Taher I. Omari

Neurogastroenterology and motility • February 08, 2025

Taher Omari, Julia C Maclean, Charles Cock, Timothy Mcculloch, Nogah Nativ Zeltzer, Ashli O'rourke, Michal Szczesniak, Peter Wu, Jacqueline Allen, Yoichiro Aoyagi, Howell Henrian Bayona, Silvia Carrión, Michelle Ciucci, Kate Davidson, Shumon Dhar, Shaheen Hamdy, Rebecca Howell, Corrine Jones, Molly Knigge, An Moonen, Gregory Postma, Jo Puntil Sheltman, Anais Rameau, Julie Regan, Mistyka Schar, Nathalie Rommel

Background: The Leuven Consensus provides a classification scheme for the diagnosis of pharyngeal and upper esophageal sphincter (UES) motor disorders using metrics derived from pharyngeal high-resolution manometry-impedance (P-HRM-I). Methods: Twenty-six experts with broad multidisciplinary backgrounds contributed their knowledge and experience to this initiative via a formal deliberative Delphi process. Guidance on a swallow assessment protocol as well as diagnostic criteria for UES dysfunction and pharyngeal contractile dysfunction is provided. Results: For UES dysfunction, the stepwise evaluation of UES and intrabolus pressure metrics under increasing bolus volume and/or viscosity conditions is used to confirm failure of manometric relaxation and opening of the UES region. For pharyngeal contractile dysfunction, the evaluation of contractile metrics is used to define pharyngeal hypocontractility or hypercontractility. Conclusions: These recommendations complement routine instrumental investigations and provide a standardized process, criteria, and nomenclature for P-HRM-I assessment of patients reporting symptoms of oropharyngeal dysphagia.

Neurogastroenterology And Motility • September 19, 2024

T Omari, A Ross, M Schar, J Campbell, A Thompson, L Besanko, D Lewis, I Robinson, M Farahani, C Cock, B Mossel

Background: Fluid thickeners used in the management of oropharyngeal dysphagia exhibit non-Newtonian shear-thinning rheology, impacting their viscosity during deglutition. This study investigated how the rheological properties of thickened fluids affect pharyngeal swallowing parameters in patients with oropharyngeal motor disorders diagnosed by pharyngeal high-resolution manometry impedance (P-HRM-I). Methods: Seventy-two patients (18-89 years) referred for P-HRM-I were diagnostically assessed with a 10 mL thin bolus. In 57 of the patients, 10 mL swallows of two moderately thick formulations-xanthan gum (XG) and sodium carboxymethylcellulose gum (CMC)-were also tested. The XG and CMC fluids had equivalent empirical thickness but different viscosity at pharyngeal phase shear rates: XG 87 mPa.s (83-91) versus CMC mean 157 mPa.s (148-164) at 300 s-1. Standard metrics of pharyngeal and upper esophageal sphincter (UES) function were derived from P-HRM-I recordings and analyzed to characterize patients into one of four disorder subtypes: (i) No Disorder, (ii) UES Disorder, (iii) Pharyngeal Disorder, and (iv) Combination UES/Pharyngeal Disorder. Impedance recordings also assessed pharyngeal bolus transit. Results: Patients with a Combination UES/Pharyngeal Disorder were most likely to have abnormal bolus transit (82%, p < 0.001). Increasing bolus viscosity significantly influenced UES residual pressure, UES opening area, and post-swallow residue. Patients with UES Disorder exhibited pronounced increases in UES residual pressure with CMC compared to XG. Pharyngeal contractility was unaffected by viscosity changes. Post-swallow residue increased with CMC, particularly in patients with a Combination Disorder. Case-by-case analysis revealed individual variability in response to the different viscosities. Conclusions: The rheological properties of thickened fluids significantly affect swallowing function, with these effects dependent upon the disorder subtype.

Journal Of Pediatric Gastroenterology And Nutrition • July 30, 2024

Sharman Tan Tanny, Assia Comella, Lisa Mccall, John Hutson, Sue Finch, Mark Safe, Warwick Teague, Taher Omari, Sebastian King

Objective: Esophageal atresia (EA) is a significant congenital anomaly, with most survivors experiencing esophageal dysmotility. Currently, there is no reliable way to predict which patients will develop significant, life-threatening dysmotility. Using high-resolution impedance manometry (HRIM), this study aimed to characterize the common pressure topography patterns in children with repaired EA. Methods: This prospective longitudinal cohort study focused on children (<18 years) with repaired EA. Utilizing HRIM, esophageal motility patterns were studied. Repeat manometric assessments were performed in a selected group. Results: Seventy-five patients with EA (M:F = 43:32, median age 15 months [3 months to 17 years]) completed 133 HRIM studies. The majority (54 out of 75, 85.3%) had EA with distal tracheo-esophageal fistula. Thirty-five out of 75 (46.7%) underwent one study, 24 out of 75 (32.0%) two studies, 14 out of 75 (18.7%) three studies, and 2 out of 75 (2.7%) four studies. Seventy-two patients had analyzable studies. Three common motility patterns were demonstrated: (1) aperistalsis (26 out of 72, 36.1%); (2) distal esophageal contraction (25 out of 72, 34.7%); and (3) pressurization (6 out of 72, 8.3%). A minority demonstrated combination patterns, including aperistalsis with weak distal contraction (10 out of 72, 13.9%) and aperistalsis with pressurization (2 out of 72, 2.8%). Contraction was normal in 3 out of 72 (4.2%). At repeat assessment, the dominant motility pattern persisted in 26 out of 38 (68.4%) of the second studies and 9 out of 15 (60.0%) of the third studies. Conclusions: Utilizing HRIM in children with repaired EA, we have demonstrated objective, distinct, and reproducible motility patterns. In this cohort, the majority of motility patterns were maintained longitudinally, and dysphagia scores remained unchanged, even after dilatation.

Neurogastroenterology And Motility • June 17, 2024

T Omari, A Ross, M Schar, J Campbell, D Lewis, I Robinson, M Farahani, C Cock, B Mossel

Background: The shear rheology of ingested fluids influences their pharyngo-esophageal transit during deglutition. Thus, swallowed fluids elicit differing physiological responses due to their shear-thinning profile. Methods: Two hydrocolloid fluids, xanthan gum (XG) and sodium carboxymethylcellulose gum (CMC), were compared in 10 healthy adults (mean age 39 years). Manometry swallowing assessments were performed using an 8-French catheter. Swallows were analyzed using the Swallow Gateway web application (www.swallowgateway.com). Grouped data were analyzed by a mixed statistical model. The coefficient of determination (r2) assessed the relationship between measures and bolus viscosity (SI units, mPa.s) at shear rates of 1-1000 s-1. Results: Rheology confirmed that the thickened fluids had similar viscosities at 50 s-1 shear rate (XG IDDSI Level-1, 2, and 3 respectively, 74.3, 161.2, and 399.6 mPa.s vs. CMC Level-1, 2, and 3 respectively 78.0, 176.5, and 429.2 mPa.s). However, at 300 s-1 shear, CMC-thickened fluids exhibited approximately double the viscosity (XG Level-1, 2, and 3 respectively 19.5, 34.4, and 84.8 mPa.s vs. CMC Level-1, 2, and 3 respectively, 41.3, 80.8, and 160.2 mPa.s). In vivo swallows of CMC, when compared to XG, showed evidence of greater flow resistance, such as increased intrabolus pressure (p < 0.01) and UES Integrated Relaxation Pressure (UESIRP, p < 0.01) and shorter UES Relaxation Time (p < 0.05) and Bolus Presence Time (p < 0.001). The apparent fluid viscosity (mPa.s) correlated most significantly with increasing UESIRP (r2 0.69 at 50 s-1 and r2 0.97 at 300 s-1, p < 0.05). Conclusions: Fluids with divergent shear viscosities demonstrated differences in pharyngeal function. These physiological responses were linked to the shear viscosity and not the IDDSI level.

Neurogastroenterology And Motility • November 29, 2023

Penelope C Fitzgerald, Vida Bitarafan, Taher Omari, Charles Cock, Karen Jones, Michael Horowitz, Christine Feinle Bisset

Background: The herbal preparation, STW5-II, improves upper gastrointestinal symptoms, including abdominal fullness, early satiation, and epigastric pain, in patients with functional dyspepsia, and in preclinical models decreases fundic tone and increases antral contractility. The effects of STW5-II on esophago-gastric junction pressure, proximal gastric tone and antropyloroduodenal pressures, disturbances of which may contribute to symptoms associated with disorders of gut-brain interaction, including functional dyspepsia, in humans, have, hitherto, not been evaluated. Methods: STW5-II or placebo (matched for color, aroma, and alcohol content) were each administered orally, at the recommended dose (20 drops), to healthy male and female volunteers (age: 27 ± 1 years) in a double-blind, randomized fashion, on two separate occasions, separated by 3-7 days, to evaluate effects on (i) esophago-gastric junction pressures following a standardized meal using solid-state high-resolution manometry (part 1, n = 16), (ii) proximal gastric volume using a barostat (part 2, n = 16), and (iii) antropyloroduodenal pressures assessed by high-resolution manometry (part 3, n = 18), for 120 min (part 1) or 180 min (parts 2, 3). Results: STW5-II increased maximum intrabag volume (ml; STW5-II: 340 ± 38, placebo: 251 ± 30; p = 0.007) and intrabag volume between t = 120 and 180 min (p = 0.011), and the motility index of antral pressure waves between t = 60 and 120 min (p = 0.032), but had no effect on esophago-gastric junction, pyloric, or duodenal pressures. Conclusions: STW5-II has marked region-specific effects on gastric motility in humans, which may contribute to its therapeutic efficacy in functional dyspepsia.