Effect of Hiatal Hernia and Esophagogastric Junction Morphology on Esophageal Motility: Evidence from High-Resolution Manometry Studies.

Background High-resolution Manometry (HRM) is the most sensitive and specific test available for clinical assessment of hiatal hernia (HH), a common condition defined as the separation between the Lower Esophageal Sphincter (LES) and crural diaphragm (CD). While the link between HH and Gastroesophageal Reflux Disease (GERD) is established, the potential association of HH with esophageal dysmotility, independently from GERD, is uncertain. This study aimed to analyze if HH, with or without GERD, can associate with esophageal motility disorders. Methods Consecutive patients without previous esophageal surgery who underwent HRM between 2018 and 2022 were enrolled. All patients with symptoms suggestive of GERD underwent impedance-pH testing off-therapy. HH was defined as a separation >1 cm between LES and CD, and esophagogastric junction (EGJ) morphology was classified as: Type I, when there was no separation between LES and CD; Type II, in case of minimal separation (>1 and <3 cm); Type III, when >= 3 cm of separation was present. Demographic and clinical characteristics were collected at baseline, including Age, Gender, Alcohol-, Coffee- and Smoke-habits, GERD diagnosis and symptoms' duration. Two cohorts of patients, with and without HH, were retrospectively individuated, and their association with Ineffective Peristalsis, Hypercontractile Esophagus and Outflow Obstruction was analyzed with univariate and multivariate Logistic regressions using the statistical software R. Key Results 848 consecutive patients were enrolled, and 295 cases of HH (34.8%), subdivided into 199 (23.5%) Type II- and 96 (11.3%) Type III-EGJ patients, were identified. Ineffective peristalsis was diagnosed in 162 (19.1%) subjects, Hypercontractile esophagus in 32 (3.8%), and Outflow Obstruction in 91 (10.7%), while GERD was present in 375 (44.2%) patients. HH was significantly associated with Ineffective Peristalsis (p < 0.001) and GERD (p < 0.001). Furthermore, HH resulted to be a risk factor for Ineffective peristalsis (OR 2.0, 95% CI 1.4-2.8, p < 0.001) both when the analysis was conducted in all the 848 subjects, independently from GERD, and when it was carried out in patients without GERD (OR 2.3, 95% CI 1.02-5.3, p = 0.04). The risk for Ineffective Peristalsis increased 1.3 times for every centimeter of HH. No statistically significant association was found between HH and Outflow obstruction or Hypercontractile Esophagus. Conclusions & Inferences An increasing separation between the LES and CD may lead to a gradual and significant elevation in the risk of Ineffective Peristalsis. Interestingly, this association with HH is true in patients with and in those without GERD, suggesting that the anatomical alteration seems to play a major role in motility change.