In the first arm, thrombolytic therapy (TT) is performed to the patients with obstructive prosthetic valve thrombosis. The TT regimen depends on the functional status of the patient. In patients with NYHA class III-IV dyspnea low dose, relatively faster TT regimen (25 mg tPA/6 hours) is performed. In patients with NYHA class I-II dyspnea TT with low dose and ultra-slow infusion of tPA (25 mg tPA/25 hours) is performed. During TT, patients are followed up with transesophageal echocardiography in every 24 hours.

In the second arm, redo valve surgery is performed for obstructive valve thrombosis. Intraoperative and postoperative results are recorded

Thrombolytic therapy is performed to the patients with obstructive prosthetic valve thrombosis

In the absence of fatal or nonfatal major complications;

Obstructive thrombus:

Doppler documentation of the resolution of increased gradient and decreased valve area.

Clinical improvement in symptoms. Reduction by ≥75% in major diameter or area of the thrombus. Complete success was defined when all 3 criteria were met and partial success was defined as less than 3

Nonobstrucive thrombus:

Complete success: ≥75% reduction in thrombus area. Partial success: 50%-75% reduction in thrombus area

Nonfatal major complication: Ischemic stroke, intracranial hemorrhage, embolism (coronary or peripheral), bleeding requiring transfusion.

Nonfatal minor complication: Bleeding without need for transfusion, TIA.

Successful redo valve surgery in the absence of fatal and non fatal major complications.

Non fatal major complications: Ischemic stroke, intracranial hemorrhage, embolism (coronary or peripheral), bleeding requiring transfusion, pericardial tamponade, sepsis, pacemaker requirement, mediastinitis, wound infections, acute renal failure Minor complications: bleeding requiring transfusion, plevral effusion, pericardial effusion without tamponade

All cause in-hospital mortality.