Double aortic arch in a dog

Vascular ring anomalies are developmental anomalies of the thoracic great vessels resulting in complete or partial encircling of the esophagus and the trachea by a vascular ring formation. Persistent right aortic arch with left ligamentum arteriosum accounts for 95% of vascular ring anomalies in dogs. The dog in this report had a double aortic arch, which is a type 4 vascular ring anomaly. Double aortic arch is a rare congenital heart defect resulting from the improper development of the embryonic arches. The prognosis for dogs that have undergone surgery for correction of double aortic arches is generally regarded as poor. The dog in this report underwent surgery for correction of double aortic arches and recovered without dilation or motility disorders of the esophagus. Results indicate that small animals that undergo early surgical correction of double aortic arches with relief of esophageal constriction can have a good prognosis. To the authors' knowledge, there have been no previous reports of dogs that have survived long enough to be discharged from the hospital after surgical correction of double aortic arches.     

Double aortic arch in a dog (Canis familiaris): a case report

We herein report a case of a double aortic arch in a 10-week-old male dog of no defined race, which presented episodes of regurgitation at the time of weaning. This vascular malformation was characterized by the persistence of two aortic arches, right and left, of varying dimensions. The right aortic arch was observed to be larger. During post mortem examination the vessels of the animal were injected with coloured latex bi-centrifuged CIS 1-4 polisopreno which revealed the patency of the two aortic arches. Concomitantly, dilation of the cranial oesophagus causing constriction was observed, indicating megaesophagus. Apart from the constriction, the oesophagus presented normal morphometric parameters in relation to its dimensions.     

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.     

Persistent right aortic arch in a yearling captive wood bison (Bison bison athabascae).

An undersized, 16-mo-old, captive wood bison (Bison bison athabascae) was observed with dysphagia and postprandial regurgitation. The animal died shortly after anesthesia was initiated for diagnostic purposes. At necropsy, a persistent right aortic arch and aberrant left subclavian artery were diagnosed. The vascular ring structure around the esophagus and the trachea caused a megaesophagus with complete esophageal obstipation and ulcerative esophagitis. The aberrant left subclavian artery did not significantly compromise the esophagus. Persistence of the right aortic arch is relatively rare in ruminants and has not previously been reported in a bison.     

Surgical treatment of a double aortic arch in a dog

An 8-month-old spayed female Labrador retriever dog was evaluated for regurgitation 6 months after surgery for a suspected vascular ring anomaly. The dog had a history of regurgitation and slow development as a puppy. An initial left-sided exploratory thoracotomy was unsuccessful in identifying and treating a vascular ring anomaly. The dog was subsequently presented to the PennVet Emergency Service for regurgitation. Thoracic radiography showed cranial thoracic esophageal dilation and an esophageal foreign body that was then removed endoscopically. Subsequent computed tomographic (CT) angiography revealed a double aortic arch. A left 4th intercostal space thoracotomy was performed. The smaller left aortic arch and a left ligamentum arteriosum were ligated and transected. The dog recovered uneventfully and was healthy at the 1-month follow-up visit. This is the 5th reported successful surgical correction of a double aortic arch in a dog. Computed tomographic angiography was essential in diagnosis and surgical planning.Key clinical message:Although uncommon, double aortic arches can occur and present a diagnostic and surgical challenge when a persistent right aortic arch is suspected. Computed tomographic angiography provides an accurate preoperative diagnosis and allows for surgical planning.     

Tracheal signs and associated vascular anomalies in dogs with persistent right aortic arch

Medical records of 55 dogs with 1 or more vascular rings around the esophagus and trachea were reviewed to determine the nature and frequency of related vascular anomalies and to determine the reliability of tracheal deviation on radiographs for the diagnosis of persistent right aortic arch (PRAA). Fifty-two (95%) of the 55 dogs had PRAA. Of the 52 dogs with PRAA, 44% had coexisting compressive arterial anomalies: 17 had retroesophageal left subclavian artery and 6 had double aortic arch with atretic left arch. Characteristic tracheal deviation was consistently present in dogs with PRAA. Moderate or marked focal leftward curvature of the trachea near the cranial border of the heart in dorsoventral (DV) or ventrodorsal (VD) radiographs was found in 100% of available radiographs of 27 dogs with PRAA. Moderate or marked focal narrowing of the trachea also was noted in 74% of DV or VD radiographs and 29% of lateral radiographs of the dogs. Tracheal position in 30 of 30 dogs with megaesophagus and 62 of 63 control dogs was midline or rightward in VD or DV radiographs. Histology in a neonatal dog with PRAA revealed evidence of tracheal deviation and compression even before birth. Focal leftward deviation of the trachea near the cranial border of the heart in DV or VD radiographs is a reliable sign of PRAA in young dogs that regurgitate after eating solid food, and contrast esophagrams are not necessary to confirm the diagnosis of vascular ring compression.     

Vascular Ring Anomalies: Case Report and Brief Review

During early fetal life six pair of aortic arches surround the esophagus and trachea. Normal maturation and selective regression of these structures form the adult vasculature. Abnormal location or development of the aortic arches may result in pressure on adjacent organs.Vascular ring anomalies must be considered with any patient with a history of regurgitating food shortly after eating. Physical examination, test feedings, survey and contrast radiographs may give an accurate impression of the problem but a final diagnosis can only be made following surgical exploration. In the case presented, the dog had all the clinical and diagnostic signs suggestive of a vascular ring anomaly. Thoracotomy and elimination of the vascular constriction around the esophagus was both diagnostic and therapeutic for the condition. It is important that owners be made aware that surgical correction of the stenosis does not guarantee a successful conclusion to the case. If the dilation of the esophagus cranial to the stenosis is severe, accumulation of food with subsequent regurgitation may persist. A dilation of the esophagus caudal to the stenosis is present in a large percentage of cases and this also may result in an unrelenting problem. Unfortunately, the probability of these complications cannot be accurately evaluated prior to treatment.The hereditary potential for this defect must also be considered. Congenital vascular anomalies such as patent ductus arteriosus would seem to have a hereditary basis. Therefore, it is probably correct to advise against breeding affected animals. Further, the inbreeding of nonaffected animals which come from litters containing affected animals should be avoided.     

Double aortic arch and persistent left vena cava in a white lion cub (Panthera leo).

A 4-mo-old female white lion (Panthera leo) cub was presented with a 2-wk history of persistent postprandial regurgitation, mild dyspnea, and poor weight gain. The cub was weak and thin but otherwise alert. Survey and contrast radiography revealed a large dilated esophagus cranial to the heart base, with an esophageal filling defect present at the level of the fourth thoracic vertebra. A vascular ring anomaly was tentatively diagnosed. Exploratory thoracotomy revealed a double aortic arch and a persistent left vena cava. The left aortic arch was ligated and divided, and recovery was uneventful. A single episode of regurgitation occurred within the first postoperative month, and the cub gained 5.5 kg in weight during the same time period. Neither double aortic arch nor persistent left vena cava has been reported in a nondomestic felid.     

Vascular ring anomaly with coarctation of the aorta in a cat

A 13-week-old, entire male domestic shorthaired cat was presented with a nine-week history of regurgitation following the ingestion of food. A diagnosis of a vascular ring anomaly with coarctation of the aorta was based on clinical signs, angiography and echocardiography. Surgical exploration via a right lateral thoracotomy confirmed the existence of a persistent right aortic arch with right ligamentum arteriosum, aortic coarctation and an aberrant left subclavian artery. Following the surgical transection of the aberrant left subclavian artery, the cat made an uneventful recovery, showing normal swallowing function with no evidence of regurgitation. Twelve months after surgery, the cat had no special dietary requirements and remained clinically normal.     

Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates

OBJECTIVE: To present details of surgical management of an unusual vascular ring anomaly in two German Shepherd littermates. STUDY DESIGN: Clinical case report. STUDY POPULATION: Three-month-old intact male and female German Shepherd littermates. RESULTS: In each dog, the esophagus was obstructed by a vascular ring comprised of the left aortic arch, an anomalous patent right ductus arteriosus, and the pulmonary artery ventrally. Surgical treatment consisted of dividing and oversewing the patent right ductus arteriosus. Neither dog has clinical signs of esophageal disease one year after treatment. CONCLUSION AND CLINICAL RELEVANCE: This vascular ring anomaly should be considered a possibility in any young dog with esophageal obstruction and a machinery murmur.     

Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs

An unusual vascular ring anomaly consisting of a persistent right aortic arch and a left ligamentum arteriosum extending from the main pulmonary artery to an aberrant left subclavian artery and left aortic arch remnant complex was identified in a German shepherd dog and a great Dane. The left subclavian artery and left aortic arch remnant complex originated at the junction between the right distal aortic arch and the descending aorta and coursed dorsal to the oesophagus in a cranial direction. The attachment of the ligamentum arteriosum to the aberrant left subclavian artery was approximately 5 cm cranial to the point of origin of the aberrant left subclavian artery and left aortic arch remnant complex from the descending aorta in both dogs. This anomaly observed in both dogs is similar to an anomaly reported in humans, in which a persistent right aortic arch is found in conjunction with an aberrant left subclavian artery and a left aortic arch remnant (Kommerell's diverticulum). Surgical ligation and division of the left ligamentum arteriosum in both dogs, along with division of the left subclavian artery in the great Dane, resulted in resolution of clinical signs in both of the dogs in this report.     

Surgical management of an aberrant left subclavian artery originating from a left patent ductus arteriosus in a dog with a right aortic arch and abnormal branching

An increase in the availability of advanced imaging modalities has led to improved recognition of cardiovascular anomalies. Computed tomography angiography (CTA) provides a non-invasive means of acquiring 3D images with a relatively short acquisition time thereby providing essential information in regards to patient anatomy and procedure planning. The dog in this report had a right aortic arch and abnormal branching with an aberrant left subclavian artery originating from the ampulla of a left patent ductus arteriosus (PDA) that was detected with CTA. The PDA was creating a volume overload to the left side of the heart as well as contributing to the vascular ring and compression of the esophagus. Therefore, ligation and transection instead of a minimally invasive catheter-based procedure was required. This aortic arch anomaly and surgical management have not been previously reported in dogs.     

Hypoplastic aberrant left subclavian artery in a dog with a persistent right aortic arch

Vascular ring anomalies (VRA) are relatively uncommon cardiovascular disorders in canine patients. The most common VRA is a persistent right aortic arch (PRAA) with a left ligamentum arteriosum, however various other vascular anomalies resulting in tracheoesophageal compression have also been reported. We report a case of a dog with a PRAA and left ligamentum arteriosum with a hypoplastic aberrant left subclavian artery resulting in asymmetric cervicobrachial circulation. Selective angiography and ECG-gated multi-detector computed tomography were utilized in the evaluation of these defects. The case presented represents a unique vascular anomaly of the aortic arch not previously described in veterinary medicine.     

Late-onset regurgitation associated with persistent right aortic arch in two dogs

Congenital persistent right aortic arch was diagnosed as the cause of weight loss and regurgitation in 2 dogs, aged 2.5 and 8 years, respectively. The first dog had 2 brief episodes of regurgitation that resolved spontaneously before the most recent onset of signs and diagnosis. The second dog had no clinical signs attributed to persistent right aortic arch until 2 months before the diagnosis was made. Dogs born with persistent right aortic arch typically have clinical signs of esophageal stenosis around the time of weaning. Evidence from the 2 dogs in this report indicate that clinical signs associated with vascular ring anomalies may not become evident until later in life. Veterinarians should consider the diagnosis of persistent right aortic arch in any age dog that is admitted because of regurgitation, weight loss, and dilatation of the cranial portion of the esophagus.     

Persistent right aortic arch and aberrant left subclavian artery in a white Bengal tiger (Panthera tigris).

A 3-mo-old male white Bengal tiger (Panthera tigris) presented with the chief complaint of regurgitation of solid food since weaning at 2 mo of age. Compared with its littermates, the tiger was in poor body condition and weighed only 10.3 kg when its littermates were estimated at 20-25 kg. Thoracic radiographs showed a megaesophagus cranial to the heart base. A contrast esophagram more clearly outlined the megaesophagus, and fluoroscopy demonstrated normal motility of the caudal esophagus. Endoscopic examination revealed a structure coursing dorsally from right to left over the esophagus and a constrictive band on the left of the esophagus at the heart base. Nonselective angiography confirmed the presence of a persistent right aortic arch, as well as an aberrant left subclavian artery. A left fourth intercostal thoracotomy was performed, and the ligamentum arteriosum was double ligated and divided. The left subclavian artery did not cause significant compromise of the esophagus and was not manipulated at surgery. The tiger recovered well from anesthesia and surgery. Solid food was slowly introduced over a 2-mo period without any regurgitation. The cub gained weight rapidly after surgery.     

Non-selective computed tomography angiography of a vascular ring anomaly in a dog

Non-selective computed tomography angiography (CTA) is an emerging imaging technique that will have continued application in veterinary medicine because of its short scan time, use of a single, peripheral venous injection and availability of more detailed anatomic information—including 3-dimensional reconstructions. The improved anatomic detail may facilitate veterinary students' learning of complex aortic arch malformations and details relative to the surgical approach. Herein we describe application of its use in a dog with a vascular ring anomaly due to a persistent right fourth aortic arch and left ligamentum arteriosum. Additionally, we compare images with a normal dog.     

Unusual vascular ring anomaly in a foal

A 2.5-month-old filly was presented with signs of esophageal obstruction. The filly was euthanized and postmortem examination revealed a vascular ring anomaly. The vascular ring anomaly was not caused by a persistent right aortic arch, which is the only vascular ring anomaly reported to occur in horses.     

Multiple cardiac anomaly in sheep: a case study and review of the literature

A multiple cardiac anomaly in sheep is presented to show how complicated the result of abnormal development can be. The heart of a 12-hour-old sheep was fixed in 8% formaldehyde solution and subsequently dissected by an anatomical method, and the abnormalities were recorded on digital pictures. The abnormal anatomy is described and compared with the simple developmental anomalies. Developmental abnormalities were found in the distal portion of the bulbus, the aortic arches and the interatrial septum. A special type of the double-outlet right ventricle was observed, which was not a real double-outlet ventricle because it occurred in combination with pulmonary atresia. Coarctation of the aorta was seen, the ductus arteriosus was absent, and there were five vessels originating from the aortic arch instead of one vessel seen in normal cases, as a result of the abnormal development of the aortic arches.     

Aberrant right subclavian artery causing megaoesophagus in three cats

Three entire, domestic, shorthair male cats (age range: 3 months to 5 years) were referred because of regurgitation. Megaoesophagus attributable to aberrant right subclavian artery, originating from the aorta at the level of the fourth intercostal space, was diagnosed in all cats using thoracic radiography and CT angiography. One cat had concurrent patent ductus arteriosus with a normal aortic arch. Three‐dimensional volume‐rendered CT images were used to assess the malformations and to plan surgery for the treatment of the vascular anomalies. Different surgical approaches were used in the two kittens. The third cat was not operated. CT angiography is well suited for preoperative planning in cats with aberrant right subclavian artery alone or in combination with other vascular anomalies.