Göteborg, Sweden — New data on the possible link between chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis (MS) have done little to clarify the relationship between these conditions, providing evidence both for and against the controversial hypothesis.

What does seem clear now, though, is that the relationship, if there is one, is not as simple as it may have first appeared. New findings suggest, for example, that venous lesions may be more common in later stages of disease and so may be a consequence or comorbidity rather than a cause of MS.

One of the issues appears to be differences in methods and imaging techniques in the cerebral venous system that mean researchers seem to be able to look at precisely the same images or data and settle on interpretations that are diametrically opposed.

Even Paolo Zamboni, MD, director of the Vascular Diseases Center at the University of Ferrara, Italy, who first proposed the link, is now considering the hypothesis that the vast majority, but perhaps not all, cases of MS may relate to CCSVI.

The state of knowledge on CCSVI, including new data from some of the leading researchers in this area, was the focus of a number of posters and presentations, as well as a symposium here at the recent 26th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS).

A Matter of Assessment?

The appealing idea that simple angioplasty of extracranial veins might cure or improve symptoms of this devastating disease caught the attention of highly educated and motivated MS patients late last year and has since engaged many in the unifying demand for access to what has been dubbed by some the "liberation procedure."

Dr. Zamboni — who denies having called it the liberation procedure — and colleagues presented new data here and addressed some of his critics. At the packed Charcot Symposium dedicated to discussion of the topic at the outset of the meeting, he first emphasized what these venous lesions are and what they are not.

"CCSVI is composed of several blockages in the main outflow routes, the jugular vein, azygous vein, but this is very important to understand," he said, displaying angiographic and high-resolution B-mode images along with a specimen, these blockages "are merely intraluminal defects; not problems in the wall, but intraluminal defects: webs, membranes, malformed valves."

One important issue in this debate on CCSVI, he said, is how venous outflow from the brain is assessed and how these lesions are imaged. Veins can be apparent or not on imaging based on a number of factors, including supine vs upright postures, respiration, or the imaging modality, and it does appear that this has some bearing in the interpretation of the contribution CCSVI may or may not be making to MS.