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Dive into the research topics where Katherine Ritter is active.

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Featured researches published by Katherine Ritter.


The American Journal of Gastroenterology | 2016

Evaluation of Esophageal Motility Utilizing the Functional Lumen Imaging Probe

Dustin A. Carlson; Peter J. Kahrilas; Zhiyue Lin; Ikuo Hirano; Nirmala Gonsalves; Zoe Listernick; Katherine Ritter; Michael Y. Tye; Fraukje A. Ponds; Ian Wong; John E. Pandolfino

Objectives:Esophagogastric junction (EGJ) distensibility and distension-mediated peristalsis can be assessed with the functional lumen imaging probe (FLIP) during a sedated upper endoscopy. We aimed to describe esophageal motility assessment using FLIP topography in patients presenting with dysphagia.Methods:In all, 145 patients (aged 18–85 years, 54% female) with dysphagia that completed upper endoscopy with a 16-cm FLIP assembly and high-resolution manometry (HRM) were included. HRM was analyzed according to the Chicago Classification of esophageal motility disorders; major esophageal motility disorders were considered “abnormal”. FLIP studies were analyzed using a customized program to calculate the EGJ-distensibility index (DI) and generate FLIP topography plots to identify esophageal contractility patterns. FLIP topography was considered “abnormal” if EGJ-DI was <2.8 mm2/mm Hg or contractility pattern demonstrated absent contractility or repetitive, retrograde contractions.Results:HRM was abnormal in 111 (77%) patients: 70 achalasia (19 type I, 39 type II, and 12 type III), 38 EGJ outflow obstruction, and three jackhammer esophagus. FLIP topography was abnormal in 106 (95%) of these patients, including all 70 achalasia patients. HRM was “normal” in 34 (23%) patients: five ineffective esophageal motility and 29 normal motility. In all, 17 (50%) had abnormal FLIP topography including 13 (37%) with abnormal EGJ-DI.Conclusions:FLIP topography provides a well-tolerated method for esophageal motility assessment (especially to identify achalasia) at the time of upper endoscopy. FLIP topography findings that are discordant with HRM may indicate otherwise undetected abnormalities of esophageal function, thus FLIP provides an alternative and complementary method to HRM for evaluation of non-obstructive dysphagia.


The American Journal of Gastroenterology | 2016

High-Resolution Impedance Manometry Metrics of the Esophagogastric Junction for the Assessment of Treatment Response in Achalasia

Dustin A. Carlson; Zhiyue Lin; Peter J. Kahrilas; Joel M. Sternbach; Eric S. Hungness; Nathaniel J. Soper; Michelle Balla; Zoe Listernick; Michael Y. Tye; Katherine Ritter; Jenna Craft; Jody D. Ciolino; John E. Pandolfino

OBJECTIVES:We aimed to evaluate the value of novel high-resolution impedance manometry (HRIM) metrics, bolus flow time (BFT), and esophagogastric junction (EGJ) contractile integral (CI), as well as EGJ pressure (EGJP) and the integrated relaxation pressure (IRP), as indicators of treatment response in achalasia.METHODS:We prospectively evaluated 75 patients (ages 19–81, 32 female) with achalasia during follow-up after pneumatic dilation or myotomy with Eckardt score (ES), timed-barium esophagram (TBE), and HRIM. Receiver-operating characteristic (ROC) curves for good symptomatic outcome (ES≤3) and good radiographic outcome (TBE column height at 5 min<5 cm) were generated for each potential predictor of treatment response (EGJP, IRP, BFT, and EGJ-CI).RESULTS:Follow-up occurred at a median (range) 12 (3–291) months following treatment. A total of 49 patients had good symptomatic outcome and 46 had good radiographic outcome. The area-under-the-curves (AUCs) on the ROC curve for symptomatic outcome were 0.55 (EGJP), 0.62 (IRP), 0.77 (BFT) and 0.56 (EGJ-CI). The AUCs for radiographic outcome were 0.64 (EGJP), 0.48 (IRP), 0.73 (BFT), and 0.65 (EGJ-CI). Optimal cut-points were determined as 11 mm Hg (EGJP), 12 mm Hg (IRP), 0 s (BFT), and 30 mm Hg•cm (EGJ-CI) that provided sensitivities/specificities of 57%/46% (EGJP), 65%/58% (IRP), 78%/77% (BFT), and 53%/62% (EGJ-CI) to predict symptomatic outcome and 57%/66% (EGJP), 57%/41% (IRP), 76%/69% (BFT), and 57%/66% (EGJ-CI) to predict radiographic outcome.CONCLUSIONS:BFT, a novel HRIM metric, provided an improved functional assessment over manometric measures of EGJP, IRP, and EGJ-CI at follow-up after achalasia treatment and may help direct clinical management.


Clinical Gastroenterology and Hepatology | 2017

Postprandial High-Resolution Impedance Manometry Identifies Mechanisms of Nonresponse to Proton Pump Inhibitors

Rena Yadlapati; Michael Y. Tye; Sabine Roman; Peter J. Kahrilas; Katherine Ritter; John E. Pandolfino

BACKGROUND & AIMS: Recognition of rumination and supragastric belching is often delayed as symptoms may be mistakenly attributed to gastroesophageal reflux disease. However, distinct from gastroesophageal reflux disease, rumination and supragastric belching are more responsive to behavioral interventions than to acid‐suppressive and antireflux therapies. Postprandial high‐resolution impedance manometry (PP‐HRIM) is an efficient method to identify rumination and belches. We investigated the distribution of postprandial profiles determined by PP‐HRIM, and identified patient features associated with postprandial profiles among patients with nonresponse to proton pump inhibitors (PPIs). METHODS: We performed a retrospective analysis of PP‐HRIM studies performed on 94 adults (mean age, 50.6 y; 62% female) evaluated for PPI nonresponsiveness at an esophageal referral center, from January 2010 through May 2016. Following a standard esophageal manometry protocol, patients ingested a solid refluxogenic test meal (identified by patients as one that induces symptoms) with postprandial monitoring up to 90 minutes (median, 50 min). Patients were assigned to 1 of 4 postprandial profiles: normal; reflux only (>6 transient lower esophageal sphincter relaxations (TLESRs)/h); supragastric belch (>2 supragastric belches/h), with or without TLESR; or rumination (≥1 rumination episode/h) with or without TLESR and supragastric belching. The primary outcome was postprandial profile. RESULTS: Of the study participants, 24% had a normal postprandial profile, 14% had a reflux‐only profile, 42% had a supragastric belch profile, and 20% had a rumination profile. In multinomial regression analysis, the rumination group most frequently presented with regurgitation, the supragastric belch and rumination groups were younger in age, and the reflux‐only group had a lower esophagogastric junction contractile integral. The number of weakly acidic reflux events measured by impedance‐pH monitoring in patients receiving PPI therapy was significantly associated with frequency of rumination episodes and supragastric belches. CONCLUSIONS: In a retrospective analysis of 94 nonresponders to PPI therapy evaluated by PP‐HRIM, we detected an abnormal postprandial pattern in 76% of cases: 42% of these were characterized as supragastric belching, 20% as rumination, and 14% as reflux only. Age, esophagogastric junction contractility, impedance‐pH profiles, and symptom presentation differed significantly among groups. PP‐HRIM can be used in the clinic to evaluate mechanisms of PPI nonresponse.


American Journal of Physiology-gastrointestinal and Liver Physiology | 2018

Mechanisms of repetitive retrograde contractions in response to sustained esophageal distension: a study evaluating patients with postfundoplication dysphagia

Dustin A. Carlson; Peter J. Kahrilas; Katherine Ritter; Zhiyue Lin; John E. Pandolfino

Repetitive retrograde contractions (RRCs) in response to sustained esophageal distension are a distinct contractility pattern observed with functional luminal imaging probe (FLIP) panometry that are common in type III (spastic) achalasia. RRCs are hypothesized to be indicative of either impaired inhibitory innervation or esophageal outflow obstruction. We aimed to apply FLIP panometry to patients with postfundoplication dysphagia (a model of esophageal obstruction) to explore mechanisms behind RRCs. Adult patients with dysphagia after Nissen fundoplication ( n = 32) or type III achalasia ( n = 25) were evaluated with high-resolution manometry (HRM) and upper endoscopy with FLIP. HRM studies were assessed for outflow obstruction and spastic features: premature contractility, hypercontractility, and impaired deglutitive inhibition during multiple-rapid swallows. FLIP studies were analyzed to determine the esophagogastric junction (EGJ)-distensibility index and contractility pattern, including RRCs. Barium esophagram was evaluated when available. RRCs were present in 8/32 (25%) fundoplication and 19/25 (76%) achalasia patients ( P < 0.001). EGJ outflow obstruction was detected in 21 (67%) fundoplication patients by HRM, FLIP, or esophagram [6 (29%) had RRCs]. On HRM, none of the fundoplication patients had premature contractility, whereas 3/4 with defective inhibition on multiple-rapid swallows and 2/4 with hypercontractility had RRCs. Regression analysis demonstrated HRM with spastic features, but not esophageal outflow obstruction, as a predictor for RRCs. RRCs in response to sustained esophageal distension appear to be a manifestation of spastic esophageal motility. Although future study to further clarify the significance of RRCs is needed, RRCs on FLIP panometry should prompt evaluation for a major motor disorder. NEW & NOTEWORTHY Repetitive retrograde contractions (RRCs) are a common response to sustained esophageal distension among spastic achalasia patients when evaluated with the functional luminal imaging probe. We evaluated patients with postfundoplication dysphagia, i.e., patients with suspected mechanical obstruction, and found that RRCs occasionally occurred among postfundoplication patients, but often in association with manometric features of esophageal neuromuscular imbalance. Thus, RRCs appear to be a manifestation of spastic esophageal dysmotility, likely from neural imbalance resulting in excess excitation.


Clinical Gastroenterology and Hepatology | 2018

Improved Assessment of Bolus Clearance in Patients With Achalasia Using High-Resolution Impedance Manometry

Dustin A. Carlson; Claire Beveridge; Zhiyue Lin; Michelle Balla; Dyanna L. Gregory; Michael Y. Tye; Katherine Ritter; Peter J. Kahrilas; John E. Pandolfino

Background & Aims: Esophageal retention is typically evaluated by timed‐barium esophagram in patients treated for achalasia. Esophageal bolus clearance can also be evaluated using high‐resolution impedance manometry. We evaluated the associations of conventional and novel high‐resolution impedance manometry metrics, esophagram, and patient‐reported outcomes (PROs) in achalasia. Methods: We performed a prospective study of 70 patients with achalasia (age, 20–81 y; 30 women) treated by pneumatic dilation or myotomy who underwent follow‐up evaluations from April 2013 through December 2015 (median, 12 mo after treatment; range, 3–183 mo). Patients were assessed using timed‐barium esophagrams, high‐resolution impedance manometry, and PROs, determined from Eckardt scores (the primary outcome) and the brief esophageal dysphagia questionnaire. Barium column height was measured from esophagrams taken 5 minutes after ingestion of barium (200 mL). Impedance‐manometry was analyzed for bolus transit (dichotomized) and with a customized MATLAB program (The MathWorks, Inc, Natick, MA) to calculate the esophageal impedance integral (EII) ratio. Results: Optimal cut points to identify a good PRO (defined as Eckardt score of ≤3) were esophagram barium column height of 3 cm (identified patients with a good PRO with 63% sensitivity and 75% specificity) and an EII ratio of 0.41 (identified patients with a good PRO with 83% sensitivity and 75% specificity). Complete bolus transit identified patients with a good PRO with 28% sensitivity and 75% specificity. Of the 25 patients who met these cut points for both esophagram barium column height and EII ratio, 23 (92%) had a good PRO. Of the 17 patients who met neither cut point, 14 (82%) had a poor PRO (Eckardt score above 3). Conclusions: In a prospective study of 70 patients with achalasia, we found EII ratio identified patients with good PROs with higher levels of sensitivity (same specificity) than timed‐barium esophagram or impedance‐manometry bolus transit assessments. The EII ratio should be added to achalasia outcome evaluations that involve high‐resolution impedance manometry as an independent measure and to complement timed‐barium esophagram.


Neurogastroenterology and Motility | 2018

High‐resolution manometry assessment of the lower esophageal sphincter after‐contraction: Normative values and clinical correlation

Dustin A. Carlson; Peter J. Kahrilas; Michael Y. Tye; Zoe Listernick; Katherine Ritter; I. Wong; Yinglian Xiao; V. Bul; John E. Pandolfino

The Chicago Classification v3.0 proposed extending the distal contractile integral (DCI) measurement domain to include the lower esophageal sphincter (LES) to enhance the detection of esophageal hypercontractility. However, normative and clinical data for this approach are unreported. We aimed to describe the application of an extended DCI measurement in asymptomatic controls and patients.


Gastroenterology | 2016

240 A Diagnostic Classification Scheme of Esophageal Motility Using Functional Lumen Imaging Probe (FLIP) Topography

Dustin A. Carlson; Zhiyue Lin; Peter J. Kahrilas; Ian Yu Hong Wong; Zoe Listernick; Fraukje A. Ponds; Joel M. Sternbach; Katherine Ritter; Michael Y. Tye; John E. Pandolfino


Gastroenterology | 2018

Mo1523 - Association Between Heart Rate Variability, Psychological Outcomes, and Symptom Severity in Gastroesophageal Reflux Disease

Livia Guadagnoli; John E. Pandolfino; Tiffany Taft; Katherine Ritter; Laurie Keefer


Gastroenterology | 2017

Mechanisms of Repetitive, Retrograde Contractions: A Study Evaluating Post-Fundoplication Dysphagia and Spastic Achalasia Utilizing Function Lumen Imaging Probe (FLIP) Topography

Dustin A. Carlson; Katherine Ritter; Zhiyue Lin; John E. Pandolfino


Gastroenterology | 2016

Su1084 Evaluation of Contractile Velocity Patterns by High-Resolution Manometry/Esophageal Pressure Topography in Patients With Achalasia Type III and Esophagogastric Junction Outflow Obstruction

Fraukje A. Ponds; Katherine Ritter; Francis O. Edeani; Dustin A. Carlson; John E. Pandolfino

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Zhiyue Lin

Northwestern University

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