Heparin promotes recanalization of venous thrombotic occlusions.

Thrombosis is a consequence of disbalance between the procoagulant and fibrinolytic activity of blood and is frequently associated with chronic sequelae, which are the consequence of chronic occlusion of affected veins. Treatment of venous thrombosis should not be oriented in the prevention of thrombus progression and associated thromboembolic events, but also in stimulation of thrombolysis and recanalization of occluded veins, which are one of the most important preventive mechanisms of late sequelae, including post-thrombotic syndrome. The treatment of acute venous thrombosis (superficial and deep) is based on drugs with anticoagulant activity, like antagonists of vitamin K, heparins, and new oral anticoagulants. One of the most frequently used anticoagulant drugs is heparin, particularly the low molecular weight heparin (LMWH). It was shown that besides strong anticoagulant activity heparin has pro-fibrinolytic effects, which promote thrombolysis and recanalization of occluded veins. LMWH markedly increases tissue factor pathway inhibitor levels and a release of tissue plasminogen activator from vascular endothelium. Heparins are also capable of increasing the nitrogen oxide level, which is responsible for circulatory homeostasis.