High hydrostatic pressure is the cause of increased varicose veins and all complications. Depending on the size of the blood pressure column, dilation of the veins and progressive worsening occur. An interesting parallel would be a waterfall, the higher and more unimpeded the force of water on the ground. The muscles of the leg and thigh and the venous valves naturally fractionate the pressure. When these factors are changed the venous disease progresses.
After CHIVA, hydrostatic pressure column fractionation reduced veins and symptoms. It would be as if the waterfall had natural barriers for falling water.