to Pet Health Network or

Answers from vets about your cat:

Aortic Thromboembolism in Cats

Reviewed by Missy Beall DVM, PhD on Thursday, August 14, 2014
Posted February 19, 2014 in Cat Diseases & Conditions A-Z

What is a feline aortic thromboembolism?
Feline cardiogenic arterial thromboembolus (ATE), also known as “saddle thrombus,” is a devastating complication of heart disease in cats. Heart disease can cause disturbances in blood flow through the heart that can lead to the formation of blood clots. In cats, these blood clots can travel downstream and become lodged in the femoral arteries -- the main arteries that provide blood flow to the hind limbs. When a saddle thrombus occurs, there is a loss of blood flow to the hind legs causing pain, decreased pulses, cold limbs and paralysis.

Who is at risk of aortic thromboembolism?
Cardiogenic arterial thromboembolus occurs most commonly in cats with advanced heart disease and is rarely seen in dogs. While certain breeds are more prone to heart disease, like the Maine Coon, Ragdoll, Sphynx, Persian, and Abyssinian; saddle thrombus can occur in cats of any breed or age, although it is usually seen in cats 8 years and older.

Symptoms of aortic thromboembolism

  • Sudden inability to use back legs
  • Dragging rear limbs
  • Vocalizing
  • Cold rear limbs
  • Pain

Diagnosis of aortic thromboembolism
Aortic thromboembolism may be diagnosed by physical examination. Your veterinarian may also suggest blood work and a cardiac work-up, which may include chest radiographs (x-rays) and/or an ultrasound of the heart (echocardiogram).

Treatment of aortic thromboembolism
Available treatments have included anti-thrombotic drugs or surgery to remove the clots but they have not been very successful. Many anti-thrombotic drugs have been used to prevent recurrences in cats with heart disease. Recent studies indicate that clopidogrel (Plavix) appears to be superior to aspirin for the prevention of recurrent ATE in cats. Cats may recover function in their rear limbs but unfortunately remain at high risk for developing additional aortic thromboembolisms.

Prognosis for aortic thromboembolism
Despite treatment, the prognosis is poor and many cats are euthanized due to recurrences and poor quality of life. However, newer anti-thrombotics that will hopefully help cats with aortic thromboembolisms live longer, are currently being evaluated and may be available in the next five years.

Clinical trials
There are several current studies looking into different treatment options for saddle thrombi and also for ways to prevent new clots from forming. Hopefully, the work of these researchers will determine the most effective medications available to prevent cats from developing blood clots and also discover a better treatment option for cats

Related symptoms: 

Share This Article

Ruth has more than 15 years of experience in the veterinary industry as a companion animal veterinarian in private practice. Along with being a writer and media personality, she is also a founding member of IDEXX’s Pet Health Network team.