Aortic Thromboembolism in Dogs: 2025 Vet Guide 🩺🐾

By Dr. Duncan Houston BVSc

Hi there, I’m Dr Duncan Houston, BVSc, veterinarian and founder of Ask A Vet. In this comprehensive 2025 article, we explore canine aortic thromboembolism (ATE)—when a blood clot lodges in the aorta—covering causes, signs, diagnosis, advanced treatment approaches, and critical home care to support your pup.

1. 🩸 What Is Aortic Thromboembolism?

ATE occurs when a blood clot (thrombus) forms and travels through the bloodstream, lodging in the aorta and cutting blood supply off to downstream tissues, most commonly the hind limbs. It is rare in dogs but is life-threatening.

2. 🧠 Underlying Causes

Unlike cats, where heart disease is a frequent cause, canine ATE often stems from diverse systemic issues:

• Protein‑losing nephropathy (PLN), causes loss of antithrombin and promotes clot formation.
• Neoplasia (cancer).
• Endocrine disorders: Cushing’s, diabetes, hypothyroidism.
• Infection or sepsis.
• Immune-mediated disease or trauma.
• Cryptogenic: in ~23% no identifiable cause.

3. 🚨 Warning Signs & Stages

ATE progresses from acute (<24 h) to chronic (>2 weeks) and variable presentations :

• Acute onset: sudden paralysis, severe pain in hind legs, absent femoral pulses, cold limbs, possible respiratory distress, shock.
• Chronic presentation: partial limb weakness, lameness, exercise intolerance, hypothermia.
• Other signs: anxiety, coughing, hemoptysis, collapse.

4. 🩺 Diagnostic Steps

1. History & Exam: assess sudden hindlimb dysfunction, femoral pulse discrepancies, limb temperature.
2. Bloodwork: CBC, biochemistry including CK, liver enzymes, electrolytes, kidney function, clotting profile, antithrombin levels.
3. Imaging:
   • Abdominal ultrasound or Doppler to visualize the thrombus.
   • Chest X‑rays and echocardiography to assess heart disease or effusion.
   • Angiography if needed for surgical planning.
4. Coagulopathy: thromboelastography, antithrombin assays to assess hypercoagulability.

5. 🧭 Treatment in 2025

5.1 Emergency & Supportive Care

• Hospitalization, IV fluids, and oxygen therapy if in shock.
• Pain control: opioids, adjuncts for severe discomfort.
• Treat the underlying cause: manage PLN, endocrine disease, and infection.

5.2 Thrombolysis & Mechanical Removal

• Thrombolytics like tPA, streptokinase, urokinase; limited canine data, but sometimes effective.
• Mechanical thrombectomy or stent retrieval from referral centers show promise—human techniques adapted. 2025 case reports indicate median survival 9 days for acute dogs, vs 293 days for chronic.

5.3 Antithrombotic & Anticoagulant Therapy

Veterinary critical care guidelines (CURATIVE) recommend multi-drug protocols :

• Antiplatelets: Aspirin (0.5 mg/kg/day), clopidogrel (1–3 mg/kg/day)
• Heparins: UFH or low-molecular-weight heparins (enoxaparin, dalteparin)
• Factor Xa inhibitors: rivaroxaban or apixaban, emerging options
• Warfarin: historically used but now discouraged due to bleeding risk.

5.4 Chronic Management & Recurrence Prevention

Ongoing antithrombotic therapy, monitoring, and treating the underlying disease is key; recurrence is common.

6. 📈 Prognosis Insights

Overall, canine ATE prognosis is guarded:

• Non‑ambulatory upon presentation → significantly lower discharge survival.
• Of 100 dogs studied, 57% survived to discharge; only 16% alive at 180 days.
• Acute cases fared worse (median survival ~9 days), chronic cases ~293 days.
• Reperfusion injury risk after clot removal needs monitoring.

7. 🏡 Home Care & Monitoring

• Strict rest, stress-free housing, and minimal stairs.
• Pain management, including NSAIDs/opioids as directed.
• Regular medication administration and side-effect checks.
• Frequent re-checks—coagulation panels, renal function, antithrombin activity.
• Oxygen or IV access may be necessary for unstable dogs.
• Exercise gradually resumed only if pulses return and comfort is stable.

8. 🐕 Breed & Age Risk Factors

• Older dogs have—higher comorbidity risk.
• Breeds predisposed to PLN (e.g., Cocker Spaniels) or endocrine disease (e.g., Dachshunds).
• Cats have a higher comparative risk—dog cases are often cryptogenic or systemic. This emphasizes proactive screening for canine patients at risk.

9. 🔬 Innovations in 2025

• Mechanical thrombectomy and stent-retrievers are adapted from human medicine.
• Factor Xa inhibitors (apixaban, rivaroxaban) are gaining traction.
• Thromboelastography and antithrombin assays for personalized antithrombotic therapy.
• AI‑driven ultrasound for clot detection and treatment planning.
• Telehealth via Ask A Vet: remote monitoring, medication reminders, emergency support.

10. 🤔 FAQs

Can dogs recover?

Yes—57% survive hospitalization; 16% remain alive at 6 months. Chronic cases fare better.

Will the clot recur? 

Yes—recurrence is common without ongoing antithrombotic treatment and care of the underlying disease.

Is surgical removal worth it?

Yes, in referral centers offering mechanical thrombectomy or thrombolysis require expertise and risk monitoring. 

Should my dog be on long-term medication? 

Typically yes: antiplatelets and/or anticoagulants alongside treatment for underlying conditions.

Is this expensive? 

Emergency hospital care, imaging, clot removal, and long-term meds can cost several thousand dollars—pet insurance is highly advised.

11. ❤️ Ask A Vet Support

At Ask A Vet, we provide:

• 24/7 telehealth for monitoring symptoms and ensuring medication compliance.
• Coordination with specialty centers for mechanical thrombectomy and advanced imaging.
• Updates on best antithrombotic protocols and lab interpretation.
• Remote support for home care, medication reminders, and emergency guidance.

Download our app to stay connected on this challenging recovery journey.

12. 🔚 Summary

Canine ATE is rare but life-threatening. Recognizing sudden hindlimb pain, absent pulses, and medical risk factors is key. In 2025, advanced mechanical and pharmacologic treatments—alongside telemedicine—offer new hope. With prompt intervention, expert care, and dedicated home support—including Ask A Vet—you can help your dog navigate this difficult condition.

— Dr Duncan Houston, BVSc