DESIGN: Manometry studies from asymptomatic adults were solicited from motility centers worldwide, and were manually analyzed using integrated relaxation pressure (IRP), distal latency (DL), and distal contractile integral (DCI) in standardized fashion. Normative thresholds were assessed using fifth and/or 95th percentile values. Chicago Classification v3.0 criteria were applied to determine motor patterns across HRM systems, study positions (upright vs supine), ages, and genders.

RESULTS: Of 469 unique HRM studies (median age 28.0, range 18-79 years). 74.6% had a normal HRM pattern; none had achalasia. Ineffective esophageal motility (IEM) was the most frequent motor pattern identified (15.1% overall), followed by EGJ outflow obstruction (5.3%). Proportions with IEM were lower using stringent criteria (10.0%), especially in supine studies (7.1%-8.5%). Other motor patterns were rare (0.2%-4.1% overall) and did not vary by age or gender. DL thresholds were close to current norms across HRM systems, while IRP thresholds varied by HRM system and study position. Both fifth and 95th percentile DCI values were lower than current thresholds, both in upright and supine positions.

METHODS: A population of 295 consecutive patients undergoing HRM and pH-study for persistent typical or atypical GERD symptoms was prospectively enrolled to build a model and a nomogram that provides a risk score for AET > 6%. Collected HRM data included IEM, EGJ-CI, EGJ type and SLR. A supplemental cohort of patients undergoing HRM and pH-study was also prospectively enrolled in 13 high-volume esophageal function laboratories across the world in order to validate the model. Discrimination and calibration were used to assess model's accuracy. Gastroesophageal reflux disease was defined as acid exposure time >6%.

RESULTS: Out of the analyzed variables, SLR response and EGJ subtype 3 had the highest impact on the score (odd ratio 18.20 and 3.87, respectively). The external validation cohort consisted of 233 patients. In the validation model, the corrected Harrel c-index was 0.90. The model-fitting optimism adjusted calibration slope was 0.93 and the integrated calibration index was 0.07, indicating good calibration.

CONCLUSIONS: A novel HRM score for GERD diagnosis has been created and validated. The MS might be a useful screening tool to stratify the risk and the severity of GERD, allowing a more comprehensive pathophysiologic assessment of the anti-reflux barrier.

DESIGN: Of 541 studies performed worldwide using two different systems (Diversatek, USA, and Laborie, Netherlands), 150 tracings with oesophageal diagnoses, behavioural disorders and study-related artefacts were excluded. The remainder studies were subject to two reviewer consensus analysis, in-person or through video conference, consisting of editing meals and pH drops, identification of impedance reflux and postreflux swallow-induced peristaltic wave (PSPW) using strict pre-established criteria and measurement of distal mean nocturnal baseline impedance (MNBI).

RESULTS: Consensus analysis was performed in 391 tracings (age 32.7 years, range 18-71, 54.2% female). Normative thresholds were significantly different between Diversatek and Laborie (total acid exposure time: 2.8% and 5%; reflux episodes: 55 and 78; MNBI at 3 cm: 1400 and 1500 ohms, at 5 cm: 1400 and 1800 ohms). Males had higher acid exposure, more reflux episodes and lower MNBI. Significant regional differences were identified, including higher PSPW scores in Western countries, and higher MNBI in Asia using Diversatek, and higher acid exposure in the Netherlands, higher MNBI in Asia and South Africa, and lower MNBI in Turkey using Laborie.

METHODS: Our aim was to determine normative EGJ metrics in a large international cohort of healthy volunteers undergoing HRM (Medtronic, Laborie, and Diversatek software) acquired from 16 countries in four world regions. EGJ-CI was calculated by the same two investigators using a distal contractile integral-like measurement across the EGJ for three respiratory cycles and corrected for respiration (mm Hg cm), using manufacturer-specific software tools. EGJ morphology was designated according to Chicago Classification v3.0. Median EGJ-CI values were calculated across age, genders, HRM systems, and regions.