The foreign guy from the Nets had the same thing.
Clots & Travel
Blood clots can sometimes form in your legs during air travel because you are immobile for long periods of time, often sitting in cramped spaces with little leg room. While commonly referred to as "economy class syndrome," the clinical term for this type of blood clot is deep vein thrombosis (DVT). The longer the flight, the more at risk you are for developing a clot. Flights lasting 8-10 hours or longer pose the greatest risk.
In some cases, the DVT will dissolve and go away on its own. However, in more serious cases, it can cause pain, swelling and warmth of the affected leg. Or it can break off and travel to the blood vessels of your lungs, causing pulmonary embolism (PE).
DVT and PE, collectively known as venous thromboembolism, are highly preventable (see prevention tips below). The U.S. Surgeon General has issued a Call to Action on DVT and PE to raise public awareness of these blood conditions and increase research on the causes, prevention, and treatment.
There are several symptoms that can be warning signs of blood clots, including the following:
Swelling of the leg, ankle, or calf
Redness or discoloration
Increased warmth over the skin