What underlying disease is most commonly associated with a saddle thrombus in cats?

Saddle thrombus, also known as aortic thromboembolism, is primarily associated with heart disease in cats, particularly hypertrophic cardiomyopathy (HCM). In cases of HCM, the heart's left atrium can become enlarged, leading to turbulent blood flow and the formation of thrombi (blood clots). When a piece of this thrombus breaks off, it can travel through the bloodstream and lodge at the bifurcation of the aorta, resulting in a saddle thrombus that typically affects the hind limbs.

This condition is characterized by sudden onset of weakness or paralysis in the hind legs, cold extremities, and a lack of pulses in those limbs due to compromised blood flow. Recognizing the connection between saddle thrombus and underlying heart disease, particularly in the context of feline patients, is crucial for timely diagnosis and treatment. In contrast, liver disease, renal disease, and thrombocytopenia do not have as direct an association with the formation of saddle thrombi in cats. While these conditions can influence clotting mechanisms and overall vascular health, they are not the primary causes of saddle thrombus formation in the feline population.