Prolonged low-dose thrombolytic therapy: a novel adjunctive strategy in the management of an infected right atrial thrombus.

An 81-year-old man presented with a large, infected right atrial thrombus that was refractory to anticoagulants and several courses of antibiotics. The risk of surgical removal of the thrombus, which was associated with a pacemaker electrode, was considered prohibitive. The patient was treated for 7 days with low-dose (40 mg/day) tissue-type plasminogen activator (t-PA). Hemostatic monitoring during infusion revealed (1) a plasma t-PA antigen that was approximately 5% of that achieved during short-course t-PA for acute myocardial infarction, (2) biochemical evidence of prolonged clot lysis, and (3) no significant depletion of fibrinogen or plasminogen. Nearly complete dissolution of the thrombus was observed. His bacteremia was eradicated by intravenous penicillin despite the presence of the pacemaker lead. This case highlights the benefits of combined antibiotic and thrombolytic therapy and documents for the first time the response of the human hemostatic system to prolonged t-PA infusion and the plasma t-PA levels attained when thrombolytic therapy is administered in this manner. Prolonged courses of fibrinolytic agents may be a good alternative to surgical intervention in selected patients with infected, right-sided intracardiac thrombi.