Is There a Relationship Between the Intensity of Heparin Treatment and Recurrent Thomboembolism?

Continuous intravenous heparin is widely used in the initial treatment of patients with venous thromboembolism. However, because it has a narrow therapeutic window and because the anticoagulant response to it varies among patients, it is standard practice to adjust the dose of heparin to achieve a predefined anticoagulant effect (therapeutic range) using the activated partial thromboplastin time (APTT). There is evidence to suggest that the efficacy of heparin is critically dependent on the starting dose used and that failure to maintain APTT results above the lower limit of the therapeutic range leads to increased rates of recurrence. We review the evidence for a rel~tic~nship between the intensity of heparin treatment and recurrence and provide recommendations for optimal dosing regimens.