Therapy

Anticoagulate all patients with suspected venous thromboembolism ^a including patients with a calf DVT. ^a

Give low molecular weight heparin (LMWH) ^a  (e.g. tinzaparin 175 units/kg subcutaneously) whilst waiting for the results of investigations. No monitoring is necessary for LMWH.  ^d

In addition ^a start warfarin ^a e.g. 5 mg ^a  at 1800 hours ^c as soon as deep vein thrombosis has been demonstrated. ^a  

Give warfarin

• for 6 weeks for transient risk factors (e.g. surgery, recently bed-ridden) ^a  
• for 6 months for permanent risk factors (e.g. cancer, leg paralysis) ^a  
• indefinitely for idiopathic cases ^a  or recurrent venous thromboembolism ^a  

An alternative is long-term LMWH ^b

Remember anticoagulation can be done on an outpatient basis in uncomplicated cases ^d  
Avoid in patients with: ^d

• recurrent venous thromboembolism
• active bleeding
• a clotting disorder
• problems being followed-up

Monitor the response to warfarin using daily INR ^c and aim for a therapeutic range of 2.0 to 3.0.  ^c  
Use a set protocol (preferably computerised) ^a  to prescribe the amount of warfarin. 

Continue the LMWH for at least 5 days, and until the INR is in range for 2 days. ^d  
Seek expert advice if there are problems. ^a. (See anticoagulation chapter for more details)

Check platelets after 5 days to exclude heparin-induced thrombocytopenia. ^b   

Ask patients to wear knee-length sized-to-fit elasticated stockings during the day. ^a  

• thrombolysis ^a   
• vena caval filters combined with anticoagulation for preventing PE in high-risk patients ^a  
  
  • Vena caval filters may by useful in patients at high-risk for further venous thromboembolism who have a contraindication to anticoagulation. ^d