🐾 Vet-Approved 2025 Guide: Saddle Thrombus (FATE) in Cats—Signs, Survival & Emergency Care 🐱🩸

By Dr. Duncan Houston, BVSc

Feline Aortic Thromboembolism (FATE), also known as a saddle thrombus, is a sudden, painful, and often fatal condition in cats. It occurs when a blood clot lodges at the base of the aorta and blocks blood flow to one or both hind legs. Prompt veterinary care is essential for survival, and long-term management requires understanding both heart health and clot prevention 🆘🐾

🔍 What Is a Saddle Thrombus?

• 🩸 A thrombus is a large blood clot formed inside the heart
• 💔 It often originates in the left atrium of cats with heart disease
• 🛑 When it breaks off and travels to the aorta, it can block blood flow at the “saddle” (where the aorta splits into arteries for the rear legs)

⚠️ This leads to severe pain, loss of leg function, blue or cold paw pads, and respiratory distress.

💔 What Causes It?

• 🫀 89% of FATE cases involve hypertrophic cardiomyopathy (HCM) or another heart disease
• 🎯 Heart disease causes turbulent blood flow, increasing the risk of clot formation
• 🩺 “Smoke” seen on heart ultrasound (echo) can predict clot risk, but most cats show no symptoms until the clot forms

🩺 Signs of Saddle Thrombus (FATE)

• 😿 Sudden paralysis of one or both rear legs
• 🥶 Cold, blue, or pale paw pads
• 😰 Severe pain, yowling, or rapid breathing
• 🐾 Weak or absent femoral pulse in the rear legs

76% of FATE cases occur as the first sign of heart disease.

📈 Survival Factors & Prognosis

🩺 Body temperature at admission is the strongest predictor of survival. Cats with temperatures above 98.9°F have a better than 50% chance of recovery.

With Heart Failure:

• 💔 Median survival is 77 days
• 💊 Requires heart meds, blood thinners, and nursing care

Without Heart Failure:

• 🕐 Median survival is 223 days
• 💉 Pain control, anti-clot therapy, and nursing care are critical

🧪 Diagnosis & Emergency Hospitalization

• 🌡️ Initial body temperature
• 💉 Compare blood glucose from front vs. rear limbs
• 🔍 Physical exam shows cold limbs, weak pulses, or blue pads
• 🧪 Bloodwork for toxins, potassium, pH, kidney values
• 🫀 Echocardiogram to assess heart disease

🏥 Hospitalization typically lasts 2–7 days for pain management, mobility monitoring, and medication adjustment.

💊 Medications for Recovery

• 💉 Strong pain relief (opioids or similar)
• 💊 Blood thinners (clopidogrel, aspirin)
• 💊 Heart medications if heart failure is present

⛑️ Recovery & At-Home Nursing

• 🛌 Cats who recover often improve within 4 days
• 🩺 Some require help with mobility, appetite, and bathroom use
• ⚠️ Repeated clots are possible—prevention meds are essential

📊 Outcome Statistics

• 📤 50% of cats survive to be discharged
• 📆 Median survival with aspirin: 192 days
• 📆 Median survival with clopidogrel: 443 days
• 🔁 25% of cats on aspirin had a repeat FATE episode within 6–12 months

😿 Euthanasia Considerations

Because the condition is severe and painful, and because of long-term medication needs and risk of recurrence, 50–75% of pet owners choose euthanasia. This is a deeply personal decision, and no two cases are the same ❤️

🩺 Saddle Thrombus Without Heart Disease

Although rare, 6% of FATE cases are caused by cancer (often lung cancer), and 3% have no identified cause. Chest x-rays and abdominal ultrasounds may be used to check for tumors if heart disease isn’t found 🧬

📲 Need Support After a FATE Diagnosis?

Facing a FATE emergency can be overwhelming—but you're not alone. For help managing care or making treatment decisions, visit AskAVet.com or download the Ask A Vet app 📱

🐱 While FATE is serious, compassionate care and quick action can give your cat the best chance of comfort, dignity, and time 💖