Royalberkshireveinclinic.co.uk

www.royalberkshireveinclinic.co.uk
Specialist treatment of leg and facial veins using
surgery, sclerotherapy and Veinwave
Timothy R Magee MD FRCS
Consultant Surgeon
72 Berkeley Avenue
0118 9745320
info@royalberkshireveinclinic.co.uk
Deep vein Thrombosis
Including Flight advice
Information for patients, December 2006
Deep Vein Thrombosis

People have become concerned about the risks of deep vein thrombosis (DVT) during
long air flights, following reports in the press about occasional deaths due to fatal
pulmonary embolism. The aims of this advice are:
· to provide reassurance that the risk for most people is miniscule
· to explain about DVT and pulmonary embolism
· to identify people who may be at increased risk
· to advise on possible precautions to reduce the risk
The advice is similar for all long journeys, whether by air, coach, car, or train.
What are deep vein thrombosis (DVT) and pulmonary embolism?

There are two systems of veins in the legs - the important deep veins (which carry
most of the blood up the legs towards the heart) and the less important superficial
veins just under the skin (which can form varicose veins).
Deep vein thrombosis (DVT) means thrombosis (clotting) of blood in the deep veins
of the legs. It can cause swelling and pain in the leg, but often occurs without giving
any symptoms. A DVT may well settle completely, as the thrombosis is dissolved by
natural processes.
If a DVT extends up the deep veins, two things can sometimes happen:
1. The thrombosis can become dislodged from the vein, and carried through the main
veins and heart to lodge in the lungs. This is called a pulmonary embolism. Small
pulmonary emboli may cause chest pain, and sometimes coughing up of blood.
Multiple or larger pulmonary emboli may cause breathlessness. A large pulmonary
embolus which blocks the main blood vessels to the lungs will be fatal.
2. The thrombosis can cause chronic blockage in the deep veins or damage to their
valves, leading to long term swelling and sometimes skin problems at the ankle.
Why does deep vein thrombosis occur?

All the veins in the leg have valves which should direct blood flow upwards, towards
the heart. The deep veins lie between the muscles, and muscular activity (moving the
legs, walking, or any leg exercise) helps to pump the blood up these veins. When the
legs are inactive, and particularly when sitting or standing, blood tends to stagnate in
the deep veins. Stagnation of blood can eventually lead to thrombosis. Sitting with the
legs bent (as in an aircraft or coach seat) may also restrict flow of blood up the veins
in the calf. The longer the period of stagnation, the more likely is thrombosis.
If the blood is unusually ·thick· or ·sticky· then the risk of thrombosis is greater: this
can be caused by dehydration and some medical conditions.

Who is at special risk of deep vein thrombosis?

We have no direct evidence about people at special risk of DVT as a result of long
journeys, but based on evidence about surgical operations the following increase the
risk of thrombosis:
· Having had a DVT or pulmonary embolism before
· Having had a recent major operation
· Pregnancy
· The contraceptive pill or hormone replacement therapy (HRT)
· Malignant disease (cancer)
· Obesity (being overweight)
· Severe heart disease
· Some blood diseases
· Varicose veins
The risks of DVT are probably highest for people with more than one of these risk
factors.
How large is the risk?

For people without any of the risk factors listed above the risk of DVT (even on a
long haul flight) is miniscule - one in hundreds at the most. For people with risk
factors who take no precautions against thrombosis, the risk of DVT detectable on
special scans is as high as one in twenty on long haul flights (but many of these
thromboses are minor and cause no problems).

Flight Advice

There is now evidence that wearing below knee graduated compression stockings
reduces the change of DVT for people with special risk factors1 . Because so few
people without risk factors ever develop DVT or pulmonary embolism as a result of
long journeys, there is no definite evidence about other measures which reduce the
risk. However, based on what is well known about the causes of DVT and the
successful methods of prevention used in hospital, the following are sensible
precautions, particularly on long haul flights and other journeys lasting several hours:
1. Move your legs.
· Don·t sit with your legs bent for hours on end. Stretch your legs out from time to
time, and move your feet up and down at the ankles. Stand up to stretch the legs now
and then. Stretching and moving the legs stops blood stagnating in the deep veins of
the calf, and is the simplest and most effective thing you can do.
· Go for a walk up and down the aisle.
2. Don·t get dehydrated.
· Drink plenty of fluid · water is ideal.
· Avoid excessive alcohol, which tends to cause dehydration.
3. Wear compression stockings.
· Graduated compression stockings reduce the risk of DVT. They also help to prevent
the ankle swelling which many people experience on long journeys.
· BELOW KNEE stockings are the most comfortable kind, and seem just as effective
as full length stockings.
· Medical graduated compression stockings are supplied in three classes: Class 1 or
Class 2 stockings are suitable for most people (Class 3 are excessively strong for this
purpose).
· Compression stockings can be prescribed by a doctor if there is a medical need.
They can be bought at chemists, surgical appliance specialists, and now at some other
shops, for example in airports.
· These stockings come in a range of sizes, and your legs will need to be measured to
get the right fitting.
· People who have trouble with the arteries of their legs should seek medical advice
before using compression stockings.
4. Aspirin.
Taking an aspirin tablet (either a 75mg ·junior aspirin· or half of a normal 300mg
aspirin tablet) a few hours before a long journey may provide a small amount of extra
protection against DVT.
5. Anticoagulants.
Special anticoagulant drugs (e.g. heparin injections, or warfarin by mouth) may be
advisable for a few people who have medical conditions with a particularly high risk
for DVT. This kind of treatment will always be on the explicit advice of a doctor.
This information is general in nature. It is for guidance only, your surgeon can advise
you on specific information relating to your condition.
December 2006

Timothy R Magee MD FRCS
Consultant Surgeon
72 Berkeley Avenue
0118 9745320
info@royalberkshireveinclinic.co.uk

Source: http://www.royalberkshireveinclinic.co.uk/deep%20vein%20thrombosis%20&%20flight%20advice.pdf