Research into Blood Flow in the Brain and Venous Insufficiency, or CCSVI, in MS
Posted Nov 13 2009 10:03pm
A few recent reports have revived ages-old speculation about a possible dysfunction of brain blood flow and/or drainage in individuals who have MS. For example, one study involving 65 people with different types of MS compared with 235 people who were healthy or had other neurological disorders, a strong relationship was found between MS and signs of venous insufficiency – suggesting that blood drainage by veins may be blocked, causing or contributing to nerve tissue damage. This study, by Paulo Zamboni, MD (University of Ferrara - Ferrara, Italy) and colleagues, was published in the June 2009 ( J Neurol Neurosurg Psychiatry 2009; 80:392-399 ). If confirmed, these findings may open up new research avenues into the underlying pathology of MS. Further research is now underway.
The idea that MS may involve a problem in blood circulation was an early idea that was eventually dismissed as more research suggested that immune-system attacks and inflammation played a pivotal role in the damage to nervous system tissues. A few recent studies have posed the idea that lower blood flow in the brain might contribute to nervous system damage.
In the recent study by Dr. Zamboni and colleagues, they screened for abnormalities of blood outflow in major veins draining from the brain to the heart in 65 people with different types of MS, compared with 235 people who were either healthy or who had other neurological disorders. They used sophisticated sonography techniques to detect abnormalities of vein drainage. The investigators found significant evidence of slowed and obstructed drainage in the veins draining the brain in many of those with MS. They also found evidence of the opening of “substitute circles” – where the flow is deviated to smaller vessels to bypass obstructions, and these were often found to have reverse flow (reflux) of blood back into the brain.
The investigators called this venous obstruction “chronic cerebrospinal venous insufficiency,” or CCSVI. The treatment status of the people with MS did not appear to influence whether they showed signs of CCSVI. The authors speculate that the reverse flow of blood back into the brain might set off the inflammation and immune-mediated damage that has been well described in MS.
If confirmed, these findings may open up new research avenues into the underlying pathology of MS, and further research is now underway. One study getting underway was described at the 2009 ECTRIMS meeting in September. It involves a collaboration between researchers in Italy, Buffalo (NY) and Birmingham (AL) who are attempting to treat venous obstruction in 16 individuals using balloon dilation such as has been used for many years to treat blocked arteries.
Many questions remain about how and when this phenomenon might play a role in nervous system damage seen in MS, and at the present time there is insufficient evidence to suggest that this phenomenon is the cause of MS.
Frequently Asked Questions About CCSVI and MS
Q: Do these reports of a possible association between insufficient vein drainage and MS mean that MS is caused by venous insufficiency? A: No. Based on results published about these findings to date, there is not enough evidence to say that obstruction of veins causes MS, or to determine when this obstruction may occur in the course of disease.
Q: If CCSVI turns out to be important in MS, can it be treated? A: No one knows yet. At least one small study is testing the effects of balloon dilation inside an obstructed vein to determine whether that procedure would be beneficial.
Q: I have MS. Should I be tested for signs of CCSVI? A: No, unless you are involved in a research study exploring this phenomenon, since at this time there is no proven therapy to resolve any abnormalities that might be observed, and it is still not clear whether relieving venous obstructions would be beneficial.
Q: Does CCSVI make the standard treatments of MS meaningless? A: No. There is ample evidence proving that the FDA-approved therapies for MS provide benefit for people with most forms of MS.
Q: Will the National MS Society fund research into CCSVI in MS? A: The National MS Society welcomes research proposals from any qualified investigators whose research questions are relevant to multiple sclerosis. All proposals received are thoroughly evaluated for their relevance and excellence by our volunteer scientific peer review panels. At the present time, we have not been approached for funding any projects related to CCSVI. If we receive a proposal related to CCSVI that is found to be outstanding and relevant to MS, we would likely commit to fund such a study.