Role of innate immunity and fibrinolysis in the development of post thrombotic syndrome: a case-control study

Post thrombotic syndrome (PTS) is a chronic complication of deep venous
thrombosis (DVT). Patients suffering from PTS have symptoms of aching pain,
tingling, heaviness, itching and/or swelling of the leg that was affected by
the DVT. These symptoms worsen by standing or walking and decrease with rest.
Edema, venous ectasia, hyperpigmentation, eczema and varicose collateral veins
can be apparent, in severe cases ulceration occurs.
Twenty to fifty percent of patients who had a DVT develop PTS, in most cases
within two years after the initial DVT. PTS has a significant negative
influence on quality of life. Furthermore, the costs of PTS for both patient
and health care are significant.
The symptoms of PTS are thought to be the end-organ manifestation of venous
hypertension. Venous hypertension following DVT is likely to be caused by three
closely linked processes: inflammation, fibrosis and residual thrombosis
through impaired fibrinolysis. Venous hypertension leads to tissue hypoxia and
reduced calf muscle perfusion, which result in the clinical manifestations of
PTS.
Why certain patients do and other patients do not develop PTS is not fully
clear.
The aim of this study is to get more insight in the pathogenesis of PTS by
measuring markers in the blood of patients with PTS and patients without PTS.
As mentioned above, inflammation, fibrosis and residual thrombosis through
impaired fibrinolysis are thought to be the three main constituent processes
leading to PTS. A marker represents one or more constituent processes, either
as an active player in a process or as a reflection of a process. Therefore,
comparing levels of different markers in patients with and without PTS might
help us to find out which of these constituent processes are (most) important
in the pathogenesis of PTS.
Learning more about the pathogenesis might give clues for new treatments of
PTS. Since there are only limited evidence-based treatment options for PTS,
basic research on PTS leading to clues for new treatment, can definitely be
valuable. In addition, besides new treatments, research in this field might
also give rise to new tools for early diagnosis of PTS.

The primary objective of this study is to establish a panel of markers that can
be used for further research into the understanding of the pathogenesis of PTS.

A multicenter, observational, hypothesis generating study that is performed as
a case-control study.

The study burden for participants will be kept minimal. Participants have to
visit the hospital once only for three tubes of blood to be drawn. They do not
need to be fasting.
The risks of a venipuncture are the only risks for subjects participating in
this study. These risks consist of hematoma or continued bleed on the place of
the venipuncture.