Canis ISSN: 2398-2942

Heart: aortic stenosis

Contributor(s): Serena Brownlie, Daniel Schrope, Mark Oyama

Introduction

  • Common congenital disease (subaortic stenosis (SAS) or more rarely, acquired (aortic valve stenosis (AVS)).
  • Cause: obstructive malformation of left ventricular outflow tract or aortic valve, less commonly supravalvular.
  • Signs: asymptomatic, exercise intolerance, syncope, sudden death; left-sided congestive heart failure (CHF).
  • Diagnosis: radiography, echocardigraphy, auscultation.
  • Treatment: symptomatic management, rarely balloon dilation, or surgery.
  • Prognosis: good to poor depending on severity of stenosis.
    Print off the owner factsheet Congenital heart disease - aortic stenosis Congenital heart disease - aortic stenosis to give to your client.

Pathogenesis

Predisposing factors

General
  • Breed.

Pathophysiology

  • SAS: developmental congenital cardiac abnormality.
  • AVS: degenerative and calcific disease leading to stiffness and calcification of the aortic valve leaflets.
  • SAS/AVS: obstruction to aortic flow can lead to a decrease in cardiac output at rest or with exercise and stress. If cardiac output is decreased at rest then clinical signs of lethargy and weakness may be evident. If cardiac output is decreased during exercise then evidence of exercise intolerance or syncope may be seen.
  • SAS/AVS: obstruction to aortic flow can result in left ventricular hypertrophy. If the hypertrophy is significant, the coronary blood flow may not be adequate to maintain normal perfusion to all of the muscle, especially the subendocardial regions. This could lead to hypoxia of the muscle. Hypoxia of the muscle could lead to the development of ventricular arrhythmias. If the arrhythmias are severe enough they could result in lethargy, weakness, exercise intolerance, syncope, or sudden death.
  • Older patients with SAS or AVS may eventually develop significant elevations in left atrial pressure and size. This could lead to the development of left-sided CHF.

Timecourse

  • The severity of SAS rarely progresses once the patient reaches 1 year of age.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Orton E C, Herndon G D, Boon J A, Gaynor J S, Hackett T B, Monnet E (2000) Influence of open surgical correction on intermediate-term outcome in dogs with subvalvular aortic stenosis: 44 cases (1991-1998). JAVMA 216 (3), 364-367 PubMed.
  • Kvart C, French A T, Luis Fuentes V L, Haggstrom J et al (1998) Analysis of murmur intensity, duration and frequency components in dogs with aortic stenosis. JSAP 39 (7), 318-324 PubMed.
  • Monnet E, Orton C, Gaynor J et al (1997) Diagnosis and surgical repair of partial AV septal defects in two dogs. JAVMA 211 (5), 569-572 PubMed.
  • Tidholm A (1997) Retrospective study of congenital heart defects in 151 dogs. JSAP 38 (3), 94-98 PubMed.
  • Monnet E, Orton E C, Gaynor J S, Boon J, Wagner A, Linn K, Eddleman L A, Brevard S (1996) Open resection for subvalvular aortic stenosis in dogs. JAVMA 209 (7), 1255-1261 PubMed.
  • Buoscio D A, Sisson D, Zachary J F & Luethy M (1994) Clinical and pathological characterization of an unusual form of subvalvular aortic stenosis in four golden retriever puppies. JAAHA 30 (2), 100-110 VetMedResource.
  • Kienle R D, Thomas W P & Pion P D (1994) The natural clinical history of canine congenital subaortic stenosis. JVIM 8 (6), 423-431 PubMed.
  • De Lellis L A, Thomas W P & Pion P D (1993) Balloon dilation of congenital subaortic stenosis in the dog. JVIM 7, 153-162 PubMed.
  • Darke P G G (1989) Congenital heart disease in dogs and cats. JSAP 30 (11), 599-607 VetMedResource.
  • O'Grady M R, Holmberg L, Miller C W & Cockshutt J R (1989) Canine congenital aortic stenosis - a review of the literature and commentary. Can Vet J 30 (10), 811-815 PubMed.
  • Breznock E M, Whiting P, Pendray D, Thomas B, Strack D, Bauer T, Koblik P, Hornof W, Ludders J D (1983) Valved apico-aortic conduit for relief of left ventricular hypertension caused by discrete subaortic stenosis in dogs. JAVMA 182 (1), 51-56 PubMed.
  • Pyle R L, Patterson D F & Chacko S (1976) The genetics and pathology of discrete subaortic stenosis in the Newfoundland dog. Am Heart J 92 (3), 324-334 PubMed.

Other sources of information

  • Bonagura J & Darke P (1995)Congenital heart disease.In:Textbook of Veterinary Internal Medicine.4th Ed. Ed S J Ettinger, W B Saunders, Philadelphia. pp 892-943.
  • Lehmkuhl L B & Bonagura J D (1995)CVT Update - Canine Subvavular Aortic Stenosis.In:Current Veterinary Therapy XIIW B Saunders, Philadelphia. pp 822-827.


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