Mobile Thrombus in Sinuses of Valsalva in a 1-Year-Old-Cat: Case Report

Animal Health, Production and Hygiene, cilt.15, sa.2, ss.1-7, 2026 (Hakemli Dergi)

Feline aortic thromboembolism is a life-threatening condition most associated with cardiomyopathy and typically

localized at the aortic trifurcation. Direct visualization of a mobile thrombus within the aortic root prior to the de-

velopment of clinical embolic signs has rarely been reported in cats. This case report describes the clinical course

of a one-year-old male British Shorthair cat in which a mobile thrombus was detected at the level of the sinuses of

Valsalva during echocardiographic examination before the onset of arterial thromboembolism. The cat was referred

for respiratory distress following elective castration. Thoracic radiography revealed pulmonary oedema. Echocardi-

ography demonstrated marked left atrial enlargement, borderline systolic function and a severe restrictive diastolic

filling pattern consistent with a restrictive cardiomyopathy phenotype. A mobile thrombus was identified within the

aortic root. Multimodal antithrombotic therapy, including low molecular weight heparin and rivaroxaban, was initi-

ated. Despite treatment, clinical arterial thromboembolism affecting both pelvic limbs developed seven days later.

Repeat echocardiography revealed resolution of the aortic thrombus but the presence of a new thrombus within the

left atrium. Coagulation testing showed normal prothrombin time, shortened activated partial thromboplastin time

and markedly increased fibrinogen concentration. The patient died six days after the embolic event. This case high-

lights the dynamic and unpredictable nature of thromboembolism in cats and suggests that mobile thrombi located

within the aortic root may be associated with a poor prognosis, even in the absence of significant haemodynamic

obstruction. Early detection and aggressive therapy may not always prevent embolization of pre-existing thrombi,

underscoring the limitations of current treatment strategies.