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.     

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.     

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.     

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.     

Double aortic arch in a Siamese cat.

A double aortic arch is described in an 8-week-old female Siamese cat. In this case a vascular ring anomaly consistent with a double aortic arch is described in a cat. Stridor and dysphagia were noted in the cat. Radiography showed an esophageal dilation, with constriction at the fifth intercostal space. At necropsy, the esophagus and trachea were constricted at the base of the heart. The cause of the constriction of both the esophagus and trachea was a vascular ring formed by well-developed right and left aortic arches. The ascending aorta divided into two asymmetrical arches. The right aortic arch was larger than the left. The origin of the major arteries from the aortic arches were anomalous.     

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.     

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.     

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.     

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.     

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.     

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.     

Fatal aortic oesophageal fistula following oesophageal foreign body removal in a dog

An eight-month-old male Pomeranian was presented with hypovolaemic shock 7 days after successful oesophageal foreign body removal. On presentation the dog was anaemic and no coagulation abnormalities were detected. A fluid-filled oesophagus was visible on thoracic radiography and frank blood was aspirated from the oesophagus following oro-oesophageal intubation. Fluid resuscitation and blood transfusions were administered but attempts at stabilisation were unsuccessful and the dog died. At post-mortem examination, a 2-mm aortic oesophageal fistula was identified on the ventral aspect of the aorta at the level of heart base that communicated with the overlying oesophagus. Aortic oesophageal fistula has been reported in human medicine and occurs secondary to a number of conditions including oesophageal foreign bodies. These prove fatal without rapid stabilisation and surgery.     

Use of 3D printer technology to facilitate surgical correction of a complex vascular anomaly with esophageal entrapment in a dog

A 10 week old female intact Staffordshire terrier was presented with a total of five congenital cardio-thoracic vascular anomalies consisting of a patent ductus arteriosus (PDA) with an aneurysmic dilation, pulmonic stenosis, persistent right aortic arch, aberrant left subclavian artery and persistent left cranial vena cava. These abnormalities were identified with a combination of echocardiogram and computed tomography angiography (CTA). The abnormalities were associated with esophageal entrapment, regurgitation, and volume overload of the left heart with left atrial and ventricular enlargement. A 2 cm diameter aneurysmic dilation at the junction of the PDA, right aortic arch and aberrant left subclavian artery presented an unusual surgical challenge and precluded simple circumferential ligation and transection of the structure. A full scale three dimensional model of the heart and vasculature was constructed from the CTA and plasma sterilized. The model was used preoperatively to facilitate surgical planning and enhance intraoperative communication and coordination between the surgical and anesthesia teams. Intraoperatively the model facilitated spatial orientation, atraumatic vascular dissection, instrument sizing and positioning. A thoracoabdominal stapler was used to close the PDA aneurysm prior to transection. At the four-month postoperative follow-up the patient was doing well. This is the first reported application of new imaging and modeling technology to enhance surgical planning when approaching correction of complex cardiovascular anomalies in a dog.     

Collateral arteries of the aortic arch of the red-rumped agouti (Dasyprocta leporina Linnaeus, 1758)

Detailed knowledge of the arterial system is an important prerequisite when interpreting experimental data in research, as well as in the diagnosis of cardiovascular disease using imaging techniques such as Doppler echocardiography and contrast radiography. Thus, considering the importance of the aortic arrangement, the objective of this study was to describe the collateral arteries of the aortic arch of agoutis in order to establish the standard model, and therefore contribute to studies involving research related to heart disease, and produce information for a more accurate diagnosis in complementary imaging examinations. In this study, 14 adult animals were used, comprising eight males and six females. The vascular system was washed with 0.9% aqueous saline solution and perfused with Neoprene 450 latex coloured with yellow or red pigment, which was subsequently dissected and analysed. One male animal was used for the digital contrast radiography technique perfused with a liquid barium sulphate solution (Bariogel^®) (1 g/ml) and Neoprene 450 latex, both diluted 1/3. The aortic arch of the agouti presented with only the brachiocephalic trunk as collateral branch in all the animals studied. Thus, agouti falls into type 1 for mammalian aortic arch vascular arrangements.     

Surgical Correction of a Persistent Right Aortic Arch in a Foal

A persistent right fourth aortic arch causing esophageal stenosis was diagnosed in a foal. Presenting signs included cervical swelling that developed following introduction to solid feed at weaning, and symptoms of chronic aspiration pneumonia. The esophagus was distended at the thoracic inlet; neither an endoscope nor a small nasogastric tube could be passed through the strictured esophagus at the heart base. The esophagus was seen to be dilated to the level of the heart base on plain and contrast radiographs. A left lateral thoracotomy through the fifth intercostal space was used to gain access for surgical correction of the defect. Radiographic and clinical evaluation of the foal 2 and 6 months following surgery showed a gradual decrease in size of the esophageal dilatation and an enlargement in the functional diameter of the esophagus at the previously strictured area at the heart base. Ten months following surgery the colt was eating normally and was of normal height and weight.     

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.     

Thoracoscopic correction of a congenital persistent right aortic arch in a young cat

A 9-week-old kitten was diagnosed with a congenital vascular ring anomaly by means of an esophageal contrast study. At 6 mo of age, a non-selective vascular study was used to diagnose a persistent right aortic arch (PRAA). Left-sided thoracoscopic surgery was performed, using a Liga-Sure vessel sealant device to seal and transect the ligamentum arteriosum.     

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.     

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.     

Fourth branchial arch defect in a Welsh section A pony mare

Fourth branchial arch defect is a term used to describe a syndrome of congenital defects affecting the extrinsic structures of the larynx, due to a failure of development of structures that derive from the fourth branchial arch. This Case Report describes a 6-year-old Welsh section A mare presented for investigation of a chronic cough that was exacerbated on exercise. A fourth branchial arch defect was identified on resting upper airway endoscopy, with dorsal pharyngeal collapse evident on dynamic respiratory endoscopy, although full abduction of both the left and right arytenoid could be achieved and maintained at exercise.