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.
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 return flight.
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 fliers.
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 DVT.
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, too.