Benefits of polidocanol endovenous microfoam (Varithena®) compared with physician-compounded foams

Abstract

ObjectiveTo compare foam bubble size and bubble size distribution, stability, and degradation rate of commercially available polidocanol endovenous microfoam (Varithena®) and physician-compounded foams using a number of laboratory tests.MethodsFoam properties of polidocanol endovenous microfoam and physician-compounded foams were measured and compared using a glass-plate method and a Sympatec QICPIC image analysis method to measure bubble size and bubble size distribution, Turbiscan™ LAB for foam half time and drainage and a novel biomimetic vein model to measure foam stability. Physician-compounded foams composed of polidocanol and room air, CO2, or mixtures of oxygen and carbon dioxide (O2:CO2) were generated by different methods.ResultsPolidocanol endovenous microfoam was found to have a narrow bubble size distribution with no large (>500 µm) bubbles. Physician-compounded foams made with the Tessari method had broader bubble size distribution and large bubbles, which have an impact on foam stability. Polidocanol endovenous microfoam had a lower degradation rate than any physician-compounded foams, including foams made using room air (p < 0.035). The same result was obtained at different liquid to gas ratios (1:4 and 1:7) for physician-compounded foams. In all tests performed, CO2 foams were the least stable and different O2:CO2 mixtures had intermediate performance. In the biomimetic vein model, polidocanol endovenous microfoam had the slowest degradation rate and longest calculated dwell time, which represents the length of time the foam is in contact with the vein, almost twice that of physician-compounded foams using room air and eight times better than physician-compounded foams prepared using equivalent gas mixes.ConclusionBubble size, bubble size distribution and stability of various sclerosing foam formulations show that polidocanol endovenous microfoam results in better overall performance compared with physician-compounded foams. Polidocanol endovenous microfoam offers better stability and cohesive properties in a biomimetic vein model compared to physician-compounded foams. Polidocanol endovenous microfoam, which is indicated in the United States for treatment of great saphenous vein system incompetence, provides clinicians with a consistent product with enhanced handling properties.

The role of clinically-relevant parameters on the cohesiveness of sclerosing foams in a biomimetic vein model

“…When considering the general experimental observations made during this series of studies, it can be seen that PCFs generated using the DSS technique were more stable and produced longer DT in the vein model compared to the same PCFs made by the Tessari method. We have observed this effect before, and have attributed this to the broader bubble size distribution in Tessari PCFs compared to DSS PCFs [ 32 ] (Fig. 8 ).…”

“…The combination of the specific gas formulation and more importantly, the low mean bubble size (no bubbles greater than ~500 μm in diameter upon foam generation) and narrow bubble size distribution (see inset in Fig. 8 a) [ 32 ] resulted in a lower rate of Ostwald ripening. In terms of clinical significance, the longer the foam DT in the vessel, the more contact time the polidocanol surfactant has with the endothelial lining of the vessel wall.…”

“…1 Schematic depiction of the experimental set-up (readapted from Ref. [ 32 ]). The biomimetic vein model was initially primed with a blood substitute.…”

“…A QICPIC particle size and shape analyser (supplied by Sympatec UK, Bury, Lancashire) was employed to measure bubble size distribution of different foam formulations (see also Ref. [ 32 ] for additional information about this measurement system).…”

Sclerotherapy – How to Achieve a Spectacular Outcome

“…The quality, stability and efficacy of foam is influenced by several variables including the specific sclerosant and concentration used to create the foam, method of preparation, the gas-to-sclerosant ratio, and the type of gas mixture used. The ideal foam should be small microbubbles with dense consistency; this allows for localized efficacy while limiting the duration of the bubbles and potential for distal effect [15,16]. Both STS and POL are widely use as the sclerosant of choice for creating foam.…”