Feline aortic thromboembolism (FATE) is a disease in which a clot forms in a heart chamber or vessel, travels through the blood stream and becomes lodged in a small vessel occluding blood flow (embolization). The most common site for embolization is to the iliac arteries (branches from the aorta that supply blood flow to the back legs). This is often referred to as a ‘saddle thrombus’. Other locations include the brachial arteries (supply blood to the front legs), renal arteries (supply blood to the kidneys), and cerebral arteries (supply blood to the brain). Symptoms of feline aortic thromboembolism can vary; however, the overall appearance and temperament of most cats are similar. Affected cats typically vocalize loudly, are weak/uncoordinated or even paralyzed in the affected limbs, develop open mouth breathing/panting, and are restless. On closer examination, the limbs may feel cool and the footpads and nail beds are blue. A low rectal temperature is also common when the hind limbs are affected.

Underlying heart disease is the most common cause of FATE with neoplasia being the second most common. Other considerations for sudden paresis or paralysis include trauma, intervertebral disc disease or other spinal disorders. Work-up includes chest x-rays to look for congestive heart failure, blood-work to evaluate electrolyte levels, acid/base status, and renal function, and an echocardiogram to confirm and characterize the presence of heart disease.

Treatment is directed at managing the underlying heart disease, increasing blood flow to the affected limb(s), pain management, and preventing further clot formation. Hospitalization is always recommended for the first 48 hours to monitor for complications including life threatening electrolyte disturbances, arrhythmias (abnormal heart rhythms), or acute renal failure. Surgical removal of the clot is usually not recommended as the majority of cats have severe heart disease as the underlying cause.

Prognosis for cats with ATE can be divided into short term and long term prognosis. One study showed that up to 45% of cats that received treatment survived the initial event and were discharged from the hospital. A better prognosis is often given if only one limb is affected, especially the front limb, and if motor function is present in the affected limb. If blood flow can be restored to the limb(s), it may take weeks to months before normal function is regained, although some patients have persistent deficits. Long term survival can depend on the presence or absence of congestive heart failure. Because FATE usually results from heart disease which cannot be cured or eliminated, it is common for cats to experience additional thromboembolic events or episodes of congestive heart failure in the following months (usually within 6 months).