Update: Chronic cerebrospinal venous insufficiency (CCSVI) and MS
Recent reports have sparked a flurry of media attention and revived an old idea of an association between a possible disruption in venous drainage and MS.
A recent study by Zamboni et al, (published in J Neurology Neurosurgery Psychiatry. 2009 Apr; 80 (4): 392-9. Epub. 2008 Dec 5.) on 65 people with different types of MS compared with 235 people who were healthy or had other neurological disorders, found a robust correlation between having MS and signs of venous insufficiency - suggesting that drainage of oxygen depleted blood by veins may be impaired in the central nervous system, causing or contributing to nerve tissue damage.
The investigators called this condition "chronic cerebrospinal venous insufficiency" (CCSVI). The treatment status of the people with MS did not appear to influence whether they showed signs of CCSVI. Venous drainage of the brain and spinal cord was examined using an ultrasound technique (Doppler). The researchers also noted that patterns of venous obstruction differed between people at different stages and courses of MS although there was no clear relation between severity of MS and extent of occlusion. The authors suggest that the abnormal venous drainage of blood back from the brain and spine might set off the inflammation and immune-mediated damage that is characteristic of MS.
If these findings were confirmed and shown to have an impact on the disease process, they would open up new avenues of research into the underlying pathology of MS and raise the possibility of new treatments. While the early data is interesting, the proposed mechanism is highly speculative. The main limitations are that the study is done on a small number of people and on those who already have clinical MS. Therefore it is not possible to distinguish whether the venous obstructions are the cause of MS or are part of the physiological changes in the central nervous venous system that result from MS. The concepts surrounding CCSVI and MS are still relatively new and require validation in much larger, well-designed scientific studies before they can be accepted as established. Further research is now underway.
Researchers at Buffalo University, New York are recruiting 1,700 adults and children from USA and Canada to test a link between CCSVI and MS. The MS Society of Canada have issued a request for research operating grants on CCSVI in relation to MS.
Several of MSIF’s member societies have commented on the findings, including those in
Canada - http://www.mssociety.ca/en/research/med ... 21_faq.htm
Germany - http://www.dmsg.de/multiple-sklerose-ne ... g&anr=1994
Ireland - http://www.ms-society.ie/news/show/ccsvi
Italy - http://www.aism.it/index.aspx?codpage=speciale_ccsvi
USA - http://www.nationalmssociety.org/news/n ... x?nid=2206
The most recent comment on the UK MS society’s website - http://www.mssociety.org.uk/news_events ... dvice.html
, includes criticism of some of the methodology of the study.
Q: Does CCSVI cause MS?
A: At this point there is not enough evidence to draw conclusions on CCSVI and MS. Based on what has been published to date, we can only say that in some people MS may occur in association with impaired venous drainage of the central nervous system. There is not enough evidence to determine whether obstruction of veins causes MS, or is caused by MS, or even to determine when this obstruction may occur in the course of disease.
Q: How has CCSVI been treated?
A: Surgical procedures for CCSVI in MS have used "balloons" to open up obstructed veins or inserted stents into veins to help keep them open. These procedures are still very experimental, have been performed on only a very small number of patients and involve risks of bleeding or the formation of abnormal blood clots. The safety and beneficial effects of this treatment can only be assessed by a large scale clinical trial.
Q: Will the treatment of CCSVI be useful for the various forms of MS?
A: As research on this question is at a very early stage, it is currently unknown whether this type of treatment will be useful in any form of MS. More clinical studies are needed before it will be considered for approval in treating people with MS.
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 for the treatment of MS.
Source: MSIF, German MS Society, Italian MS Society, MS Ireland, MS Society of Canada, UK MS Society and US National MS Society