When venous disease is long standing, it can become chronic venous insufficiency (CVI). CVI occurs from chronic pooling and congestion caused by leaky varicose veins, from chronic obstruction in veins due to repeated clots (thrombosis), or from repeated inflammation of the veins (phlebitis). As this condition worsens and become severe, skin changes and leg ulcerations can occur. Treatment is aimed at relieving the swelling in the legs. This can be achieved with compression stockings or with endovenous laser or radiofrequency ablation.