Summary
The treatment course of all thromboembolic events in the patients with congenital
deficiency of antithrombin III (AT III) in the national Swedish register was reviewed
in order to assess the appropriate medical therapy in this situation. The medical
treatment of 70 events of venous thromboembolism was evaluated. There were eight cases
with signs of clinical progression. The risk of therapeutic failure with heparin could
be as low as 1.5% or as high as 9.2%. It would not be cost-effective to substitute
with concentrates of AT III in every case with congenital deficiency thereof in connection
with acute venous thromboembolism. “Heparin resistance” does not seem to be a problem
in the vast majority of these patients.