of blood, abnormalities of the vessel wall, and changes in the soluble
and formed elements of the blood are the major contributors to
thrombosis. All of these alterations can contribute to venous
thrombosis, depending on the specific risk factors that are present in
a given patient.
Antithrombotic regimens modify one or more of these abnormalities.
These regimens include drugs that inhibit blood coagulation, such as
the various heparins and heparinoids; warfarin; direct thrombin
inhibitors; drugs that inhibit platelet function, such as aspirin and
dextran; and techniques that counteract venous stasis, such as
compression stockings and pneumatic compression devices. In this broad
sense, thrombolytic agents are also antithrombotic (Table 1
). This section will describe the effectiveness of antithrombotic agents
in the treatment of venous thromboembolism (VTE), a disease that
encompasses both deep venous thrombosis (DVT) and pulmonary embolism
(PE). Several of these agents are also useful for the primary
prevention of VTE, and this application of antithrombotic therapy is
reviewed in the preceding chapter.