By Katherine Kozlowski, Medical Author and Contributor to Vein News and www.VeinsVeinsVeins.com
A randomized controlled trial of extended anticoagulation treatment versus standard treatment for the prevention of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome in patients being treated for a first episode of unprovoked VTE (the ExACT study)
Bradbury et al investigated the effect of extended anticoagulation treatment versus the standard, limited duration anticoagulation treatment following a first unprovoked proximal deep vein thrombosis (DVT) or pulmonary embolism (PE).
Subjects followed up for 24 months following their first episode of venous thromboembolism (VTE).
281 patients were randomized into two groups:
(1) Adults who completed 24 months of anticoagulation treatment following first VTE (extended treatment) and
(2) Adults who discontinued anticoagulation treatment following first VTE (standard treatment).
What outcomes were studied?
The primary outcome researchers were looking at was the time between the patient's first VTE and their first recurrent VTE.
Other outcomes the researchers studied were the incidence and severity of post-thrombotic syndrome (PTS), bleeding events, quality of life (QoL), and D-dimers (a blood test to rule out blood clots).
What are the results?
There was a significant reduction in recurrent VTE in the extended treatment group (2.75 versus 13.54 events/100 patient years; p<.001)
There was an increase in major bleeding events in the extended treatment group, although this value only approached significance (3.54 versus 1.18 events/100 patient years; p=.10) This means that given the sample size and study methods, we cannot conclude that the length of anticoagulation treatment is related to these differences. However, further investigation is warranted.
VTE recurrence was not significantly related to PTS, D-dimer results, or QoL in either group.
In the study, 87% of participants who developed recurrent VTE had a previous negative D-dimer test—implying that their likelihood of having a blood clot was low. This suggests that using a standard D-dimer test on anticoagulated patients is not predictive of later venous thromboembolism and should not guide clinical decision-making in stopping anticoagulant therapy.
What do we conclude from this?
Extended anticoagulation treatment lead to a decrease in venous thromboembolism recurrence.
There was no relationship between the length of treatment and post-thrombotic syndrome or quality of life.
The standard D-dimer test has limited clinical utility on patients receiving anticoagulation treatment.
Reference: Bradbury C., Fletcher K., Yongzhong S. A randomized controlled trial of extended anticoagulation treatment versus standard treatment for the prevention of recurrent venous thromboembolism (VTE) and post-thrombotic syndrome in patients being treated for a first episode of unprovoked VTE (the ExACT study). Br J Haematol 2020; 188, 962-975.