Reducing the risk of venous thromboembolism (VTE) and air travel

Travellers' thrombosis is the occurrence of venous thromboembolism (VTE) (deep vein thrombosis (DVT) or pulmonary embolism (PE)) related to travel.

• unfortunately, good quality randomised controlled trials are lacking in this area (1,2)
  • according to a research, all forms of transport involving a journey of 4 hours or more are associated with DVT
  • the risk of flight related DVT is increased in both shorter and taller individuals and in the overweight and is associated with location in a window seat
  • risk is also increased in combined oral contraceptive pill use and carriage of factor V Leiden
  • there is no evidence to suggest that dehydration is an important factor
• the UK Department of Health (DH) recommends that patients with a personal or family history of VTE or clotting abnormalities, a history or current treatment of cancer, those who have suffered a stroke or have had recent major surgery, obtain medical advice before travelling.
• some experts advise patients who have had a hip or knee replacement to avoid long haul flights for three months
• travellers at an increased risk of VTE are advised to consider the use of properly fitted below knee graduated compression socks providing 15 to 30mmHg of pressure at the ankle. These socks reduce the risk of symptomatic VTE. (3)
• pregnant travellers with additional risk factors may be advised to have low molecular weight heparin whatever the duration of the flight (4)
  • During the trip

• After the trip
  • if you develop swollen, painful legs, especially if one is more affected than the other, or if breathing difficulties occur, see a local doctor urgently or visit the nearest accident and emergency department.
  • in the general population, there is evidence that prophylactic use of graduated compression stockings during air travel reduces the rate of flight related DVT (3)

For the majority of healthy air travellers the risk of deep vein thrombosis or pulmonary embolus is very small:

• risk of symptomatic venous thromboembolism increases with flight duration
• most air travellers who develop thrombosis have additional risk factors for venous thromboembolism
• patients at risk of venous thromboembolism should be warned of the dangers of long haul flights
• compression stockings reduce the incidence of deep vein thrombosis (3)
• low molecular weight heparin is effective, but should only be used in those at highest risk (5)
• there is currently no evidence that aspirin is effective and UK guidelines support the view that aspirin should not be used for the prevention of VTE in travellers (5)

References:

1. Scottish Intercollegiate Guidelines Network (SIGN) 2010. Prevention and Management of Venous Thromboembolism.
2. Department of Health (DH) 2007. Advice on travel-related DVT.
3. Hopewell S, Juszczak E, Eisinga A,et al. Compression stockings for preventing deep vein thrombosis in airline passengers. Cochrane Database Syst. Rev 2006; CD004002
4. Royal College of Obstetricians and Gynaecologists. Air Travel and Pregnancy (Scientific Impact Paper No. 1) 2013
5. Watson HG, Baglin TP. Guidelines on travel-related venous thrombosis. Br J Haematol. 2011 Jan; 152(1):31-4