The Heartbreak of a Saddle Thrombus Blood Clot

Over the past couple months many people have asked that I republish my Muse Medallion winning article here on our blog since the majority of Canidae's content was removed when their blog shut down. Here it is, in its entirety. 

The July 4th weekend in 2015 was much like any other – way too hot for my liking – and I was looking forward to spending some lazy days in the air conditioning with my tortie Truffles. Starting to weigh on my mind was the fact that Truffles’ breathing was noticeably heavier than usual. Having lost a cat two years earlier to congestive heart failure I had become somewhat paranoid about watching my cats breathe, but she was otherwise acting perfectly normal, it had been very hot, and she had been trying to bring up a hairball. At only four years old there had to be an innocent explanation. Trying not to let myself get overly worked up, I was glad I had the long weekend to monitor her. Something in my gut told me a vet visit would be in order that coming week. 

Returning home from work Monday afternoon I found her enjoying a long nap in the screened-in bathroom window. After dinner I curled up on the couch to watch TV and Truffles came out to see me. Suddenly she became very uncomfortable, moving from spot to spot on the rug. Then she got up and ran for the bathroom crying, typical behavior when she felt a hairball coming, so I was relieved that it might be coming out. Instead she just laid down again and then headed for the kitchen floor.

That's when it got really bad. She started writhing all over and opening her mouth to gasp for breath. Then she started screaming, getting up to head for another room but her back legs went out from under her and she couldn't walk.

We headed straight to the emergency vet, which we found packed with patients. As soon as I yelled that my cat couldn’t breathe a vet standing there grabbed the carrier and ran out back with her. After filling out some paperwork I was brought to a room where I could still hear her screaming.

After what seemed like an eternity the vet came in and asked what my cat’s name was. She explained that Truffles' back legs were cold, and a test of her blood sugar showed a big difference between her front and back legs. This told her that she had a blood clot that broke off and cut off the blood supply to her back legs - a saddle thrombus. She said Truffles was in extreme pain and the kindest thing would be to let her go, because even if she survived the chances were very high that it would happen again.

Knowing I would never be able to live with myself if she had even the slightest chance, the choice was made to put Truffles on powerful pain medication, blood thinners, and time in the oxygen cage. If she was stable in the morning an echocardiogram and further testing would be done. I was allowed to visit her in the back room where the oxygen cage was located in order to say good night, then I reluctantly went home.

I hadn't been home for a half hour when the vet called saying the pain meds had already worn off and she was screaming again, gasping for breath. She didn't even dare take Truffles out of the oxygen cage to evaluate her. I knew I had no choice but to end her suffering. I told the vet I would be there as fast as I could so I could comfort her one last time, but by the time I got there my baby was already gone. It still kills me to think she died surrounded by strangers, likely wondering where her Mommy was. I was assured nothing could’ve been done to save her, that as incomprehensible as it was, it was just “her time”.

There’s no overstating the cruelty of a saddle thrombus blood clot. I think it’s safe to say it’s something most cat owners have never even heard of until they find themselves facing it, yet it’s a frighteningly common occurrence and devastating diagnosis.

What is a Saddle Thrombus?

Feline aortic thromboembolism (FATE), also known as a saddle thrombus, occurs in cats with heart disease and affects as many as 25 percent of cats with hypertrophic cardiomyopathy, a common feline heart condition. FATE usually occurs without warning and can be the first and only sign of heart disease in some cats. Ninety percent of cats with FATE have a pre-existing heart problem.

An aortic thromboembolism is a blood clot that forms in the left atrium of the heart. Part of the clot dislodges and travels through the aorta, the largest artery in the body which runs down the entire length of the back. The aorta splits into two arteries (the left and right iliac arteries) to supply the back legs. That split is called the saddle. The dislodged blood clot often gets stuck in the wedge at the top of the saddle, preventing blood flow to the back legs.

Symptoms:

Usually the signs of saddle thrombus will come on incredibly quickly, and include:

• Paralysis or weakness of the back legs
• Restlessness initially, presumably due to pins and needles type feelings in the leg(s) as blood supply diminishes.
• Crying or screaming
• Panting or open-mouthed breathing

Your vet will look for:

• Loss of pulse in the affected limb(s)
• Rear legs that are cool to the touch
• Leg muscles that are hard and extremely painful
• Paw pads and nail beds that appear blue-tinged
• If clipped beyond the quick, claws on the affected limb fail to bleed
• Reduced glucose level in the affected limbs
• Abnormal cardiac sounds

Diagnosis:

A saddle thrombus is typically diagnosed based on its distinctive clinical presentation. Additional testing may be needed, such as a complete blood count and biochemistry profile, chest x-rays and/or echocardiogram (ultrasound) to evaluate the size and shape of the heart, and doppler test to confirm the absence of blood flow in the legs.

Treatment:

Because of the excruciating pain a cat with a blood clot is experiencing, the administration of strong morphine-derived pain killers is the first course of action. Medication will be given to dissolve the clot, as well as anticoagulants such as aspirin or Plavix to thin the blood and help stop additional blood clots forming. (The cat I had prior to Truffles with heart disease was on Plavix for a couple years as a preventive measure.) Cats in concurrent heart failure will receive diuretics to remove fluid build-up and oxygen therapy.

Cats with acute FATE require intensive care in a hospital setting for the first 48 hours or more. Strict cage rest is required at home and may last several days to weeks. Around the clock care will be necessary to keep the paralyzed cat clean and comfortable while the hind legs slowly heal and regain function.

Prognosis:

Due to the devastating nature of the condition, extreme pain, and subsequent long term management of the underlying heart disease, at least a quarter of pet parents choose euthanasia over any form of treatment. Even if the cat recovers from the initial event, the risk of another clot forming is extremely high. There is a slightly better prognosis for cats with milder blockages that affect only one leg or don't cause complete paralysis of the legs. These cats may eventually recover full function and do relatively well. Incredibly, medicinal leeching is being studied as an alternative treatment, with an Israeli veterinarian claiming to have a 90% success rate in returning cats to a normal life using leech therapy.

I can easily say without a moment’s hesitation that watching what Truffles endured that night is the most heartbreaking thing I have ever experienced. A saddle thrombus is truly every cat parent’s worst nightmare. My heart soars when I learn about a cat who beats the odds and recovers, and my greatest hope is that ongoing medical research will one day discover new treatment options to offer a glimmer of hope to an otherwise incredibly grim diagnosis.