Use of an algorithm for administering subcutaneous heparin in the treatment of deep venous thrombosis

Despite the widespread use of subcutaneous heparin in the initial treatment of deep venous thrombosis, there are no guidelines for achieving adequate anticoagulation with this drug.

To implement a weight-based algorithm for the administration of subcutaneous unfractionated heparin after an intravenous loading dose.

Prospective cohort study.

University hospital.

70 outpatients with proximal venous thrombosis.

An intravenous bolus of heparin followed by a subcutaneous injection of heparin in doses adjusted for body weight. Subsequent adjustments of the subcutaneous heparin dose were scheduled twice daily according to the algorithm; the activated partial thromboplastin time (aPTT) was measured in the mid-interval (target range, 50 to 90 seconds).

The therapeutic threshold aPTT (> or = 50 seconds) was achieved in 61 patients (87%) within 24 hours and in 69 patients (99%) within 48 hours. In 7 patients (10%), a supratherapeutic aPTT lasted more than 12 hours. No major bleeding episodes or cases of heparin-induced thrombocytopenia were seen. Three patients (4.3% [95% CI, 0.9% to 12.0%]) had recurrent thromboembolism during 3 months of follow-up.

The administration of subcutaneous heparin according to a weight-based algorithm allows the rapid achievement of effective and safe anticoagulation in patients with deep venous thrombosis.