25 May 2006

 

Compression Stockings and the Prevention of Travel Related Deep Vein Thrombosis (DVT)

A recent systematic review and meta-analysis by the Cochrane collaboration assessed of the use of compression stockings for the prevention of deep vein thrombosis (DVT) in airline passengers on long haul flights [1].

The authors assessed nine trials that compared travellers on flights of seven or more hours in duration who wore below-knee compression stockings with travellers who did not wear stockings.  The compression strength ranged from 10 to 30 mm Hg at the ankle. The primary outcome was the development of symptomatic or asymptomatic DVT; secondary outcomes were superficial vein phlebitis, pulmonary embolus, death, and oedema. Diagnosis of symptomatic or symptomless DVT was by ultrasound, venogram or isotope.

A total of 2,821 persons were examined in the trials; 1,548 participants in seven trials were considered to be at low or medium risk of a DVT, and 1,273 in two trials were considered to be at high risk (e.g. previous DVT, blood clotting disorder, recent surgery, cancer, smoking, pregnancy and obesity).  Follow-up was available on 2,637 (93%) participants.

Symptomless DVT occurred in 50 persons; 47 did not wear stockings, three did. The overall incidence of symptomless DVT was 2.4% in high risk participants and 1.5% in low to medium risk participants. Wearing compression stockings resulted in a 90% reduction in the odds of developing a symptomless DVT and translated to a reduction in risk from about 10 to 30 episodes per 1,000 long-haul travellers to 1 to 3 episodes per 1,000 travellers.

The trials also reported a significant reduction in the subjective and objective incidence of oedema in those who wore stockings compared to those who did not. There was no effect on the development of superficial phlebitis, and no cases of pulmonary embolus, death, symptomatic DVT occurred.  Wearing the stockings was well-tolerated.

 

Recommendations for travellers

The evidence for an association between DVT and long-haul travel has been reviewed previously [2-4] and is summarised in NaTHNaC Health Information Sheet: Travel Related Deep Vein Thrombosis.

Updated advice for travellers is also available from the British Society of Haematology and includes a classification of risk and suggested precautions for travel lasting more than 6 hours [5]. It is also anticipated that the results of World Health Organization research into air travel related DVT will be published later this year.

Previous recommendations to prevent DVT found on NaTHNaC Health Information Sheet: Travel Related Deep Vein Thrombosis do not change as a result of this study. However this review demonstrates that the risk of developing symptomless DVT during long-haul travel is reduced with the use of properly fitted compression stockings.  Travellers who wore stockings also experienced less lower leg oedema. The impact of preventing symptomless DVT on the subsequent development of pulmonary embolus, symptomatic DVT or death cannot be determined from the review.

References

1. Clarke M, Hopewell S, Juszczak E, Eisinga A, Kjeldstrøm M. Compression stockings for preventing deep vein thrombosis in airline passengers. The Cochrane Database of Systematic Reviews 2006, Issue 2. Art. No.: CD004002. DOI: 10.1002/14651858.CD004002.pub2. http://www.mrw.interscience.wiley.com/cochrane/clsysrev/ articles/CD004002/pdf_fs.html

2. Chee YL, Watson HG. Air travel and thrombosis. Br J Haematol. 130:671-80, 2005.

3. Ansari MT, Cheung BMY, Huang JQ, et al Traveller’s thrombosis: asystematic review. J Travel Med. 12:142-54, 2005.

4. Geerts WH, Pineo GF, Heit JA et al. Prevention of venous thromboembolism. The seventh ACCP Conference on Antithrombotic and Thrombotic Therapy. Chest. 126(3 Suppl):338S-400S, 2004.

5. British Committee for Standards in Haematology. Risk of venous thrombosis and long distance travel (including air flights). Information for travellers. 2005. Available at: http://www.bcshguidelines.com/pdf/venousthromb_23050 5.pdf

Links

The Cochrane Collaboration  http://www.cochrane.org/index.htm