Abstract
BACKGROUND: Gastroesophageal reflux disease (GERD) arises from dysfunction of the anti-reflux barrier. While high-resolution manometry (HRM) is routinely performed in suspected GERD, traditional metrics are poor predictors. The routine adoption of the straight leg raise (SLR) maneuver has unveiled a series of unaddressed challenges. This study aimed to determine the minimum intra-abdominal pressure (IAP) increase for effectively stressing the esophago-gastric junction (EGJ), the optimal intra-esophageal pressure (IEP) increase threshold for GERD prediction, and explore EGJ behavior in GERD and non-GERD patients. METHODS: We performed a retrospective review of HRM tracings and pH-impedance studies of consecutive adult patients with GERD symptoms. Peak and mean IAP and IEP during the reference period and SLR were recorded. The SLR was effective if the EGJ-contractile integral (EGJ-CI) during the maneuver increased by 50% compared to baseline. GERD was diagnosed based on Lyon 2.0. The optimal thresholds for effective and positive SLR were determined using the receiver operator characteristics analysis. RESULTS: Among the 298 patients included (53% females, age 52 years, BMI 24 kg/m(2)), 145 had GERD. A delta mean IAP increase of 15.4 mmHg best predicted effective EGJ challenge (AUC 0.825). A delta peak IEP increase of 11.4 mmHg optimally predicted GERD (AUC 0.777), aligning with the prior threshold (11 mmHg). Non-GERD patients exhibited higher EGJ-CI during SLR, reflecting intact anti-reflux barrier function. CONCLUSIONS: The SLR maneuver enhances GERD diagnosis in HRM by dynamically assessing EGJ competence. Our study validated the thresholds to define an effective (mean IAP increase of 15.4 mmHg) and positive (peak IEP increase of 11.4 mmHg) maneuver.