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.
Clinical spectrum of clotting
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 discolouration 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 centre (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.
Signs and symptoms
Deep vein thrombosis
- Swelling mostly in one leg
- Leg pain or tenderness
- Reddish or bluish skin discolouration
- Leg warm to touch
- May be asymptomatic
- Sudden shortness of breath
- Stabbing chest pain worse on taking a deep breath.
- Rapid heart rate
- An unexplained cough sometimes with bloody mucus
- Apprehension, anxiety
- Feeling faint
- Some people may be asymptomatic
Signs and symptoms in thrombophilic conditions
- Recurrent pregnancy loss and miscarriage could be due to clotting disorder (thrombophilia) especially in females with Factor V Leiden mutation, prothrombin gene mutation, antiphospholipid syndrome or lupus anticoagulants and in women with protein C & S and antithrombin deficiencies.
- Pregnancy loss and recurrent miscarriage may be due to excessive clotting in the small placental vessels.
- Mesenteric vein clots are rare but characteristic of inherent clotting disorder.
- Family history of blood clots.
- Blood clots in persons under 40 years
- Neo-natal Purpura fulminans is rare and associated with homozygous protein C & S deficiencies.
- These patients are mostly asymptomatic and diagnosed because of a family history suggestive of a clotting disorder.
- They block the blood flow in the veins below the skin causing pain and irritation.
- Redness and inflammation along the vein may be seen
- There is warmth, tenderness and itching along the vein
- Pain along the vein – throbbing or burning – may interfere with sleep.
- May develop fever along with episodes of thrombophlebitis.
- Clinical signs are like those of other clotting disorders
- Patients with significant Hyperhomocysteinemia develop DVT with or without PE in 64%; superficial thrombophlebitis in 24%; Thrombosis of the mesenteric or cerebral veins in 12%.
- Clotting signs are associated with other triggering factors like oral contraceptives, trauma/surgery, pregnancy and immobilisation.
- If DVT involves the femoral vein we give compression stocking and leg elevation till the body finds its way around the blockage.
- In the first 3 weeks we perform lysis to reduce the long term effects of venous hypertension.
- There is little we can do to improve chronic venous thrombosis.
- If venous obstruction involves the pelvic veins then thrombolysis and venous stenting is done and has been successful.
- Clots one month old are not helped by thrombolysis but stenting may help. Stents could be applied to the IVC if needed.
- Stents give good success in improving chronic blockage of the pelvic venous system. This reduces the pressure of the veins in the legs and improves the symptoms.
Pelvic / abdominal vein obstruction
- This causes unexplained pain in the legs and swelling, pelvic pain or leg ulcers that are difficult to heal.
- The leg pain worsens with exercise because of the increased flow of blood in the legs with exercise. This increased flow in the legs cause an increase in the pelvic veins which dilate to accommodate around the obstruction causing pelvic pain. This may be intermittent or constant.
- Pain shortly after intercourse (dyspareunia) due to infection of the uterus, ovaries or endometrium.
- The commonest cause of pelvic pain is compression of the iliac veins in the pelvis as it is squeezed between the iliac artery and the spine. Besides ovarian or uterine cyst or cancer may compress the vein.
Pelvic vein compressed between the iliac artery and the spine with a stent within
- It can also recur in those with previous iliac vein DVT.
- Pelvic vein may be totally occluded or may rechannalise leaving it narrow
- Most IVC obstructions are due to scarring at the site of IVC filters. The IVC filters prevent large clots from moving to the lungs from the legs of pelvic veins.