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 6

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/