As these findings confirmed initial diagnosis of massive PE, tissue plasminogen activator (tPA) and heparin were administered in accordance with the standard protocol for thrombolytic and anticoagulant therapy for massive PE. After intravenous infusion of 100-mg tPA for over 2 hours, intravenous infusion of heparin was started at the dose of 18 IU/kg per hour, followed by adjustment of the dose every 6 hours to maintain a mean aPTT between 1.5 and 2.5 times the control value. The
heparin dose was maintained at 18 IU/kg per hour for 12 hours and then changed to 16 IU/kg per hour according to the aPTT level.