High-resolution manometry and impedance-pH/manometry: novel techniques for the advancement of knowledge on esophageal function and their clinical role.

The study of esophageal function is based on the study of esophageal motor activity using conventional esophageal manometry (CEM), which has proven useful in the diagnosis of patients with functional dysphagia and other esophageal motor disorders (1). Most consensus guidelines recommend contractile activity monitorization with 4 to 8 sensors, including a 6-cm “e-sleeve” to minimize displacement at the lower esophageal sphincter (LES) (2). In the last few years new techniques are allowing a better understanding of esophageal motor disorders. These include high-resolution manometry (HRM) and impedance combined with manometry. Both are relevant research tools that are being increasingly implemented in daily clinical practice (3). The study of pathological acid reflux as a potential cause for most motor disorders and symptoms as experienced by patients with functional esophageal disease is undertaken with a 24-hour ambulatory pH-metry with one or several recording sites, and is still considered the gold standard for the study of non-erosive gastroesophageal reflux disease (GERD). However, there is a growing interest in the diagnosis of patients with atypical reflux complaints and of those refractory to therapy with proton-pump inhibitors (PPIs), where pH-metry plus impedance plays a relevant role given its ability to detect weakly acidic or non-acidic reflux episodes (4).