ABSTRACT
Native heart valve thrombosis (NHVT) is a rare valvular pathology, usually associated with prothrombotic state or disturbed intracardiac blood flow related to structural valve abnormalities. While different venous and arterial thromboembolic complications of COVID-19 have been widely described, so far NHVT has not been reported in the context of the disease. The authors describe 4 cases of NHVT associated with COVID-19, revealed on aortic, mitral (2 patients) and tricuspid valve. In a 29-yearold male with mild pneumonia, large thrombus developed on bicuspid aortic valve (BAV), which resulted in fatal brain emboli. In a 76-yearold male with a history of rheumatoid arthritis (RA) being in a recovery period after COVID-19, central retinal artery occlusion (CRAO) was the first sign of mitral valve thrombus, which disappeared after 3 weeks, during apixaban use. Such therapy was also successful in a 46-yearold female with multiple cardiovascular risk factors in whom mitral valve thrombus was found in a routine echocardiography after she got COVID-19 the third time. In a 75-year-old man with moderate COVID-19 pneumonia and bacterial coinfection, coexistent transient focal LV dysfunction and tricuspid valve thrombus were observed. The patient was treated with apixaban as well; however, in this case only reduction in the thrombus size was seen after 4 months therapy. The authors indicate that in patients with COVID-19 and NHVT, other prothrombotic conditions can usually be found. This complication may involve different valves and occur irrespective of COVID-19 severity. Interdisciplinary evaluation of such patients is necessary.