A correlation of computed tomographic esophageal hiatal cross-sectional surface area between brachycephalic and nonbrachycephalic cats.

In humans and dogs, especially brachycephalics, enlargement of the esophageal hiatus and insufficiency have been correlated with decreased lower esophageal sphincter pressure and increased frequency of gastroesophageal reflux. In cats, it has been suggested that gastroesophageal reflux occurs frequently with upper airway obstruction, including brachycephalics. Therefore, the purpose of the study was to determine whether the esophageal hiatal cross-sectional surface area (EH-CSA) differs between brachycephalic and nonbrachycephalic cats. Clinical records and CT images of cats that underwent thoracic, abdominal, and entire skull CT at multiple centers between January 2015 and September 2022 were retrospectively reviewed. Esophageal hiatal parameters (EH-CSA, EH-long axis diameter, and EH-short axis diameter) and craniometric indices (cranial index, skull index, and facial index) were measured by using multiplanar reconstruction, and the correlation of craniometry with EH-CSA was investigated. Ninety-eight cats (group 1: 42 brachycephalic cats and group 2: 56 nonbrachycephalic cats) were included. Esophageal hiatal cross-sectional surface area in brachycephalic cats was significantly larger than that in nonbrachycephalic cats. The EH-CSA significantly increased with the craniometric indices tending to increase with brachycephalism. The present study contributes to the veterinary literature by providing the EH-CSA as anatomical evidence that could likely correlate to gastroesophageal reflux predisposition in brachycephalic cats.