The risk assessment in patients with venous thrombosis (VTE) is
based on the reported recurrence rate. Epidemiology studies show that
despite anticoagulant therapy, VTE recurs frequently in the first few months
after the initial event, with a recurrence rate of ≈7% at 6 months1.
Therefore the thrombosis risk is assessed as high in patients undergoing surgery
within 3 months of a thrombosis. After 12 months the risk is low unless there
are additional risk factors. Active cancer increases the risk and patients with
a prior history of thrombosis have a
higher incidence of further events.
Severe thrombophilia is
listed as a risk factor in the ACCP guidelines but there is little evidence to
show that thrombophilia increases the risk of thrombosis at the time of surgery
and there is no clear link between thrombophilia and an increased recurrence
rate.
The following are
listed as severe thrombophilia in the ACCP guidelines:
The Epidemiology of Venous Thromboembolism.
Richard
H. White, MD
Circulation. 2003;
107: I-4