Introduction to CCSVI

Welcome to, a site dedicated to information about chronic cerebrospinal venous insufficiency (CCSVI) from the Multiple Sclerosis Society of Canada. We have created this space as a resource for people who are interested in learning about CCSVI.

If you're looking for information about multiple sclerosis more generally, including resources with respect to living with MS, information about currently approved treatments, or ways to get involved, visit

Discussion about CCSVI, particularly on the internet, is growing at a tremendous rate. The topic has ignited spirited debate - as do many new concepts - and has sparked a range of passionate opinions. The process of raising questions, concerns and skepticisms to new medical theories is part of the process of identifying and answering key questions.

What is CCSVI?

Chronic cerebrospinal venous insufficiency (CCSVI) is a term coined by Dr. Paolo Zamboni. Dr. Paolo Zamboni from the University of Ferrara in Italy published preliminary findings about an apparent association between CCSVI and MS in June 2008, following a study of 65 patients.

CCSVI describes a theory in which portions of the venous system (the body's network of large and small veins) in the head and neck are narrowed or blocked and therefore unable to efficiently remove blood from the brain and spinal cord (central nervous system).

What is Dr. Zamboni's theory about CCSVI and MS?

Dr. Zamboni believes that CCSVI and MS are linked. According to Dr. Zamboni, CCSVI results in slowed draining of blood from the brain. The pressure caused by the build-up of blood in turn causes reflux of blood back into the central nervous system through new blood vessels which develop when the others are not working properly. Dr. Zamboni's initial hypothesis suggested that because these compensatory blood vessels don't have the same wall integrity as larger veins, they tend to leak blood into the adjacent tissue, depositing iron in the central nervous system and thereby triggering an immune response associated with multiple sclerosis.

Based on the results of his initial findings, Dr. Zamboni and others stated that a subsequent larger and better controlled study was warranted in order to definitively evaluate the possible impact of CCSVI on the disease process in MS.

Research to date

Research is taking place around the world. Research on CCSVI was presented at various meetings such as the European Committee for Treatment and Research in MS (ECTRIMS) in October, 2010, the International Society for Neurovascular Disease (ISNVD), in March, 2011 (the first conference of its kind, attended by vascular surgeons, interventional radiologists, basic scientists, physicists, neurologist, neurosurgeons, technologists and others), the Society of International Radiology in March 2011, and the American Academy of Neurology in April, 2011.

When taken individually, many research papers have conclusions that could seem to contradict findings of the others. Some researchers have shown an association between vein abnormalities and MS while others have not. With more study we will have more knowledge and whether this association exists as well as whether or not vein dilation benefits MS patients. Researchers are still seeking to understand CCSVI.

In October 2011, the Canadian Medical Association Journal published an article by Dr. Andreas Laupacis which systematically reviewed published studies on the relationship of CCSVI and MS.

  • The meta-analysis looked at eight high quality studies from around the world.
  • The primary purpose of the review was to examine the association between venous abnormalities and MS. The secondary purpose was to evaluate the current evidence about the benefits and harms of endovascular treatment for MS.
  • The review found a strong and statistically significant association between CCSVI and MS as compared to healthy controls. However, poor blinding (steps taken to avoid the bias that could come from the researcher knowing who does or does not have MS) and the inconsistency of the results led the author to conclude that more high quality studies are needed to determine whether CCSVI is more frequent in people with MS as compared to those without MS.
  • Currently, no randomized trials have been reported of endovascular therapy for MS. Therefore, the authors concluded that the impact of this intervention upon the signs and symptoms of MS cannot be reliably assessed.

Systematic reviews of the evidence of chronic cerebrospinal venous insufficiency (CCSVI) and multiple sclerosis

What do we know so far?

Research indicates that CCSVI does not cause MS.

In April, 2011, Dr. Zivadinov published the largest CCSVI study to date in Neurology. This study reported an increased prevalence of CCSVI in MS, but with a considerably lower prevalence than reported in Dr. Zamboni's work. CCSVI was also found in healthy controls and in those with other neurological conditions. In summary, the degree of prevalence of CCSVI in those with MS indicates that CCSVI does not cause MS.

There are potential complications associated with CCSVI-related procedures.

As with any invasive procedure, there is risk. There is general agreement that balloon angioplasty has less risk than the treatment of CCSVI involving stents. Please read our Risks and Safety section for more detailed information.

Individuals who have obtained CCSVI-related procedures are self-reporting quality of life benefits (e.g., less fatigue, warmer limbs, better balance). These self-reported benefits are often of limited duration.

Read stories from people who have gone for CCSVI-related procedures here.

What do we still need to find out?

Further investigation into the relationship between CCSVI and MS is needed. While the recent study published in Neurology indicates that CCSVI does not cause MS, CCSVI may be a factor for a significant number of MS patients. As with many other emerging areas in MS research, the MS Society of Canada remains hopeful that investing in step-wise research will give us the definitive answers we're seeking.

The next steps can be understood in two parts:

Part 1: Determine the relationship between CCSVI and MS and the best way to image it

Researchers generally agree that there needs to be consensus on a 'gold standard' (best practice) of imaging for CCSVI. Currently a variety of imaging technologies and a lack of a standardized diagnostic protocol could easily result in inaccurate diagnoses. You can read more about CCSVI diagnosis in our Considering CCSVI-Related Procedures section. As well as ensuring that we are consistent in the way we image and diagnose CCSVI, more information must be gathered on the frequency and prevalence of CCSVI in MS before we move on to test the CCSVI procedure itself; this is required even though compelling evidence is now available that the relationship between CCSVI and MS is not causal. Here are some questions that need to be answered in this first step:

  • What is the best way to image CCSVI?
  • What is the relationship between ultrasound findings and both normal variation and true venous insufficiency?
  • Why might CCSVI occur more frequently in those with progressive illness?
  • Why might children present with CCSVI?
  • What is the relationship between CCSVI and other aspects of MS, such as MRI measures, disease duration, and disease progression?

Part 2: Determine the effects of treating venous insufficiency

If part 1 is successfully completed and the results demonstrate that people with MS do have blocked veins that are associated with MS or its symptoms, researchers would then look at how treatment of the condition could benefit people with MS. Questions that will need to be answered include:

  • Do the effects of the treatment work in all or any types of MS?
  • How long do the treatment effects last?
  • Can the results be replicated in a 'blinded' study, as required for scientific rigour, where neither participants nor researchers are aware of the treatment they are receiving?
  • What are the reliability, risks and benefits of the treatment?
  • How does this treatment compare in effectiveness and safety to existing therapies?

The MS Society of Canada shared great interest in expediting this research, as it would any research that presents a potential lead in stopping, repairing or preventing MS.

On June 11, 2010, the National MS Society (USA) and the MS Society of Canada announced the commitment of over $2.4 million to support 7 new research projects focusing on the role of CCSVI in the MS disease process.

The MS Society has called on governments across Canada to take action on CCSVI and many have.

We are pleased that the federal government and CIHR have kept MS at the top of their healthcare agendas. On June 29, 2011, the Honourable Leona Aglukkaq, Minister of Health, announced that the federal government will fund Phase I/II level clinical trials on CCSVI and MS. Read more from the MS Society of Canada, which has committed $1 million towards the financial cost of a clinical trial. We encourage governments of provinces and terrorities to fund therapeutic clinical trials.

In November, 2011, the government announced that it was ready to accept research proposals for the Phase I/II clinical trial on chronic cerebrospinal venous insufficiency (CCSVI). The request for research proposals is a collaborative initiative between the CIHR and the MS Society of Canada. CIHR will also continue to work with the provinces and territories as it moves forward with this initiative. The MS Society of Canada has committed funding towards the financial cost of a clinical trial.

On March 23, 2011, in responding to requests from the MS Society, the federal minister of health announced a new monitoring system for MS. Once in place, it will capture information to help identify disease patterns and track treatments and long-term outcomes for people living with MS, including those who have undergone treatment for CCSVI.

The MS Society of Canada continues to ask governments to ensure that no Canadian, who undergoes treatment for CCSVI outside of Canada, is denied necessary post-treatment and follow-up medical care they require when they return home. This is primarily the responsibility of provinical and territorial governments.

Read more about governmental action.

Read Your Questions and Your Stories.

The MS Society of Canada is committed to helping the MS community find answers. Please stay tuned.