When being "Back in the Saddle" is NOT a good thing!

This is a condition we call a "saddle thrombus" - technically it's called thromboembolic disease (TE) or aortic thromboembolism (ATE).


This is something I truly hate seeing in practice because it carries such a poor prognosis with it and often, when I lay out the likely long term outcomes, the owner chooses euthanasia. 


The blood clots that can form in cats with heart disease (they typically don't just GET blood clots without this) travel out of the heart via the aorta and commonly get stuck where the end of the aorta branches off to the left and right to supply blood to the hind legs and continues on to the rest of the end of the cat.  This looks like a "saddle" over the back of the cat hence the name.

Here's a more graphic image taken at post mortem on a cat. The arrow points to the location of the blood clot that was found in this cat. 

Cats come in unable to use one or both hind legs. They are often in pain (imagine how you feel when you have something on a finger too tight for just a short while!) or distress (sometimes this is due to the underlying cardiac issue). What most owners think is that kitty got hit by a car or had some type of trauma. Further examination, however, tells us that this is not the case. Typically we find that these cats have cold hind legs with poor or no pulses or pads that are bluish. We can hear usually hear a heart murmur too. X-rays can help rule out a fractured spine. 


There are treatments that have helped some cats regain function depending on how long this has been going on. Eventually the tissue is going to die off without the blood flow supplying oxygen and nutrients to it.  These treatments are what you can think of as clot busters and preventatives (like Plavix that people take) - but we usually use heparin and aspirin (NEVER just give a cat ASPIRIN!!! This is a very carefully dosed thing - cats do NOT Handle NSAIDS well at all - we are usually giving a LOW dose EVERY THREE days or so!!). 
And of course, we can address the underlying heart disease as previously discussed.


However, there is a very high incidence of recurrence. After all, the heart is not functioning normally and is very likely to throw more clots. I've seen cats where the clots were affecting other parts of the body - front legs, brain, etc.  And of course, not all cats even respond to treatment. They must be carefully monitored in the hospital and often times we need to take repeated blood samples to measure clotting ability (we want to stop the clotting but not to the point of making them bleed out!).


Fortunately most cats with heart issues DO NOT develop this. 






Good article on TE


A more detailed scientific article from a boarded veterinary cardiologist