Foam Sclerotherapy for Varicose Veins Linked to Microembolism

Researchers are reporting that microembolism of foam particles is common during foam sclerotherapy for varicose veins, and among patients with patent foramen ovale (PFO), these microemboli might be linked to neurologic symptoms.

The possible link is discussed in correspondence in the April 3 issue of the New England Journal of Medicine, by authors Roeland P.M. Ceulen, MD, and Anja Sommer, PhD, from the GROW School for Oncology and Developmental Biology, and Kevin Vernooy, MD, PhD, from the Cardiovascular Research Institute, both in Maastricht, the Netherlands.

After 2 index cases, a man with transient scotomas and a woman who developed a migraine attack immediately after the initiation of foam sclerotherapy treatment, the researchers undertook to monitor 33 such patients for the distribution of foam using echocardiography during the procedure.

"In all patients studied, we detected foam microemboli in both the right atrium and ventricle between 45 seconds and 15 minutes after foam injection," they write. "In 5 patients, microembolism was also detectable in the left atrium and ventricle; however, neurologic signs did not develop in any of them."

Careful echo examination of these latter 5 patients showed each had a right-to-left shunt from a PFO, and subsequent examination of the 2 symptomatic index patients also revealed each had a PFO.

"These findings suggest that foam-induced microembolism is a common phenomenon during foam sclerotherapy," the authors write. The prevalence of PFO in the population is about 26%, and serious neurologic complications associated with foam sclerotherapy are estimated to occur in 2% or less of patients, they note. The findings of their analysis are in line with these estimates.

"Nevertheless, we suggest that caution be exercised when foam sclerotherapy is performed in patients with a known patent foramen ovale and that patients with overt neurologic symptoms undergo additional echocardiographic examination for the presence of a patent foramen ovale," they conclude. "Further prospective studies are needed to evaluate and confirm our observations."

N Engl J Med 2008;358:14.