For those planning a trip, there can be plenty of things to worry about: airport security, the cost of travel and flight delays. It can also be a health hazard for some people who are at risk of getting blood clots.

Deep vein thrombosis (DVT) is the term for a deep blood clot, usually in the leg. Patients may have no symptoms at all, or they can get pain, swelling, redness or warmth along the affected vein. A blood clot is easily treatable, but it requires immediate attention since a piece can break off and travel to the lungs.

Dr. Deepak Nair, chief of vascular surgery at Sarasota Memorial Hospital in Florida and a member of the Society for Vascular Surgery, answered some common questions about this syndrome.

Is deep vein thrombosis really related to travel or is it mostly because the patient is not moving? Is travel more dangerous than working at a desk all day long?

“Inactivity for four hours or more may contribute to DVT. Long journeys that offer few options to move pose an increased risk. The risk of DVT doubles after four hours or more of travel, but the absolute risk is still only about 1 in 6,000. That’s because DVT occurs when there is a perfect storm of other risk factors.”

What are those risk factors?

“Injury to any blood vessel releases chemicals that promote clotting. Recent surgery, a recent IV (intravenous line), or injuries such as a sprained ankle or blunt trauma, all increase the risk of deep venous thrombosis. The longer one waits between these injuries and travel, the less the chance of DVT.”

There are reports that people can get DVT from traveling even days after their trip. Why is that?

“There likely isn’t a time lag. The clot may have already been there during travel and it just grew or matured and then caused symptoms afterwards. However, one study found that the risk of blood clot complications remains elevated for up to four weeks after a flight.”

Why is a clot in the leg life-threatening?

“A DVT can be life-threatening if it travels to the lungs and gets stuck in a major blood vessel which then limits blood flow to one or both lungs. This puts a major strain on the heart as well.”

If I am treated with blood thinners, am I still in danger during this treatment time? How long would I have to be on them?

“If the blood thinners are working, then the risk of another blood clot or worsening of the current one is very low. Your physician will determine the length of treatment based on your particular situation.”

What if I am at higher risk? I still want to travel.

“During a trip, try some seated leg and foot exercises like ankle circles, leg lifts and calf stretches. This encourages blood flow and reduces blood stagnation. Wear loose clothing so that blood flow is not constricted. As your doctor if compression stockings will help.”

Society for Vascular Surgery
vascular.org