Written by Dallas Vein Specialists on February 6, 2011
Since the 1990’s much has been written about the so-called “traveler’s thrombosis”, the development of clots in the veins of the legs in patients who have recently traveled and been relatively motionless for extended periods of time. It has been called “economy class syndrome” and “coach class syndrome”; however, other travelers who fly first class or spend hours in automobiles or trains are also at risk for this potentially dangerous condition.
When the clots involve the deep veins of the leg, so-called “deep vein thrombosis” or DVT, the condition is potentially life-threatening. If the clot extends, breaks off, and travels in the bloodstream to the heart and lung (acute pulmonary embolism), obstruction of blood flow occurs resulting in lung damage and even death. One may recall the case of 39 year-old NBC reporter David Bloom, who in 2003 died suddenly in Iraq after confining himself to long hours of travel in a military vehicle. In fact the association of prolonged inactivity in cramped conditions was first made in England during World War II when people slept in deck chairs in air raid shelters and suffered fatal acute pulmonary embolisms.
DVT and its complications can occur with any prolonged immobility such as being bedridden after surgery or a prolonged illness when the blood flow in the veins of the leg is slowed or restricted. Other conditions that are associated with DVT include obesity, pregnancy, cancer, and inherited clotting disorders.
Who is at greatest risk for Traveler’s Thrombosis?
Studies have shown than the risk of clots with air travel is related to the duration of the flight. The longer the flight the greater is the risk. For flights less than 4 hours the risk is slight, but for flights more than 8 hours the risk in one large study was development of leg deep vein clots in 1 of every 200 passengers. The rate of severe pulmonary embolism, a clot traveling to the lung, is rare for flights less than 8 hours but increases with longer duration flights.
Travel-related thrombosis is higher in persons with pre-existing risk factors for the development of deep vein thrombosis. These factors include recent surgery within 1 month, active cancer, prior unprovoked deep vein clotting, inherited predisposition to blood clots within veins, and prior travel-related clotting events. Pregnancy and obesity could be added to this list of risk factors as well.
Preventing Traveler’s Thrombosis
Since immobility and confinement to cramped quarters for long durations is the common denominator of traveler’s thrombosis, common sense would dictate that movement, especially walking about with some frequency, would lessen the risk. Interestingly, children are not at risk for traveler’s thrombosis, because they are so active. When walking is not easily accomplished, sessions of repeated leg calf tensing exercises serve to compress and empty the deep veins that course within the muscles. Avoidance of excessive alcohol intake and taking adequate water and fluids has been advocated. For some who have had bouts of traveler’ thrombosis and who are to experience a long flight, a single dose of heparin anticoagulant just prior to the trip may be advisable. In preventing clot formation in the veins there is little benefit in taking aspirin or Plavix (clopidogrel bisulfate).
Perhaps the easiest and best preventive measure one can take is wearing a good (prescription grade) pair of compression stockings. These are fitted to measure and are “graduated”, meaning that the compression is highest at the foot and ankle and less as the stocking goes up the leg. Thus the pressure gradient promotes the normal flow and emptying of the blood within the veins of the leg. This below knee hosiery is relatively inexpensive and with good care and occasional use will last for years. For any flight or journey lasting for more than 3 hours compression hose should be a regular part of the traveler’s dress.
Knowledge and understanding of the condition called “traveler’s thrombosis” and measures to help prevent it will promote better health among the traveling public. Certainly any person who develops leg or calf swelling, tenderness, or pain or has shortness of breath or chest pain after a prolonged journey should seek immediate medical attention.