Deep Vein Thrombosis (DVT) is a condition in which blood clots form in the deep veins of the leg causing it to become swollen and painful due to fluid accumulation. 

This may lead to swelling of the leg and is hazardous to life, because bits of clot in the leg may fall off and travel via the main veins to the heart. Here they pass through without a problem, but become stuck in the arteries to the lungs. This is called a 'pulmonary embolism'. This condition causes shortness of breath, collapse and chest pain. Left untreated this may lead to death.

DVT is potentially life-threatening if sections of the clot break off and travel to the lung.  This is a condition called 'pulmonary embolism' and results in sudden shortness of breath and chest pain.  Left untreated it can be fatal.

Risk factors include obesity, immobility, long surgery and an inherited clotting disorder known as 'thrombophilia'.  Any treatment of varicose veins incurs a risk of DVT because the superficial veins that we are treating, connect with the deep veins that we want to leave unharmed. A DVT risk of 1 per 400 patients is quoted for all varicose vein treatment methods, but the use of foam is likely to be the lowest risk. Patients with significant risk factors will be given an anti-coagulant medication after the treatment to reduce the risk of DVT development.