The formation of a thrombus, or a blood clot, IN DEEP VEINS OF LEGS IS CALLED deep vein thrombosis (DVT) .This is a very serious,LIFE THREATNING condition that may cause damage to the leg that is permanent. This is also known as post thrombotic syndrome. It may also cause a life-threatening pulmonary embolism, or blood clot in the lungs. 600,000 new cases are diagnosed each year. Of every 100 people who have DVT, one those will die.
The veins are surrounded by powerful muscles that contract and force oxygen-less blood back to the lungs and the heart. These deep veins are near the center of the leg.
Because blood is squeezed up the leg against gravity and the valves prevent it from flowing back to our feet, one-way valves prevent the back-flow of blood between the contractions.
Blood can pool when the circulation of the blood slows down due to illness, injury or inactivity, providing an ideal setting for clot formation.
· Above the age of 40
· Limb trauma and/or orthopedic procedures
· Cancer (malignancy)
· Previous DVT or family history of DVT (Hereditary)
· Immobility, such as bed rest or sitting for long periods of time
· Recent surgery
· Hormone therapy or oral contraceptives
· Pregnancy or post-partum
· Coagulation abnormalities
Deep vein obstruction can be caused by DVT (Deep Venous Thrombosis) e.g. in economy class syndrome or by tumours in the pelvis compressing the veins. If it persists it causes valve failure too. Muscle pump failure occurs in any condition where the calf muscles are very weak. If this persists it also causes valve failure. By far the commonest reason for venous insufficiency and varicose veins is valve failure which can result from inherited valve defects (most common); hormones (e.g. in pregnancy); trauma, previous thrombosis or weak calf muscles. Once one valve is damaged allowing reflux through it this causes the vein below to stretch. This causes the next valve down to be pulled apart and also fail, leading to a domino type effect with more and more valves failing and eventually a varicose vein becomes prominent. So you can see the most important factor is your genes; did your mother have varicose veins? When the valves fail blood flows the wrong way through the veins away from the heart. This is called reflux. The detection, localisation and treatment of reflux is crucial to the effective management of all venous insufficiency problems including varicose veins, reticular veins, spider veins and ulceration.