Retrospective analysis of esophageal imaging features in brachycephalic versus non-brachycephalic dogs based on videofluoroscopic swallowing studies

Anatomical differences of the cervical esophagus in brachycephalic dogs

This study investigated anatomical variations of the cervical esophagus in brachycephalic dogs (n=16 Shih Tzus/French Bulldogs) compared to mesocephalic controls (n=16 mixed-breed) through cadaveric dissection. Results revealed that 93.75% of brachycephalic dogs exhibited ventral esophageal sacculation, with 100% prevalence in French Bulldogs versus 92.3% in Shih Tzus. The esophagus showed abnormal ventral/lateral positioning at the thoracic inlet, overlapping the trachea (93.75% of cases) and obscuring its left lateral view, contrasting with mesocephalic anatomy. These alterations correlate with literature reports of esophageal dysfunction in brachycephalic breeds, including reflux (67.39% prevalence in CT studies) and hiatal herniation. The findings suggest that extreme craniofacial conformation exacerbates anatomical deviations, potentially contributing to clinical complications like dysphagia and aspiration. Surgical implications include modified approaches for airway procedures due to altered vascular relationships (left common carotid artery proximity) and esophageal fragility. Limitations include sample bias toward Shih Tzus (81.25%). This study highlights the need for breed-specific anatomical assessments in clinical/surgical management of brachycephalic dogs.

Comparing methods for detection of gastro-oesophageal reflux in anaesthetized dogs

OBJECTIVE

To compare the sensitivity and specificity of pH with multichannel intraluminal impedance (pH-MII), pH-metry (pH) alone and MII alone to direct observation of GOR by endoscopy in anaesthetized dogs.

STUDY DESIGN

A prospective comparative trial in a live canine model.

ANIMALS

A group of 35 (22 females, 13 males) dogs of various breeds. The mean (range) body weight and age were 31.9 (14-40) kg and 5.6 (0.75-12) years, respectively.

METHODS

All dogs were premedicated with medetomidine and morphine, anaesthesia was induced with propofol and maintained on isoflurane in oxygen. A monitoring assembly consisting of an endoscopy camera, endotracheal tube and a disposable flexible pH-MII catheter was used to measure oesophageal pH, MII and directly visualize reflux. Visual reflux score was (0-3) and pH was recorded on a data capture sheet. Reflux was considered to have occurred whenever oesophageal pH was < 4.0 or > 7.5, device software analysing MII data detected fluid or a visual reflux score of 2 or 3 were assigned. Receiver operator curves (ROC) analysis was used to determine sensitivity and specificity for each monitoring method to detect GOR.

RESULTS

Endoscopy identified GOR in 20 dogs (57%), pH-MII in 19 dogs (54%), pH alone in 13 dogs (37%) and MII alone in 12 dogs (24%). ROC analysis showed fair accuracy for pH-MII and pH alone, whereas MII demonstrated low accuracy.

CONCLUSIONS AND CLINICAL RELEVANCE

In conclusion, pH-MII is a reliable method for detecting GOR and emerges as a promising tool for future research. Endoscopy is reliable and provides the ability to subjectively quantify the volume of reflux; however, it lacks the ability to discern the pH of refluxate. pH alone misses reflux events with intermediate pH (4.1-7.4). Incorporation of impedance addresses some of the limitations associated with pH alone and enhances diagnostic accuracy.

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.

Evaluating acidic gastroesophageal reflux with wireless pH monitoring in French bulldogs with sliding hiatal herniation

BACKGROUND

Sliding hiatal herniation (SHH) and gastroesophageal reflux (GER) commonly occur in French bulldogs. Wireless pH monitoring can quantitatively assess acidic GER in dogs affected by SHH.

HYPOTHESIS/OBJECTIVES

Measure acidic GER in French bulldogs with SHH, pre- and post-brachycephalic obstructive airway syndrome (BOAS) surgery, utilizing a wireless pH capsule (Bravo Calibration-free, Medtronic, Minnesota), and correlate with owners' observations of regurgitation.

ANIMALS

Eleven French bulldogs diagnosed with SHH via swallowing fluoroscopy.

METHODS

Prospective cohort study. A pH capsule was endoscopically placed in the esophagus. Up to 96 hours of data were acquired as the owner logged clinical signs. Spearman's correlation and Wilcoxon rank-sum tests evaluated factors correlated with acid exposure time (AET), defined by the % time pH < 4. In 4/11 dogs, Bravo monitoring was repeated 2-4 months after BOAS surgery.

RESULTS

Medians (Q1-Q3) for age and weight were 21 months (17-35.5) and 10.0 kg (8.9-11.5). BOAS severity was mild (3), moderate (4), or severe (4). Medians (Q1-Q3) for AET and reflux events were 3.3% (2.6-6.4) and 70 (34-173). Clinical score (P = .82) and BOAS severity (P = .60) were not correlated with AET, but age was negatively correlated (rho = -.66, P = .03). Median probability (Q1-Q3) that regurgitation was associated with a reflux event was 72.5% (0-99). Percent AET numerically improved in all 4 dogs that underwent BOAS surgery although not statistically assessed.

CONCLUSIONS AND CLINICAL IMPORTANCE

Wireless pH monitoring documented acidic GER in French bulldogs with SHH, captured subclinical events, and showed improvements after BOAS surgery.

Influence of feline brachycephaly on respiratory, gastrointestinal, sleep, and activity abnormalities

OBJECTIVE

To determine the influence of brachycephaly on respiratory, gastrointestinal, sleep, and activity-related parameters in cats.

STUDY DESIGN

Prospective questionnaire-based study.

ANIMALS

A total of 194 BC and 1003 non-BC cats.

METHODS

Owners completed an online questionnaire regarding respiratory, gastrointestinal, sleep, and activity-related parameters. Response options were scored, and individual scores summed to give a total clinical severity score for each cat.

RESULTS

Brachycephalic cats had more frequent snoring (odds ratio [OR] 6.89; 95% confidence interval [CI]: 5.06-9.41), sneezing (OR 6.52; CI: 4.75-8.98), nasal discharge (OR 8.26; 95% CI 5.77-11.85), coughing (OR 1.75; CI: 1.17-2.59), and dyspnea (OR 5.32; CI: 3.42-8.28); shorter activity before becoming dyspneic (OR 2.71; CI: 1.93-3.79), slower recovery from activity (OR 3.17; CI: 2.19-4.57), lower activity levels (OR 2.16; CI: 1.59-2.95), and increased respiratory noise (OR 6.68; CI: 4.71-9.52); and more hypersalivation (OR 2.50; CI: 1.47-4.16), halitosis (OR 1.40; CI: 1.00-1.95), and difficulty chewing (OR 5.19; CI: 3.65-7.38). Median clinical severity scores were higher for BC cats than non-BC cats (p < .0001).

CONCLUSIONS

Brachycephalic cats (BC) were at risk for respiratory, gastrointestinal, and activity-related symptoms compared to non-BC cats.

CLINICAL RELEVANCE

Some BC cats exhibit clinically relevant symptoms and behaviors as reported by owners. Medical or surgical interventions may improve these symptoms and warrant investigation.

Ala vestibuloplasty improves cardiopulmonary and activity-related parameters in brachycephalic cats

OBJECTIVE

To evaluate the effects of ala vestibuloplasty on cardiopulmonary and lifestyle-related parameters in brachycephalic (BC) cats.

STUDY DESIGN

Prospective cohort.

ANIMALS

Client-owned BC cats (n = 19).

METHODS

Cats were assessed preoperatively by airway computed tomography (CT), endoscopy, contrast echocardiography, cardiac biomarkers, and structured owner questionnaire. Ala vestibuloplasty was performed bilaterally, and blood values, imaging, and owner questionnaire responses were re-evaluated 8-20 weeks postoperatively.

RESULTS

Cats were presented for predominantly respiratory clinical signs attributable to brachycephaly. Preoperatively, all cats had stenotic nares, prolonged normalized pulmonary transit time (nPTT) (mean 5.43 ± 1.10 s), and a hyperattenuating pulmonary pattern. No complications occurred following surgery. Postoperatively, nPTT (mean 3.89 ± 0.74 s, p < .001) and frequencies of sneezing (p = .002), snoring (p = .006), open-mouth breathing (p = .0004), and nasal discharge (p = .019) were decreased. Cats exhibited increased activity (p = .005), less frequent dyspnea during activity (p < .001), longer duration of activity before becoming dyspneic (p = .002), faster recovery from activity (p < .001), and decreased respiratory noise (p < .001). Median questionnaire scores improved from preoperative to postoperative (p < .001).

CONCLUSION

Anatomic, echocardiographic, and CT changes were common in this cohort of clinically affected BC cats. Pulmonary blood flow and respiratory function were improved after surgery.

CLINICAL SIGNIFICANCE

Stenotic nares are the predominant airway abnormality in BC cats. Ala vestibuloplasty is a safe procedure that improves cardiac and CT abnormalities and respiratory and other clinical signs in BC cats.

Prevalence of gastroesophageal reflux in dogs undergoing MRI for a thoracolumbar vertebral column pathology

OBJECTIVES

The aims of the study were to investigate the prevalence and extent of gastroesophageal reflux, and the prevalence of regurgitation in dogs undergoing thoracolumbar spine magnetic resonance imaging, and to explore possible associations of reflux and regurgitation with signalment (breed, age, sex, neuter status), bodyweight, body condition score and drugs used in the anaesthetic protocol.

MATERIALS AND METHODS

The thoracic part of the oesophagus was retrospectively assessed for presence and quantification of fluid on two T2 weighted sequences. Patient breed, age, sex, neuter status, weight and body condition score were recorded. Anaesthetic records were reviewed for the presence of regurgitation and detailed anaesthetic protocols.

RESULTS

Fifty percent [95% confidence interval (44.99, 56.81)] of included dogs had evidence of gastroesophageal reflux. Reflux was not associated with the individual breed, age, sex, neuter status or body weight. Brachycephalic dogs did not demonstrate significantly higher rates of reflux compared to non-brachycephalic dogs. A larger volume of reflux was associated with a higher chance of regurgitation.

CLINICAL SIGNIFICANCE

Gastroesophageal reflux is a common finding in dogs undergoing thoracolumbar spine magnetic resonance imaging. Dogs which regurgitated had higher volumes of reflux. Early detection and quantification of the volume of reflux is helpful as it may allow the anaesthetist to take measures which may reduce the risk of associated complications.

Extraesophageal reflux and reflux aspiration in dogs with respiratory diseases and in healthy dogs

BACKGROUND

Salivary bile acids are used to diagnose extraesophageal reflux (EER) and to evaluate the risk of reflux aspiration that is associated with respiratory diseases in dogs.

OBJECTIVES

To study total bile acid (TBA) concentrations in saliva and in bronchoalveolar lavage fluid (BALF) to investigate EER and reflux aspiration in dogs with respiratory diseases and in healthy dogs.

ANIMALS

 Thirty-one West Highland White Terriers (WHWTs) with idiopathic pulmonary fibrosis (IPF), 12 dogs with inflammatory airway disease (IAD), 6 dogs with recurrent pneumonia (RP), 26 brachycephalic dogs (BD), 27 healthy WHWTs (HW), 52 healthy dogs (HD). All privately-owned dogs.

METHODS

Saliva and BALF were collected from dogs in each group.

RESULTS

Salivary TBA concentrations were higher in IPF (median 0.1692 μM, interquartile range [IQR] 0.1115-0.2925 μM, Cohen's d 3.4, 95% confidence interval [CI] 2.2-4.0, P < .001) and BD (0.0256 μM, IQR 0.0086-0.0417 μM, d 0.5, CI -0.1 to 1.1, P = .003) compared to HD (0 μM, IQR not quantifiable [n.q.]-0.0131 μM). Bronchoalveolar lavage fluid TBA concentrations were higher in IPF (0.0117 μM, IQR 0.0048-0.0361 μM, d 0.5, CI 0-1.1, P < .001) compared to HD (0 μM, IQR n.q.-0.0074 μM).

CONCLUSION AND CLINICAL IMPORTANCE

Extraesophageal reflux and reflux aspiration occur in healthy dogs and those with respiratory diseases.

Evaluation of aerodigestive disease and diagnosis of sliding hiatal hernia in brachycephalic and nonbrachycephalic dogs

Background

Aerodigestive diseases (AeroD), hybrid disorders between the respiratory and gastrointestinal (GI) tracts, may present without GI signs. Sliding hiatal hernia (sHH) is an important AeroD in brachycephalic dogs linked to respiratory pathology. The spectrum of other AeroD and respiratory clinical signs (CS) in brachycephalic and nonbrachycephalic dogs with sHH is unknown.

Objectives

Characterize CS of AeroD in dogs with sHH, compare CS between brachycephalic and nonbrachycephalic dogs, and compare thoracic radiographs and videofluoroscopic swallow study (VFSS) for diagnosing sHH.

Animals

Sixty‐seven client‐owned dogs with sHH.

Methods

Medical records of dogs with sHH presented to the veterinary teaching hospitals at Auburn University and the University of Missouri between 1 January 2009 and 31 December 2020 were retrospectively reviewed. Between group, comparisons were made using Mann‐Whitney test, Chi‐square analysis, and Spearman correlation (P < .05).

Results

Dogs with sHH presented with exclusively GI signs (28/67), mixed respiratory and GI signs (22/67), or with exclusively respiratory signs (17/67). Wheras brachycephalic dogs were not significantly more likely to present with respiratory CS (P = .145), they were younger (P < .001), and more likely to present in respiratory distress (P = .02), and with radiographic evidence of aspiration pneumonia (P < .001) compared to nonbrachycephalic dogs. Six of 12 dogs with normal thoracic radiographs having sHH presented with respiratory CS. For detection of sHH, VFSS was superior to radiographs (P < .001).

Conclusions and Clinical Importance

Dogs with sHH may present with exclusively respiratory signs. Respiratory signs may be more severe in brachycephalic compared to nonbrachycephalic dogs. Videofluoroscopic swallow study was superior to thoracic radiographs for detection of sHH in dogs.

A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

Swallowing impairment is a highly prevalent and clinically significant problem affecting people and dogs. There are myriad causes of swallowing impairment of which gastroesophageal reflux is the most common in both species. Similarities in anatomy and physiology between humans and canines results in analogous swallowing disorders including cricopharyngeus muscle achalasia, esophageal achalasia, hiatal herniation, and gastroesophageal reflux with secondary esophagitis and esophageal dysmotility. Accordingly, the diagnostic approach to human and canine patients with swallowing impairment is similar. Diagnostic procedures such as swallowing fluoroscopy, high-resolution manometry, pH/impedance monitoring, and endolumenal functional luminal imaging probe can be performed in both species; however, nasofacial conformation, increased esophageal length, and the difficulty of completing several of these procedures in awake dogs are inherent challenges that need to be considered. Human patients can convey their symptoms and respond to verbal cues, whereas veterinarians must rely on clinical histories narrated by pet owners followed by comprehensive physical examination and observation of the animal eating different food consistencies and drinking water. Dogs may also be unwilling to drink or eat in the hospital setting and may be resistant to physical restraint during diagnostic procedures. Despite the species differences and diagnostic challenges, dogs are a natural animal model for many oropharyngeal and esophageal disorders affecting people, which presents a tremendous opportunity for shared learnings. This manuscript reviews the comparative aspects of esophageal anatomy and physiology between humans and canines, summarizes the diagnostic assessment of swallowing impairment in both species, and discusses future considerations for collaborative medicine and translational research.

Digestive Diseases in Brachycephalic Dogs

In addition to presenting with respiratory signs, many dogs with brachycephalic airway obstructive syndrome show digestive tract signs related to the same conformational abnormalities. A detailed diagnostic investigation is usually required, including clinicopathologic analyses, thoracic radiographs, fluoroscopic studies, abdominal ultrasound examinations and both upper airway and gastrointestinal tract endoscopy. In most cases, medical therapies are successful in managing clinical signs, but surgery can occasionally be required to resolve hiatal hernia or pyloric stenosis. In determining prognosis, the features of each individual case should be considered, with the overall prognosis depending on the severity and extent of all the identified lesions.

Retrospective analysis of esophageal imaging features in brachycephalic versus non-brachycephalic dogs based on videofluoroscopic swallowing studies

Background

Idiopathic esophageal dysmotility (ED) is increasingly recognized in young dogs of brachycephalic breeds. Few studies have objectively associated specific videofluoroscopic swallowing study (VFSS) features with brachycephaly, leading to under‐recognition of ED in brachycephalic breeds.

Hypothesis/objectives

To describe and compare VFSS in brachycephalic dogs versus non‐brachycephalic dogs presented for dysphagia or regurgitation, and to investigate associations between these imaging findings and patient signalment.

Methods

Retrospective analysis of VFSS of dogs presented for dysphagia or regurgitation (not megaesophagus) from 2006 to 2017. Cases were divided into brachycephalic and mesaticephalic breeds. The VFSS were reviewed using a standardized protocol by 2 examiners. Esophageal motility was assessed using specific criteria, and particular imaging features were noted and graded. Fisher's exact test was used to determine associations among signalment (including brachycephaly), final diagnosis, outcomes, and ED features.

Results

Thirty‐six dogs were included (n = 10 normal, n = 26 presumed ED). Twenty dogs (77%) with presumed ED were brachycephalic with a median age of 1 year (range, 0.2‐10.5 years). Most common were prolonged esophageal transit time (ETT; n = 21/26), decreased propagation of secondary peristaltic waves (n = 20/26), and gastroesophageal reflux (GER; n = 18/28). Eight dogs (all brachycephalic) had hiatal herniation (HH). Morphological esophageal variations were only observed in brachycephalic dogs. Brachycephaly was significantly associated with ED (P = .005), prolonged ETT (P = .41), GER (P = .02), and HH (P = .03).

Conclusions and Clinical Importance

The majority of dogs with presumed ED was young and brachycephalic and had specific abnormalities that were less frequent in mesaticephalic dogs with regurgitation or dysphagia.