Despite high mortality and morbidity, the best treatment strategies for prosthetic valve thrombosis (PVT) have been controversial. In this study the investigators wanted to identify the most effective and safe regimen among different thrombolytic strategies.Transesophageal echocardiography (TEE) guided thrombolytic treatment was administered to 182 consecutive patients with PVT in 220 different episodes (156 women, mean age 43.2±13.06 years) between 1993 and 2009. These regimens included rapid streptokinase (Group I, 16 episodes), slow streptokinase (Group II, 41 episodes), high dose (100 mg) tissue plasminogen activator (t-PA) (Group III, 12 episodes), half-dose (50 mg) slow infusion (6-hours) of t-PA without bolus (Group IV, 27 episodes), and low dose (25 mg) and slow infusion (6-hours) of t-PA without bolus (Group V, 124 episodes). The study endpoints were thrombolytic success and in-hospital mortality and non-fatal complication rates.