INTRODUCTION AND BACKGROUND
The use of oesophageal high resolution manometry (HRM) to evaluate patients who present with oesophageal symptoms in the absence of a structural lesion has revolutionised the measurement of oesophageal motility. Oesophageal HRM analysis by the Chicago Classification1 based on measurements during 10×5 mL single water swallows (SWS) is the current gold standard for the diagnosis of oesophageal motility disorders. However, prior studies have shown that testing oesophageal motility with SWS alone is not representative of normal oesophageal function2-4 and the findings do not correlate well with symptoms.5 Dysphagia usually occurs during rapid drinking or consuming food rather than during SWS. In a retrospective series of patients who underwent routine HRM with SWS and a solid test meal (STM), we demonstrated an increased diagnostic yield of major motility disorders.6 We further validated the use of a STM in a prospective study of patients presenting with oesophageal symptoms in an Asian cohort. The aims of the study were to determine if addition of a standardised STM in routine clinical practice i) improves the sensitivity of oesophageal HRM to clinically relevant oesophageal dysfunction and ii) improves detection of symptom-associated oesophageal dysfunction.
In this prospective single-centre study conducted at Changi General Hospital, Singapore between December 2014 and June 2016, all patients presenting with dysphagia or reflux evaluation underwent routine HRM after acid suppressive medications and/or prokinetics were stopped for 1 week. A minimum period of fasting for 6 hours was required, and informed consent was obtained. HRM was performed using a 36-channel solid-state catheter with circumferential pressure sensors arranged at 10 mm intervals (ManoScan™ 360, Sierra Scientific Instruments, California, USA). Patients underwent evaluation in the seated position, with 10×5 mL SWS followed by a STM (200 g boiled rice). HRM analysis was performed using Manoview 3.0 (Sierra Scientific Instruments). Our classification of water swallows and solid swallows was based on the Chicago Classification version 3.01 modified for use in the upright position.3,4 The key difference in the analysis for a STM was the upper limit of normal for the integrated relaxation pressure (25 mmHg rather than 15 mmHg). This was due to the increased viscous resistance to bolus transport of solids compared to liquids.
Out of 152 patients recruited, a total of 146 patients (68 male) with a mean age of 50.1±16.8 years underwent HRM with SWS and STM for evaluation of dysphagia (n=72), reflux evaluation (n=59), and unexplained chest pain (n=21). More patients were diagnosed with oesophageal gastric junction outflow obstruction with a STM (n=9/146, 6.2%) compared to SWS alone (n=2/152, 1.3%, p<0.005). Similarly, we observed an improved yield for a diagnosis of hypercontractile (jackhammer) oesophagus (n=9/146, 6.2% versus n=5/152, 3.3%) and oesophageal spasm (n=5/146, 3.4% versus (n=2/152, 1.3%) for STM compared to SWS respectively, although the differences for these rare disorders were not significant. We observed the reverse for patients diagnosed with ineffective oesophageal motility, with significantly more patients diagnosed with ineffective oesophageal motility with SWS alone (n=23/152, 15.1%) versus STM (n=8/146, p=0.0075). Furthermore, compared to SWS alone, STM improved the detection of oesophageal symptoms with 31/146 (21%) of patients having a positive symptom associated dysfunction compared to 0.7% with SWS alone. Most of the symptomatic patients (n=20/31 65%) had a positive symptom associated dysfunction for dysphagia.
Diagnostic sensitivity was improved with more patients diagnosed with a major motility disorder and a positive symptom associated dysfunction, whilst diagnostic specificity was enhanced with fewer patients diagnosed with a clinically irrelevant minor motility disorder during the STM study. This relatively easy intervention does not increase costs and procedural times (including analysis), which are <10 minutes. We consider that the additional diagnostic yield supports the inclusion of this adjunctive test during routine oesophageal HRM and potentially represents a paradigm shift from the conventional practice of using SWS alone.