Familial Subvalvular Aortic Stenosis in the Rottweiler

1. 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

2. SAS in Rottweilers • Devastating disease • Mild forms of disease can go unrecognized • Rottweilers over represented • Appears familial

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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)

9. Prognosis for dogs with SAS • Highly variable • No clinical consequences • Sudden Death • Congestive Heart Failure • Potential to pass on more severe form to offspring

10. 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

11. 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

12. 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

13. 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

14. Our Study • Enroll affected and normal Rottweilers • Use SNParray to analyze entire genome • Identify regions that are different between normal and affected

15. 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

16. We Are Still Enrolling • Normal or affected Rottweilers of variable lineage • Echocardiography results from cardiologist • 3 generation pedigree • Blood sample (3ccs purple top tube)

17. 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

18. 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/