Risk factors for blood clots identified

Reported by Susan Aldridge, PhD, medical journalist

Prolonged immobility on a flight, especially just before surgery, is a risk factor for deep vein thrombosis.
There is increased interest in the issue of deep vein thrombosis (DVT) which can affect people when they are on a long distance flight. A clot forms in the leg which may break off and travel to the lungs, where it can have a potentially fatal effect.

Doctors at the Mayo Clinic have been investigating this problem since a 37-year old man traveling nearly 5,000 miles prior to surgery died from a pulmonary embolism (blood clot on the lungs). They analyzed patient information and found that of 181, 765 patients undergoing operations at the Mayo Clinic between 1998 and 2002, a total of 3,736 lived outside the USA, Canada and Mexico and travelled more than 5,000 miles prior to surgery.

These long-haul travelers had over 30 times higher incidence of blood clots within 28 days of surgery compared to those who did not travel or who traveled within North America. Although travelers and airlines are now very aware of the dangers of DVT, it may be that special measures are needed for those traveling to have surgery. Immobilisation during the flight is a particular risk factor in such cases, so people should move around more. It may also be possible for them to take medication prior to the flight to reduce the risk of a blood clot.

Source
Mayo Clinic Proceedings 31st May 2005