Why could thrombolysis be an option for cats with acute aortic thromboembolism?

Feline aortic thromboembolism, or ‘saddle thrombus’, is a common syndrome initiated by the sudden migration of a left atrial thrombus into the systemic arteries. It is usually caused by cardiomyopathy of varying types and severity. It is easily diagnosed clinically using the ‘5P rule’ (pulselessness, pallor, polar, pain and paralysis). Although the prognosis for feline aortic thromboembolism has historically been considered poor, this is not validated by retrospective or prospective studies. Indeed, a prospective study on cats with aortic thromboembolism and bilateral pelvic limb paralysis showed a 37.5% discharge rate, with a calculated 95% confidence interval of 22.5% to 52.5%, and with some cats surviving for more than a year. Treatment includes supportive care, treatment of cardiac disease if applicable and nursing care. Thrombolysis is recommended in many thromboembolic diseases in humans, including pulmonary thromboembolism, acute myocardial infarction and acute ischemic stroke, and has been recently suggested in cats suffering from acute (within 6 hours) aortic thromboembolism. Most clinicians will use the tissue plasminogen activator alteplase. Complications of treatment of feline aortic thromboembolism, with or without thrombolysis, include acute kidney injury (20%) as well as reperfusion injuries (25%). Thromboprophylaxis with clopidogrel or clopidogrel and rivaroxaban is recommended for long-term management of cats with aortic thromboembolism.