We learn that constant high pressure pushing out against the delicate vein walls can stretch the veins out of shape. When that happens the one-way valves do not close well, so blood can go backwards and high pressure can build up. It's called chronic venous insufficiency, or chronic ambulatory venous hypertension. We learn that high pressure and damaged veins and valves can happen for many reasons. Often it's a blood clot, called deep vein thrombosis, that causes the damage to the valves and veins.
Pregnancy can be a factor, too.
The hostess explains that many times, the first sign of high venous pressure in the legs is persistent swelling near the ankles, usually at the end of the day. This is called edema. Varicose veins are a visible sign of increased pressure and damaged veins. Standing may cause a dull aching pain that goes away when the legs are raised. Next we see how a venous leg ulcer can get started.