The best-known case of DVT related to air travel was that of the late former President Richard M. Nixon who had suffered a DVT of his left leg in 1965. In 1974, during a long trip to Europe, the Middle East, and the Soviet Union, he developed swelling and pain in the left leg. His personal physician diagnosed a DVT and started anticoagulation therapy. He also informed the President about the risk of fatal PE, but despite these warnings, the President continued the trip, experiencing recurrent symptoms in Egypt and the Soviet Union. After his resignation in August 1974, Mr. Nixon experienced several serious recurrences of swelling in the leg and episodes of PE. Hospitalization for treatment prevented him from testifying at the Watergate trial. Despite anticoagulation therapy, the thrombus extended into the iliac vein, causing severe swelling of the leg. Surgical ligation of the iliac vein resulted in bleeding complications and shock. Mr. Nixon's condition was serious for several days before he was able to make a full recovery.
Today, it is well recognized that prolonged quiet sitting, especially during prolonged air travel, carries a risk of VTE. Although healthy passengers seem to be at very little risk, even during long flights, passengers with associated risk factors for thromboembolism seem to have a considerable risk.