Bolus clearance in esophagogastric junction outflow obstruction is associated with strength of peristalsis

Background: A manometric diagnosis of esophagogastric junction outflow obstruction (EGJOO) without a mechanical cause creates a therapeutic conundrum. The aim of this study was to assess esophageal bolus clearance in EGJOO and assess manometric factors associated with clearance in EGJOO. Methods: Bolus clearance was assessed using line-tracing method and contour method to determine Complete Bolus Transit (CBT) and Functional Clearance (FC), respectively, on combined High-Resolution Impedance Manometry (HRIM). HRIM studies of EGJOO patients, as well as a sample of achalasia types I-III and asymptomatic controls, were retrospectively analyzed. In EGJOO, associations between Integrated Relaxation Pressure (IRP) or Distal Contractile Integral (DCI) and clearance were assessed using receiver-operating-characteristic (ROC) curves. Key Results: Seventy-five EGJOO, 28 achalasia, and 11 normal subjects were included. Agreement between CBT and FC was good (Kappa=0.75). CBT across swallows in each group was as follows: type I achalasia: 14%, type II achalasia: 8%, type III achalasia: 61%, EGJOO: 86%, and normal: 98% (p values.023,.006, and <.0001 for EGJOO vs normals, type III achalasia, and all achalasia, respectively). In idiopathic EGJOO, CBT ≥60% of swallows was seen in 96.4% of patients when mean DCI>610 mmHg-s-cm (accuracy 87.7%, P=.004). Complete Bolus Transit(CBT) across individual swallows was 97.8% when DCI>884 mmHg-s-cm (accuracy 81.9%, P<.0001). IRP was poorly associated with bolus clearance. Conclusions & Inferences: Bolus clearance in EGJOO is impaired compared to normal, but not as severely as in achalasia. In idiopathic EGJOO, weak peristalsis is associated with poor bolus clearance. Bolus transit appears to be unimpaired when DCI>900 mmHg-s-cm.