Saddle Thrombus in Cats

Saddle Thrombus in Cats

Pet owners will often tell you that it’s easier to keep their cat healthy than it is to keep a dog healthy. Most pet cats spend the majority of their time indoors, so they’re not as at risk of contracting diseases or injuries as dogs. However, cats may still develop a disease that requires veterinary care. Taking your feline friend to the vet for an annual exam is the best way to keep them healthy and avoid losing a cat due to a disease like saddle thrombus.

What is Saddle Thrombus?

Saddle thrombus, also known as feline cardiogenic arterial thromboembolism (ATE) or saddle thrombosis, is serious complication stemming from heart disease in cats. It’s caused by a blood clot that starts in the left atrium of the heart and travels to the aorta. Once it gets to the aorta and into iliac arteries, it prevents blood from flowing into the back legs.

In 90% of the cases of saddle thrombus, the condition is caused by an underlying heart condition, such as hypertrophic or dilated cardiomyopathy. Since saddle thrombus is caused by heart disease in cats, it can create serious and life-threatening health problems. What makes saddle thrombus so serious is that instead of the blood flowing freely through the body, it causes the blood to clot, and these blood clots become jammed in the femoral arteries.

Because they’re blocking the arteries, blood can’t flow freely through the body. This can cause cold limbs, extreme pain, decreased pulses, paralysis and even eventual death. Symptoms of saddle thrombus in cats include:

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

What Cats are Susceptible?

Saddle thrombus, which is seldom seen in dogs, may be found in any cats but is most common with cats suffering from advanced heart disease. Cats of any age or breed may get saddle thrombus, but it’s typically found in cats 8 years or older. Breeds more prone not just to saddle thrombus but heart disease in general include:

  • Maine Coon
  • Persian
  • Sphynx
  • Ragdoll
  • Abyssinian

How is it Diagnosed?

Although a veterinarian usually diagnoses saddle thrombus, the cat often displays symptoms that prompt the owner to take their cat to the vet. The main symptoms, weakness or paralysis of the back legs, can be easily spotted. The hind legs may also be colder than the rest of the body and even have a bluish color to them. Often, it comes on suddenly and the cat will begin to hyperventilate and scream in pain.

Once the owner takes the cat to the vet, the vet will give the cat a full physical examination. Because the symptoms of saddle thrombus are so obvious, a physical examination may be all that’s needed to make a diagnosis.

However, if the vet is uncertain or wants to be extremely thorough, he may perform blood work on the cat. The vet may also order a complete cardiac workup, which includes an echocardiogram (ultrasound of the heart) and/or a chest radiograph (x-ray).

How to Treat

The treatment for saddle thrombus varies from cat to cat. It also depends on a few different factors.

  • If there is an underlying heart condition
  • How long since the symptoms were first noticed
  • How far the cat’s owners want to go with treatment

Treatment options are most often determined by the cost. Unfortunately, many cat owners can’t afford to pay high vet bills, and the bills can get quite high when the animal requires many diagnostic tests. This is the main reason why many pet owners are choosing to purchase pet insurance.

Treatment, first and foremost, includes pain management. The vet will try to dissolve the blood clot and control the underlying heart condition so the cat will be in less pain. The vet may recommend surgery in some situations. Although it’s not really common in saddle thrombus cases, it is possible if the clot is small. Some vets give the cat aspirin to help thin the blood and prevent future clotting of the blood.

In some cases, the clot is so large, it covers the entire length of the artery, which makes surgery impossible. Euthanasia is a form of treatment for cats with advanced saddle thrombus, especially in cases were the cat will not gain back mobility in the back legs. Approximately 25% of cat owners choose euthanasia when their cat is diagnosed with saddle thrombus.


Even with early diagnosis and treatment, the prognosis for cats with saddle thrombus is not very good. What’s unfortunate is that by the time the symptoms are visible, it’s often too late for the cat. Of the many cases of saddle thrombus, about 50% of them have an underlying heart problem, which means also that 50% do not have a heart problem.

The prognosis for those that don’t have heart disease, other than saddle thrombus, is obviously better but still not good. If a cat does survive saddle thrombus or doesn’t have heart disease, the cat may need to be on blood thinners for the rest of its life and may not have full use of the back legs.

Some cats are euthanized due to the poor quality of life and recurrences of the disease. Every case is different. If a cat treated for saddle thrombus does regain movement in the rear legs, it usually happens within a week after treatment. The cat will need lots of help during this period.