Sclerotherapy is a medical procedure that treats problematic veins, such as varicose and spider veins. It involves injecting a chemical solution directly into the affected vein to close it, causing it to fade from view. This improves both appearance and associated symptoms.
Common Sclerosing Agents
Sclerotherapy primarily uses chemical solutions called sclerosing agents to close veins. Two of the most frequently used are Polidocanol and Sodium Tetradecyl Sulfate (STS).
Polidocanol is a detergent-based sclerosant available in various concentrations. It is often chosen for treating smaller spider and reticular veins, typically ranging from 1 to 3 mm in diameter. It is considered gentler and may cause less pain during injection.
Sodium Tetradecyl Sulfate (STS) is another widely used detergent-based agent. It is available in different concentrations, such as 1% or 3%, with higher concentrations often used for larger varicose veins. STS is effective in causing significant damage to the vein lining.
Glycerin is a less common osmotic agent, often used at a 72% concentration for very small veins. It irritates the inner lining of blood vessels, leading to their collapse. Glycerin is particularly effective for spider veins measuring between 0.2 to 0.4 mm in diameter and often has a lower incidence of side effects like hyperpigmentation.
How Sclerosing Solutions Work
Sclerosing solutions work by irritating and damaging the inner lining of the targeted vein, known as the endothelium. Detergent-based sclerosants like Polidocanol and STS disrupt the cell membranes of endothelial cells through protein denaturation, triggering an inflammatory response within the vein.
Following this initial damage, platelets aggregate at the site, attaching to the vein wall. This leads to the formation of a thrombus, or blood clot, which occludes the vessel and prevents blood flow. Over time, the damaged vein undergoes fibrosis, where it is replaced by fibrous connective tissue and is gradually reabsorbed by the body.
Osmotic agents, such as glycerin, work by drawing water out of endothelial cells, causing them to dehydrate and damage. While both detergent and osmotic agents aim to induce irreversible endothelial injury, detergents generally exert a more profound and widespread damaging effect on the vein wall. The aim is to permanently close the vein without affecting surrounding healthy tissues.
Selecting the Right Solution
Medical professionals consider several factors when choosing a sclerosing solution. The size and type of vein are primary considerations, as different agents and concentrations suit various vein diameters. For instance, smaller spider veins might be treated with lower concentrations of Polidocanol or Glycerin, while larger varicose veins may require STS or higher concentrations of Polidocanol.
The solution can also be prepared as a liquid or a foam, which influences its application. Foam sclerotherapy, created by mixing the liquid sclerosant with air or a physiological gas, is often favored for larger veins because it can displace blood more effectively and increase contact time with the vein wall. This foaming can make the sclerosant more potent for a given concentration and volume. Patient history, including potential allergies, also guides the selection process, and the physician’s experience with a particular agent plays a role in achieving the best results.
Safety Profile of Sclerosing Agents
Sclerosing agents generally have a favorable safety profile when administered by a qualified professional, though some side effects can occur. Common, temporary reactions at the injection site include bruising, swelling, tenderness, or mild pain and cramping. Skin discoloration, known as hyperpigmentation, can also occur along the treated vein, which is usually temporary but may persist for several months.
Rarer, more serious complications are infrequent. Allergic reactions to the sclerosant, though uncommon, can manifest as hives, swelling, or difficulty breathing, and medical staff are prepared to manage these. Skin ulceration or tissue necrosis at the injection site can occur if the solution extravasates, meaning it leaks outside the vein. Temporary visual disturbances or neurological symptoms, such as headaches or migraines, have been reported, especially with foam sclerotherapy, but serious events like deep vein thrombosis or pulmonary embolism are rare.