[Thrombo-embolic events in patients with mechanical prosthetic valves--echocardiography in diagnostic and therapeutic decision making]

Abstract

Mechanical prosthetic valves (PV) are prone to thrombosis which may result in death or cripple hood due to PV blockade and embolisation (EM). In most pts with clinical symptoms of PV thrombosis (TPV) and in pts with a history of EM transthoracic echocardiography (TTE) and Doppler echocardiography are sufficient in diagnosing but not in stating the exact mechanism of PV stenosis. Transesophageal echocardiography (TEE) is a method of choice in the therapeutic decision making in this group of pts. PV replacement is indicated in pts with a thrombus floating in the left atrium (LA), large, peduncle-like thrombus in LA, TPV in mitral or aortic position with blockade of the disc and symptoms of heart failure < III NYHA, TPV with a high risk of spontaneous or post-thrombolytic EM (large thrombus on the PV annulus >5 mm or >0.8 cm2, highly mobile thrombus, history of EM). Thrombolysis is recommended in tricuspid TPV, TPV in mitral or aortic position with blockade of the disc and symptoms of heart failure III/IV NYHA. Intravenous heparin infusion can be effective as a short-term bridging to PV replacement or an alternative for thrombolysis in case of TPV with no signs of disc blockade. The results of thrombolysis and heparin infusion should be controlled by TEE. In pts with proper function of PV on clinical examination and negative history of EM, TTE/TEE should be considered if the risk factors of EM are present: incorrect INR control, atrial fibrillation, left ventricular dysfunction, III/IV NYHA, diabetes, certain types of PV cage PV, pivoting-disc PV other than Medtronic-Hall valve.