Deep Vein Thrombosis (DVT) is a common and often preventable cause of death worldwide. It affects about one in every 1,000 people in the UK according to the NHS Choices and over 10 million people in Europe and the USA, according to the World Thrombosis Day organisation.
What is DVT and why is it dangerous?
DVT is a blood clot that develops within a deep vein in the body, usually in the leg, in a large vein that runs through the muscles of the calf and the thigh. DVT can be very dangerous or possibly fatal if the blood clot grows to cause obstruction in the body’s most important large veins, especially those that transport blood from heart to the lungs. The blood from the clot can break off and flow towards the heart and can subsequently be pumped into the lungs, causing a pulmonary embolism (PE) (where a blood vessel that supplies the lung becomes clogged by a blood clot).
Anyone can develop DVT at any age but it is predominantly a disease of the elderly and it becomes more common over the age of 40. According to the NHS there are several risk factors that can increase the chances of developing DVT:
- Having a history of DVT and PE.
- Conditions or factors that make your blood thicker or more likely to clot than normal. Some inherited blood disorders (such as factor V Leiden) will do this. Hormone therapy or birth control pills can also increase the risk of clotting along with cancer (including chemotherapy and radiotherapy treatment), heart and lung disease, thrombophilia (increased tendency for blood to form clots) & Hughes syndrome (a disorder of the immune system that causes an increased risk of blood clots).
- Blood vessel damage which can result in the formation of a blood clot.
- Slow blood flow in a deep vein due to inactivity. This may occur after surgery, if you're ill and in bed for a long time, or if you're travelling on long-duration air flights which is also known as ‘’economy class syndrome’’.
- Pregnancy – blood clots can form quicker during pregnancy due to the increase in pressure in the veins in a woman’s pelvis and legs.
- Being overweight or obese, as this increases the pressure in the veins.
- Having undergone surgery under general anaesthetic lasting longer than 30 minutes in the previous two months.
DVT and PE together are known as Venous Thromboembolism (VTE) - a blood clot in a vein which is a serious and potentially fatal medical condition.
- When travelling on a long-distance flight, NHS Choices recommends keeping yourself hydrated and drink a lot of water, avoid consuming alcohol as it can cause dehydration, avoid taking sleeping pills as they can cause immobility and take an occasional short walk. Also avoid keeping baggage between seats to allow room for your legs and buy flight socks which significantly reduce your risk of DVT; they are available at airports, pharmacies and plenty of other retail outlets.
- If you have undergone surgery in the previous 2 months under general anaesthetic for longer than 30 minutes, or have known thrombophilia or cancer, according to the NHS you are at high risk of DVT. So, if you are planning to travel, the National Institute for Health and Care Excellence (NICE) recommends you assess your suitability for long-distance travel by seeking specialist advice or consider delaying or cancelling the trip. However, if you can’t avoid travelling and the journey is to last for more than 6 hours, NICE advises you to think about wearing graduated compression stockings which may reduce the risk of developing DVT. They also suggest seeking specialist advice from a haematologist on whether to use low molecular weight heparin (LMWH, used to treat DVT).
- To lower your risk of DVT you can make some lifestyle changes such as not smoking, exercising regularly, eating a healthy and balanced diet, maintaining a healthy weight or, if you are overweight, losing weight.
DVT is a scary illness and it can be very dangerous if untreated, but there are many precautions that you can take to lower your risk of developing it.