Obstructive Thrombosis of Left-Sided Mechanical Heart Valves: Clinical Profile and Thrombolytic Therapy

Thrombosis of a mechanical prosthetic heart valve is a potentially life-threatening complication associated with a high mortality. Although thrombolytic therapy has been considered highly beneficial in this situation, very few studies have been conducted to monitor the effectiveness of such thrombolytic therapy among Asian populations. Hence, the study aim was to evaluate the clinical profile, efficacy and safety of the thrombolytic agent streptokinase (SK) in patients with obstructive thrombosis of a left-sided mechanical heart valve.

Patients (n = 30) with left-sided mechanical heart valve thrombosis (LSMHVT) who had been managed with SK during the past four years were included in this retrospective study. Clinical features such as presenting symptoms based on NYHA functional class, prosthetic valve position, oral anticoagulant compliance, International Normalized Ratio (INR) and imaging methods including fluoroscopy, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were evaluated. In addition, the effectiveness and complications of SK were analyzed.

The majority of patients presented with advanced NYHA class (III and IV, each 40%). Obstructive thromboses were observed at the mitral prosthesis in 70% of cases, at the aortic prosthesis in 27%, and at both valves in 3%. All patients underwent TTE, but fluoroscopy was used more often than TEE. Despite compliance with oral anticoagulation therapy, a sub-therapeutic INR was observed in 40% of cases at the time of presentation. Overall, thrombolysis was successful in 80% of patients using intravenous SK, with 100% success in patients in NYHA classes I-III and 42% for NYHA class IV. Moreover, embolic complications occurred in only a small number of patients.

In patients with obstructive thrombosis of LSMHVT, intravenous SK was effective and should be considered as first choice in patients in NYHA classes I-III, and as an acceptable alternative in those in NYHA class IV.