Assessment of Esophagogastric Junction Barrier Function With the Supine-Upright Transition of the Chicago Classification Protocol

Background & Aims: The straight leg raise (SLR) is a provocative maneuver used to assess the esophagogastric junction (EGJ) barrier function during high-resolution manometry (HRM) and is part of the Milan Score (MS). The Chicago Classification 4.0 (CCv4.0) protocol requires patients to perform a supine-upright transition (SUT), increasing intra-abdominal pressure (IAP). The aim of this study was to compare the SUT and SLR maneuvers for efficacy in increasing IAP and in predicting pathologic gastroesophageal reflux disease (GERD). Methods: Consecutive adult patients with persistent GERD symptoms undergoing HRM and pH-impedance were prospectively enrolled. After completion of the supine swallows of the CCv4.0 protocol, the SLR maneuver was performed and the patients were asked to get up to the upright position (SUT). IAP and intra-esophageal pressure (IEP) were recorded at baseline and during the maneuvers. GERD was defined as acid exposure time > 6% according to Lyon 2.0. Results: Among the 110 patients included (age 55 years; 59.1% female, BMI 25.4 kg/m²) SUT was effective in 94 and SLR in 85. SUT was more sensitive than SLR (77.4% vs. 71.0%) but less specific (63.5% vs. 79.6%) in predicting GERD. On ROC analysis, the AUC of the MS-SUT was 0.825 and MS-SLR 0.854. When both maneuvers were effective (73 patients) SUT predicted GERD in 69.9%, SLR in 76.7% (p = 0.192). When concordant (52 patients) sensitivity and specificity were 88% and 80%, and the AUC of the MS was 0.872. Conclusions: SUT is comparable to SLR, with higher sensitivity but lower specificity. When both are concordant, the SUT can strengthen confidence in SLR and increase the accuracy of the Milan Score.