familial subvalvular aortic stenosis in the rottweiler

Familial Subvalvular Aortic Stenosis in the Rottweiler

Kathryn M Meurs, DVM, PhD, ACVIM (Cardiology)Joshua A Stern, DVM

Veterinary Cardiac Genetics LaboratoryNorth 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

Josh_Stern@ncsu.edu

www.cvm.ncsu.edu/vhc/csds/vcgl/