Deep Vein Thrombosis

Deep vein thrombosis is the most often cause of pulmonary embolism. Thrombosis is localized in deep vein system of lower limb (but the same type of thrombosis can be localized in deep vein system of upper limb). Typical localization is deep vein of lower leg, popliteal vein, femoral vein, iliac vein.

Pathophysiology
Virchow’s triad: There is an equilibrium in blood clotting in common situation. For thrombus formation is necessary impulse.
 * endothelial dysfunction,
 * blood flow deceleration,
 * blood hyperviscosity (change in the composition of blood).

High Risk Patient
We have several groups of patients with high risk of thrombus formation:
 * patients with inborn risk:
 * protein C or protein S defficite
 * Leiden’s mutation
 * elevated level of clotting factors (II, ..)
 * patients with acquired risk:
 * immobilization
 * surgery (abdominal surgery, oncosurgery, orthopedics - total endoprothesis)
 * trauma
 * hormonal contraception
 * infection
 * central vein catheter (typically in subclavial artery)
 * pregnancy - especially the 2nd and 3rd trimester (because of physiological elevation of clotting factors)
 * postpartum period

Symptoms

 * pain - painful palpation, painful dorsiflection of foot (Homans sign)
 * edema - because of decreased vein blood drainage, grater limb circumference
 * peripheral (superficial) vein dilatation - because of decreased vein blood drainage, superficial veins must take grater amount of blood
 * peripheral pulsation can not disappear just only because of deep vein thrombosis, there must be affected arteries

Diagnostic Methods

 * laboratory:
 * elevated D-dimers - thrombolysis marker
 * duplex sonography - basic noninvasive method
 * venography - with contrast agent
 * CT angiography - in suspected iliac vein trombosis

Therapy

 * anticoagulation:
 * LMWH - works immediately, preferred in pregnancy and short time therapy (acquired risk - surgery ...), e.g. fraxiparine, enoxaparine.
 * heparin - is less performed, just in patients with contraindicated LMWH or in patient suspected on pulmonary embolism
 * warfarin - peroral anticoagulant, unfortunately it takes several days (3-6) before in really starts work, but the patient should have specific therapy immediately (start with warfarin and LMWH in the same time and stop with LMWH in 4-5 days). This drug should be performed in patients with inborn high risk of thrombosis. Needed INF level is 2-3.


 * thromolysis - is an extensive method in patients with high iliac vein thrombosis, these patients are in high risk of pulmonary embolisation.

Prevention

 * soon mobilization of patients (after surgery)
 * bandage of limbs
 * LMWH before surgery

Complications

 * pulmonary embolization
 * deep vein valves dysfunction
 * deep vein system hypertension → vein insufficiency

Related articles

 * Pulmonary Embolism