With provoked DVT, the duration of anticoagulation therapy is three months. Unprovoked and recurrent DVT needs screening for genetic deficiencies and the treatment is often life long.

I normally commence heparin and warfarin at the same time, ceasing heparin when INR reached therapeutic target.

Regards

Dear Osaid, standard practice is to start heparin and warfarin on day 1, then to stop heparin when INR is 2 or more for two days. Anyway, heparin therapy should last at least 5 days. The initial dose of warfarin is usually 5 mg. However, if the patient has active cancer, it is better to treat him/her with six months of LMWH without warfarin. After six months the patient should be re-evaluated for oral anticoagulant therapy (OAT).

Provoked DVT should be treated for three months, whereas for unprovoked DVT there is no consensus yet. The decision to stop OAT, or to prolong it, should be individualized on the basis of the personal benefit/risk profile and patient preferences. If you decide in favor of extended therapy, the patient should be re-evaluated at least annually. Now, we have some robust literature supporting aspirin or low-dose apixaban (where available) for extended therapy.

The current consensus on the type and duration of anticoagulant therapy in deep venous thrombosis and pulmonary embolism was published in the 2012 American guidelines (ACCP), in the 2014 European guidelines (ESC) on pulmonary embolism and, more recently, in the 2015 Canadian guidelines. I am attaching the original publications for you.

Best regards

Hello.

CHEST guidelines published in 2016 can be of good help for you.

In oncologic patients: LMWH is the first option because it has better results than warfarin.

In other cases: new oral anticoagulants (rivaroxaban, apixaban, ...) are now the first option. I am using them for the last 2 years with good results.

Nowadays warfarin does not have a place in DVT treatment. It has a lot of side effects and needs INR monitoring.

Duration of treatment is difficult to decide in many cases. A clinical decision with the help of image and D-dimer must be the rule:

1. Provoked DVT - treat for 3 months and suspend if provocative factor has been eliminated

2. Unprovoked DVT - treat for a minimum of 3-6 months; then evaluate patient (physical examination, duplex ultrasound, D-dimer); then you can decide to continue or not

3. Second unprovoked DVT - prolong treatment for a minimum of 6-12 months or treat for indefinite time (indefinite can have two meanings: don't know how long, or for life); I use for life definition

4. DVT with active cancer - treat as long as cancer is active (active cancer - if any treatment for cancer was performed in the last 6 months)

5. DVT with non-active cancer - treat for 6-12 months; then perform same evaluation mentioned above and decide to continue or not

6. DVT and thrombophilia: minimum of 6-12 months and then evaluate patient (for life can be an option)

7. Note: I do perform a thrombophilia study after the first unprovoked event. If there are two thrombophilic factors or antiphospholipid syndrome I will treat for life.

All these ideas are based in guidelines, however the decision to continue or not must be individualized according to patient characteristics. Thrombotic risk must be compared with hemorrhagic risk.

Best regards