Retrospective review: congenital pulmonary artery stenosis in dogs (prevalence forms)
Authors: Illarionova Vladislava , Kadyrova Adelya 
Published: November 2021

Objective: to determine the occurrence and clinical characteristics of different types of PS (pulmonary stenosis) in dogs

Reseach tasks: to identify the breed predisposition to PS, to study the clinical, echocardiographic and electrocardiographic characteristics of various types of PS and to analyse their dependence on the severity of the heart defect.

Materials and methods: a retrospective analysis of Biocontrol veterinary clinic medical records throughout six years (2014–2020). Cardiological examination of dogs presented to the primary ambulatory appointment included physical examination, echocardiography using the Philips HD15 ultrasound system, radiography and electrocardiography.

Animals: 31 dogs with isolated pulmonary artery stenosis (17 males and 14 females). Breeds: French Bulldog, English Bulldog, Yorkshire Terrier, German Spitz, American Pit Bull Terrier, Staffordshire Terrier, Toy Terrier, Cane Corso, Whippet, Biewer Yorkshire Terrier, Chihuahua, Entlebucher, German Boxer, East European Shepherd, American Bully.

Results and discussion: 43 dogs with a PS were examined from 1 January 2014 to 31 December 2020. Of these, 31 dogs (72 %) with isolated PS and 12 dogs (28 %) with a combination of PS with other congenital heart defects. The most common combinations were PS with aortic stenosis (25 %) and PS with ventricular septal defect (25 %). The most common form of isolated PS was type A valve stenosis (68 %). Severe stenosis prevailed (58 %). The most common breeds were French Bulldogs (22.6 %), English Bulldogs (16.1 %) and Yorkshire Terriers (9.7 %). Males were more prevalent (55 %). 61 % of animals from the group of dogs with severe PS visited clinic because of signalment, and syncope was the most frequently reported symptom (28 %).

The symptoms associated with congenital heart defect were not identified in the group of animals with moderate and mild degrees of PS. ECG showed that 100 % of dogs were diagnosed with sinus rhythm. Electrical right axis deviation of the heart was detected in 45 % of dogs. Direct dependency was between the severity of the stenosis and the severity of electrical right axis deviation. According to echocardiographic studies — 100 % of animals with severe and moderate stenosis and 14% with mild stenosis were diagnosed with concentric, eccentric or mixed forms of right ventricle myocardial hypertrophy, enlargement of the right atrial. Direct dependency is founded between the severity of stenosis, the type of right ventricle hypertrophy and the size of the right atrium.

The more severe stenosis, the more mixed form of hypertrophy; increase of the right atrium was recorded in dogs with mixed right ventricular hypertrophy. Post-stenotic dilatation of the trunk and branches of the pulmonary artery was determined in all dogs with single right coronary artery type R2A.

Conclusions: PS is most commonly found in French Bulldogs. The most common type of PS is type A valvular stenosis in the form of an isolated defect. Severe PS is prevalent. There is direct dependency is between the severity of the defect and the severity of right ventricular myocardial hypertrophy, the large size of the right atrium and electrical right axis deviation of the heart.