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.
The Principal Investigator will maintain research data on an encrypted file server with
access controls only accessible to approved study investigators. Research records will be
de-identified using coded subject identifiers prior to transfer from sites to the Principal
Investigator to protect patient confidentiality. Study data will be maintained by the
Principal Investigator and deleted 3 years after the end of the study.
Data from each site will be electronically transferred to Principal Investigator. The
electronic copy will contain no patient identifying data elements such as name, date of
birth, medical record numbers. Participating institutions will create unique patient
participant numbers based on a standard formula allocated by Principal investigator (two
digit institution code, two digit patient identifier, 01-20).