Efficacy of dual therapy with rivaroxaban and clopidogrel in canine aortic thrombosis resistant to clopidogrel monotherapy: two case reports

Aortic thrombotic disease occurs in both dogs and cats. In dogs, it typically presents as aortic thrombosis (ATh), whereas in cats, it most commonly manifests as aortic thromboembolism (ATE). Canine ATh is rare, with no standardized treatment. Rivaroxaban, a direct factor Xa inhibitor, is increasingly used in veterinary medicine. Recently, the efficacy of dual antithrombotic therapy with clopidogrel and rivaroxaban in feline ATE has been suggested. Here, we report two canine ATh cases. Clopidogrel monotherapy was insufficient, but adding rivaroxaban improved gait, relieved pain, and reduced thrombus size on ultrasonography. This combination therapy may be effective for canine ATh, as has been suggested for feline ATE. Further case studies are needed to evaluate the efficacy of rivaroxaban for canine ATh.