A sclerosant is injected into the selected vein using a fine needle. The medicine acts on the inner lining of the vessel, producing a controlled inflammatory response that makes the walls stick together and the vein close. Blood then returns through other healthy veins.
The closed vessel is gradually converted into fibrous tissue and broken down by the body, so fading takes time. Liquid sclerosant is commonly used for small surface vessels, while foam can displace blood and remain in contact with the wall of a larger vein; foam treatment is often guided by ultrasound. The formulation and concentration are selected according to the vein and the patient.
