HSC Section 6 Nov2016 Green Book

Reprinted by permission of Laryngoscope. 2013; 123(10):2463-2468.

The Laryngoscope V C 2013 The American Laryngological, Rhinological and Otological Society, Inc.

The Role of Impedance Monitoring in Patients With Extraesophageal Symptoms

Robert T. Kavitt, MD, MPH; Elif Saritas Yuksel, MD; James C. Slaughter, DrPH; C. Gaelyn Garrett, MD; David Hagaman, MD; Tina Higginbotham, MPA; Michael F. Vaezi, MD, PhD, MSc (Epi)

Objectives/Hypothesis: Ambulatory esophageal impedance monitoring is commonly employed to assess for nonacid reflux in patients with extraesophageal reflux. We aimed to determine if on therapy impedance data can be predicted from off therapy upper endoscopy, manometry, or pH parameters. Study Design: Prospective Cohort Study. Methods: Patients with extraesophageal reflux symptoms and either partial- or nonresponders to twice-daily PPI under- went impedance monitoring on twice-daily PPI, as well as manometry, upper endoscopy, and 48-hour wireless pH monitoring off acid-suppressive medications for 1 week. Percent time pH < 4 and number of reflux episodes were obtained. Multivariable linear regression was used to determine association between the impedance data on therapy and upper endoscopy, manome- try, and pH parameters measured off therapy. Results: Seventy-five patients (77% female, median BMI 29, 38% with hiatal hernia, and 19% with esophagitis) were studied both on and off therapy. Thirty-five percent had abnormal impedance monitoring on therapy and 84% had abnormal pH testing off therapy. There was no significant ( P ¼ 0.184) overall correlation between total number of impedance events and the baseline physiologic parameters of hiatal hernia, degree of acid reflux, or manometric findings, with only weak corre- lation (r ¼ 0.54, P ¼ 0.045) with % time pH < 4 among patients with esophagitis. Conclusions: In patients with suspected extraesophageal reflux refractory to PPI therapy, impedance measures on ther- apy cannot be predicted from traditional baseline esophageal physiologic parameters. We recommend caution regarding over- interpretation of impedance data. Laryngoscope, 000:000–000, 2013 Key Words: Impedance, GERD, refractory reflux. Level of Evidence: 2b. Laryngoscope, 123:2463–2468, 2013

consistent compared to those with classic GERD. 5 Patients with presumed EER refractory to initial empiric medical therapy are often referred for further testing. Current guidelines recommend diagnostic testing, which can include the use of upper endoscopy and pH and/or impedance monitoring. 6 Combined impedance-pH monitoring can detect var- ious types of esophageal refluxate: gas, liquid, acid, or nonacid, and is used to clarify the mechanisms of PPI-re- fractory symptoms. 7–11 Multicenter studies utilizing impedance-pH testing in patients with PPI-refractory symptoms suggest that approximately one-third of patients exhibit weakly acid or nonacid reflux. In the background of potent acid suppression, the clinical significance of these findings currently remains contro- versial. While some advocate for the clinical utility of impedance-pH monitoring in assessing the impact of weakly acidic material on patients’ persistent symptoms, others are not as enthusiastic. Studies have suggested that 40% to 50% of patients with persistent symptoms on acid-suppressive therapy have no temporal correla- tion between their symptoms and any type of reflux. 12,13 While there is no doubt that impedance-pH testing is currently the most accurate and detailed method for detecting reflux of all kinds, the clinical indications for its use are still evolving. Its role in the management of GERD patients awaits further definition, mainly due to

INTRODUCTION Gastroesophageal reflux disease (GERD) is a com- mon disorder with increasing prevalence in the Western world. 1 Approximately 40% of adults frequently com- plain of heartburn, 2 and GERD remains the leading outpatient physician diagnosis for gastrointestinal disor- ders in the United States. 3 Extraesophageal reflux (EER) is widely implicated in the etiology of laryngeal, pharyngeal, and pulmonary symptoms, and controversy exists regarding the diagno- sis and management of this condition. 4 Currently, most patients with signs and symptoms attributed to EER are empirically treated with proton pump inhibitors (PPIs). However, symptomatic improvement on PPIs is not as From the Division of Gastroenterology, Hepatology and Nutrition ( R . T . K ., E . S . Y ., T . H ., M . F . V .), the Department of Biostatistics ( J . C . S .), the Vanderbilt Voice Center; Department of Otolaryngology ( C . G . G .), and the Allergy, Sinus and Asthma Program ( D . H .), Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A. Editor’s Note: This Manuscript was accepted for publication August 22, 2012. The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Michael F. Vaezi, MD, PhD, MSc (Epi), Division of Gastroenterology, Hepatology and Nutrition, Vanderbilt Uni- versity Medical Center, 1660 TVC, 1301 22nd Ave. South, Nashville, TN 37232-5280. E-mail: Michael.vaezi@vanderbilt.edu

DOI: 10.1002/lary.23734

Laryngoscope 123: October 2013

Kavitt et al.: The Role of Impedance Monitoring in Extraesophageal Symptoms

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