flying and reducing the risk of pulmonary embolism (PE)

Last reviewed 07/2021

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.
  • the DH has also issued further specific advice to travellers (3)
    • Before the trip
      • some experts advise patients who have had a hip or knee replacement to avoid long haul flights for three months
      • patients who are in a high-risk group (including women taking the pill or HRT) may wish to consider the use of elastic stockings
    • During the trip

      • guidance for the avoidance of deep vein thrombosis and venous thromboembolism (4)

        Blood clots - Deep venous thrombosis (DVT) and venous thromboembolism (VTE)	Risk criteria	Risk reduction advice for passengers
        Low Risk	-no history of DVT / VTE -no recent surgery (four weeks) -no other known risk factor	Keep mobile.Drink plenty of non alcoholic drinks.Do not smoke. Avoid caffeine and sedative drugs.
        Medium Risk	-history of DVT/VTE -surgery lasting more than 30 minutes between 4 and 8 weeks ago -known clotting tendency -pregnancy -obsesity (BMI.30)	As for 'low risk'with addition of compression stockings
        High Risk	-previous DVT with known additional risk including known cancer -surgery lasting more than 30 minutes within the last 4 weeks	As for moderate risk but sub cutaneous injections of Enoxoparin 40 mg before the flight and on the following day

    • 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.

There is also guidance suggesting that individuals with a high risk of developing VTE, who wish to fly, should wear graduated elasticated compression stockings.

• in the general population, there is evidence that prophylactic use of graduated compression stockings during air travel reduces the rate of flight related DVT (5,6)

Also a review of air travel and venous thromboembolism stated (7):

• 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
• low molecular weight heparin is effective, but should only be used in those at highest risk
• there is currently no evidence that aspirin is effective

Notes:

• the use of AES for prevention of VTE during and after long-haul travel is not routinely recommended. When used, care should be taken to ensure an appropriate fit

Reference:

• 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) House of Lords' Session 1999-2000:5th report: Select Committee on Science and Technology. Air travel and Health. 15ht November 2000
• 4) British Heart Foundation (September 2010). Factfile - Fitness to fly for passengers with cardiovascular disease.
• 5) Hsieh HF et al. Graduated compression stockings as prophylaxis for flight-related venous thrombosis: systematic literatures review. J Adv Nur 2005;51:83-98.
• 6) Clarke M et al. Compression stockings for prevention of deep vein thrombosis in airline passengers. Cochrane Database Syst Rev 2006;(2):CD004002.
• 7) British Heart Foundation (February 2006). Air Travel and Venous Thromboembolism.