Speaking at the International Union of Phlebology chapter meeting (UIP 2019; 25–27 August, Krakow, Poland), Neil Khilnani (New York, USA) underlined that the current literature on sclerotherapy, in addition to guidelines from the European Consensus and American Society for Dermatologic Surgery (ASDS), does not find a “tremendous advantage for foam” over liquid. Although sclerotherapy is recommended for the treating C1 veins, foam sclerotherapy is only considered appropriate when it is in a weaker form.
Before addressing the potential advantages and disadvantages of using foam, Khilnani commented: “I think it is fairly well established that the treatment for C1 disease, regardless of whether you use liquid or foam, begins with the larger C1 veins and progresses to the smaller C1 veins. Most practitioners use detergent sclerosants for C1 sclerotherapy: either polidocanol or sotradecol.
“To get successful sclerosis, as opposed to thrombosis, you need to have an adequate concentration and you need to deliver that concentration to the endothelium for an appropriate length of time to get the injury that we are looking for.”
With regard to the benefits of foam over liquid, Khilnani highlighted the difference in kinetics between the two and how important this may be. While liquids layer when injected into the vein, as well as mixing with blood and diluting the concentration of the sclerosant, foam displaces blood and “allows a more circumferential contact,” stopping flow at least transiently to increase contact time and slow the rate at which the sclerosant dilutes. “Effectively, foam is a stronger sclerosant for a similar drug concentration and volume with regard to sclerotherapy,” added Khilnani.
Despite these advantages, especially in larger and medium-size veins, it was also emphasised that some of the benefits of foam are lost in the smaller veins, “primarily because liquid can displace blood fairly effectively in the telangiectasia and smaller reticular veins”.
Furthermore, the use of foam in sclerotherapy procedures can also lead to irritating complications which, as Khilnani revealed, “take up time in the doctor-patient relationship” when discussing them as part of informed consent. Citing a systematic review completed by Alun Davies (London, UK) et al, which reported that up to 2% of patients treated with foam sclerotherapy are affected by visual disturbances, Khilnani added that while these side-effects can occur with liquid sclerotherapy too, it is almost entirely the result of foam being used.
As well as the potential drawbacks of using foam, its production is also said to “involve some thought and some work,” with different techniques of producing and maintaining that foam varying in terms of the drug used, the initial concentration of the drug, and the syringe that is used. Other factors may determine the quality of the foam used, including the time from production to its use, and the gas that is used. “Foam stability is an issue too,” argued Khilnani, “as there is definitely more work required when you are doing foam sclerotherapy than when you are doing liquid sclerotherapy, concerning the management of your sclerosant”.
Khilnani also drew attention to literature published on the effectiveness of foam compared to liquid; in a trial conducted by Jean-Patrick Benigni (Paris, France), ten patients who were treated with either polidocanol (foam) or liquid sclerotherapy, with each patient undergoing five sessions. Commenting on the results, Khilnani explained: “When we look at the data from that paper, less injections for foam were needed to complete the study than for liquid, and patient satisfaction was a bit higher, but there was more staining and matting in the patients who were treated with foam.”
The findings of this study support those of another investigation conducted by Philippe Kern (Vevey, Switzerland), in which patients were randomised to either 0.25% polidocanol foam during one treatment session—in addition to the use of graduated compression stockings—or liquid sclerotherapy with a 0.25% pure chromated glycerin, 0.25% polidocanol solution. Focusing on the outcome of the trial, Khilnani asserted that there was no difference in patient satisfaction and no difference in the blinded photographic analysis. Moreover, side effects were more prevalent in patients treated with foam.
Considering this evidence and the recommendations of sclerotherapy guidelines, Khilnani concluded: “Foam is certainly an appropriate tool to be used but at this point it has not been established as superior to liquid and so in my own personal opinion, I use liquid sclerotherapy for all C1 disease, reticular veins and spider veins.