Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German pinschers

The objective of this study was to describe a specific form of persistent right aortic arch (PRAA) in three German pinscher dogs and to analyse the mode of inheritance in the breed. This type of PRAA is characterised by a left retro-oesophageal subclavian artery in combination with a ligamentum arteriosum originating at the aberrant left subclavian artery (PRAA-SA-LA). This rare combination of anomalies has only been reported in two isolated cases in other dog breeds and the occurrence of any form of PRAA was not previously known to occur in the German pinscher. In the present study, 18 cases of this congenital anomaly were ascertained and their high degree of relatedness and inbreeding could be shown through pedigree analysis. Three of the affected dogs underwent further clinical investigations, and post-mortem examination (two cases) and findings at surgery (one case) verified the diagnosis of PRAA-SA-LA. A monogenic autosomal recessive mode of inheritance was not likely.     

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.     

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.     

Video-assisted thoracoscopic division of the ligamentum arteriosum in two dogs with persistent right aortic arch

Video-assisted division of the ligamentum arteriosum can be performed successfully in dogs with minimal postoperative complications and hospitalization time. Single-lung ventilation and thoracic insufflation are not mandatory and standard instrumentation may be used for most of the procedure.     

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.     

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.     

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.     

Thoracoscopic correction of persistent right aortic arch in a dog.

A 15-week-old, male intact, miniature schnauzer presented for signs consistent with persistent right aortic arch (PRAA). Esophagram and esophagoscopy confirmed this diagnosis. Following selective intubation, the constricting ligamentum arteriosum was visualized and completely resected via thoracoscopy. No complications were noted with this procedure. Advantages of thoracoscopy for management of persistent right aortic arch observed in this case were better visualization of the ligamentum arteriosum, minor postoperative discomfort, and minimal intraoperative hypothermia. Therefore, thoracoscopy is a potential alternative to intercostal thoracotomy for correction of PRAA.     

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.     

Investigation of the potential heritability of persistent right aortic arch in Greyhounds

In 2 successive matings of the same dam and sire in a Greyhound kennel, 1 of 6 puppies and 2 of 6 puppies were born with persistent right aortic arch (PRAA) in the first and second litters, respectively. Many congenital heart defects in dogs are believed to be heritable; however, proof of this has been difficult to obtain. Genetic predisposition to PRAA has been reported in German Shepherd Dogs and Irish Setters. The occurrence of PRAA in related Greyhounds within a kennel suggested a genetic predisposition to PRAA in a breed with which it has not been associated previously. Although the number of matings available for analysis was insufficient to conclusively prove a genetic basis for these observations, the occurrence of PRAA in puppies arising from successive matings of the same dam and sire strongly suggests that some lines of dogs of various breeds may be genetically predisposed to PRAA.