Endovenous treatment for varicose veins of the lower limbs: Comparative histological evaluation of different techniques.

Background: In recent years, tumescent ablative techniques have been joined by non-tumescent ablative techniques. The aim of the research is to study and compare the effects produced by the different endovascular ablative techniques, from the histological point of view, at the level of the venous wall (endothelium, tunica media and adventitia).

Method: The study involves the use of three ablative endovascular techniques (EVLA, MOCA, CGO) on bench for the treatment of the great saphenous vein. The bench procedure was performed in the same way as described in the instructions for use (IFU) of the technical specifications. Tissue samples were formalin-fixed and paraffin-embedded (FFPE). They were stained with hematoxylin and eosin and, in a case, with anti-ERG antibody (MA5-26,245, Termo Fisher).

Result: No perivascular tissue was present. No hematoma or perforation of the vein wall was observed. Histopathological changes after EVLA indicated that the intima including the endothelium and sub-endothelium was completely necrotized. It was observed that the thermal-energy-induced injury in the intima did not reach deeper than the media. Overview shows that in this case the damage is homogenously spread along the entire perimeter. The most evident change in the sample treated with mechanical-chemical ablation (MOCA) technique was the endothelial damage with loss of endothelial cells. Specifically, with the ERG immunostaining it was possible to observe the presence of numerous nuclei exposed towards the lumen of the vein. In the sample treated with cyanoacrylate (CGO), no significant structural alterations were observed. However, an almost complete collapse of the endoluminal walls and the presence of cyanoacrylate residues were observed.

Conclusion: Different histological patterns characterize the individual treatments. However, all techniques have a common feature: the damage is not transmural and the three different layers of the venous walls are always recognizable.