Delineation of a Giant Thrombus on a Prosthetic Mitral Valve Successfully Thrombolysed with Low Dose Slow Infusion of Tissue Plasminogen Activator

Abstract

A 46 year-old woman who had undergone mitral valve replacement (29 mm St. Jude Medical) fi ve years earlier was admitted to our institution with exertional dyspnea and palpitation. She had no other complaints or previous history of stroke. International normalized ratio (INR) was sub-therapeutic (1,2) . Transthoracic echocardiography (TTE) revealed an increased mitral transvalvular gradient of 24/12 mmHg with a decreased mitral valve area of 1.4 cm 2 (Figure 1A). Two-dimensional (2D) transesophageal echocardiography (TEE) demonstrated a giant mobile thrombus located on the prosthetic mitral valve, which was prolapsing into the left atrial cavity during systole (Figure 2A) and obstructing the mitral infl ow during diastole (Figure 2B). A subsequently performed real-time threedimensional (RT3D) TEE clearly demonstrated the presence of a huge thrombus with two mobile components moving up and down during systole (Figure 2C) and diastole (Figure 2D). Thrombolytic therapy (TT) with slow-infusion (6 hours) of low dose (25 mg) tissue plasminogen activator (tPA) was administered according to our protocol reported previously (1,2) . TTE revealed a decreased mitral transvalvular gradient of 14/6 mmHg with an increased mitral valve area of 2.5 cm 2 (Figure 1B). Two-dimensional TEE after TT confi rmed successful thrombolysis (Figure 3A) and RT3D TEE revealed a residual annular thrombus, which was published recently (2) (Figure 3B). There was no evidence of embolic complications or bleeding. The patient was discharged under adequate anticoagulation. This case report highlights that TT with slow infusion (6 hours) of very low tPA (25 mg) doses may be successfully performed in a relatively short time as a fi rst line therapy (1,2) . RT3D TEE has an incremental value in delineation of prosthetic heart valve thrombosis (3) .