Straight Leg Raise Test Predicts Abnormal Acid Exposure Time in GERD Patients

The straight leg raise maneuver can help clinicians identify pathologic GERD.

Using a straight leg raise maneuver can increase the diagnostic value of high-resolution manometry (HRM) testing in patients with persistent gastroesophageal reflux disease (GERD) symptoms, according to study findings published in Clinical Gastroenterology and Hepatology.

Researchers conducted a prospective multicenter study ( Identifier: NCT04813029) across 13 high-volume esophageal function laboratories throughout Asia, Europe, and North America between July 2021 and March 2022. The objective of the study was to ascertain if increased esophageal pressure during a straight leg raise (SLR) predicted pathological esophageal acid exposure time (AET).

Researchers analyzed the data obtained from 364 adult patients between the ages of 18 and 75 years with persistent GERD symptoms. These patients underwent HRM testing according to the Chicago Classification version 4.0 protocol as well as esophageal pH and pH-impedance assessments.

Following this procedure, patients were asked to perform the straight leg raise (SLR) maneuver, lifting one leg with knee straight to an angle of 45 degrees for 5 seconds and repeating after 20 to 30 seconds.

The SLR maneuver can predict abnormal AET, thereby increasing the diagnostic value of HRM when GERD is suspected.

Prior to and during the SLR maneuver, intra-abdominal pressure and intraesophageal pressure were measured. If the intra-abdominal pressure increased by 50%, the SLR was considered effective. Out of the 364 patients, 295 (81%) demonstrated effective SLR maneuvers that increased intra-abdominal pressure by 50%, while the rest were excluded from the study.

Of the 295 patients with effective SLRs, 115 (39%) demonstrated AETs greater than 6%, which defined GERD. Patients with GERD had significantly higher peak intraesophageal pressure during SLR compared with those who had AETs below 6% (29.7 vs 13.9 mm Hg; P <.001).

An increase of 11 mm Hg of peak intraesophageal pressure from baseline was the optimal increase needed to predict AET greater than 6% (area under the curve [AUC], 0.84) with a sensitivity of 79% and a specificity of 85%.

Factors in addition to peak intraesophageal pressure that significantly predicted AET over 6% included the esophagogastric junction contractile integral and the morphology of esophagogastric junctions classified as subtypes 2 and 3. Subtypes 2 and 3 indicated the presence of a hiatal hernia to varying degrees.

“The SLR maneuver can predict abnormal AET, thereby increasing the diagnostic value of HRM when GERD is suspected,” the study authors wrote.

Study limitations include the fact that 19% of enrolled patients demonstrated noneffective SLRs; the different HRM and pH impedance systems used, which may have impacted metrics; and the higher body mass index (BMI) among patients in the GERD group, which increases intra-abdominal pressure. Additionally, the study did not include a control group with asymptomatic volunteers to determine normal SLR data.

Disclosures: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.


Siboni S, Kristo I, Rogers BD, et al. Improving the diagnostic yield of high-resolution esophageal manometry for GERD: The “straight leg-raise” international study. Clin Gastroenterol Hepatol. Published online October 18, 2022. doi:10.1016/j.cgh.2022.10.008