Current diagnostic tests, surgical treatments, and prognostic indicators for vascular ring anomalies in dogs

Keaton R. S. Morgan Veterinary Specialist Group, 97 Carrington Rd, Mt Albert, Auckland 1025, New Zealand

Search for other papers by Keaton R. S. Morgan in
Current site
Google Scholar
PubMed
Close
 BVSc
and
Jonathan P. Bray Fitzpatrick Referrals—Oncology and Soft Tissue, 70 Priestly Rd, Guildford GU2 7AJ, England.

Search for other papers by Jonathan P. Bray in
Current site
Google Scholar
PubMed
Close
 MVSc, MSc

Vascular ring anomalies are congenital disorders of the aortic vasculature that involve complete or partial encircling of the esophagus and trachea. These abnormalities are a result of aberrant embryonic development, whereby abnormalities of the third, fourth, or sixth aortic arches result in 1 or 2 vessels coursing around the esophagus and trachea.1 The underlying, softer esophagus may be completely, partially, or inconsequentially compressed, depending on the abnormal vessel.2,3 This results in the classic clinical manifestation of postprandial regurgitation of solid foods by young dogs soon after weaning.4,5

A commonly quoted statistic is that 95% of vascular ring anomalies are composed of a “persistent right aortic arch with a left ligamentum arteriosum.”3,5–9 However, this is a misrepresentation of the existing evidence that could have clinical consequences. A classification scheme has previously been proposed to characterize the common vascular ring anomalies encountered in dogs.10 The surgical approach, intraoperative dissection, and precise aberrant vessel or vessels that require transection or removal differ among each type of vascular ring anomaly, and so ideally, the specific type of anomaly would be identified prior to surgery.

To the authors' knowledge, the last major review of vascular ring anomalies was published in 1989.6 Since then, considerable advances have been made in the diagnostic process, characterization, and surgical treatment of this disease process. Additionally, several studies9,11,12 have been conducted to pinpoint prognostic indicators, with differing results. The purposes of this review article are to describe these developments, to increase awareness of the wide variety of vascular ring anomalies possible in dogs by supplementing the classification scheme already proposed by Joly et al,10 and to discuss the use of advanced diagnostic imaging to identify and visualize the compressive vessels for surgical correction.

Epidemiology

The incidence of vascular ring anomalies has not been extensively evaluated in dogs. In a retrospective study13 of 98 dogs that underwent thoracic surgery, 11 (11%) had vascular ring anomalies. Another retrospective study14 with a specific focus on lateral thoracotomy surgical procedures revealed that 4 of 70 (6%) treated dogs had a vascular ring anomaly. Given these data, surgeries to correct vascular ring anomalies may represent between 1 in 10 and 1 in 20 thoracic surgeries.

Vascular ring anomalies commonly affect purebred dogs.9,15,16 Irish Setters were once believed to be predisposed to such anomalies4; however, a recent retrospective study9 involving 52 dogs with PRAA showed that 85% (44/52) of affected dogs were purebred, of which 23% (12/52) were German Shepherd Dogs, 15% (8/52) were Labrador Retrievers, and 8% (4/52) were Greyhounds. A sex predilection has not been established,4,15 although in the aforementioned retrospective study,9 69% (35/51) of dogs were female and 31% (16/51) were male. It has also not been established that vascular ring anomalies are congenital or heritable in nature,3 although they have been identified in multiple German Shepherd Dogs and Greyhounds of the same litter,16,17 providing support for the recommendation that affected dogs be neutered. Cats can also have vascular ring anomalies, but the incidence appears less common than in dogs.18–20

Normal embryonic development

During canine embryonic development, the arterial system arises from dorsal and ventral paired aortas. These dorsal and ventral paired aortas are connected by 6 paired aortic arches surrounding the embryonic foregut, which in turn develops into the esophagus and trachea.6 Selective involution or persistence of the paired dorsal and ventral aortas and the 6 aortic arches gives rise to the descending aorta and pulmonary arteries, while releasing the trachea and esophagus from an enclosed ring. The ventral aortas fuse with the embryonic heart, and the dorsal aortas fuse caudal to the 6 arches to form the descending aorta.

Typically, the first 2 pairs of aortic arches involute and disappear. The third arches join to the dorsal aortas to continue cranially as the brachiocephalic trunk and the right and left carotid arteries. The left fourth aortic arch expands to accommodate most of the blood from the ventral aortas and become the adult arch of the aorta. The right fourth arch forms into the origins of the right subclavian artery. The fifth arches bilaterally involute, leaving the sixth arches to form the pulmonary arteries but retaining a connection between the left sixth arch and the left dorsal aorta, known as the ductus arteriosus. The ductus arteriosus, ultimately connecting the pulmonary artery with the aorta, functions to shunt blood away from the lungs during fetal development and closes shortly after birth, forming the ligamentum arteriosum. The dorsal aortas also give off intersegmental arteries that give rise to the left subclavian artery from the seventh intersegmental artery.6

Aberrant development

The persistence of the embryonic right fourth aortic arch as the adult arch of the aorta is the basis of the commonly known anomaly of PRAA. In this situation, because the adult aortic arch now passes on the right side of the esophagus, vessels can cause esophageal compression as they track over the esophagus to follow their normal anatomic paths. However, the left fourth aortic arch can persist as the normal adult arch of the aorta and a vascular ring anomaly can still develop through the abnormal development and tracking of another aberrant vessel (Table 1).

A classification scheme has been proposed that includes 4 of the more commonly reported vascular ring anomalies.10 Type 1 anomalies are those involving a PRAA and left ligamentum arteriosum (Table 1). Occasionally, a patent ductus arteriosus can be present instead of a ligamentum arteriosum, which is uncommonly associated with a heart murmur.21,22 Type 2 anomalies involve a PRAA with an aberrant left subclavian artery. Type 3 anomalies involve a PRAA with a left ligamentum arteriosum and an aberrant left subclavian artery that has the potential for 2 sites of compression. Type 4 anomalies are those involving a double aortic arch, whereby both the left and right fourth aortic arches persist as the adult arch of the aorta, encircling the esophagus and trachea to reconnect as the descending aorta. This is the only vascular ring anomaly that can result in sufficient tracheal compression to cause respiratory clinical signs (eg, coughing, dyspnea, or stridor) in addition to regurgitation.6

Five additional vascular ring anomalies have been reported. The precise details of these anomalies are scattered among the literature, and we propose that they be added to the aforementioned classification scheme. A type 5 anomaly can be considered an anatomically normal left aortic arch with an anomalous right ductus arteriosus (Table 1).4,17 Affected dogs are reported to have a continuous, machinery-like heart murmur.17 A type 6 anomaly is an anatomically normal left aortic arch with an aberrant right subclavian artery.23 A type 7 anomaly is an anatomically normal left aortic arch with a right-sided ligamentum arteriosum and aberrant right subclavian artery that can result in 2 sites of esophageal compression.4 A type 8 anomaly is a persistent right dorsal aorta, composed of a patent vessel that joins the anatomically normal aorta to the anatomically normal right subclavian artery, while entrapping the esophagus and trachea.6 Finally, a type 9 anomaly is an anatomically normal left aortic arch with aberrant intercostal arteries, which may cause partial esophageal compression resulting from the first 2 intercostal arteries branching off the dorsal aorta.6

It is important to note that although types 3 and 7 are generally considered to involve 2 sites of compression, in recent reports,22,24,a the abnormal vessels (ligamentum arteriosum and subclavian artery) were described as originating from the same site. In the affected dogs, only 1 site of compression (rather than 2) was present, but both vessels required surgical removal because both contributed to the constriction.

In the veterinary literature, the frequency of reports of dogs with vascular ring anomalies varies with the type of anomaly, which may reflect the extent of investigation by attending clinicians or, for uncommonly reported types, perhaps genetic mutation as an underlying cause. For example, to the authors' knowledge, no cases of type 8 and 9 vascular ring anomalies in dogs have been reported since 1989.6

Diagnosis and Treatment

Typically, a vascular ring anomaly is diagnosed through consideration of patient history, clinical signs, and barium esophagrams, which reveal esophageal dilation cranial to the heart base caused by an apparent constriction.6,25 Standard ventrodorsal or dorsoventral radiographic findings can provide a reliable indicator of a vascular ring anomaly if a focal leftward deviation of the trachea at the heart base is seen.4 Esophagoscopy is useful for ruling out other causes of compression and can simultaneously reveal mucosal lesions. Visualization of a heart beat on the right side of the esophagus can also raise the index of suspicion of a vascular ring anomaly.26 However, these diagnostic tests reveal little about the type of vascular ring that is responsible for the constriction.

Table 1—

Types of vascular ring anomalies in dogs, including types 1 to 4 as characterized by Joly et al10 and 5 additional types (5 to 9) reported in the veterinary literature.

TypeAortic arch presentAberrant vessel
1RightLeft ligamentum arteriosum
2RightLeft subclavian artery
3RightLeft ligamentum arteriosum and left subclavian artery
4Both
5LeftRight ductus arteriosus and ligamentum arteriosum
6LeftRight subclavian artery
7LeftRight ligamentum arteriosum and right subclavian artery
8LeftVessel joining the aorta to the right subclavian artery
9LeftIntercostal arteries

— = No other vessel involved.

Because of the variety of vascular derangements known to occur with this condition, advanced diagnostic imaging is necessary to identify the specific compressive vessels to facilitate surgical planning. Such identification can be achieved via CT angiography or echocardiography.3,8 Computed tomographic angiography has been advocated as a useful, noninvasive means to identify a PRAA with a patent ductus arteriosus and aberrant left subclavian artery (type 3) and aid in surgical planning to correct the anomaly.22 Numerous case reports22,27–29 in the recent literature support the usefulness of CT angiograms in the diagnostic process for dogs with vascular ring anomalies. In addition, a CT angiogram was recently used to create a 3-D printed model to assist preoperative and intraoperative planning for a dog with a type 3 vascular ring anomaly, including a patent ductus arteriosus.27

Another useful diagnostic tool is MRI; however, the limited access to and high cost of MRI equipment preclude its use in many veterinary clinical settings.9 In human medicine, MRI is the preferred method of diagnosis for congenital heart diseases because it can be used with or without contrast medium, whereas CT requires contrast enhancement to highlight the vessel lumens.9 Although the reported use of MRI in veterinary medicine for diagnosing vascular ring anomalies is limited, the anatomic characteristics of healthy hearts and blood vessels in dogs as assessed by means of contrast-enhanced MRI have been reported with the intent of aiding in the diagnosis of congenital heart disease.30

Surgical planning

In 1968, Buchanan31 reported that “PRAA and its related anomalies” accounted for approximately 95% of vascular ring constrictions in dogs. In 2004, he used this same description in another study,4 which included dogs with a single left ligamentum arteriosum (29/52 [56%]; type 1 anomaly), an aberrant left subclavian artery with a left ligamentum arteriosum (17/52 [33%]; type 3 anomaly), and double aortic arches (6/52 [12%]; type 4 anomaly). However, over time, the term “PRAA and its related anomalies” has become truncated in various texts, and it is now commonly quoted that 95% of vascular ring anomalies are “persistent right aortic arches with a left ligamentum arteriosum” (ie, type 1 anomalies).3,5–9

This distinction is important for surgical planning purposes. Type 3 and 4 vascular ring anomalies may require different surgical approaches and treatment to successfully remove the compressive vessels, compared with type 1 anomalies. Identification and surgical removal of all vascular anomalies are considered important to correct esophageal obstruction.21 Computed tomographic angiography allows veterinary surgeons to accurately assess the abnormalities prior to surgery and plan an appropriate surgical approach, thereby reducing reliance on intraoperative dissection and advanced knowledge of anatomy during surgical correction.32

Surgical management

Vascular ring anomalies require surgical management. Medical management is unable to address the underlying esophageal obstruction. Affected dogs will continue to have chronic regurgitation, which poses a risk of aspiration pneumonia. Early surgical correction is advisable to prevent progressive dilation of the cranial portion of the esophagus and reduce the risk of aspiration pneumonia and chronic esophageal changes prior to surgical correction. The extent of esophageal dilation cranial to the ligamentous constriction may have an important bearing on postoperative prognosis.

A left or right intercostal thoracotomy at the third or fourth interspace of the ribs (based on the precise location of the abnormality) is typically performed for surgical management of vascular ring anomalies. A right intercostal thoracotomy is required for the management of type 5 and 6 anomalies. For the management of type 4 anomalies (double aortic arches), ligation and resection of the least patent aortic arch is required, and the side of the thoracotomy should be ipsilateral to the smaller, less patent vessel to provide better visibility for ligation and resection.8,25 If the 2 aortic arches are symmetric, then intraoperative assessment via occlusion and palpation of the femoral artery can allow subjective evaluation of the more patent vessel.25 The vessel that provides the stronger femoral pulse when occluded is the vessel to be resected. Although unreported, echocardiographic assessment of the aortic pressures through each aortic arch may allow objective identification of a pressure difference between the 2 vessels. Various reports1,4,8,25 of double aortic arches in dogs include a wide range of sizes and patencies of each arch, ranging from 1 atretic arch, 1 smaller but patent arch (right or left), and 2 symmetric aortic arches. Consequently, no assumptions can be made about the precise nature of type 4 anomalies, and appropriate diagnostic imaging should be performed prior to surgery. For the remaining vascular ring anomalies, a left intercostal thoracotomy will be required.

To ensure good visibility of the area of mediastinum cranial to the heart, the lungs should be packed off caudally with damp sterile sponges.3,31 Respiratory effort and arterial oxygen saturation should be monitored to ensure respiration is not compromised by this action. The major anatomic structures around the heart should be identified and the tight restrictive band crossing the esophagus noted. Placement of stay sutures on the esophagus can allow elevation of the tissue and identification of any constricting structures passing over the surface. The pleura should then be dissected to isolate the constricting structure or structures and these structures double-ligated with silk or polypropylene suture.31 It is important to avoid the vagosympathetic and phrenic nerves during this dissection. The ligamentous or vascular band can then be resected. If 2 sites of compression are present, they both should be addressed.

Once the band has been resected, the anesthetist should pass a Foley catheter or stomach tube into the esophagus, past the constricted region. The balloon should be inflated and the catheter moved up and down the esophagus to allow distention of the esophageal wall.3 Many small fibrous bands will often continue to restrict the esophagus; these must be identified and resected thoroughly. Packing swabs should then be removed and the lungs allowed to reinflate. The thoracotomy incision can subsequently be closed routinely and a thoracotomy tube put in place for postoperative care.3

Successful thoracoscopic dissection of type 1 and 3 vascular ring anomalies has reportedly been achieved in dogs.26,33 The procedure involves insertion of an endoscope at the costochondral junction of the left fifth intercostal space, a lung retractor at the costochondral junction of the left seventh intercostal space, and 2 other cannulas at the costochondral junction of the third intercostal space and the dorsolateral aspect of the fifth intercostal space. This procedure has also been described in a cat.34 Simultaneously performed esophagoscopy can provide transesophageal illumination for guiding surgical dissection of vascular ring anomalies during thoracoscopy.33 The advantages of thoracoscopy include better visibility, less postoperative pain, and less risk of hypothermia in pediatric, cachectic animals.26 The disadvantages of thoracoscopy are the technically more challenging nature and greater risk of life-threatening complications such as hemorrhage (with dissection around great vessels) and esophageal perforation.33

Type 4 vascular ring anomalies (double aortic arch) pose a unique surgical challenge. Ligation and resection of 1 aortic arch may reduce the functional volume of the aorta, leading to an increase in left ventricular afterload, pulmonary hypertension, cardiac insufficiency, and death.1,25 An alternative surgical approach has been proposed, involving reanastomosis of the affected vessel so that the esophagus and trachea can be free of constriction and the risk of reduced functional aortic volume can simultaneously be eliminated.25

To the authors' knowledge, no reports of interventional radiology procedures exist in the veterinary literature. In human medicine, interventional radiology is used to further characterize or confirm a diagnosis, but interventional procedures for correction are never recommended, given the need to physically resect the vascular ring to relieve the compression.35,36

Postoperative management

Effective analgesia is an important element of all thoracic surgical procedures. With appropriate perioperative care, juvenile dogs usually make an excellent recovery from thoracic surgery, with younger dogs having a better rate of survival to hospital discharge than older dogs.13,14 After surgery, preexisting megaesophagus can persist, and so elevated feeding with pureed or liquid food provided on a little-and-often basis should be recommended initially.10,11 The duration that dietary management will be required is case dependent and should be continued as long as regurgitation continues. However, clinicians should be aware that documented postoperative megaesophagus does not always correlate with poor outcome, with 1 case series11 revealing persistent megaesophagus in all dogs that underwent esophagoscopy 4 months after surgery. At that point, 9 of the 13 dogs that underwent esophagoscopy were free of clinical signs after being fed moistened food at a height and the other 4 dogs had infrequent regurgitation. Best clinical judgement is therefore advised.

Postsurgical complications and prognosis

To date, all reported studies of postoperative prognosis for dogs with vascular ring anomalies have been focused on the surgical treatment of type 1 anomalies specifically. Early reports provided a poor long-term outlook, with only 9% of surgically treated dogs in 1 study37 considered clinically normal following surgery but most (67%) having relief of clinical signs to within acceptable limits.

A lifelong risk of aspiration pneumonia is to be expected in dogs for which the regurgitation fails to resolve following surgical correction of PRAA.3,6 No factors have been definitively identified as associated with such persistent regurgitation. One may presume that the severity of preoperative esophageal dilation and degree of permanent damage should influence surgical outcome. However, such a relationship has not been confirmed clinically. In a small retrospective study12 involving 10 dogs, a nonsignificant association was identified between preoperative esophageal dilation (ie, ratio of the maximum diameter of the esophageal dilation cranial to the heart base to the height of the narrowest portion of T5) and outcome of surgical treatment for PRAA.

In other studies,11,b the association between postoperative esophageal dilation and dysmotility on long-term prognosis or persistence of clinical signs appeared irrelevant. In a small retrospective studyb involving 10 dogs and 2 cats, preoperative and postoperative fluoroscopic findings were evaluated for associations with clinical outcome. In that study, 7 animals were considered normal with no signs of regurgitation following surgery; however, all of those animals had abnormal esophageal morphology and function identified on postoperative fluoroscopic examination. This finding is reinforced by the aforementioned study,11 in which postoperative mega-esophagus was identified in all dogs that underwent esophagoscopy but 9 had no clinical signs and the other 4 had infrequent regurgitation.

The long-term outcome with respect to regurgitation appears good, with 92% (23/25) of dogs that survived > 6 months having no episodes of regurgitation after eating in a retrospective study.11 The remainder (8%) had only occasional episodes of regurgitation. However, because of the nature of the included dogs (survival for > 6 months), these results are likely optimistic and poorly generalizable to the general population of dogs surgically treated for PRAA. More recently, Krebs et al9 performed a larger study of 52 dogs that were all regurgitating more than once per day prior to surgery. The short-term mortality rate and long-term prognosis were evaluated following surgical correction. Between surgery and hospital discharge, 8% of dogs had died, and this proportion increased to 18% within 2 months after surgery. Necropsies were performed on 5 of the 9 dogs that failed to survive for 2 months, confirming the presence of various degrees of bronchopneumonia in each. No information was provided regarding the postmortem identification of additional vascular abnormalities that were potentially missed or left uncorrected at surgery. It remains unknown whether some dogs had a type of vascular ring anomaly other than type 1, thereby contributing to a poor outcome. Most (87%) owners of dogs that survived > 2 months in that study9 reported a good or excellent long-term outcome, with 30% of those dogs having complete resolution of clinical signs or no need for dietary modifications (excellent outcome) and 57% having persistent mild clinical signs (regurgitation frequency less than once per week) or requiring dietary medical management but also having a good quality of life.

No consistent relationship has been identified between patient age and prognosis for dogs surgically treated for vascular ring anomalies. In a 2014 retrospective study,9 no correlation was found between dog age and survival to hospital discharge following surgical treatment for PRAA. However, in a 1981 retrospective study37 involving 25 dogs surgically treated for PRAA, a poorer prognosis was identified for those between 2 weeks and 2 months of age, compared with the prognosis for older dogs.

Given the aforementioned findings, we believe clients should be strongly advised that many dogs may continue to regurgitate and will need continued dietary medical management after surgery. There is also a potential for some dogs to respond poorly, despite surgical correction. However, with good postoperative support, > 70 % of dogs might be expected to have considerable improvement in their quality of life.9,11

Conclusion

Vascular ring anomalies are congenital abnormalities of the aortic vasculature that result in pathological compression of the esophagus. Several types have been described and classified in dogs, each with unique characteristics and sites of compression. Because of this variation, a generic diagnosis of PRAA is overly simplistic, ignoring the identity of the compressive vessel involved. Advanced diagnostic imaging is strongly recommended in the surgical planning for dogs with a clinical suspicion of a vascular ring anomaly because the optimal approach can vary, depending on the compressive vessel or vessels. Prognostic indicators remain to be established, and esophageal dilation that persists following surgery may not be associated with a poor prognosis. Although its usefulness has not been investigated, esophagoscopy may provide prognostic information by allowing evaluation of esophageal mucosal lesions and, at a minimum, can guide the need for postoperative medical management with gastroprotectants. The immediate postoperative prognosis may be guarded, and 1 in 5 dogs may fail to respond to surgery. However, the available evidence suggests that most dogs that survive > 2 months after surgery will have an improvement in quality of life, although a small number may require continued dietary management.

Acknowledgments

No third-party funding or support was received in connection with this study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.

ABBREVIATIONS

PRAA

Persistent right aortic arch

Footnotes

a

Rizza M, Claeys S, Billen F, et al. Persistent right aortic arch associated with an aberrant left subclavian artery arising from a patent ductus arteriosus in a puppy (abstr). Available at: hdl.handle.net/2268/158841. Accessed Aug 31, 2013.

b

Komtebedde J, Koblik P, Mattoon J, et al. Preoperative and postoperative fluoroscopy in dogs with persistent right aortic arch (abstr). Vet Surg 1991;20:340.

References

  • 1. Ferrigno CR, Ribeiro AA, Rahal SC, et al. Double aortic arch in a dog (canis familiaris): a case report (Erratum published in Anat Histol Embryol 2002;31:128). Anat Histol Embryol 2001;30:379381.

    • Search Google Scholar
    • Export Citation
  • 2. Menzel J, Distl O. Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German Pinschers. Vet J 2011;187:352355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Kyles AE. Esophagus. In: Tobias KM, Johnston SA, eds. Veterinary surgery: small animal. Vol 2. St Louis: Elsevier Saunders, 2012;14691473.

    • Search Google Scholar
    • Export Citation
  • 4. Buchanan JW. Tracheal signs and associated vascular anomalies in dogs with persistent right aortic arch. J Vet Intern Med 2004;18:510514.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Kim NS, Alam MR, Choi IH. Persistent right aortic arch and aberrant left subclavian artery in a dog: a case report. Vet Med 2006;51:156160.

    • Search Google Scholar
    • Export Citation
  • 6. VanGundy T. Vascular ring anomalies. Compend Contin Educ Pract Vet 1989;11:3648.

  • 7. Isakow K, Fowler D, Walsh P. Video-assisted thoracoscopic division of the ligamentum arteriosum in two dogs with persistent right aortic arch. J Am Vet Med Assoc 2000;217:13331336.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Vianna ML, Krahwinkel DJ. Double aortic arch in a dog. J Am Vet Med Assoc 2004;225:12221224.

  • 9. Krebs IA, Lindsley S, Shaver S, et al. Short and long-term outcomes following surgical correction of a persistent right aortic arch. J Am Anim Hosp Assoc 2014;50:181186.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Joly H, D'Anjou MA, Huneault L. Imaging diagnosis—CT angiography of a rare vascular ring anomaly in a dog. Vet Radiol Ultrasound 2008;49:4246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Muldoon MM, Birchard SJ, Ellison GW. Long-term results of surgical correction of persistent right aortic arch in dogs: 25 cases (1980–1995). J Am Vet Med Assoc 1997;210:17611763.

    • Search Google Scholar
    • Export Citation
  • 12. Rallis T, Papazoglou LG, Patsikas MN, et al. Persistent right aortic arch: does the degree of oesophageal dilatation affect long-term outcome? A retrospective study in 10 dogs and 4 cats. Eur J Comp Gastroenterol 2000;5:2933.

    • Search Google Scholar
    • Export Citation
  • 13. Tattersall JA, Welsh E. Factors influencing the short-term outcome following thoracic surgery in 98 dogs. J Small Anim Pract 2006;47:715720.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14. Moores AL, Halfacree ZJ, Baines SJ, et al. Indications, outcomes and complications following lateral thoracotomy in dogs and cats. J Small Anim Pract 2007;48:695698.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15. Patterson DF. Canine congenital heart disease: epidemiology and etiology hypothesis. J Small Anim Pract 1971;12:263287.

  • 16. Gunby JM, Hardie RJ, Bjorling DE. Investigation of the potential heritability of persistent right aortic arch in Greyhounds. J Am Vet Med Assoc 2004;224:11201122.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 17. Holt D, Heldmann E, Michel K, et al. Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates. Vet Surg 2000;29:264270.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 18. McCandlish IA, Nash AS, Peggram A. Unusual vascular ring in a cat: left aortic arch with a right ligamentum arteriosum. Vet Rec 1984;114:338340.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19. Yarim M, Gultiken E, Ozturk S, et al. Double aortic arch in a Siamese cat. Vet Pathol 1999;36:340341.

  • 20. Shannon D, Husnik R, Fletcher JM, et al. Persistent right aortic arch with an aberrant left subclavian, Komerell's diverticulum and bicarotid trunk in a 3-year-old cat. J Feline Med Surg 2015;1:14.

    • Search Google Scholar
    • Export Citation
  • 21. Christiansen KJ, Snyder D, Buchanan JW, et al. Multiple vascular anomalies in a regurgitating German Shepherd puppy. J Small Anim Pract 2007;48:3235.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Saunders AB, Winter RL, Griffin JF, et al. 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. J Vet Cardiol 2013;15:153159.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23. Yoon HY, Jeong SU. Surgical correction of an aberrant right subclavian artery in a dog. Can Vet J 2011;52:11151118.

  • 24. Biasato I, Lanteri G, Guarda F, et al. Unusual combination of multiple vascular ring anomalies in a German Shepherd puppy with megaoesophagus. Anat Histol Embryol 2017;46:216219.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25. Du Plessis CJ, Keller N, Joubert KE. Symmetrical double aortic arch in a Beagle puppy. J Small Anim Pract 2006;47:3134.

  • 26. MacPhail CM, Monnet E, Twedt DC. Thoracoscopic correction of persistent right aortic arch in a dog. J Am Anim Hosp Assoc 2001;37:577581.

  • 27. Dundie A, Hayes G, Scrivani P, et al. Use of 3D printer technology to facilitate surgical correction of a complex vascular anomaly with esophageal entrapment in a dog. J Vet Cardiol 2017;19:196204.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28. Miller R, Wilson C, Wray J, et al. Adult-onset regurgitation in a dog with an aberrant right subclavian artery: a CT angiographic study. Vet Rec Case Rep 2015;3:14.

    • Search Google Scholar
    • Export Citation
  • 29. Yoon H, Kim J, Kwon GB, et al. Imaging diagnosis—computed tomographic angiography characteristics of multiple vascular anomalies in a senior dog with late-onset regurgitation. Vet Radiol Ultrasound 2018;59:E44E49.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Contreras S, Vazquez JM, Miguel AD, et al. Magnetic resonance angiography of the normal canine heart and associated blood vessels. Vet J 2008;178:130132.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 31. Buchanan JW. Symposium: thoracic surgery in the dog and cat—III: patent ductus arteriosus and persistent right aortic arch surgery in dogs. J Small Anim Pract 1968;9:409428.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 32. House AK, Summerfield NJ, German AJ, et al. Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs. J Small Anim Pract 2005;46:585590.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33. Townsend S, Oblak ML, Sing A, et al. Thoracoscopy with concurrent esophagoscopy for persistent right aortic arch in 9 dogs. Vet Surg 2016;45:O111O118.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 34. Plesman R, Johnson M, Rurak S, et al. Thoracoscopic correction of a congenital persistent right aortic arch in a young cat. Can Vet J 2011;52:11231128.

    • Search Google Scholar
    • Export Citation
  • 35. Juraszek AL, Guleserian KJ. Common aortic arch anomalies: Diagnosis and management. Curr Treat Options Cardiovasc Med 2006;8:414418.

  • 36. Turner A, Gaval G, Coutts J. Vascular rings—presentation, investigation and outcome. Eur J Pediatr 2005;164:266270.

  • 37. Shires PK, Liu W. Persistent right aortic arch in dogs: a long-term follow-up after surgical correction. J Am Anim Hosp Assoc 1981;17:773776.

    • Search Google Scholar
    • Export Citation
  • 1. Ferrigno CR, Ribeiro AA, Rahal SC, et al. Double aortic arch in a dog (canis familiaris): a case report (Erratum published in Anat Histol Embryol 2002;31:128). Anat Histol Embryol 2001;30:379381.

    • Search Google Scholar
    • Export Citation
  • 2. Menzel J, Distl O. Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German Pinschers. Vet J 2011;187:352355.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Kyles AE. Esophagus. In: Tobias KM, Johnston SA, eds. Veterinary surgery: small animal. Vol 2. St Louis: Elsevier Saunders, 2012;14691473.

    • Search Google Scholar
    • Export Citation
  • 4. Buchanan JW. Tracheal signs and associated vascular anomalies in dogs with persistent right aortic arch. J Vet Intern Med 2004;18:510514.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Kim NS, Alam MR, Choi IH. Persistent right aortic arch and aberrant left subclavian artery in a dog: a case report. Vet Med 2006;51:156160.

    • Search Google Scholar
    • Export Citation
  • 6. VanGundy T. Vascular ring anomalies. Compend Contin Educ Pract Vet 1989;11:3648.

  • 7. Isakow K, Fowler D, Walsh P. Video-assisted thoracoscopic division of the ligamentum arteriosum in two dogs with persistent right aortic arch. J Am Vet Med Assoc 2000;217:13331336.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8. Vianna ML, Krahwinkel DJ. Double aortic arch in a dog. J Am Vet Med Assoc 2004;225:12221224.

  • 9. Krebs IA, Lindsley S, Shaver S, et al. Short and long-term outcomes following surgical correction of a persistent right aortic arch. J Am Anim Hosp Assoc 2014;50:181186.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Joly H, D'Anjou MA, Huneault L. Imaging diagnosis—CT angiography of a rare vascular ring anomaly in a dog. Vet Radiol Ultrasound 2008;49:4246.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Muldoon MM, Birchard SJ, Ellison GW. Long-term results of surgical correction of persistent right aortic arch in dogs: 25 cases (1980–1995). J Am Vet Med Assoc 1997;210:17611763.

    • Search Google Scholar
    • Export Citation
  • 12. Rallis T, Papazoglou LG, Patsikas MN, et al. Persistent right aortic arch: does the degree of oesophageal dilatation affect long-term outcome? A retrospective study in 10 dogs and 4 cats. Eur J Comp Gastroenterol 2000;5:2933.

    • Search Google Scholar
    • Export Citation
  • 13. Tattersall JA, Welsh E. Factors influencing the short-term outcome following thoracic surgery in 98 dogs. J Small Anim Pract 2006;47:715720.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14. Moores AL, Halfacree ZJ, Baines SJ, et al. Indications, outcomes and complications following lateral thoracotomy in dogs and cats. J Small Anim Pract 2007;48:695698.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15. Patterson DF. Canine congenital heart disease: epidemiology and etiology hypothesis. J Small Anim Pract 1971;12:263287.

  • 16. Gunby JM, Hardie RJ, Bjorling DE. Investigation of the potential heritability of persistent right aortic arch in Greyhounds. J Am Vet Med Assoc 2004;224:11201122.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 17. Holt D, Heldmann E, Michel K, et al. Esophageal obstruction caused by a left aortic arch and an anomalous right patent ductus arteriosus in two German Shepherd littermates. Vet Surg 2000;29:264270.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 18. McCandlish IA, Nash AS, Peggram A. Unusual vascular ring in a cat: left aortic arch with a right ligamentum arteriosum. Vet Rec 1984;114:338340.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19. Yarim M, Gultiken E, Ozturk S, et al. Double aortic arch in a Siamese cat. Vet Pathol 1999;36:340341.

  • 20. Shannon D, Husnik R, Fletcher JM, et al. Persistent right aortic arch with an aberrant left subclavian, Komerell's diverticulum and bicarotid trunk in a 3-year-old cat. J Feline Med Surg 2015;1:14.

    • Search Google Scholar
    • Export Citation
  • 21. Christiansen KJ, Snyder D, Buchanan JW, et al. Multiple vascular anomalies in a regurgitating German Shepherd puppy. J Small Anim Pract 2007;48:3235.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Saunders AB, Winter RL, Griffin JF, et al. 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. J Vet Cardiol 2013;15:153159.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23. Yoon HY, Jeong SU. Surgical correction of an aberrant right subclavian artery in a dog. Can Vet J 2011;52:11151118.

  • 24. Biasato I, Lanteri G, Guarda F, et al. Unusual combination of multiple vascular ring anomalies in a German Shepherd puppy with megaoesophagus. Anat Histol Embryol 2017;46:216219.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25. Du Plessis CJ, Keller N, Joubert KE. Symmetrical double aortic arch in a Beagle puppy. J Small Anim Pract 2006;47:3134.

  • 26. MacPhail CM, Monnet E, Twedt DC. Thoracoscopic correction of persistent right aortic arch in a dog. J Am Anim Hosp Assoc 2001;37:577581.

  • 27. Dundie A, Hayes G, Scrivani P, et al. Use of 3D printer technology to facilitate surgical correction of a complex vascular anomaly with esophageal entrapment in a dog. J Vet Cardiol 2017;19:196204.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28. Miller R, Wilson C, Wray J, et al. Adult-onset regurgitation in a dog with an aberrant right subclavian artery: a CT angiographic study. Vet Rec Case Rep 2015;3:14.

    • Search Google Scholar
    • Export Citation
  • 29. Yoon H, Kim J, Kwon GB, et al. Imaging diagnosis—computed tomographic angiography characteristics of multiple vascular anomalies in a senior dog with late-onset regurgitation. Vet Radiol Ultrasound 2018;59:E44E49.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Contreras S, Vazquez JM, Miguel AD, et al. Magnetic resonance angiography of the normal canine heart and associated blood vessels. Vet J 2008;178:130132.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 31. Buchanan JW. Symposium: thoracic surgery in the dog and cat—III: patent ductus arteriosus and persistent right aortic arch surgery in dogs. J Small Anim Pract 1968;9:409428.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 32. House AK, Summerfield NJ, German AJ, et al. Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs. J Small Anim Pract 2005;46:585590.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33. Townsend S, Oblak ML, Sing A, et al. Thoracoscopy with concurrent esophagoscopy for persistent right aortic arch in 9 dogs. Vet Surg 2016;45:O111O118.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 34. Plesman R, Johnson M, Rurak S, et al. Thoracoscopic correction of a congenital persistent right aortic arch in a young cat. Can Vet J 2011;52:11231128.

    • Search Google Scholar
    • Export Citation
  • 35. Juraszek AL, Guleserian KJ. Common aortic arch anomalies: Diagnosis and management. Curr Treat Options Cardiovasc Med 2006;8:414418.

  • 36. Turner A, Gaval G, Coutts J. Vascular rings—presentation, investigation and outcome. Eur J Pediatr 2005;164:266270.

  • 37. Shires PK, Liu W. Persistent right aortic arch in dogs: a long-term follow-up after surgical correction. J Am Anim Hosp Assoc 1981;17:773776.

    • Search Google Scholar
    • Export Citation

Advertisement