President Donald Trump has been diagnosed with chronic venous insufficiency, the White House announced on Thursday. Here's what to know about the condition.

A recent medical checkup of President Donald Trump revealed that mild swelling he had noticed in his lower legs was “chronic venous insufficiency,” a common medical condition among the elderly. CVI, as it’s abbreviated, is due to pooling of blood in the veins.

Chronic Venous Insufficiency (CVI) is a long-term medical condition in which the veins in the legs are unable to efficiently return blood back to the heart. This occurs when the valves in the leg veins - which normally keep blood flowing upward - become damaged or weakened, causing blood to pool in the lower limbs.