Defining High-Resolution Manometry Thresholds of Backward Pressure Across the Lower Esophageal Sphincter Through Straight Leg Raise Maneuver Predictive of Pathologic Acid Exposure Time

It has been demonstrated a low sensitivity and specificity of HRM for GERD (53.6% and 72.5% respectively), since there was a significant overlap between patients and controls in the majority of parameters. Masuda et al. attempted to improve HRM accuracy using a comprehensive index and new parameters, such as the backflow preventive and promotive pressure through the lower esophageal sphincter (LES). Although a significant correlation between reflux burden and the new index was found, sensitivity and specificity of HRM for GERD remained unchanged.

Recently, provocative tests have been added to the standard protocol of HRM studies. Among these, a traditional maneuver in water perfused manometry (straight leg raise maneuver, SLR) appeared promising in predicting reflux even with HRM.

A multicenter study with a large number of patients could provide more precise thresholds to predict pathologic esophageal acid exposure time and proof of real-life generalizability of SLR.

A thorough clinical evaluation will be performed. GerdQ, GERD Health Related Quality of Life (GERD-HRQL) and Reflux Symptom Index (RSI) questionnaires will be administered. HRM will be performed according to the standard protocol defined by Chicago Classification 4.0. Upon completion of the test, the SLR maneuver will be performed. With the patient in supine position, one leg is raised to form an angle of at least 45 degrees with the bed. The patient will be asked to keep that position for at least 5 seconds. The maneuver will be repeated after 20-30 seconds. The first adequate maneuver will be considered for the study. Intra-esophageal and intra-abdominal pressure will be analyzed both during baseline and SLR maneuver. Intra-esophageal pressure is measured as peak and mean over 5 seconds, 1 cm and 5 cm above the proximal margin of the LES. Intra-abdominal pressure will be measured as peak and mean over 5 seconds 1 cm below the distal margin of the diaphragm notch.

Primary aim is to determine the optimal threshold of intra-esophageal pressure augmentation during straight leg raise (SLR) maneuver that predicted pathological esophageal acid exposure time (AET). Secondary aim is to assess the diagnostic performance of HMR with SRL maneuver in patients with GERD symptoms, calculating sensitivity, specificity, false-positive rate (FPR), false-negative rate (FNR) and total misclassification rate.