Epidemiological study of congenital heart diseases in dogs: Prevalence, popularity, and volatility throughout twenty years of clinical practice

Abstract

The epidemiology of Congenital Heart Diseases (CHDs) has changed over the past twenty years. This study aimed to evaluate the prevalence of CHDs in the population of dogs recruited in a single referral center (RC); compare the epidemiological features of CHDs in screened breeds (Boxers) versus non-screened (French and English Bulldogs, German Shepherds); investigate the association of breeds with the prevalence of CHDs; determine the popularity and volatility of breeds over a 20-year period; analysed the trends of the most popular breeds in the overall population of new-born dogs registered in the Italian Kennel Club (IKC) from 1st January 1997 to 31st December 2017. The RC's cardiological database was analysed, and 1,779 clinical records were included in a retrospective observation study. Descriptive statistics and frequencies regarding the most representative breeds and CHDs were generated. A logistic regression model was used to analyse the trends of the most common CHDs found in single and in cluster of breeds. The relationship between breed popularity and presence of CHDs was studied. The most common CHDs were Pulmonic Stenosis, Patent Ductus Arteriosus, Subaortic Stenosis, Ventricular Septal Defect, Aortic Stenosis, Tricuspid Dysplasia, Atrial Septal Defect, Double Chamber Right Ventricle, Mitral Dysplasia, and others less frequent. The most represented pure breeds were Boxer, German Shepherd, French Bulldog, English Bulldog, Maltese, Newfoundland, Rottweiler, Golden Retriever, Chihuahua, and others in lower percentage. Chihuahuas, American Staffordshire Terriers, Border Collies, French Bulldogs, and Cavalier King Charles Spaniel were the most appreciated all of which showed a high value of volatility. This study found evidence for the value of the screening program implemented in Boxers; fashions and trends influence dog owners' choices more than the worries of health problems in a breed. Effective breeding programs are needed in order to control the diffusion of CHDs without impoverishing the genetic pool.

Fig 1. Average age (months) of the pure breed dogs belonging to the most represented isolated CHD_s.

AS, Aortic Stenosis; ASD, Atrial Septal Defect; TD, Tricuspid Dysplasia; SAS, Subaortic Stenosis; rPDA, Reverse Patent Ductus Arteriosus; PS, Pulmonary Stenosis; PDA, Patent Ductus Arteriosus; VSD, Ventricular Septal Defect; DCRV, Double Chamber Right Ventricle; MD, Mitral Dysplasia; TOF, Tetralogy of Fallot.

Fig 2. Probability of identifying Pulmonic Stenosis in Boxers, French Bulldogs and English Bulldogs.

Red line: Boxer; Green line: English Bulldog; Blue line: French Bulldog.

Fig 3. Probability of identifying Pulmonic Stenosis in Boxers and other large breeds admitted from 1997 to 2017.

Blue line: Boxer; Orange line: other large breeds (American Staffordshire Terrier; Golden Retriever; German Shepherd; Rottweiler). P, Probability (%). X-axis: years.

Fig 4. Probability of identifying Patent Ductus Arteriosus in large breeds vs German Shepherd admitted from 1997 to 2017.

Blue line: German Shepherd; Red line: other large breeds (Bull Terrier; Dobermann; Golden Retriever; Labrador Retriever; Newfoundland; Rottweiler). P, Probability (%). X-axis: years.

Fig 5. Associated congenital heart defects admitted from 1997 to 2017.

PS, pulmonic stenosis; SAS, Subaortic Stenosis; VSD, Ventricular Septal Defect; PDA, Patent Ductus Arteriosus; DCRV, Double Chamber Right Ventricle; ASD, Atrial Septal Defect; AVCD, Atrioventricular Canal Disease.