Subaortic Stenosis (SAS) in Boxers
Cardiac condition — Boxer — Medium-Large breed
Very High Risk
What is Subaortic Stenosis (SAS)?
Subaortic stenosis is a congenital heart defect in which a fibrous ring or ridge forms just below the aortic valve, obstructing blood flow from the left ventricle to the aorta. Mild cases are often asymptomatic; severe cases cause exercise intolerance, syncope, and sudden cardiac death. It has a heritable basis in several large breeds.
Symptoms of Subaortic Stenosis (SAS)
- Heart murmur detected by veterinarian (left base systolic murmur)
- Exercise intolerance in moderate to severe cases
- Fainting or collapse during or after exercise
- Sudden death (in severe, unmanaged cases)
- In mild cases, may be asymptomatic throughout life
How Is Subaortic Stenosis (SAS) Diagnosed?
Echocardiogram is required to confirm SAS, measure the pressure gradient across the obstruction, and assess severity. Cardiac auscultation alone cannot grade severity reliably. Annual cardiac screening is recommended for predisposed breeds.
Treatment & Cost
Mild SAS (low pressure gradient) requires no treatment but warrants activity restriction and annual monitoring. Moderate to severe SAS may be treated with beta-blockers to reduce cardiac workload and risk of arrhythmia. Balloon valvuloplasty (catheter-based) and surgery have been used but results are variable. Severe SAS carries a guarded prognosis.
Most pet insurance plans cover subaortic stenosis (sas) treatment in full when the policy is active before diagnosis. Compare plans below.