoperative dysphagia.

Esophageal contractile segment impedance from high-resolution impedance manometry correlates with mean nocturnal baseline impedance and acid exposure time from 24-hour pH-impedance monitoring

Summary Esophageal baseline impedance (BI) acquired during esophageal contraction (contractile segment impedance [CSI]) is proposed to improve BI accuracy in gastroesophageal reflux disease (GERD). We evaluated associations between CSI and conventional and novel GERD metrics. We analyzed high-resolution impedance manometry (HRIM) and ambulatory pH-impedance studies from 51 patients (58.6 ± 1.5 years; 26% F) with GERD symptoms studied off antisecretory therapy. Patients with achalasia or absent contractility were excluded. CSI (averaged across 10 swallows) and BI-HRIM (from the resting landmark phase) were acquired from the distal impedance sensors (distal sensor and 5 cm above the lower esophageal sphincter). Acid exposure time (AET) and mean nocturnal baseline impedance (MNBI) were calculated. Associations between CSI, BI-HRIM, MNBI, and AET were evaluated using correlation (Pearson) and receiver operating characteristic (ROC) analysis. Presenting symptoms included heartburn (67%), regurgitation (12%), cough (12%), and chest pain (10%). CSI-distal and CSI-5 each correlated with BI-HRIM, AET, and distal MNBI. Associations with AET were numerically stronger for CSI-distal (r = −0.46) and BI-HRIM-distal (r = −0.44) than CSI-5 (r = −0.33), BI-HRIM-5 (r = −0.28), or distal MNBI (r &lt; −0.36). When compared to AET &lt;4%, patients with AET &gt;6% had significantly lower CSI-distal and BI-HRIM-distal values but not CSI-5, BI-HRIM-5, or MNBI. ROC areas under the curve for AET &gt;6% were numerically higher for CSI-distal (0.81) than BI-HRIM-distal (0.77), distal MNBI (0.68–0.75), CSI-5 (0.68), or BI-HRIM-5 (0.68). CSI from HRIM studies inversely correlates with pathologic AET and has potential to augment the evaluation of GERD.

Does the nissen fundoplication procedure improve esophageal dysmotility in patients with barrett’s esophagus?

ABSTRACT Objective: to evaluate esophageal dysmotility (ED) and the extent of Barrett’s esophagus (BE) before and after laparoscopic Nissen fundoplication (LNF) in patients previously diagnosed with BE and ED. Methods: twenty-two patients with BE diagnosed by upper gastrointestinal (GI) endoscopy with biopsies and ED diagnosed by conventional esophageal manometry (CEM) were submitted to a LNF, and followed up with clinical evaluations, upper GI endoscopy with biopsies and CEM, for a minimum of 12 months after the surgical procedure. Results : sixteen patients were male (72.7%) and six were females (27.3%). The mean age was 55.14 (± 15.52) years old. and the mean postoperative follow-up was 26.2 months. The upper GI endoscopy showed that the mean length of BE was 4.09 cm preoperatively and 3.91cm postoperatively (p=0.042). The evaluation of esophageal dysmotility through conventional manometry showed that: the preoperative median of the lower esophageal sphincter resting pressure (LESRP) was 9.15 mmHg and 13.2 mmHg postoperatively (p=0.006). The preoperative median of the esophageal contraction amplitude was 47.85 mmHg, and 57.50 mmHg postoperatively (p=0.408). Preoperative evaluation of esophageal peristalsis showed that 13.6% of the sample presented diffuse esophageal spasm and 9.1% ineffective esophageal motility. In the postoperative, 4.5% of patients had diffuse esophageal spasm, 13.6% of aperistalsis and 22.7% of ineffective motor activity (p=0.133). Conclusion: LNF decreased the BE extension, increased the LES resting pressure, and increased the amplitude of the distal esophageal contraction; however, it was unable to improve ED.

Topographical plots of esophageal distension and contraction: effects of posture on esophageal peristalsis and bolus transport

Each swallow induces a wave of inhibition followed by contraction in the esophagus. Unlike contraction, which can easily be measured in humans using high-resolution manometry (HRM), inhibition is difficult to measure. Luminal distension is a surrogate of the esophageal inhibition. The aim of this study was to determine the effect of posture on the temporal and quantitative relationship between distension and contraction along the entire length of the esophagus in normal healthy subjects by using concurrent HRM, HRM impedance (HRMZ), and intraluminal ultrasound (US). Studies were conducted in 15 normal healthy subjects in the supine and Trendelenburg positions. Both manual and automated methods were used to extract quantitative pressure and impedance-derived features from the HRMZ recordings. Topographical plots of distension and contraction were visualized along the entire length of the esophagus. Distension was also measured from the US images during 10-ml swallows at 5 cm above the lower esophageal sphincter. Each swallow was associated with luminal distension followed by contraction, both of which traversed the esophagus in a sequential/peristaltic fashion. Luminal distension (US) and esophageal contraction amplitude were greater in the Trendelenburg compared with the supine position. Length of esophageal breaks (in the transition zone) were reduced in the Trendelenburg position. Change in posture altered the temporal relationship between distension and contraction, and bolus traveled closer to the esophageal contraction in the Trendelenburg position. Topographical contraction-distension plots derived from HRMZ recordings is a novel way to visualize esophageal peristalsis. Future studies should investigate if abnormalities of esophageal distension are the cause of functional dysphagia. NEW & NOTEWORTHY Ascending contraction and descending inhibition are two important components of peristalsis. High-resolution manometry only measures the contraction phase of peristalsis. We measured esophageal distension from intraluminal impedance recordings and developed novel contraction-distension topographical plots to prove that similar to contraction, distension also travels in a peristaltic fashion. Change in posture from the supine to the Trendelenburg position also increased the amplitude of esophageal distension and contraction and altered the temporal relationship between distension and contraction.

Study on Effects of Electrical Stimulation on Rabbit Esophageal Body Motility In Vivo

Electric stimulation (ES) could induce contraction of intestinal smooth muscle. The aim of this study was to analyze the effects of ES on esophageal motility and the underlying mechanism in vivo. Twenty-eight rabbits were equipped with a pair of subserosa electrodes (connected to an electrical stimulator) in the lower segment of the esophagus. The ES signal consisted of bipolar rectangular pulse trains, lasting for 3 s, with different amplitudes (1 mA, 3 mA, 5 mA and 10 mA), and frequencies (10 Hz, 20 Hz and 50 Hz). The amplitude of the contraction was recognized by high-resolution manometry. The effect of ES was tested under anesthesia and following administration of atropine, phentolamine or L-NAME. ES induced esophageal contraction at the stimulated site. A statistically significant increase in esophageal pressure was observed when the stimulation amplitude was above 3 mA. The increase in esophageal pressure was associated with the amplitude of stimulus as well as the frequency. During stimulation, atropine, phentolamine and L-NAME had no effect on the increase of esophageal pressure induced by ES. These findings implied that ES induced esophageal contraction were not mediated via the NANC, adrenergic or cholinergic pathway. The amplitude of esophageal contraction was current and frequency dependent.

Effect of nasal noninvasive respiratory support methods on pharyngeal provocation-induced aerodigestive reflexes in infants

The pharynx is a locus of provocation among infants with aerodigestive morbidities manifesting as dysphagia, life-threatening events, aspiration-pneumonia, atelectasis, and reflux, and such infants often receive nasal respiratory support. We determined the impact of different oxygen delivery methods on pharyngeal stimulation-induced aerodigestive reflexes [room air (RA), nasal cannula (NC), and nasal continuous positive airway pressure (nCPAP)] while hypothesizing that the sensory motor characteristics of putative reflexes are distinct. Thirty eight infants (28.0 ± 0.7 wk gestation) underwent pharyngoesophageal manometry and respiratory inductance plethysmography to determine the effects of graded pharyngeal stimuli ( n = 271) on upper and lower esophageal sphincters (UES, LES), swallowing, and deglutition-apnea. Comparisons were made between NC ( n = 19), nCPAP ( n = 9), and RA ( n = 10) groups. Importantly, NC or nCPAP (vs. RA) had: 1) delayed feeding milestones ( P < 0.05), 2) increased pharyngeal waveform recruitment and duration, greater UES nadir pressure, decreased esophageal contraction duration, decreased distal esophageal contraction amplitude, and decreased completely propagated esophageal peristalsis (all P < 0.05), and 3) similarly developed UES contractile and LES relaxation reflexes ( P > 0.05). We conclude that aerodigestive reflexes were similarly developed in infants using noninvasive respiratory support with adequate upper and lower aerodigestive protection. Increased concern for GERD is unfounded in this population. These infants may benefit from targeted oromotor feeding therapies and safe pharyngeal bolus transit to accelerate feeding milestones.