This patient's warfarin should be discontinued. Patients who have experienced a single venous thromboembolism (VTE) due to a major transient risk factor only require short-term anticoagulation for 3 months. This patient experienced a deep venous thrombosis following a traumatic tibia fracture. Generally, the clinical setting of a thrombotic event (unprovoked versus provoked) provides greater prognostic information regarding recurrence risk than the results of thrombophilia testing. Therefore, in most instances, thrombophilia testing results will not influence treatment duration and testing is not indicated. If thrombophilia testing is considered, it should be targeted to persons in whom finding a strong thrombophilia may influence length of anticoagulant treatment or have an impact on other family members if they also tested positive for the higher risk thrombophilia. However, consensus is limited on what defines higher risk thrombophilias.
Elevated plasma homocysteine levels are associated with an increased risk for a first venous or arterial thromboembolic event. Homocysteine levels can be lowered with folic acid, vitamin B6, and vitamin B12. However, this does not change the risk of a first thromboembolic event, which this patient has already experienced, nor of recurrent VTE.
Homozygosity for the methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism can be associated with elevated homocysteine levels but alone is not a risk factor for VTE. Thus, no clinical indication exists for testing for the MTHFR polymorphism in patients or first-degree relatives.