Introduction

Varicose veins: veins: deep vein thrombosis:

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Travellers Thrombosis

Travel Supplement Study

Introduction

Traveller’s thrombosis is now a well-recognised condition affecting many more travellers than was originally thought. Only a few travellers will experience a serious deep vein thrombosis giving rise to major leg symptoms and even fewer will suffer from a major pulmonary embolic episode. We know that small clots form (thrombosis) and these clots then dissolve (lysis) during every day life. Recent studies suggest as many as 1 in 10 people will develop small asymptomatic clots during long haul flights. In the majority of cases these clots will dissolve without the patient being aware of any symptoms.

What is unclear is how many of these will go on to form larger clots, or whether there is a cumulative effect. The cumulative effect could affect business travelers, or people travelling on a frequent basis for whatever reason.

We know that three factors are important in the development of a blood clot - prolonged immobility leading to venous stasis, damage to the vein walls often caused by pressure and a change in the blood’s ability to coagulate. Recent studies suggest that hypoxia and reduced atmospheric pressure may enhance the clotting mechanisms, increasing the risk of a thrombotic episode. Studies on patients who have undergone major surgical procedures have identified risk factors and it is now widely accepted that the more risk factors, the greater the risk of developing a thrombotic complication. Identifying passengers at risk is clearly helpful. Passengers with a past history of thrombosis, gross obesity, underlying medical, surgical conditions and recent trauma are important factors. What is more difficult to explain is why young people spontaneously develop a large deep vein thrombosis and/or a pulmonary embolism. Some of these people may have an underlying thrombophilia, but in many instances there is no specific indication.

Because of some genuine concerns about the risk of developing thrombotic episodes, there has been much discussion about the use of prophylactic devices and medication. Any device aimed at promoting the flow of blood through the veins should be effective and that includes graduated compression stockings and foot exercising devices. Proven medications include low molecular weight heparin and anti-coagulants. Medications which may be beneficial but where the scientific evidence remains controversial, includes aspirin and anti-platelet agents. The anti-platelet properties of aspirin may be beneficial, but aspirin is associated with a 7% incidence of gastro-intestinal bleeding which on occasions may be very severe.

There is a need to have an effective simple prophylactic agent which can be taken by everyone, with no serious side-effects. There are a number of naturally occurring substances which have proven venotonic effect. By increasing blood flow and reducing venous stasis, these substances may well prove to have an anti-thrombotic effect.

Pine Bark Extract is naturally occurring and is known to affect the venous circulation. This substance has many of the properties of the veno-routicides in terms of promoting venous flow, reducing capillary leakage and tissue oedema. Separate studies would appear to reduce leg swelling in dependent patients.

One further property of this drug includes anti-platelet activity, very similar to the effect seen with aspirin, but without the risk of serious gastro-intestinal bleeding.

A combination of Pine Bark Extract and Ginger is currently being evaluated in the prevention of travel related venous thrombosis. Ginger has anti-emetic and anti-oxidant properties. Pine Bark Extract has venotomic properties, promoting flow of blood through the veins. Both Ginger and Pine Bark Extract are naturally occurring food supplements.

Study Group

100 Passengers travelling long haul (greater than eight hours) and returning to the UK within one month will be recruited. Passengers must be 18 or greater and be in a position to give informed consent to enter the study. Prior to entry a full medical history will be obtained and a travel history, detailing the number of flights and the duration of flights in the previous twelve months. A history of previous deep vein thromboses and travel related problems will also be recorded. The patients will also be asked to state their current medication and any medication taken during the study period.

There are no restrictions to entering this study, no advice about travel will be given specifically, but patients taking prophylactic measures or wearing flight socks will be noted, but still included in the study.

On their return, a similar questionnaire will be completed looking at events that occurred during and following the flight. Patients will be asked specifically about symptoms, including leg swelling, foot swelling, pain and discomfort in the leg and respiratory symptoms.

All passengers entered into the study will be given a travel supplement. They will be given two packs – each pack contains 5 tablets. Passengers will be advised to take 1 tablet the day before departure, 2 on the morning of departure and 1 tablet on each of the second and third days. They will repeat the supplement for the return trip.

Results

These will be analysed on an intention to treat basis. Failure to take the supplement will not exclude the patient from the study, but it will be noted. Passengers with symptoms will be subject to further investigation including Duplex ultrasound imaging. Any patient found to have sustained a deep vein thrombosis will be fully investigated and treated appropriately.

Discussion

The purpose of this study was to assess patient compliance, efficacy and to note the presence of any side effects. Pine Bark Extract and Ginger are classified as food substances and although bioactive do not count as medication. Further studies are currently being designed to investigate the efficacy of a travel supplement in preventing venous thrombosis in travellers. Current theoretical evidence leads us to believe this substance is effective and should be considered as a substitute to aspirin for prophylaxis in normal risk passengers.

Whilst this substance can be taken effectively with or without graduated compression stockings, it should not be considered a substitute for a proper fitness to fly assessment.

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