Computed tomographic comparison of esophageal hiatal size in brachycephalic and non-brachycephalic breed dogs.

Abstract

OBJECTIVE: To determine whether an anatomical difference in esophageal hiatus (EH) size exists between brachycephalic and nonbrachycephalic dogs. STUDY DESIGN: Retrospective clinical study. ANIMALS: Client-owned dogs (n = 87). METHODS: Clinical records and images of dogs that underwent computed tomography between June 2015 and September 2018 were reviewed. For the first part of the study, EH and aortic (Ao) cross-sectional surface areas were measured in brachycephalic (group 1) and nonbrachycephalic dogs of similar body size (<15&#x2009;kg) without respiratory or gastroesophageal (GE) signs (group 2) by using multiplanar reconstruction. Esophageal hiatus:aortic ratio was calculated. In the second part of the study, absolute EH measurements were also compared in weight-matched (WM) dogs (8-10&#x2009;kg) from groups 1 and 2. RESULTS: Mean (&#xb1;SD) of EH:Ao values for group 1 (8.1&#x2009;&#xb1;&#x2009;2.8) were higher (P&#x2009;<&#x2009;.0001) than those for group 2 (3.7&#x2009;&#xb1;&#x2009;1.1). In addition, EH measurements of 20 WM dogs in group 1 were higher than those of 20 dogs in group 2 (P&#x2009;<&#x2009;.05). CONCLUSION: Esophageal hiatus cross-sectional surface area (directly and indirectly measured) in brachycephalic dogs was considerably larger than that in nonbrachycephalic dogs of generally similar body size. CLINICAL SIGNIFICANCE: Results of this study provide evidence to support the existence of a specific anatomical factor that could likely correlate to functional GE alterations (eg, regurgitation, gastroesophageal reflux, and sliding hiatal hernia) commonly seen in brachycephalic dogs.