NICE Advice
Mr. Coleridge Smith wrote to NICE in response to misleading advice on their web site.
I am most concerned about the recently published draft advice on ultrasound foam sclerotherapy. In this you say that foam sclerotherapy causes blindness. This is WRONG!
I have searched the literature on this subject and enquired about this complication amongst UK vascular surgeons as well as colleagues from other countries and can find no case reported in which blindness has followed from sclerotherapy of any type used to treat varicose veins.
The conclusion that this treatment causes blindness is therefore NOT JUSTIFIED on the basis of published literature. It will also cause alarm amongst patients who have had the treatment are who are undergoing the treatment at present.
It is not the role of NICE to cause alarm amongst the public, especially when there is no scientific justification for this. I insist that this assertion should be removed without delay from your website on the grounds that IT IS WRONG!
In more detail, the problems I have with this publication are these.
According to the World Health Organisation, Blindness and Low Vision are defined as in the International Classification of Diseases 10th edition (ICD10):
Blindness defined as visual acuity of less than 3/60 or corresponding visual field loss in the better eye with best possible correction.
There is no evidence that foam sclerotherapy has ever produced blindness according to this definition. You are therefore wrong to say it has.
I agree that sclerotherapy whether performed using either liquid or foam sclerosants may produce visual disturbance in susceptible individuals. This still does not amount to blindness and has in any case been reported in publications for at least 20 years. Two authors mention the development of a transient scotoma following foam sclerotherapy with sodium tetradecyl as the sclerosant. Henriet, in his series of more than 10,000 patients treated by foam sclerotherapy, also records this problem. Henriet used polidocanol foam and not sodium tetradecyl sulphate (STS) foam. He mentions 9 patients with visual disturbance all of which resolved within 2 hours. He also records that in 7 patients migraine was provoked by a session of foam sclerotherapy. All of these patients were known to suffer from migraine before sclerotherapy commenced. Transient visual disturbance is mentioned by Cabrera following foam sclerotherapy in which he also used polidocanol. In fact, visual disturbances have also been reported following sclerotherapy using the liquid sclerosants STS and chromated glycerine. Goldman and Bergan mention this complication in their book of sclerotherapy in connection with liquid sclerosants, although no detailed publication has ever appeared on the subject. Their description is of scintillating scotomata and they comment that monocular retinal migraine may occur in patients with a migraine diathesis. These may well be very similar events and all appear to resolve without complication.
Transient visual disturbance may be an occasional sequel to sclerotherapy whether this is performed with foam or liquid. My own experience is that it most frequently occurs in, but is not limited to, those patients with a previous history of migraine with visual aura. In my own series of more than 1000 patients treated by foam sclerotherapy this amounted to about 2% of patients. A simple strategy has been developed to prevent this problem which is invariably effective when correctly applied.
There has been much discussion of bubbles and PFOs of late. However, there is no evidence that this phenomenon has any relationship to a PFO. In fact, these occur in 10 – 20% of the adult population and yet visual disturbance occurs in 2% or less of patients following liquid or foam sclerotherapy. The available evidence suggests that this most commonly occurs in patients with a genetic susceptibility to migraine attacks with visual aura.
I strongly suggest that your website should NOT say that sclerotherapy causes blindness. This is clearly wrong. If you are concerned about this phenomenon you should say that it causes 'visual disturbance' and acknowledge that it may be caused by liquid sclerosants as well as foam. STS, one of the main sclerosants used in the UK, has been injected for the purposes of sclerotherapy for at least 60 years and no case of blindness has been reported despite a few patients developing visual disturbance after treatment. I therefore consider that this is evidence of safety of sclerotherapy rather than something to become alarmed about.
NICE has responded and will be correcting the published information
Tessari L, Cavezzi A, Frullini A. Preliminary experience with a new sclerosing foam in the treatment of varicose veins. Dermatol Surg. 2001; 27: 58-60.
Henriet JP. Expérience durant trois années de la mousse de polidocanol dans le traitement des varices réticulaires et des varicosités. Phlebologie, 1999; 52:277-82.
Cabrera J, Cabrera J Jr, Garcia-Olmedo MA. Sclerosants in microfoam. A new approach in angiology. Int Angiol. 2001; 20:322-9.
Wallois P. Incidents et accidents del la sclérose. In Tournay R, ed la Sclérose des varices, 4th ed. Expansion Scientifique Française, 1985, pp 297-319.
Complications and adverse sequelae of sclerotherapy. Goldman MP, Bergan JJ. 3rd edition, 2001. p 231.
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