Varicose Veins: Enlarged and tortuous VEINS.Saphenous Vein: The vein which drains the foot and leg.Veins: The vessels carrying blood away from the capillary beds.Sclerotherapy: Treatment of varicose veins, hemorrhoids, gastric and esophageal varices, and peptic ulcer hemorrhage by injection or infusion of chemical agents which cause localized thrombosis and eventual fibrosis and obliteration of the vessels.Venous Insufficiency: Impaired venous blood flow or venous return (venous stasis), usually caused by inadequate venous valves. Venous insufficiency often occurs in the legs, and is associated with EDEMA and sometimes with VENOUS STASIS ULCERS at the ankle.Femoral Vein: The vein accompanying the femoral artery in the same sheath; it is a continuation of the popliteal vein and becomes the external iliac vein.Ultrasonography, Doppler, Duplex: Ultrasonography applying the Doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the Doppler shift frequency.Sclerosing Solutions: Chemical agents injected into blood vessels and lymphatic sinuses to shrink or cause localized THROMBOSIS; FIBROSIS, and obliteration of the vessels. This treatment is applied in a number of conditions such as VARICOSE VEINS; HEMORRHOIDS; GASTRIC VARICES; ESOPHAGEAL VARICES; PEPTIC ULCER HEMORRHAGE.Popliteal Vein: The vein formed by the union of the anterior and posterior tibial veins; it courses through the popliteal space and becomes the femoral vein.Vascular Surgical Procedures: Operative procedures for the treatment of vascular disorders.Laser Therapy: The use of photothermal effects of LASERS to coagulate, incise, vaporize, resect, dissect, or resurface tissue.Stockings, Compression: Tight coverings for the foot and leg that are worn to aid circulation in the legs, and prevent the formation of EDEMA and DEEP VEIN THROMBOSIS. PNEUMATIC COMPRESSION STOCKINGS serve a similar purpose especially for bedridden patients, and following surgery.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Sodium Tetradecyl Sulfate: An anionic surface-active agent used for its wetting properties in industry and used in medicine as an irritant and sclerosing agent for hemorrhoids and varicose veins.Compression Bandages: Strips of elastic material used to apply pressure to body parts to control EDEMA and aid circulation.Varicose Ulcer: Skin breakdown or ulceration caused by VARICOSE VEINS in which there is too much hydrostatic pressure in the superficial venous system of the leg. Venous hypertension leads to increased pressure in the capillary bed, transudation of fluid and proteins into the interstitial space, altering blood flow and supply of nutrients to the skin and subcutaneous tissues, and eventual ulceration.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Jugular Veins: Veins in the neck which drain the brain, face, and neck into the brachiocephalic or subclavian veins.Ultrasonography, Doppler, Color: Ultrasonography applying the Doppler effect, with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography is well-suited to identifying the location of high-velocity flow (such as in a stenosis) or of mapping the extent of flow in a certain region.Venous Valves: Flaps within the VEINS that allow the blood to flow only in one direction. They are usually in the medium size veins that carry blood to the heart against gravity.Venous Pressure: The blood pressure in the VEINS. It is usually measured to assess the filling PRESSURE to the HEART VENTRICLE.Photoplethysmography: Plethysmographic determination in which the intensity of light reflected from the skin surface and the red cells below is measured to determine the blood volume of the respective area. There are two types, transmission and reflectance.Leg: The inferior part of the lower extremity between the KNEE and the ANKLE.Klippel-Trenaunay-Weber Syndrome: A congenital disorder that is characterized by a triad of capillary malformations (HEMANGIOMA), venous malformations (ARTERIOVENOUS FISTULA), and soft tissue or bony hypertrophy of the limb. This syndrome is caused by mutations in the VG5Q gene which encodes a strong angiogenesis stimulator.Groin: The external junctural region between the lower part of the abdomen and the thigh.Ligation: Application of a ligature to tie a vessel or strangulate a part.Tourniquets: Devices for the compression of a blood vessel by application around an extremity to control the circulation and prevent the flow of blood to or from the distal area. (From Dorland, 28th ed)Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Transillumination: Passage of light through body tissues or cavities for examination of internal structures.Recurrence: The return of a sign, symptom, or disease after a remission.Plethysmography: Recording of change in the size of a part as modified by the circulation in it.Mesenteric Veins: Veins which return blood from the intestines; the inferior mesenteric vein empties into the splenic vein, the superior mesenteric vein joins the splenic vein to form the portal vein.Renal Veins: Short thick veins which return blood from the kidneys to the vena cava.Umbilical Veins: Venous vessels in the umbilical cord. They carry oxygenated, nutrient-rich blood from the mother to the FETUS via the PLACENTA. In humans, there is normally one umbilical vein.Iliac Vein: A vein on either side of the body which is formed by the union of the external and internal iliac veins and passes upward to join with its fellow of the opposite side to form the inferior vena cava.Thrombophlebitis: Inflammation of a vein associated with a blood clot (THROMBUS).Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Angioplasty, Laser: A technique utilizing a laser coupled to a catheter which is used in the dilatation of occluded blood vessels. This includes laser thermal angioplasty where the laser energy heats up a metal tip, and direct laser angioplasty where the laser energy directly ablates the occlusion. One form of the latter approach uses an EXCIMER LASER which creates microscopically precise cuts without thermal injury. When laser angioplasty is performed in combination with balloon angioplasty it is called laser-assisted balloon angioplasty (ANGIOPLASTY, BALLOON, LASER-ASSISTED).Lower Extremity: The region of the lower limb in animals, extending from the gluteal region to the FOOT, and including the BUTTOCKS; HIP; and LEG.Bandages: Material used for wrapping or binding any part of the body.Ambulatory Surgical Procedures: Surgery performed on an outpatient basis. It may be hospital-based or performed in an office or surgicenter.Hemorrhoids: Swollen veins in the lower part of the RECTUM or ANUS. Hemorrhoids can be inside the anus (internal), under the skin around the anus (external), or protruding from inside to outside of the anus. People with hemorrhoids may or may not exhibit symptoms which include bleeding, itching, and pain.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Hepatic Veins: Veins which drain the liver.Contusions: Injuries resulting in hemorrhage, usually manifested in the skin.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Clothing: Fabric or other material used to cover the body.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Peroneal Neuropathies: Disease involving the common PERONEAL NERVE or its branches, the deep and superficial peroneal nerves. Lesions of the deep peroneal nerve are associated with PARALYSIS of dorsiflexion of the ankle and toes and loss of sensation from the web space between the first and second toe. Lesions of the superficial peroneal nerve result in weakness or paralysis of the peroneal muscles (which evert the foot) and loss of sensation over the dorsal and lateral surface of the leg. Traumatic injury to the common peroneal nerve near the head of the FIBULA is a relatively common cause of this condition. (From Joynt, Clinical Neurology, 1995, Ch51, p31)Subclavian Vein: The continuation of the axillary vein which follows the subclavian artery and then joins the internal jugular vein to form the brachiocephalic vein.Telangiectasis: Permanent dilation of preexisting blood vessels (CAPILLARIES; ARTERIOLES; VENULES) creating small focal red lesions, most commonly in the skin or mucous membranes. It is characterized by the prominence of skin blood vessels, such as vascular spiders.Catheter Ablation: Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.Splenic Vein: Vein formed by the union (at the hilus of the spleen) of several small veins from the stomach, pancreas, spleen and mesentery.Cerebral Veins: Veins draining the cerebrum.