Aortic Thromboembolism in a Cat

Abstract

Background: The aortic thromboembolism in cats is usually associated with cardiomyopathy, when a thrombus or a clot is formed in the heart, transported through the bloodstream and fixed at somewhere. According to Virchow’s triad, changes in the endocardial surface or in the blood flow/composition can result in thrombus formation. The most common clinical signs are: hind limb paralysis, lack of femoral pulse, cold and cyanotic extremities. The treatment should be performed as soon as possible and it is based on antiplatelet agents, anticoagulants, thrombolytics agents or surgical procedures. It is reported the case of a cat presenting aortic thromboembolism.Case: Macroscopically it was observed that the hind limb extremities were with a dark red color and with a bad odor on cut. There were in the subcutaneous tissue of the hind limbs a severe and diffuse accumulation of a reddish material, translucent, shiny, gelatinous (intense diffuse edema) and the skeletal muscles of the hind limbs had extensive pale and friable areas. Inside the medial saphenous vein lumen there was a greyish-white and soft material which adhered to the vessel wall. The lungs were not fully collapsed, it had a smooth and shiny surface and an extensive dark red area in the right middle lobe (moderate extensive bleeding). The spleen was with slightly bulging edges and on cut flowed moderate amount of blood (moderate congestive splenomegaly). In the kidneys there was numerous whitish and slightly depressed areas measuring approximately 0.5 cm in diameter, which was deep and wedge-shaped on cut (multifocal infarction). Microscopically it was observed mild diffuse congestion in the spleen; mild diffuse congestion and moderate focal bleeding in the lungs; intense multifocal neutrophilic infiltrate associated with coagulation necrosis in the cortical and medullary with multifocal cysts in moderate amounts in the kidneys; abdominal aorta artery with intense accumulation of fibrin, red blood cells and cellular debris organized and stuck in the tunica intima featuring a multifocal thrombosis area. The saphenous artery contained fibrin organization in the lumen, which was compatible with embolus.Discussion: The patient presented paralysis of hind limbs, absence of superficial and deep pain, cyanotic and cold hind limb extremities, loss of proprioception of the limbs and absence of detectable pulse in the vascular Doppler, which is characteristic of thromboembolic disease, but no specific sign of the underlying cause. Thromboembolic episodes are compatible with thrombus in the trifurcation of the abdominal aorta artery and the embolus in the saphenous artery. The focal lung bleeding can be the clinical sign of pulmonary thromboembolism. The unilateral renal infarction may have been induced after surgical excision of the thrombus, as the patient had no change in renal biochemical parameters prior to the surgical procedure. This is a complication, because small thrombus fragments can break off and cause thromboembolism elsewhere. The surgical procedure is generally non indicated because most domestic cats that have arterial thrombus have significant heart disease and more than half have congestive heart failure, making them poor candidates for surgery, which did not occur in the clinical case described. The repetitions of the events are common, and significant embolization of the kidney, intestines or other organs worsen the prognosis.Keywords: aortic thromboembolism, feline.