It has been very instructive, from a science-based medicine perspective, to watch the story of alleged chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis (MS) unfold over the last three years. In 2009 Dr. Paolo Zamboni, an Italian vascular surgeon, published a paper in which he claimed that 100% of MS patients he investigated showed signs of blockage in the veins that drain blood from the brain, a condition he named CCSVI. This paper sparked immediate controversy. This controversy has been in the news again recently with the making public of the results of an observational study of the liberation procedure to treat CCSVI.
Existing research over the last half century strongly indicate that MS is primarily a disease of immune dysfunction (an autoimmune disease), resulting in inflammation in the brain that causes damage, specifically to the myelin, the insulation around nerve fibers that allows them to conduct signals efficiently. Zamboni is suggesting that MS is primarily a vascular disease causing back pressure on the veins in the brain and iron deposition which secondarily results in inflammation. This would be a significant paradigm shift in MS. It would also not be the first time such a dramatic shift in MS science has been proposed but failed in replication.
The MS community did not give much credence to the notion of CCSVI, but despite this there has been an incredible amount of research on the idea over the last three years (a PubMed search on “CCSVI” gives 103 results). Most of the research has simply attempted to replicate Zamboni’s findings, with mixed but generally unimpressive results. No one has found the 100% results that Zamboni originally reported. The studies have found a range of venous insufficiency in MS patients, down to 0%, but many finding results in the range of 20-40%. However, patients with other neurological disease and healthy controls have also been found to have similar rates of venous insufficiency. Some studies have found a positive correlation with MS, others have not.