Histology of saphenous veins after treatment with the ClariVein® device - an ex-vivo experiment

Background: Endovenous treatment modalities are used increasingly to treat varicose veins. The ClariVein((R)) catheter is a new endoluminal mechanico-chemical obliteration technique which can be used without tumescent anesthesia. It is still unclear what changes the mechanical tip of the catheter has on the walls of the vein. Patients and methods: Five great saphenous vein specimens were obtained atraumatically by crossectomy. Then the veins were treated ex vivo with the ClariVein((R)) catheter without sclerotherapy. The activated catheter rotating tip (3 500 U/min) was steadily withdrawn at 1-2 mm per second. Subsequently, histological and immunohistochemical investigations of treated (cv) and untreated specimens (plain) were performed. A 4-point score was calculated to compare the results. Results: The mechanical part of the catheter caused a subtle incomplete destruction of the endothelium (endothelium cv: 2.2 vs. plain: 1, p = 0.04). Changes in the media or adventitia were not seen. Immunohistochemical presentation of the endothelium of the intima was demonstrated with antibodies against CD31 (cv: 3.4 vs. plain: 2.8), CD34 (cv: 3.8 vs. plain: 3.2) and factor VIII (cv: 2.2 vs. plain: 1, p = 0,004). Conclusions: The mechanical part of the ClariVein((R)) catheter caused a subtle incomplete destruction of endothelium, which was confirmed histologically and immunohistochemically. The reduced expression of factor VIII in the treated vein could be caused by the release of preformed factor VIII granules due to the minimal mechanical irritation.