An association between patent foramen ovale and varicose veins must be explored, according to David Wright of BTG PLC, London, UK, who addressed delegates at the American Venous Forum, Arizona, USA, in February.
Foam sclerotherapy, an increasingly popular endovenous treatment for varicose veins, introduces bubble emboli in the venous circulatory system.
“Obviously, only patients with a right-to-left shunt have the possibility that bubbles will cross from the venous circulation into the arterial circulation,” said Wright.
“Once there, they’re going to be distributed to all organs, most importantly, to the brain.”
Wright says that neurological events have been reported as occuring in about one or two per cent of patients treated with foam sclerotherapy. These events range from mild onset migraine to stroke.
Of the right-to-left shunt causes, patent foramen ovale is by far the most common and is a contraindication of endovenous ablation treatment.
Wright’s study took a cohort of 217 varicose vein patients, aged between 18 and 60 years, and tested them for right-to-left shunt using transcranial Doppler middle cerebral artery blood-flow monitoring. One hundred and twenty eight patients (59%) tested positive, either at rest or after Valsalva manoeuvre.
This, said Wright, is significantly higher than the 26-27% prevalence of patent foramen ovale reported to be present in the general population.
“There is an association between varicose veins and right-to-left shunt,” Wright concluded, “and almost certainly with patent foramen ovale.
“Unfortunately, these data really don’t give us any clue as to what the nature of this association is.”
For in-depth exploration of the issues around foam sclerotherapy, be sure to attend the CX Symposium Venous Day (7 April 2009), featuring presenations from high-profile phlebologists, including Nick Morrison, Phoenix, USA.