Characterization of pharyngeal hypocontractility patterns during deglutition: High Resolution Impedance Manometry findings

Introduction High resolution impedance manometry (HRIM) provides an objective measure of pharyngeal pressurization and bolus flow and can be analysed using pressure flow analysis (PFA). The aim of the study is to investigate different types of pharyngeal hypocontractility and their distribution in patients with pharyngeal dysphagia. Material and Methods A cohort study was conducted on patients with dysphagia referred for HRIM. Inclusion criteria were abnormal (<5th percentile) pharyngeal contractile integral (PhCI) or abnormal regional contractile integrals (velo- or meso- or hypo-pharyngeal integrals). PFA was performed on 10ml liquid swallows using the Swallow GatewayTM open access analysis portal. Patients were classified based on a proposed HRIM scheme. The distribution of PFA metrics was compared between patients with normal and abnormal PhCI using the chi-squared test. Results In total 38 patients were studied and 137 swallows were analysed. Absent pharyngeal contractility was found in 5.3% (2/38) of the patients, ineffective pharyngeal contractility in 68.4% (26/38), and fragmented pharyngeal contractility in 26.3% (10/38). Regional weakness was mainly observed in the mesopharynx (94.7% of the patients), followed by the hypopharynx (50%) and the velopharynx (15.8%). A combined disorder of pharyngeal propulsion and UES restriction was seen in 44.7% (17/38) of the patients. Patients with a normal PhCI (fragmented pharyngeal contractility) were more likely to present an abnormal integrated relaxation pressure at the level of the upper esophageal sphincter (χ2=14.56, p=0.001) Conclusion Based on the pharyngeal contractile integrals, two main types of pharyngeal hypocontractility are present in the clinical population of patients: ineffective and fragmented pharyngeal contractility. Totally absent peristalsis in uncommon. In almost half of the patients, pharyngeal propulsion disorders are combined to disorders of UES restriction.