Optimisation of minimally invasive therapy for primary varicose veins

Introduction: Primary varicose veins are common with a multitude of non-optimal treatments. Foam sclerotherapy has seen renewed interest but lacks efficacy versus more expensive modalities. The hypothesis of this thesis is that increasing the half-life of foams will improve efficacy as will mechanical adjuncts.

Methods: The most efficacious proprietary sclerosants are examined in terms of their foam half-life and histopathological effects in-vitro. The best proprietary foam has its half-life increased and histopathological effects of the three most promising resultant foams similarly assessed. Arterial cutting balloons are assessed as an adjunct for foam sclerotherapy in the same in-vitro human GSV model. The best foams are tested against each other and with cutting balloon adjuncts in an animal vein model with results established after three months.

Results: half-life of 3% polidocanol foam is longer than 3% STD. 3% STD damages the vein wall more than polidocanol. Longer lasting STD foams do not enhance its activity against vein wall in-vitro. Cutting balloons increase depth of penetration of foam into vein wall by affording it a deeper starting point in-vitro. Cutting balloons damage the structure of the vein wall leaving them varicose in-vivo. This is likely due to available cutting balloons being too large for tested pig veins. Longer lasting 0.15% xanthum and 3% STD foam outperformed proprietary 3% STD in causing vein occlusion in a pig model.

Conclusions: The active ingredient in sclerosant foams determine its efficacy in-vitro more so than the longevity of the foam however longer lasting 3% STD foam shows improved efficacy in-vivo in pigs as opposed to in an in-vitro human GSV model. Cutting balloons though promising in-vitro as adjuncts to foam sclerotherapy are likely best used as a guide to a more optimal mechanical adjunct.