Do you utilize D-dimer to inform anticoagulation duration in the treatment of VTE?

I had developed a policy during my last eight or ten years of practice evaluating how long patients should be treated after a thrombosis and I'd like to share some impressions over these years as well as conclusions that I reached. These conclusions formed the basis of my approach to this problem.

I feel the division between provoked and unprovoked blood clots is rather artificial for many reasons including the fact that patients who are susceptible to clots having surgery or taking birth control pills may develop a problem whereas many will not. That having been said, my approach was to utilize D dimer, factor VIII levels, and residual thrombotic changes as guides to the treatment of the patients. This is admittedly the hardest part of the...

I use D-dimer in patients with unprovoked clots who are unsure if they want to continue long-term anticoagulation or not. I follow the excellent algorithm (Fig. 1) outlined in the Kearon/Kahn Blood review series.

I find that most patients now opt to continue anticoagulation given the ease of doac use, especially with the option for reduced dose. There are some people who decline further anticoagulation completely. But for the undecided, checking D-dimer (and APLA) at 4 weeks can help them make the decision. If positive, stay on. If negative, the patient still decides.

I get repeat ultrasounds, not to decide on ongoing treatment, but to have a new baseline to compare in the future if they have leg swelling.

I tend to use D-dimer more often than is recommended in guidelines. My late mentor, Dr. Neil Lachant, referred to D-dimer testing to guide anticoagulation as a "lost art."

Here are situations in which I will use it:

I will utilize it for superficial venous thrombosis (refer to the excellent algorithm on UpToDate diagnosis and management of phlebitis and thrombosis of the superficial veins) to guide the duration of prophylactic anticoagulation.

In the DVT/PE setting, for DVT/PE with transient non-surgical risk factors (long travel, estrogen-containing OCPs) where I am considering time-limited anticoagulation rather than indefinite anticoagulation, there is often a baseline dimer available from the patient's emergency department visit for t...

I hope that my message is clear that the combination of d-dimer, factor VIII synergism is key as well as consideration regarding residual venous changes, damaged valves, lack of complete clot resolution, fibrin changes in the vein, etc. This is a complex algorithm that was very successful for me but not necessarily something everyone is equipped to do.

Regards,

Dr. Caprini