ABSTRACT
The main objective of treatment of venous thromboembolism (VTE) is the prevention
of the extension, embolization, and recurrence of thrombosis. The long-term aim is
to prevent late recurrences and the post-thrombotic syndrome. Heparin and oral anticoagulants
(OACs) have been the cornerstones of VTE treatment in the last 30 years. Low molecular
weight heparins (LMWHs) have been introduced more recently in the treatment of the
acute phase of VTE, and they have allowed the home treatment of deep vein thrombosis
(DVT) in selected cases. The optimal duration of OAC therapy after VTE is still controversial.
Several studies have been conducted, and several are ongoing with the aim to stratify
patients into risk categories for recurrence. Patients at high risk are candidates
for long-term oral anticoagulation as the benefits of extended oral anticoagulation
would outweigh the risk of bleeding. Patients are currently stratified into risk categories
on the basis of clinical characteristics of the VTE event: (1) first or recurrent
event; (2) idiopathic or due to a transient risk factor such as surgery, trauma, hormonal
therapy, or immobilization; (3) presence of active cancer; (4) location (proximal
DVT and/or pulmonary embolism, PE, or distal DVT); and (5) presence of known hereditary
or acquired thrombophilia. Patients with distal VTE or VTE due to a transient risk
factor are at a low risk of recurrence and short-term anticoagulation is indicated
(3 months). Patients with an idiopathic event or with known thrombophilic defects
such as FV Leiden or the G20210A prothrombin mutation are candidates for a longer
course of therapy (6 months). Patients with cancer, antiphospholipid antibodies syndrome,
recurrent idiopathic event, antithrombin deficiency, protein C or protein S deficiency,
homozygosity for FV Leiden, and double heterozygosity are candidates for extended
long-term anticoagulation. More recently, studies have indicated that other factors
such as D-dimer levels after the discontinuation of OAC therapy or the residual vein
thrombosis could be additional predictive factors for recurrences. In patients with
VTE and cancer, oral anticoagulation poses a higher risk of bleeding, and such patients
are more prone to recurrences. Alternative treatment with LMWH could be safer and
more effective in these patients.
KEYWORDS
Venous thromboembolism - oral anticoagulants - deep vein thrombosis
