Compression Stockings Cut Fliers' DVT
Deep Vein Thrombosis Is Rare, but Compression Stockings May Help
April 20, 2006 -- Wearing compression stockings on long flights may help
avoid deep vein thrombosis (DVT) -- clots that form in legs' deep veins.
Researchers recently reviewed 10 studies of compression stockings for DVT
prevention in long-distance flights. The studies included a combined total of
more than 2,800 people, all of whom flew for at least seven straight hours.
Compression stockings cover the lower leg, stretching up to the knee. They
apply gentle pressure (especially at the ankle) to encourage blood flow in
order to cut clotting risk in deep veins.
The review, published in The Cochrane Database of Systematic Reviews, shows
a "substantial reduction" in symptomless DVT and leg swelling (edema) in
passengers who wore the stockings.
The researchers who wrote the review included Mike Clarke, director of the
U.K. Cochrane Center. They note that DVT was rare in the studies and even rarer
in participants wearing compression stockings.
About the Studies
Roughly half of the participants were randomly chosen to wear compression
stockings on their flights. In one study, 35 participants wore a compression
stocking on one leg on their departure flight and on the other leg on their
In the reviewed studies, participants were carefully checked after their
flights for any circulation problems in their legs, even if they felt fine,
write Clarke and colleagues.
The point was to look for DVT after long flights and to see if the stockings
affected DVT risk.
None of the participants in any of the studies had DVT with obvious
symptoms, but 50 had DVT without symptoms. No serious events -- such as blood
clots in the lungs (pulmonary embolismpulmonary embolism) -- were seen in any
Pulmonary embolism is a potentially fatal consequence of DVT. But DVT
doesn't always lead to pulmonary embolism.
"There was a big difference in symptomless DVT between the two groups,
equivalent to a reduction in the risk from a few tens per thousand passengers
to two or three per thousand," write Clarke and colleagues.
"Not all trials reported on possible problems with wearing stockings but in
those that did, the researchers said that the stockings were well tolerated,
without any problems," Clarke's team adds.
As those studies showed, the vast majority of travelers didn't develop
Experts have suggested that long-distance fliers drink plenty of water,
stand up, stretch, and walk around the airplane's cabin occasionally, Clarke
and colleagues note, adding that "aspirin and low doses of the blood thinner
heparin have also been suggested as preventive strategies."
Of course, travelers should check with their doctors about medication use or
clotting risk factors. DVT isn't just a problem on lengthy flights. Being
motionless for long periods of time can up the risk of DVT on the ground,