Chronic venous insufficiency has a high prevalence Chronic venous insufficiency is caused by venous valve dysfunction, deep venous lesions, and lower extremity venous hypertension due to reduced calf muscle pump function, which ultimately leads to a range of clinical symptoms. The prevalence of chronic venous insufficiency is high, with statistics ranging from about 3 to 8% depending on the region and population. 27% of Americans have more or less clinical manifestations of chronic venous insufficiency. Venous stasis ulcers (old feet) are the most serious and impactful clinical manifestation of chronic venous insufficiency, with European studies showing that approximately 1.5% of adults will develop lower extremity stasis ulcers (“old feet”) in their lifetime. A study of 259 patients with lower extremity ulcers by vascular surgeons found that 57% of the ulcers were caused by chronic venous insufficiency. Specific pathogenesis In the human lower extremity, the venous system mainly consists of deep veins, traffic veins and superficial veins. If we take a highway as an analogy, the deep vein is equivalent to the “motorway”, most of the blood flow is returned through the deep vein; while the superficial vein is the “bicycle lane”, the blood flow is not large; the traffic vein is the path on the isolation belt, connecting the deep vein and superficial vein, the blood flow is also small. The traffic veins are small paths in the isolation zone, connecting the deep and superficial veins, and the blood flow is also small. In an adult, the total length of veins is 160 km. The main function of the veins of the lower extremities is to carry blood back to the heart. However, due to gravity and upright walking, a large amount of venous blood is retained in the lower extremities, so the human body has several specific structures to correct this tendency, mainly venous valves and calf muscle pumps. The venous valves can be thought of as one-way valves in a pipe, which open to allow blood flow through as it flows from the bottom up back to the heart, and close to stop the accumulation of blood in the lower extremities once the blood flows backwards toward the soles of the feet. The calf muscle pump means that the major veins of the calf (deep veins) are located in the calf muscle group, and when the calf muscle contracts, there is a compression effect on the deep veins of the calf, which drives the blood in the deep veins toward the heart (this is why athletes cannot rest immediately after exercise, but continue to walk and move their calves). Every day, about 7000 liters of blood flow back to the heart through the veins of the lower extremities, what a tremendous amount of work! In some cases (e.g. congenital dysplasia, dilated vein walls, pregnancy, prolonged weight bearing, etc.), the venous valves can become insufficiently closed, when the valves are unable to completely stop the backflow of blood from the veins, causing blood to pool in the lower extremities. Likewise, if there are obstructions such as thrombosis in the deep veins that prevent blood from flowing back smoothly, or if the calf muscles have reduced pump function and are unable to squeeze the veins effectively, this can also lead to massive blood stagnation in the lower extremities, resulting in a series of manifestations of venous hypertension in the lower extremities. Varicose veins are the most common clinical manifestation The clinical manifestations of chronic venous insufficiency can be divided into: capillary dilation, varicose veins, limb edema, dystrophic skin lesions (skin darkening, bruising dermatitis, eczema, etc.), and ulcers (“old rotten feet”) according to the progression of the disease. Varicose veins are the most common clinical manifestation, while the presence of dystrophic skin lesions and ulcers means that the disease has entered a severe stage. Patients may feel discomfort such as soreness and swelling of the lower extremities and even walking disorders (venous claudication) and itching of the skin. Chronic venous insufficiency may be accompanied by bleeding, thrombotic superficial phlebitis or even deep vein thrombosis of the lower limbs. The bleeding is due to the thin wall of the diseased vein, combined with skin malnutrition, so it is easy to bleed after encountering external friction or injury, this bleeding is terrible and often not felt, the patient only feels hot on the legs or in the blanket. Thrombotic superficial phlebitis and deep vein thrombosis of the lower extremities are due to the formation of blood clots in the superficial and deep venous system due to slow blood flow in the varicose veins.