The commonest cause of Venous Blockage is clots in the veins. These could be superficial or deep veins. If it involves the deep veins it is called deep vein thrombosis (DVT) and if it involves the superficial veins it is superficial thrombophlebitis. If the clot reaches the lungs it blocks the pulmonary artery causing pulmonary embolism.
Deep Vein Thrombosis (DVT)
- Blood clots form in the deep veins of the legs and pelvis blocking the normal blood flow from the legs to the heart.
- Clots in the veins are slow to moderately flowing and are made of a mixture of red cells, platelets, and fibrin and known as mixed platelet-fibrin thrombi.
- Clots that partially block the veins may be asymptomatic until there is a significant reduction in flow.
- Clotting below the knee – your body repairs this in 90% by finding a way around the blockage and restoring blood flow which takes 6 months. During this time the patient gets anticoagulants and is monitored by serial ultrasounds.
- Blockage above the knee – causes venous hypertension in 40 – 60% cases causing pain and swelling which further restricts blood flow leading to discoloration and ulceration.
- This is a condition when a portion of the clot or whole of the clot moves from the site of thrombosis and moves via the circulation to the lungs where it blocks the pulmonary vessels.
- The size of the clot and the location of the blocked blood flow in the vessel determine the extent and the severity of PE.
- Clots closer to the body center (proximal clots) are more likely to lead to a deadly PE compared to clots in the calf veins.
- The occurrence of deadly PE can greatly reduce if DVT is treated with anticoagulant therapy.
- certain genetic factors, Medical conditions like obesity and pregnancy, certain medications, lifestyle changes like smoking, sedentary life, increase the risk of DVT.
Superficial vein swelling (Thrombophlebitis)
- This is due to blood clots in veins nearer to the skin and associated with inflammation.
- Superficial thrombophlebitis is observed in people who are homozygous or heterozygous for Factor V Leiden mutation.