Chronic cerebrospinal venous insufficiency (CCSVI)
What is CCSVI?
CCSVI is a syndrome characterised by poor removal of oxygen-depleted blood from the central nervous system. This is thought to be caused by a constriction of blood vessels in the brain and neck which affects brain blood flow and drainage.
Why has CCSVI been linked to MS?
An early-stage study published in 2009 looked at the prevalence of CCSVI in people with MS, and found that CCSVI was present in 90 per cent of people with MS. Since then, there has been an enormous amount of interest in the potential link between CCSVI and MS.
What is the latest research about CCSVI?
Numerous small studies into CCSVI diagnosis rates and treatment have been carried out and reported, all with varying results. This is due to great differences in the techniques used to diagnose CCSVI and the fact that the interpretation of results from these techniques is highly subjective, meaning diagnosis or treatment effect can be biased by the clinician or scientist reviewing the information.
However, 2 key studies published in 2013 concluded that there is no link between CCSVI and MS by addressing the issues above:
- Both studies used a large numbers of people both with and without MS
- Both studies used the same technique, called neurosonography, to identify CCSVI. This is a type of ultrasound carried out on the brain which can identify and display how blood flows in the nervous system.
- In both studies, diagnosis was carried out by experts who were ‘blinded’. This means they were not told if the images they assessed were from people with or without MS so the study results were not biased.
The first study was carried out by researchers in the US involved over 200 people with, and 70 people without MS. An initial assessment of the imaging results was unable to identify a difference in blood flow patterns between people with and without MS. A further report from this study showed that the rate of CCSVI was much lower in general than previous reports, and that diagnosis was in fact higher in people without MS (7 per cent) than people with MS (under 4 per cent).
The second study was carried out in Italy and involved 1,165 people with MS, 226 people with other neurodegenerative conditions (like Parkinson’s Disease) and 376 people without MS. They found that the number of people with CCSVI was extremely low (just over 3 per cent), and there was no significant difference in the rate of CCSVI between the 3 groups.
These large studies provide evidence that there is no link between CCSVI and the risk of developing MS.
The PREMiSe Trial
In 2014, researchers in the USA reported the results of a Phase 2 (mid-stage) trial into treating CCSVI as a means of therapy for people with both relapsing remitting and progressive MS. Nineteen people were involved in the trial, 9 of whom underwent a procedure to widen the veins in the neck called venous angioplasty. Compared to the group who didn’t undergo the surgery, there was a trend among the angioplasty group to have a higher relapse rate and a higher number of new lesions.
The results of this trial shows that treating CCSVI does not effectively prevent the progression of MS, and may in fact exacerbate some aspects of the condition, like number of lesions and relapses.
Some people with MS have had treatment for CCSVI privately. The MS Society recommends against seeking an unproven treatment, like CCSVI, outside of a properly regulated clinical trial, due to the potential risk of undergoing such unknown therapies.