Double aortic arch in a dog

Computed tomographic features of double aortic arch in six dogs

Double aortic arch (DAA) is a rare, congenital anomaly in small animals, resulting in a complete vascular ring encircling the esophagus and trachea, and subsequent compression of these organs. Few studies have reported utilizing CT angiography (CTA) for diagnosing DAA in dogs; thus, the imaging features are currently lacking in the literature. The objectives of this retrospective, multicenter, descriptive case series were to report the clinical and CTA characteristics of DAA in surgically treated cases. Medical records and CTA images were reviewed. Six juvenile dogs met the inclusion criteria (median age: 4.2 months; range: 2-5 months). The most common clinical signs included chronic regurgitation (100%), decreased body condition (67%), and coughing (50%). Common CTA features of DAA included a dominant left aortic arch (median diameter: 8.1 mm) and minor right aortic arch (median diameter: 4.3 mm; 83%), an aberrant right subclavian artery arising directly from the right aortic arch (83%), segmental esophageal constriction (100%), and variable degrees of dilation cranial to the heart base, and marked tracheal luminal compression (median percent change: -55%; 100%) and leftward curvature of the trachea at the level of the bifurcation of the aortic arches (100%). All dogs underwent successful surgical correction with only minor postoperative complications. Due to the similarity of clinical and imaging characteristics described to that of other forms of vascular ring anomalies (VRA), CTA is vital for the specific diagnosis of DAA in dogs.

Clinical findings, surgical treatment and long-term outcome of dogs and cats with double aortic arch: four cases (2005-2022)

OBJECTIVE

To describe the clinical presentation, diagnostic findings, treatment and long-term outcome following surgery of dogs and cats undergoing surgical treatment for a double aortic arch.

MATERIALS AND METHODS

Medical records of dogs and cats diagnosed with a double aortic arch between 2005 and 2022 at three small animal referral hospitals were retrospectively reviewed. Long-term outcome was assessed by a clinical examination and/or by contacting the owners or referring veterinarians.

RESULTS

Two dogs and two cats were included. Regurgitation after eating, stunted growth and poor weight gain were the predominant clinical features. All animals had thoracic radiography and oesophagography; a dilation of the cranial thoracic oesophagus cranial to the heart base, was described in all animals. CT angiography confirmed double aortic arch in three of these and the right aortic arch was larger and appeared more well developed compared with the left aortic arch in all based on CT or surgical findings. Surgery was performed via a left fourth intercostal thoracotomy; ligation and transection of the lesser left aortic arch was performed. Follow-up time ranged from 360 to 1563 days. All animals showed a marked improvement during the postoperative period, and all gained weight gradually. Owners' perception of the surgical procedure outcome and quality of life was described as excellent for all animals.

CLINICAL SIGNIFICANCE

Surgical ligation of the lesser aortic arch in dogs and cats with double aortic arch is associated with a favourable prognosis for recovery, resolution of clinical signs, and quality of life with only minor feeding modifications.

Ligation of the ligamentum arteriosum and aberrant left subclavian artery in five dogs in which persistent right aortic arch had been diagnosed

OBJECTIVE

To determine and report the diagnosis, treatment, and outcome in dogs with persistent right aortic arch (PRAA) with an aberrant left subclavian artery (ALS) that underwent thoracoscopic surgery.

ANIMALS

Dogs with PRAA and an ALS (n = 5).

STUDY DESIGN

Short case series.

METHODS

Medical records were reviewed from 2014 to 2019. Dogs that underwent thoracoscopy for PRAA with an ALS at an academic referral hospital were included. Signalment, clinical signs, diagnostic imaging, surgical approach, complications, and short- and long-term outcomes were recorded.

RESULTS

Persistent right aortic arch with an ALS was identified in five dogs. Dogs initially underwent a three-port intercostal thoracoscopic approach, and an intercostal thoracotomy was performed in converted cases. In all five dogs, the ligamentum arteriosum (LA) and ALS were divided; three were performed by a thoracoscopy alone. Two cases were converted because of poor exposure (1) and requirement to temporary occlude an ALS (1). The ALS was ligated and divided in all dogs without apparent negative effects. No intraoperative or postoperative complications occurred. Four dogs had resolution of regurgitation, three of which required diet modification. One dog had reported regurgitation when it was excited. Median follow-up was 188 days (range, 150-1133).

CONCLUSION

Ligation and division of both the LA and the ALS in all dogs in this case series was safe and allowed for improvement in clinical signs and good to excellent long-term outcomes. In addition, both thoracoscopy and thoracotomy were used safely and successfully for ligation and transection of the LA and ALS in all dogs.

New findings of branching variations in subclavian arteries and supra-aortic arteries in Felis catus

The branching of blood vessels around the heart is varied in each animal. Three branching patterns of the brachiocephalic trunk in cats have been reported. However, supra-aortic arteries in the hearts of cats have never been investigated. In this study, we hypothesized that the variations of the aortic arch, supra-aortic arteries, and vena cava were observed in domestic cats. Sixty-one hearts obtained from the cadavers of domestic cats (Felis catus) were analyzed in terms of anatomical characteristics, size, and the length of these supra-aortic vessels by using a 3D scanner. New variations of the left and right subclavian arteries were observed using the location of the internal thoracic (ITA) and vertebral artery (VA) as the criterion to group the varying patterns. We found four patterns of the left subclavian artery, which included ITA budding contralateral before VA (5%), VA budding opposite to ITA (75%), VA budding contralateral before ITA (13%) and ITA budding ipsilateral before VA (7%). In contrast, only three patterns were found in the right subclavian artery, which included VA budding opposite to ITA (20%), VA budding contralateral before ITA (19%), and ITA budding contralateral before VA (61%). Moreover, although an average vascular diameter in male cats was higher than in female subjects, the supra-aortic blood volume in both sexes was not different. The findings of this study could help fill the existing gap of knowledge on the anatomical variations of supra-aortic arteries in cats and could be used in clinical applications based on relevant anatomical data.

Successful Surgical Therapy of a Double Aortic Arch in a 10-Month-Old Mixed Breed Dog

A 10-month-old female spayed mixed breed dog with a suspected vascular ring anomaly was presented for exercise intolerance and wheezing. Computed tomography (CT) revealed a double aortic arch. The smaller right aortic arch was successfully ligated via right 4th intercostal thoracotomy. The patient was discharged one day postoperatively and continued to have good outcome at recheck 3.5 weeks after surgery. This is the 4th documented case of double aortic arch with a successful outcome. Preoperative CT scan was vital in preoperative planning and should be strongly recommended in all cases of suspected vascular ring anomalies with atypical presentation.

Aberrant Left Subclavian Artery in a Beagle Puppy With a Persistent Right Aortic Arch. Use of Cone Beam Computed Tomography to Diagnose a Vascular Ring Anomaly

A 7-week-old, 1.045kg female beagle dog was referred to investigate a supposed vascular ring anomaly. Cone beam computed tomography with contrast enhanced arterial phase accomplished by a rapid manual intravenous injection of iodinated agent during the scanning process revealed a persistent right aortic arch and an aberrant left subclavian artery that compressed dorsally the esophagus in the cranial mediastinum. Third left intercostal thoracotomy was performed to transect the left subclavian artery. This is the first description of a vascular ring anomaly that was diagnosed with a cone beam computed tomography in veterinary medicine.

Short- and Long-Term Outcome of Dogs Following Surgical Correction of a Persistent Right Aortic Arch

This study reports the survival to discharge, postdischarge survival, and long-term outcome of dogs following surgical correction of a persistent right aortic arch (PRAA). Information for 52 dogs, 28 dogs, and 23 dogs was available for analysis of survival to discharge, postdischarge survival, and long-term outcome, respectively. Ninety-two percent of dogs survived to the time of discharge and 18% of dogs surviving to discharge were euthanized within 2 mo of surgery. Breed, age at the time of presentation, and gender were not correlated with increased odds of death prior to discharge from the hospital. Long-term outcome for dogs was excellent in 30%, good in 57%, and poor in 13% of dogs. Although this study shows a relatively high mortality rate prior to discharge from the hospital and within 2 mo of surgical treatment, the long-term outcome is good or excellent in 87% of survivors. Dogs frequently display either residual clinical signs or require dietary modification long-term, but owner satisfaction is high.

Imaging evaluation of dogs and cats with Dysphagia

The current literature is reviewed in this paper regarding the application of diagnostic imaging in the evaluation of swallowing disorders of the dog. The applications of radiography, contrast radiography, and contrast videofluoroscopy are discussed with pertinent case examples provided for emphasis. The indications for image-guided interventions are also described.

Multidetector-row computed tomography of thoracic aortic anomalies in dogs and cats: patent ductus arteriosus and vascular rings

BACKGROUND

Diagnosis of extracardiac intrathoracic vascular anomalies is of clinical importance, but remains challenging. Traditional imaging modalities, such as radiography, echocardiography, and angiography, are inherently limited by the difficulties of a 2-dimensional approach to a 3-dimensional object. We postulated that accurate characterization of malformations of the aorta would benefit from 3-dimensional assessment. Therefore, multidetector-row computed tomography (MDCT) was chosen as a 3-dimensional, new, and noninvasive imaging technique. The purpose of this study was to evaluate patients with 2 common diseases of the intrathoracic aorta, either patent ductus arteriosus or vascular ring anomaly, by contrast-enhanced 64-row computed tomography.

RESULTS

Electrocardiography (ECG)-gated and thoracic nongated MDCT images were reviewed in identified cases of either a patent ductus arteriosus or vascular ring anomaly. Ductal size and morphology were determined in 6 dogs that underwent ECG-gated MDCT. Vascular ring anomalies were characterized in 7 dogs and 3 cats by ECG-gated MDCT or by a nongated thoracic standard protocol. Cardiac ECG-gated MDCT clearly displayed the morphology, length, and caliber of the patent ductus arteriosus in 6 affected dogs. Persistent right aortic arch was identified in 10 animals, 8 of which showed a coexisting aberrant left subclavian artery. A mild dilation of the proximal portion of the aberrant subclavian artery near its origin of the aorta was present in 4 dogs, and a diverticulum analogous to the human Kommerell's diverticulum was present in 2 cats.

CONCLUSIONS

Contrast-enhanced MDCT imaging of thoracic anomalies gives valuable information about the exact aortic arch configuration. Furthermore, MDCT was able to characterize the vascular branching patterns in dogs and cats with a persistent right aortic arch and the morphology and size of the patent ductus arteriosus in affected dogs. This additional information can be of help with regard to improved diagnoses of thoracic anomalies and the planning of surgical interventions.

Esophageal dysfunction in four alpaca crias and a llama cria with vascular ring anomalies

CASE DESCRIPTION

3 alpaca crias and cadavers of an alpaca cria and a llama cria were evaluated for evidence of esophageal dysfunction.

CLINICAL FINDINGS

All 5 crias were between 3 and 5 months of age when clinical signs developed, and all had a thin body condition when examined. Clinical signs included coughing, regurgitation, and grossly visible esophageal peristaltic waves. A barium esophagram was used to diagnose esophageal obstruction, megaesophagus, and a vascular ring anomaly (VRA). Fluoroscopy was used to evaluate deglutition, esophageal peristalsis, and the extent of esophageal dilation in 1 alpaca cria. A persistent right aortic arch was identified in 1 alpaca cria, and a left aortic arch with right ductus arteriosus or ligamentum arteriosum and an aberrant right subclavian artery were identified in the 4 remaining crias.

TREATMENT AND OUTCOME

Surgical correction of the VRA was attempted in the 3 live alpaca crias. It was complicated by the conformation and location of each VRA and inaccurate anatomic diagnosis of the VRAs before surgery. Treatment was universally unsuccessful because of intraoperative complications and the persistence of clinical signs after surgery.

CLINICAL RELEVANCE

Megaesophagus is typically an idiopathic condition in camelids. However, these findings suggested that camelids with esophageal dysfunction during the neonatal period may have a VRA. The prognosis is grave for camelids with VRA, and accurate anatomic diagnosis of the VRA via the use of advanced imaging techniques (eg, angiography, computed tomography, or magnetic resonance imaging) may improve the success of surgical intervention.

Delayed primary surgical treatment in a dog with a persistent right aortic arch

A 5-year-old, 1.36-kg, neutered male Yorkshire terrier was referred for evaluation of a persistent right aortic arch with concurrent megaesophagus. The dog was 3 months old when clinical signs were first noted, 2 years of age when diagnosed with megaesophagus, and 4 years of age when diagnosed with vascular ring anomaly (VRA). Surgical correction of the VRA was performed when the dog was 5 years of age, after gastrostomy tube feeding for 1 year to maintain nutritional requirements and mitigate the degree and duration of the esophageal distention. Thirteen months after surgery, the dog was eating soft dog food with no vomiting or regurgitation.

Symmetrical double aortic arch in a beagle puppy

Double aortic arch denotes the persistence of both fourth aortic arches and has been reported as 'very rare' in the dog. Most reported cases have been seen in German shepherd dogs. An eight-week-old, male, 1.5-kg beagle presented with a three-week history of regurgitation and dyspnoea. A barium oesophagram showed severe oesophageal constriction cranial to the base of the heart, and a provisional diagnosis of a persistent right aortic arch was made. A left-sided fourth intercostal thoracotomy was performed. The ligamentum arteriosum was ligated and divided. The oesophagus was seen lying on the right-hand side of the aorta. Postoperatively, the puppy deteriorated and was euthanized. Postmortem revealed a double aortic arch entrapping both the oesophagus and trachea. The inexperienced surgeon could consider computed tomography or angiography to determine the exact vascular ring, and other possible concurrent vascular anomalies present, before surgery.