Severe reflux disease is associated with an enlarged unbuffered proximal gastric acid pocket

Background: An unbuffered pocket of highly acidic juice is observed at the gastric cardia after a meal in healthy subjects. Aims: To compare the postprandial acid pocket in healthy subjects and patients with severe reflux disease and define its position relative to anatomical and manometric landmarks. Methods: 12 healthy subjects and 16 patients with severe reflux disease were studied. While fasted, a station pull-through was performed using a combined dual pH and manometry catheter. Position was confirmed by radiological visualisation of endoscopically placed radio-opaque clips. The pull-through study was repeated 15 min after a standardised fatty meal. Barium meal examination was performed before and following the meal. Results: A region of unbuffered acid (pH <= 2) immediately distal to the proximal gastric folds was more frequent in reflux patients (23/32 studies) than in healthy subjects (11/24) (p < 0.05). This unbuffered acid pocket was longer in the reflux patients than in the healthy subjects (median length 3 cm (range 1-15) vs 2 cm (range 1-5); p < 0.05). The acid pocket extended proximally as far as the proximal gastric folds in the patients but stopped a median of 1.1 cm distal in healthy subjects (p=0.005). In healthy subjects the acid pocket occupied the distal portion of the sphincter which opened postprandially, whereas in reflux patients it corresponded to the proximal displacement of the gastric folds-that is, hiatus hernia. Conclusion: This enlarged region of unbuffered postprandial acidic juice observed in the patients just below the gastro-oesophageal junction may contribute to the aetiology of severe reflux disease.