South Georgia Vein Center: Treatment of CVI.

Causes of chronic venous insufficiency.

The Causes of Varicose and Spider Veins

All spider and varicose vein problems arise because of leaky valves or other deficiencies within the veins. We call this condition chronic venous insufficiency (CVI).

Valves are very thin, two-leaflet structures that allow blood to flow in only one direction. A healthy valve, as shown on the right, permits blood to flow up your legs, but not down. When everything is working properly, the pumping action of your muscles will steadily and efficiently push a steady flow of blood upward through your veins and back to your heart.

However, if the valves in your veins become defective as depicted in the second illustration (left), blood will begin to flow in the wrong direction (downward).

An insufficient, or incompetent, vein valve (on the left) and a healthy valve.

Due to the force of gravity, it will tend to accumulate, or pool, in your lower legs and feet under ever-increasing pressure.

Over time, this pressurized pooling will cause the walls of your veins to become weaker and thinner.

It’s not uncommon for them to become inflamed or enlarged (dilated), to bulge out (a symptom of varicose veins, in particular), and to develop scar tissue.

Since veins have sensory nerve fibers, this can result in considerable discomfort, especially after prolonged periods of sitting or standing. It can also dramatically increase the risk of blood clots, which are a major hazard to health and life.