PWE-178 Hiatus hernia in healthy volunteers is associated with lengthening of the cardiac mucosa and intrasphincteric acid exposure without traditional reflux

Abstract

<h3>Introduction</h3> Hiatus hernia (HH) is a key mediator of reflux in patients with gastro-oesophageal reflux disease but little is known about the role of HH in the general population. Adenocarcinoma of the gastro-oesophageal junction (GOJ) often occurs in those with no prior history of reflux. We studied the GOJ in healthy volunteers with and without HH to determine if asymptomatic HH is associated with abnormalities which might predispose individuals to adenocarcinoma. <h3>Method</h3> We compared 15 volunteers with HH but without gastro-oesophageal reflux disease with 15 age and gender matched controls. Jumbo biopsy specimens were taken across the squamocolumnar junction (SCJ). High resolution pHmetry (12 sensors) and manometry (36 sensors) was performed in the upright and supine postures, before and after a meal. The SCJ was marked with an endoscopically placed clip and visualised fluoroscopically using the manometer as internal reference. <h3>Results</h3> The cardiac mucosa was significantly longer in those with HH (3.5mm, IQR 1.0) compared with controls (2.5mm, IQR 1.0) (p = 0.014). The SCJ was more proximally sited within the lower oesophageal sphincter (LOS) in those with HH at 1.23cm (IQR 2.07) from upper border LOS in HH group compared with 2.53cm (IQR 1.57) in controls (p = 0.019). There was more proximal extension of acid within the LOS in the HH group (1.1 cm (IQR 3.0) from upper border LOS in HH group vs 2.55cm in controls (IQR 4.73) (p = 0.022). Short segment reflux, measured 1cm above LOS was more pronounced in those with HH in the supine posture after the meal (pH below 4 5.45% of time in HH group vs 0.30% in controls, p = 0.011) but similar in the other phases studied. There was no evidence of excessive acid reflux at 5cm above LOS in either group. <h3>Conclusion</h3> In healthy volunteers with HH, there is intra-sphincteric extension of acid and short segment acid reflux without traditional reflux. The cardiac mucosa is lengthened which may represent metaplastic transformation and predispose to adenocarcinoma. <h3>Disclosure of interest</h3> None Declared.