Download Familial Subvalvular Aortic Stenosis in Rottweilers

Familial Subvalvular Aortic
Stenosis in the Rottweiler
Kathryn M Meurs, DVM, PhD, ACVIM (Cardiology)
Joshua A Stern, DVM
Veterinary Cardiac Genetics Laboratory
North Carolina State University College of Veterinary Medicine
SAS in Rottweilers
• Devastating disease
• Mild forms of disease can go unrecognized
• Rottweilers over represented
• Appears familial
Background:
Subvalvular Aortic Stenosis
• Commonly reported congenital heart disease
• Characterized by aortic subvalvular ridge
• Most common in large breed dogs
• Familial link demonstrated in Newfoundlands & golden
retrievers
Physiologic Consequences of SAS
• Aortic stenosis increases
pressure in the left side of
the heart
• Left ventricular heart
muscle thickens in
response to pressure
• Aorta can dilate after the
stenosis
Consequences of SAS Continued
• Aortic valve may leak
• Thick heart muscle does not oxygenate well
• The thick muscle with less oxygen can lead to rhythm
disturbances
Diagnosis:
• Gold Standard – Necropsy
demonstration of subvalvular
ridge, ring, band or nodules
• Antemortem test
– Echocardiography : elevated
aortic velocities
– Auscultation: not specific for
SAS
– Angiography: presence of
subvalvular stenosis
Auscultation Screening
• Auscultation screening is a good first step
– Dogs that pass are unlikely to have SAS
– Dogs that fail may or may not have SAS
– Echocardiography can help differentiate dogs with
functional murmurs from those with SAS
Aortic Velocities
• ARCH Recommendations
– <1.9 m/s normal (clear for breeding)
– 1.9-2.4 m/s equivocal (breeding assumes a certain
risk level)
– > 2.4 affected (breeding not recommended)
*ARCH = ACVIM Registry of Cardiac Health
(guidelines established by veterinary cardiologists)
Prognosis for dogs with SAS
• Highly variable
– No clinical
consequences
– Sudden Death
– Congestive Heart
Failure
– Potential to pass on
more severe form to
offspring
Prognosis
• Based on echocardiographic analysis of severity as Mild
– Typically have normal lifespan
– Increased risk of bacterial endocarditis
– May produce puppies with disease more severe than
their own
Prognosis
• Based on echocardiographic analysis of severity as
Moderate
– Increased risk of sudden death, heart failure
– May live normal lifespan
– Increased risk of bacterial endocarditis
Prognosis
• Based on echocardiographic analysis of severity as
Severe
– High risk of sudden death, heart failure
– Few live normal lifespan (19-45 months)
– Increased risk of bacterial endocarditis
Breeding Considerations
• SAS appears familial in
Rottweiler
• Removing dogs from
breeding pool should be
done with caution
– Small gene pool
– Equivocal category is
still uncertain
– Aortic velocity is not a
static measure
Our Study
• Enroll affected and normal Rottweilers
• Use SNParray to analyze entire genome
• Identify regions that are different between normal and
affected
Our Study Continued
• Focus search in regions of interest for a mutation
• Identification of a mutation or mutations that cause SAS
(a potential screening tool)
• Participation is confidential
We Are Still Enrolling
• Normal or affected Rottweilers of variable lineage
• Echocardiography results from cardiologist
• 3 generation pedigree
• Blood sample (3ccs purple top tube)
Conclusion
• SAS is a life threatening disease
• Appears to be inherited in the Rottweiler
• Pattern of inheritance is still unclear
• Screening is important in reducing prevalence
• Genetic studies are underway to identify possible
mutations
Contact Us
Kathryn M Meurs DVM, PhD, ACVIM (Cardiology)
Joshua A Stern, DVM
North Caroline State University College of Veterinary Medicine
Veterinary Cardiac Genetics Laboratory
Research Bldg. 460
1060 William Moore Dr
Raleigh, NC 27607
(919) 513.8279
[email protected]
www.cvm.ncsu.edu/vhc/csds/vcgl/