The cause of this high blood pressure is the breaking of valves inside the veins of the legs and pelvis.
All veins have many one-way valves. They are the reason that blood can make its way uphill from our feet to our heart. When we are standing on our feet, we flatten the veins in our feet, forcing the blood upward through these one-way valves into the calf muscle. As we take a step, our calf muscles flex, flattening the veins inside, and again propel the blood upward. The calf pump is an important adjunct to the heart for pumping blood upward. In time the blood climbs the “ladder” of these valves, making its way to the heart.
In roughly 25% of the population, these valves break over time. This typically begins with the legs. When standing gravity exerts a downward pull on the blood inside the veins. One by one, as the valves break, the pressure on the next valve below it increases. Eventually, with most or all of the valves breaking inside the veins, the pressure rises to very high levels. This is called “venous hypertension.”
When venous hypertension occurs, the pressure in branch veins connected to the larger veins also begins to rise and their valves break in a cascading fashion. If these branches bulge through the skin in a bumpy or rope-like fashion, they are considered varicose veins.
So you see, varicose veins are a sign of a more serious condition—chronic venous hypertension (CVH).