Enhancing Surgical Decision-Making with High-Resolution Manometry and Distal Contractile Integral in Preoperative Assessment for Magnetic Sphincter Augmentation (LINX)

Abstract Background Preoperative assessment for magnetic sphincter augmentation (MSA) (LINX) involves evaluating the Mean Distal Amplitude (MDA) on conventional manometry to assess the patient suitability and risk of post-operative dysphagia. In the last decade high-resolution manometry (HRM) has superseded conventional manometry owing to obtaining more clinical information on the oesophageal motility, including the Distal Contractile Integral (DCI) that incorporates contractile amplitude, duration and contractility propagation length within the oesophageal body. The purpose of this study is to translate the MDA to modern DCI as preoperative marker to MSA. Methods This retrospective study includes patients referred to oesophageal laboratory at Guy’s Hospital between March and May 2023. Patients underwent HRM with ten 5ml water swallows that provided manometric information to compute mean DCI and MDA (MDA waveforms at 11cm, 7cm and 3cm above the GOJ were used). Statistical analysis investigated the relationship between MDA and mean DCI using Pearson correlation, Student t-test, ROC curve analysis and relevant metrics assess the cut-off threshold accuracy and reliability in classifying normal MDA. Results 270 patients were included in the study (female:male=190:80 males, mean age 52.1 years). There was strong direct correlation between MDA and mean DCI (r=0.71, p<0.0001) (Figure 1). Patients with normal MDA had a significantly higher mean DCI compared with weak MDA at 11cm (601mmHgscm vs 167.15mmHgscm, p<0.0001) 7cm (286.4mmHgscm vs 741mmHgscm, p<0.001), 3cm (592mmHgscm vs 192.6mmHgscm, p<0.0001) and overall MDA (714.2mmHgscm vs 259mmHgscm, p<0.001) (Figure 2). ROC curve analysis revealed the mean DCI thresholds for normal MDA to be 615mmHgscm at 11cm, 419mmHgscm at 7cm, 318mmHgscm at 3cm and 453mmHgscm for the overall MDA (Table 1). Conclusions The findings of this study show HRM and the clinical measurement DCI may be a suitable preoperative assessment for MSA. This translation of MDA to modernisation in manometry may assist surgeons adopt DCI which is regarded as more robust assessment that offers more detailed clinical information of the oesophageal motility health and disorder.