The frequency of major bleeding complications in the setting of fibrinolysis for PE is thought to be related, in part, to the dose of fibrinolytic agent. In 1990, the Food and Drug Administration approved full-dose peripheral venous administration of tissue-plasminogen activator (t-PA) 100 mg over 2 hours for PE. Half-dose fibrinolytic therapy may offer a reduced risk of ICH.9,10 Pharmacomechanical catheter-directed fibrinolytic therapy utilizes lower doses of fibrinolytic drug than systemic therapy, and the pharmacological effect is concentrated in the area of greatest thrombotic burden. One of the most extensively studied pharmacomechanical catheter-based techniques is ultrasound-facilitated, catheter-directed, low-dose fibrinolytic therapy, which we evaluated in SEATTLE II for treatment of massive and submassive PE.