US Vice President Dick Cheney is being treated for deep vein thrombosis in his left leg which could have been fatal if left undiscovered.

It comes after here turned last week from about 65 hours spent on a plane during a nine-day, round-the-world trip.

The 66-year-old visited his doctor after feeling pain in his calf and an ultrasound showed a blood clot or deep vein thrombosis (DVT).

Cheney, who has a history of heart problems, will be treated with blood-thinning medication for several months.

Blood clots can kill if they break loose and lodge in the lungs.

Long-haul travel, recent surgey or other periods of inaction as well as taking birth control pills can increase the risk of blood clots.