A new research has found that travelers who are prone to travel-related blood clots during long flight can cut their risk by pulling on a pair of elastic support hose before boarding.
The review examined the evidence that compression stockings can prevent deep vein thrombosis. Sometimes called "traveler's thrombosis," DVT is a circulatory condition in which blood coagulates into small clots inside a blood vessel.
Compression stockings made from elasticized material provide graduated, gentle pressure and are designed to keep blood flowing properly.
Lead researcher Mike Clarke, Ph.D., and his team uncovered strong evidence that flight stockings work. The review found that compression stockings reduce the risk of symptomless DVT to one to three cases per 1,000 long-haul passengers, down from 10 to 30 cases per 1,000.
"It's an extremely dramatic reduction, but it's of something that in the first place wasn't very common. So these stockings reduce a fairly small risk, to something tiny," said Clarke, director of the United Kingdom Cochrane Centre.
Deep vein thrombosis usually causes no symptoms because small clots are easily broken down by the body. But larger clots can block the flow of blood resulting in noticeable problems like ankle swelling or calf pain.
Years ago traveler's thrombosis was dubbed "economy-class syndrome" but researchers say that term is a misnomer because the small risk of thrombosis is present anytime a person is stationary for many hours, be it on a plane or train, in luxury accommodations or in coach quarters.
There is no definitive link between air travel and increased risks for traveler's thrombosis, but some evidence suggests that flights of eight hours or more increase the chances that a person with existing risk factors will develop DVT.
The review gathers data for more than 2,800 passengers. About half of these travelers wore some type of compression stockings, the others did not. The researchers' tests turned up symptomless blood clots in 50 people, just three of those passengers were in the compression stockings group. The other 47 travelers were in the no-stockings group.
The reviewers also found that the stocking-footed passengers reported much less discomfort and swelling in their legs, compared with the travelers who flew without flight stockings.
No one in any of the studies developed a blood clot accompanied by noticeable symptoms, and no one suffered a serious thrombosis-related medical condition. In very rare instances, DVT complications can be life-threatening.
Vascular specialist Jack Hirsh, M.D., said before embarking on a long-haul flight people who have had blood clots in the past or a strong family history of thrombosis should consult their doctor and consider using compression stockings or medication therapy to prevent blood clots. People who have had a chronic illness that kept them immobilized also have an elevated risk for blood clots during long-distance air travel.
The reviewed studies did not find any serious safety issues associated with using compression stockings, and Clarke said the risks and costs appear to be moderately low.