The fixed-dose regimen of t-PA was 24 mg for both unilateral and bilateral PE. A continuous catheter-directed pulmonary artery infusion of t-PA (Genentech, San Francisco, CA, USA) was started at 1 mg/hour for 24 hours for unilateral PE. For patients with bilateral PE, two drug delivery devices were placed, and a continuous infusion of t-PA was started at 1 mg/hour per catheter for 12 hours. No adjunctive interventional techniques to assist thrombus removal or dissolution were permitted. During the procedure, intravenous unfractionated heparin was continued at intermediate intensity with a goal activated partial thromboplastin time (aPTT) of 40–60 seconds. After removal of the catheters, the access site was manually compressed for a minimum of 5 minutes. Fifteen minutes after achieving hemostasis, full therapeutic anticoagulation was reinitiated.