Aortic thrombosis in dogs.

OBJECTIVE: To review information regarding etiology, pathophysiology, and treatment options for aortic thrombotic disease in dogs. ETIOLOGY: Diseases resulting in hypercoagulable states can cause thrombus formation in the distal aorta, and account for the majority of cases of aortic thrombosis (ATh) in dogs, although a substantial number of cases have no identifiable underlying cause. Aortic thromboembolism (ATE) also occurs but appears to be much less frequently documented. DIAGNOSIS: The presentation of ATh and ATE in dogs is more varied compared to cats. Diagnosis can be challenging due to nonspecific clinical signs. Definitive diagnosis involves direct visualization of the thrombus, which is often obtained via ultrasound; however, other imaging modalities such as computed tomography scans can be utilized. THERAPY: The optimal treatment for aortic thrombotic disease in dogs has yet to be determined. Although not always possible, treatment of concurrent diseases that may promote thrombosis is an important aspect of thrombus resolution. A recent retrospective study reported positive results with long-term warfarin therapy; however, other studies have not reported similar results. Unfractionated or low-molecular weight heparins are additional anticoagulants that have been utilized. Platelet inhibitor therapy should also be considered in combination with anticoagulant therapy. PROGNOSIS: Survival for dogs with ATh or ATE is reported to be between 50% and 60%. Dogs that present with chronic clinical signs appear to have a better prognosis than those who are acutely affected or those who are severely affected. © Veterinary Emergency and Critical Care Society 2016.