Mechanochemical endovenous ablation and new frontiers in venous intervention

Abstract

Venous insufficiency of the lower extremities is a common condition and related to various symptoms, including venous ulcers. The effect of venous insufficiency on patients’ health-related quality of life is substantial and comparable with other chronic diseases such as arthritis, diabetes, and cardiovascular disease. Superficial venous reflux, to a greater or lesser extent, will develop in approximately 40% of women and 20% of men during their lifetime. Until the 1990s, high ligation combined with surgical stripping was the gold standard in the treatment of venous insufficiency. Since then, new endothermal techniques, as endovenous laser or radiofrequency ablation, have revolutionized the standard of care, due to their excellent results. To minimize damage of surrounding tissue, tumescent anaesthesia is necessary in these techniques. Nonetheless, heat-related complications, such as prolonged pain or nerve injury, may still occur. Mechanochemical endovenous ablation (MOCA) is a innovative technique, combining mechanical abrasion of the endothelium with simultaneous infusion of sclerosant. Because MOCA is a non-thermal technique, the need for tumescence and heat-related complications are abolished. The first part of this thesis is dedicated to studying MOCA. A general overview on MOCA is provided including results of a systematic review of literature. The first results of MOCA in the great (30) and small (50) saphenous veins are evaluated and showed that MOCA is feasible, safe and effective. MOCA treatment leads to excellent short term anatomical and clinical success rates. Partial or complete recanalization might occur in around 10% of cases. A study in 68 patients treated with MOCA (34) or RFA (34), showed that MOCA is associated with significantly less postoperative pain. Early quality of life scores improved in both groups. Due to the anatomical proximity of the sural nerve the treatment of small saphenous veins (SSVs) is known for an increased change of nerve injury. A systematic review and meta-analysis on the treatment of SSVs showed that endothermal ablation leads to the best anatomical success rates. The risk of nerve injury is significant. Although the MOCA technique theoretically should minimize the risk for major complications, the available data was not sufficient to draw conclusions on the role of MOCA in SSV. A protocol for a RCT studying MOCA in SSV compared to endothermal ablation is included in this thesis. The second part of the thesis contains 3 studies on innovations in venous intervention. The first reports on the results of laser ablation in insufficient perforator veins, showing it to be feasible and safe. The anatomical success rate is highly dependable on the amount of energy delivered. The second evaluated a new percutaneous venous closure device, to place a keyring-shape implant around the target vein. Although results are promising, future developments regarding sizing, applications of biomaterials and increasing accuracy in positioning are essential. The final study describes a new deep venous valve concept. Whereas previous valve designs were hampered with thrombotic occlusion, the current single, "spinnaker-shaped" leaflet functioned well and remained patent in a short-term animal experiment. Future studies regarding optimizing leaflet material or coating are on-going.