There are several anatomical and positional problems in using endovenous thermal ablation to treat varicose veins caused by saphenous vein incompetence.1,2,3 Although laser and radiofrequency ablation are considered to be gold-standard modalities with high vein closure rates, neither is appropriate to treat refluxing great saphenous veins from the knee to the ankle because of the risk for saphenous nerve paresthesia, a known complication of thermal technologies. Torturous or scarred veins that cannot be navigated by a laser fiber or radiofrequency catheter also require an alternative modality to close refluxing segments.
We have found that polidocanol endovenous microfoam (Varithena; BTG International Group) provides excellent clinical results in patients whose venous anatomy makes them unsuitable for thermal ablation. Before Varithena came on the market, we typically used physician compounded foam (PCF) to ablate refluxing accessory veins or tributaries from the ankle to the knee, as well as tortuous venous anatomy not accessible to catheter-based modalities.
Our observation is that polidocanol microfoam has more even distribution through the branches of the great saphenous veins compared with PCF. Whereas the bubbles in PCF vary in size, Varithena’s polidocanol endovenous microfoam and its microbubbles are of uniform size and density, with a median bubble diameter of approximately 100 μ and no bubbles greater than 500 μ.
The uniformity of microbubbles causes the foam to remain intact much longer than PCF and allows extended contact with the venous endothelium, making it more effective than PCF. One treatment with polidocanol endovenous microfoam provides clinical benefit, whereas I have had to frequently re-treat patients with PCF.
In our experience, the vein closure rate with PCF is about 85%, or close to 95% with polidocanol microfoam.
Theoretically, polidocanol endovenous microfoam has a better safety profile than PCF.4 The pharmaceutical-grade endovenous microfoam is generated from a 2-to-1 mixture of oxygen to carbon dioxide, both of which are easily soluble in blood, and contains only trace amounts of nitrogen (<0.8%). Physician-compounded foam, in contrast, is produced from polidocanol mixed with room air, which contains 70% nitrogen. Nitrogen is poorly soluble in blood, creating a small risk for gas embolic adverse events such as stroke, seizure, or transient ischemic attack if the patient has a right-to-left cardiac shunt, such as a patent foramen ovale.
There are no safety data available for PCF, which is not approved by the US Food and Drug Administration. In randomized, placebo-controlled trials of Varithena, adverse events were mostly mild or moderate; no pulmonary emboli were detected, and no clinically important neurologic adverse events were reported.5,6 The risk for adverse events is directly proportional to the volume of sclerosant foam used, however, and we have had no complications, as we always stay within volume limits of PCF.
I have also used microfoam sclerosant therapy to treat truncal incompetence above the knee in patients who have had previous thermal ablations that have failed. Previously treated veins by ablation are often thickened and tortuous, making polidocanol microfoam the treatment of choice. Patients report minimal discomfort with microfoam sclerosant therapy and are highly satisfied with the minimally invasive procedure and the results.