Utilizing intraluminal pressure gradients to predict esophageal clearance: a validation study.

BACKGROUND: Esophageal bolus clearance requires a preferential esophagogastric pressure gradient sustained for a sufficient period. We aimed to validate a high-resolution manometry (HRM) paradigm for predicting bolus clearance.
METHODS: Twenty volunteers and 30 patients were studied with HRM during barium swallows with concurrent fluoroscopy. Simultaneous bolus domain pressure and esophagogastric junction (EGJ) obstruction pressure were plotted and flow permissive time was tallied during which the bolus domain pressure exceeded the EGJ obstruction pressure. Distal peristaltic integrity was assessed at incrementally increasing pressure isobaric contour thresholds from 15-40 mmHg. ROC analysis was performed to assess the sensitivity and specificity of cutoff values for flow permissive time and peristaltic amplitude for predicting incomplete clearance as verified fluoroscopically.
RESULTS: Flow permissive time < or =2.5 s had a sensitivity of 86% and specificity of 92% for predicting incomplete clearance. In contrast, a 30-mmHg peristaltic amplitude had a sensitivity of only 48% and specificity of 88%. Incomplete clearance was variably attributable to functional EGJ obstruction, hiatus hernia, or impaired peristalsis.
CONCLUSIONS: A detailed analysis of intraluminal pressure gradients in the distal esophagus and across the EGJ in the postdeglutitive period predicts esophageal bolus clearance with far greater accuracy than any threshold value of peristaltic amplitude.