This occurs when veins weaken and lose their ability to conduct blood effectively6.
With the onset of vein disease, veins become dilated and the venous valves, responsible for the blood-flow to the heart, no longer close properly. In many cases the venous valves remain open and the blood accumulates in the dilated vein. As a result, the blood flows back into the vein and pools in the leg tissue, causing swelling.6
Through the increased pressure, the veins become permeable and the fluid passes out into the surrounding tissue. This results in the accumulation of fluid, so called oedema. The increased amount of fluid in the tissues of the legs causes pain and swelling and this can cause further damage to the veins.6