New Guidelines Debunk 'Economy Class Syndrome'

Risk of Blood Clots Low for Most Air Travelers

By Salynn Boyles
WebMD Health News

Reviewed by Laura J. Martin, MD

Feb. 7, 2012 -- New guidelines debunk evidence to support the existence of an "economy class syndrome" -- the idea that passengers in the cheaper seats with the least leg room have an elevated risk for developing deep-vein blood clots.

Likewise, the guideline committee concluded that there is "no definitive evidence" to support the notion that dehydration or drinking alcohol increase blood clot risk.

Most healthy airline passengers have a very low risk for developing life-threatening blood clots during long flights, but oral contraceptive use, advanced age, and sitting in a window seat (where passengers are less likely to get out of their seat and move) all raise the risk somewhat, according to the American College of Chest Physicians (ACCP).

Blood Clot Risk Low, Group Finds

The flight travel guidelines were included in the updated ACCP recommendations for preventing and treating deep vein thrombosis (DVT), potentially serious blood clots that can lead to potentially fatal blockages in the lungs.

"Traveling in economy class does not increase your risk for developing a blood clot, even during long distance travel; however, remaining immobile for long periods of time will," says researcher Mark Crowther, MD, of McMaster University in Ontario, Canada.

In other words, there is nothing inherently risky about sitting in a cramped tourist-class seat if you stretch your legs or get up and move around occasionally.

Frequent movement and stretching the calf muscles is recommended for air travelers with an increased risk for DVT on flights of more than six hours' duration, as well as sitting in an aisle seat, if possible, to make it easier to move around.

At-risk passengers should also consider wearing below-the-knee compression stockings, but the stockings are not recommended for people without DVT risk factors.

Those risk factors include:

  • Having a history of blood clots or having cancer
  • Having a known thrombophilic disorder -- a medical disorder that predisposes you to forming blood clots
  • Undergoing a recent surgery
  • Use of oral contraceptives or other estrogen treatments
  • Pregnancy
  • Obesity
  • Sitting in a window seat if this prevents getting up and moving around

"Most people really don't need to worry too much about this complication," Crowther tells WebMD. "Blood clots after airline travel are extremely rare, even in people with these risk factors."

ACCP Calls for Daily Aspirin After 50

The revised ACCP guidelines include more than 600 recommendations for the prevention, diagnosis, and treatment of deep vein blood clots.

One change calls for daily low-dose aspirin use (75-100 milligrams daily) starting at age 50, even in people without a history of heart attacks or other major risk factors for heart disease.

Daily aspirin therapy is associated with an increased risk for gastrointestinal bleeding, and the recommendation does not apply to people with ulcers or other conditions linked to such bleeds, Crowther says.

He says there is increasing evidence linking daily low-dose aspirin use to a lower risk of death from both heart and non-heart-related causes.

The American Heart Association (AHA) recommends daily aspirin therapy for people who have had heart attacks, noting that everyone else should talk to their doctor about the risks and benefits of such treatment before taking a low-dose aspirin every day.

"Aspirin therapy is reasonable for the prevention of [heart] disease, but it is important to weigh this benefit against the potential bleeding risk," says Duke University Medical Center professor of medicine Richard Becker, MD, who is also an AHA spokesman. "Careful assessment of risk has to include the use of other medications that can increase bleeding risk, and that can only be accomplished by talking to your doctor."

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SOURCES: Guyatte, G.H. Chest, February 2012.Mark Crowther, MD, department of medicine, McMaster University, Hamilton, Canada.Richard Becker, MD, professor of medicine, Duke University School of Medicine; spokesman, American Heart Association.News release, American College of Chest Physicians.

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