06/03/2014 09:51 EDT | Updated 06/03/2014 09:59 EDT

CCSVI MS Theory Cast Into Doubt By CMA Study

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A potential tool in the battle against multiple sclerosis has been found wanting by health professionals.

Canadian doctors found no connection between blocked neck veins and multiple sclerosis (MS) in a recent study that has cast yet more skepticism on any link between the two.

In the study, which was published in the Canadian Medical Association Journal on Monday, Dr. Fiona Costello and several colleagues sought to investigate the link between chronic cerebrospinal venous insufficiency (CCSVI) and MS, which has been the topic of popular discussion since it was first advanced by Dr. Paolo Zamboni in 2009.

CCSVI is a condition in which veins in the head and neck are blocked or narrowed, making it difficult for them to remove blood from the brain and the spinal cord, according to the MS Society of Canada.

Zamboni has said that iron deposits from backed-up blood can cause lesions in the brain that are also signs of MS.

He said CCSVI patients who underwent a balloon venoplasty — which involves opening up the neck veins — saw a reduction in symptoms. Thousands of MS patients have since sought the treatment.

The CMA study tested 120 patients with MS and 60 healthy controls to determine whether a link existed between the disease and CCSVI.

They found none.

Fifty-eight per cent of MS patients and 63 per cent of controls met one or more of the criteria that could lead to a CCSVI diagnosis, but they spotted no differences between the groups, said a news release.

The authors also found "methodologic concerns that challenge the validity of the criteria used to define (CCSVI)" and are disputing the authenticity of its diagnosis, Costello said in a statement.

This is hardly the first study to cast doubt on the link between these conditions.

Last October, The Lancet published a study that was called the "death knell" of the theory that blocked neck vessels could cause MS.

It tested 177 MS patients, non-affected siblings and volunteers, and found that only one in each of these groups had CCSVI as Zamboni defined it.

The study also found that two-thirds of people who did have MS, and those who didn't, had 50 per cent or more narrowing in their jugulars or other neck veins.

Seventy-four per cent of MS patients in the study had narrowed neck veins, but so did 66 per cent of healthy siblings and 70 per cent of volunteers.

"Using the best method available, we were unable to confirm Dr. Zamboni's theory that MS is caused by CCSVI," lead author Dr. Anthony Traboulsee said.

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