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Understanding and Managing Aortic Thromboembolism in Cats: Symptoms, Treatment, and Prognosis


As cat owners, it is important to understand the possible health problems that could impact feline friends. Aortic thromboembolism is a painful, emergency condition that requires veterinary care.

What is Thromboembolism of the Aorta?

Thrombosis occurs when a clot forms within a heart chamber or blood vessel, which can then travel through the bloodstream and become lodged in the blood vessel, causing blockage of the affected artery and resulting in local tissue damage due to a lack of blood flow. Aortic thromboembolism (ATE) occurs in the main artery, the aorta, that carries blood away from the heart.

Causes of Aortic Thromboembolism

Cats with heart diseases, such as cardiomyopathy, have a high incidence of arterial thromboembolism. Other potential causes include abnormalities in the blood vessel wall, abnormal blood flow, altered blood coagulability, neoplasia, systemic inflammation, and diseases of other organs. Certain breeds, including domestic shorthair, ragdoll, British shorthair, and Persian cats, are predisposed to a high risk of developing ATE.

Understanding these risk factors and cases of cat clotting can help pet owners take preventive measures and monitor their cats’ health more closely.

Symptoms of Aortic Thromboembolism

Most cats with ATE often have underlying heart disease, but signs are not usually apparent before ATE occurs. Blood clot events are typically the initial indication of heart disease in some cats. Affected cats may exhibit varying initial symptoms depending on where the clot travels, how long it impedes circulation, and how well collateral circulation functions. If a limb artery is obstructed, they may suddenly display signs of weakness and vocalization due to pain and discomfort.

Other cats may also experience difficulty breathing or rapid respiration because of concurrent congestive heart failure. Signs related to their limbs may include intense pain and weakness, cold distal limbs without a pulse due to lack of arterial circulation, tense muscles 10–12 h after the obstruction, and persistent tenderness when touched. Additionally, their nail beds and pads might appear pale or bluish, depending on the severity and duration of reduced blood flow. Most of the affected cats were dehydrated and cold.

Warning Sings of Aortic Thromboembolism

Recognizing the signs of ATE is essential. Cats with ATE may suddenly show severe paralysis in their hind limbs, making movement difficult. Pet owners should also be alert to indications of pain, discomfort, and vocalization, as these can signal the seriousness of the condition. Aortic Thromboembolisms are considered a veterinary emergency, and prompt veterinary care can affect the outcome.

Diagnosis of Aortic Thromboembolism

If thromboembolism is suspected, the veterinarian will perform a clinical examination first, which is often sufficient to diagnose an aortic thrombus. Thoracic radiography, electrocardiography, echocardiography, biochemical profile, hematology, and urinalysis may be pursued following examination.

Heart auscultation can show a murmur or arrhythmia, but many cats have normal auscultation findings; therefore, underlying heart disease cannot be ruled out based on normal auscultation.

Electrocardiography can show changes in heart rate and rhythm. Thoracic radiographs usually reveal cardiomegaly, but there is a possibility that the heart will appear normal. This exam is critical because the symptoms of cardiac heart failure are similar to those of aortic thrombosis. Echocardiography allows rapid and noninvasive evaluation of cardiac structure and function and should search for possible clots inside the heart chambers.

The biochemical profile can reveal elevated renal parameters because many cats are dehydrated, as well as elevated liver enzymes due to hepatic or muscle inflammation and necrosis that may occur due to thrombosis and local ischemia. Hyperthyroidism may be a risk factor for ATE; therefore, senior cats should be screened for hyperthyroidism. Coagulation abnormalities may also be detected, particularly in cats with cardiac diseases or normal findings.

Veterinary Treatment of Aortic Thromboembolism

The treatment aims to manage pain for the cat’s comfort in the initial phase. Unfortunately, the treatment options for a complete aortic thromboembolism, which impedes all blood flow to the hind limbs, are very limited. This is a sudden, painful, and usually irreversible condition. Sadly, euthanasia of the affected pet is often the most humane option.

Anticoagulant therapy may seem intuitive because it can rapidly resolve arterial occlusions and is theoretically beneficial for the patient. However, it carries the risk of bleeding complications. If anticoagulant therapy is chosen, cats need intensive 24-hour monitoring.

Anticoagulant therapy does not affect established thrombi but can prevent thrombosis through activated blood clotting pathways. The objective of anticoagulants is to inhibit or reduce thrombus extension. Various medications, including heparin, aspirin, and clopidogrel, can be used in less severe thromboembolic situations.

Prognosis and Recovery of Aortic Thromboembolism

Most cats affected by ATE experience recurrent episodes, and most do not survive this disorder. Chronic heart failure alone significantly affects long-term survival.

Rehabilitation therapy can begin after the initial incident of ATE. It involves gentle passive range of motion exercises and helps the cat assume a standing position to re-establish the standard placement of the pelvic limbs and feet. Additionally, gentle massage from the hip to the limb is beneficial. Owners can be taught how to administer rehabilitation therapies. In many cases, motor and neurologic functions in the affected limb return over time, but some cats may experience persistent issues due to tendon contracture or tissue necrosis. Usually, treatment can only be effective when a single limb is affected. Your veterinarian will work closely with pet owners to help them understand the individual prognosis of their cat and provide necessary care and support during the recovery process.


Navigating the intricate challenges associated with feline aortic thromboembolism (ATE) requires close collaboration between veterinarians and pet owners. By staying informed about treatment options, comprehending the diagnostic process, and adhering to essential guidelines, cat owners can actively contribute to their feline companion’s recovery and general health.

Regular veterinary check-ups and proactive observations are the foundation for ensuring a long and healthy life for cats, particularly those with a higher likelihood of developing ATE.