Chronic cerebrospinal venous insufficiency (CCSVI)
CCSVI is a term used to describe the narrowing of veins in the neck, which has been suggested to affect blood flow out of the central nervous system.
A link between CCSVI and MS was first suggested in 2009, but this has since been challenged. Trials of treatments for CCSVI found that it did not reduce MS symptoms or damage on MRI but might worsen relapses and activity on MRI scans.
Find out more about CCSVI
Why has CCSVI been linked to MS?
A link between CCSVI and MS was first suggested in 2009, when a small Italian study reported that 90% of people with MS also had CCSVI.
The researchers suggested the reduced blood flow seen in CCSVI could cause blood to leak into surrounding tissue and a build-up of iron deposits in the CNS. And this could trigger the immune system to cause damage in MS.
This has since been overwhelmingly challenged.
CCSVI and MS - what do we know?
Since 2009 a number of large studies have investigated the link between CCSVI and MS. This includes seven projects funded by the National Society in the US and the MS Society of Canada, and a large Italian study.
All of these studies involved large numbers of people with and without MS, and used many different techniques to look for CCSVI.
None of these large studies have found a link between CCSVI and MS.
How common is CCSVI in MS?
A large Italian study found that CCSVI was rare, and was not more common in people with MS. The study involved 1,165 people with MS, 226 people with other neurodegenerative conditions (like Parkinson’s) and 376 people without MS.
This was confirmed by a study based in Texas. Researchers found that CCSVI diagnosis was actually higher in people who didn't have MS than those with MS, and that blood flow rates were similar in both groups. This study involved over 200 people with MS and 70 people who didn't have MS.
Comparing techniques for diagnosis
Researchers in Canada and Cleveland have also reported that CCSVI is not more common in people with MS. They found the number of people diagnosed with CCSVI varied depending on the technique they used.
This could explain why it's been so difficult to determine how common CCSVI is, and why results have varied from trial to trial.
These two studies involved 347 people – 169 people with MS and 178 people who didn't have MS. They looked at blood flow using a number of different techniques, including ultrasound and catheter venography.
Researchers in Alberta have expressed concerns about how CCSVI is diagnosed. They found that not only did the technique used affect diagnosis, but that blood flow in the neck can be affected by how the person is sat or if they are lying down.
Their study involved 20 people with MS and 60 people without MS. It used ultrasound and MRI techniques.
CCSVI and childhood MS
A Toronto study found that CCSVI did not increase the risk of childhood MS. The study involved 26 children with MS, 26 age-matched controls who did not have MS, and 13 young adults with childhood-onset MS.
CCSVI research - next steps
There is still one ongoing study at the University of Wisconsin. Researchers are investigating the rate of vein drainage in 112 people with MS, 56 people without MS and 56 people with other neurological conditions. We look forward to seeing the results.
Clinical trials investigating the effect of treating CCSVI on MS
Treatment for CCSVI involves surgery to open blocked or narrowed veins in the back of the neck. It's called venoplasty, but is also referred to as angioplasty and sometimes referred to as 'liberation therapy'.
The treatment has been tested in small scale clinical trials, but has not found to be effective for people with MS. It's a risky treatment and can have serious side effects.
In 2017 Dr Zamboni, the proponent of venoplasty, published his own clinical trial that concluded “Venous PTA cannot be recommended for patients with relapsing-remitting multiple sclerosis” because it was a “largely ineffective technique”.
Potential risks of CCSVI treatment
- Developing clots in the vein
- Arrhythmias (disruptions to the heart beat and rhythm)
- Vein dissection (separation of the vein)
- In-stent thrombosis (bleeding at the site of the stent placement)
- Vein rupture
- Groin hematoma (collection of blood outside the blood vessel).
In May 2012 the US Food and Drug Administration (FDA) issued a safety warning for liberation therapy.
Some people with MS have had treatment for CCSVI privately. We do not recommend seeking an unproven treatment, like CCSVI, outside of a properly regulated clinical trial, due to the potential risk of undergoing any unknown therapy.
Results from a clinical trial of CCSVI treatment in Canada were announced in spring 2017. Researchers found that surgery to relieve CCSVI did not reduce MS symptoms or damage detected on MRI scans. The trial involved 100 people with MS who also had a narrowing of veins in their neck.
A trial run by the proponent of venoplasty for MS, Dr Zamboni, was published in autumn 2017. The trial involved 115 people with relapsing MS diagnosed as having CCSVI. It concluded that "Venous PTA cannot be recommended for patients with relapsing-remitting multiple sclerosis" because it is a "largely ineffective technique".
An earlier small trial called PREMiSe found that treating CCSVI does not effectively prevent the progression of MS, and could worsen relapses and MS activity on MRI scans. The trial involved 19 people with relapsing and progressive MS, with nine people having the CCSVI procedure.