Injection sclerotherapy causes damage to the endothelium within an injected vein. Endothelial destruction in the injected section of the vein results in the exposure of sub-endothelial collagen fibres in the vein wall and the vein goes into spasm. The response to the damage is the initiation of the coagulation pathways and the subsequent formation of a 'sclerothrombus' occludes the vein.
The 'sclerothrombus' is very hard and firmly attached to the vein wall, unlike a soft thrombus, the strongest fixation occurs where the entire endothelium has been destroyed. Over time fibroblasts from the vein wall infiltrate the sclerothrombus and it is re-organised. Eventually the vein and sclerothrombus form a thin fibrous cord and the vein is obliterated.
Compression after the injection is important to keep the sclerothrombus to an absolute minimum while the vein is in spasm. Keeping the sclerothrombus to a minimum helps to reduce complications such as pigmentation and thrombophlebitis.
In practice it is difficult to fully compress some veins, particularly the larger truncal veins but the use of stockings and local eccentric compression over the injection site using pads certainly helps. Local eccentric compression can be applied by using a foam pad between a bandage and stocking.
For more information on compression please visit fibrovein.co.uk.