P339 Novel approach to assess retention in dysphagia patients with post anti-reflux surgery

Introduction There are no high-resolution manometry (HRM) classification guidelines to assess patients’ dysphagia occurring post anti-reflux surgery. In this study we will explore the use of multichannel intraluminal impedance transit (MIIT) to explain patients’ post-surgical dysphagia. Method Subjects were selected between January 2018 and December 2019 who underwent HRM with normal motility findings1 followed by MIIT study.2 Subjects were grouped into (i) patients asymptomatic of dysphagia with treatment-naive oesophagus (control group) and (ii) patients with dysphagia and intact post antireflux operation (patient group). The oesophageal transit times in the patient group was compared with the control group and then compared with the oesophageal transit observed in OGJ obstruction (>1.64 mins) that was previously published.2 Results Total of 59 subjects were selected (F:M=38:21, aged 20–75 years old). 32.2% (19/59) were post-surgical patients complaining of dysphagia (15 Nissen fundoplication and 4 LINX procedure) (these patients had mean integral relaxation pressure of 12.4 mmHg). The 5%-95% confidence interval in oesophageal transit time demonstrated in the patient group and control group were respectively 2.57 – 12.06 mins and 0.32 - 0.41 mins (p=0.0051). The oesophageal transit time in 63.2% (12/19) patients exceeded 1.64 mins which is consistent with oesophageal transit time found in OGJ obstruction. Conclusion This novel MIIT technique may explain patients’ post-surgical dysphagia which HRM failed to capture. Notably, the majority of patients actually show oesophageal transit time comparable to OGJ obstruction who may benefit from dilatation or BoTox. References Kahrilas P, et al. Neurogastroenterol Motil 2015;27(2):p160–174. Miah I, et al. BMJ Gut 2019;68:pA214.