Chronic cerebrospinal venous insufficiency is a chronic problem in which blood
from the brain has difficulty returning to the heart. It is caused by a

narrowing or "stenosis" in the veins that drain the brain.

The MS Society of Canada describes CCSVI as "a hypothetical disruption of blood flow in which the venous system is not able to
efficiently remove blood from the central nervous system, resulting in

increased pressure in the veins of the brain and spinal cord, which in

turn results in damage to these areas."

Small studies on people with MS suggest the blockages lead to different patterns of blood flow back to the heart. Blood leaves the
central nervous system differently than normal. For example, it may flow

more slowly, leading to swelling, or may move backwards or "reflux"

into the brain.

In November 2009, Dr. Robert Zivadinov of the neuroimaging analysis centre in Buffalo, N.Y., presented his preliminary results trying to
confirm the link between blocked veins and MS. Zivadinov said a

combination of being born with narrow veins in the neck or thorax, along

with environmental and genetic factors such as vitamin D deficiency or

exposure to the Epstein Barr virus, may play a role in causing MS, an

autoimmune disorder.

Veins of the neck, including internal jugular shown in blue. (Gray's Anatomy)

Different tests are used to diagnose CCSVI. Doppler ultrasound of the neck and skull may show if blood is refluxing. Venography, which
involves injecting a dye into the veins to watch blood flow and possible

stenosis in the azygous vein in the chest and the two internal jugular

veins, is also used.

Doctors may also turn to more sophisticated tests using magnetic resonance venography and magnetic resonance imaging to look for
abnormalities. Researchers are still investigating the best protocols

and tests to use. People doing the tests need to be trained to do it

effectively.

Treating the condition is more controversial. Zamboni's angioplasty-like procedure involves a small incision in the groin to
insert a catheter into the blocked vein that is opened with a small

balloon. In his small study, most of the 65 patients who had the

procedure had fewer MS attacks and brain lesions, although the

improvement was temporary for about half.

One U.S. clinic that started doing Zamboni's procedure stopped after a metal stent put into a patient's vein went into his heart. Another
patient died of a cerebral hemorrhage after the procedure, said Dr. Jock

Murray, an expert on multiple sclerosis who helped found the Dalhousie

MS Research Unit in Halifax.

There are some clinics in Canada and the United States that offer testing for CCSVI, but none that will perform the procedure. It is
available in several countries, including India, Mexico, Poland,

Romania, Bulgaria and Serbia.

A review article in the Annals of Neurology challenged the role of CCSVI in MS and discouraged people with MS from having invasive
procedures until the benefits are demonstrated more conclusively.

The findings need to be repeated in more patients and controls with consistent MRI protocols, the reviewers concluded. Further studies also
need to be blinded, that is, researchers can't know which subjects have

the disease and which don't, to help prevent bias. Given ethical

concerns, MS patients who have the treatment are told to continue taking

their disease modifying medications, which makes it harder to determine

the effectiveness of the surgical treatment.

On Nov. 23, 2009, the MS Society of Canada called for research into CCSVI. However, Health Canada has so far refused to fund a large-scale trial of the procedure because there is no scientific
evidence yet that CCSVI works, is safe or that there is an established

link between blocked veins and MS.

On June 11, 2010, the MS Society of Canada and the U.S. National MS Society announced that they had committed $2.4 million to study CCSVI and its relationship with MS. Research into the treatment's potential will take significant time.

On Sept. 16, 2010, the MS Society of Canada's board of directors said it had unanimously approved a motion to set aside $1 million to contribute to a possible pan-Canadian clinical trial — so the money will be ready if one is developed and approved.