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.