2-3 Therapeutic groups
The choice of treatment approach was based on the discretion of
attending physicians. There were three therapeutic strategies, including
thrombolytic therapy, anticoagulant intensification, and surgery. In
thrombolytic group, the most common protocol included intravenous
streptokinase with a loading dose of 250,000 IU in 30 minutes followed
by 100,000 IU per hour for 24-72 hours, intravenous reteplase with a
bolus of 10 units over 2 minutes followed by a second dose of 10 units
given after 30 minutes, and alteplase with a bolus of 10 mg in 1 minute
plus 90 mg within 2-3 hours. The fibrinolytic agents initiated when the
INR was <2.5. The heparin infusion was started after
fibrinolytic therapy as a 70 IU/kg bolus (maximum 5000 IU) and a 16
IU/kg per hour (up to 1000 IU/hour) to reach a target activated partial
thromboplastin time (a-PTT) of 1.5-2 times of the average reference
range, followed by warfarin with an overlap period of at least 5 days
until desired INR maintained. The anticoagulant intensification group
comprised of a high dose of unfractionated heparin to obtain 2-3 times
of normal a-PTT and warfarin was also continued during this period. The
surgical modality included re-replacement of prosthetic valve by a
mechanical or biologic valve and/or thrombus/pannus excision.