Vascular ring anomaly

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Persistent right aortic arch with aberrant left subclavian artery and bicarotid trunk in a German Pinscher. Left lateral volume-rendered 3-dimensional MDCT image showing an aberrant left subclavian artery (ALSA) with mild dilation at its origin. The bicarotid trunk arises as the first branch from the aortic arch, which is followed by the right subclavian artery (RSA) and the ALSA, which arises from the proximal part of the descending aorta. LCA = left carotid artery, RCA = right carotid artery[1]

Vascular ring anomalies are a relatively rare genetic cardiovascular disorder of dogs characterized by abnormal persistent of the fetal aortic arch[2].

The most common vascular ring anomaly is a persistent right aortic arch with a left ligamentum arteriosum, however various other vascular anomalies resulting in tracheoesophageal compression have also been reported, such as persistent right aortic arch and left ligamentum arteriosum with a hypoplastic aberrant left subclavian artery[3]. This latter anomaly has a genetic predisposition in the German Pinscher[4] and Great Dane[5].

In most dogs with this genetic defect, patent ductus arteriosus is commonly observed concurrently and these are two of the most common vascular anomalies of the thoracic aorta[6][7][8].

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[1]. Magnetic resonance imaging and multidetector-row computed tomography are 3-dimensional, noninvasive modalities that are emerging modalities in veterinary medicine[9].

Clinical signs are usually first evident in young pups with regurgitation, often as puppies start to eat solid food at the time of weaning. Affected animals are often thin and smaller than their littermates, and some are dyspneic because of aspiration pneumonia.

Lateral survey and contrast radiographs of these animals commonly show esophageal constriction at the heart base and precardial esophageal dilation. Ventrodorsal radiographs show a leftward curvature of the trachea[10].

Definitive diagnosis is achieved by surgical exploration, which excludes other presurgical differentials such as persistent left cranial vena cava and cor triatriatum[11].

Treatment usually requires surgical intervention. Most vascular ring anomalies are well managed by a left intercostal approach. Post-operative complications are relatively rare[12].

In some dogs, primary surgical intervention has been delayed for years and patients invariably have to contend with chronic regurgitation due to megaesophagus, persistent aspiration pneumonia and varying degrees of congestive heart failure[13].

References

  1. 1.0 1.1 Henjes CR et al (2011) Multidetector-row computed tomography of thoracic aortic anomalies in dogs and cats: patent ductus arteriosus and vascular rings. BMC Vet Res 7:57
  2. Menzel J & Distl O (2011) Unusual vascular ring anomaly associated with a persistent right aortic arch and an aberrant left subclavian artery in German pinschers. Vet J 187(3):352-355
  3. Bottorff B & Sisson DD (2012) Hypoplastic aberrant left subclavian artery in a dog with a persistent right aortic arch. J Vet Cardiol 14(2):381-385
  4. Philipp U et al (2011) A rare form of persistent right aorta arch in linkage disequilibrium with the DiGeorge critical region on CFA26 in German Pinschers. J Hered 102(1):S68-S73
  5. House AK et al (2005) Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs. J Small Anim Pract 46(12):585-590
  6. Patterson DF (1968) Epidemiologic and Genetic Studies of Congenital Heart Disease in the Dog. Circ Res 23:171–202
  7. Ellison GW (1980) Vascular Ring Anomalies in the Dog and Cat. Compend Contin Educ Vet II:693–705
  8. VanGundy T (1989) Vascular Ring Anomalies. Compend Contin Educ Vet 11:36–48
  9. Pownder S & Scrivani PV (2008) Non-selective computed tomography angiography of a vascular ring anomaly in a dog. J Vet Cardiol 10(2):125-128
  10. Buchanan JW (2004) Tracheal Signs and Associated Vascular Anomalies in Dogs with Persistent Right Aortic Arch. J Vet Intern Med 18:510–514
  11. Larcher T et al (2006) Persistent left cranial vena cava causing oesophageal obstruction and consequent megaoesophagus in a dog. J Comp Pathol 135(2-3):150-152
  12. Tattersall JA & Welsh E (2006) Factors influencing the short-term outcome following thoracic surgery in 98 dogs. J Small Anim Pract 47(12):715-720
  13. Loughin CA & Marino DJ (2008) Delayed primary surgical treatment in a dog with a persistent right aortic arch. J Am Anim Hosp Assoc 44(5):258-61
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