MS Society of Canada and National MS Society funded study finds chronic cerebrospinal venous insufficiency is not associated with MS
A condition known as chronic cerebrospinal venous insufficiency (CCSVI) was first described by Italian doctor Paolo Zamboni in 2009, who believed that abnormality in blood drainage from the brain and spinal cord was a contributing factor in the development of multiple sclerosis. This theory has since been tested in laboratories and clinics around the world using similar imaging methods. As well, venous dilation approaches are being evaluated in clinical trials, such as one MS Society-funded trial led by Dr. Anthony Traboulsee at the University of British Columbia.
In June 2010, the National MS Society (USA) and MS Society of Canada jointly committed over $2.4 million to support seven research projects that would study the relationship between CCSVI and MS. One of these studies, led by Dr. Robert Fox at the Cleveland Clinic in Ohio was recently published in The Canadian Journal of Neurological Sciences.
Subjects with a definitive diagnosis of MS, aged 21-65 years were recruited and assessed for CCSVI at the Mellen Center in Cleveland, OH. They were compared with age-matched healthy controls as well as individuals with other neuro-inflammatory disorders. All 81 participants underwent ultrasound, conducted by sonographers who were appropriately trained to identify signs of CCSVI, and blinded to diagnosis (i.e. they did not know if the person they were doing the ultrasound on had MS or not). The number of subjects who met the necessary criteria for CCSVI was determined using two different interpretations of the ultrasound data.
In the first interpretation of the data described in the article, the incidence of subjects meeting two or more CCSVI criteria was 20% in controls and 21.3% in MS. In the second interpretation of the data, the incidence of subjects meeting two or more CCSVI criteria was 40% in controls and 36.1% in MS. In both assessments, the data revealed no significant different in the presence of CCSVI between MS and controls.
The study conducted by Dr. Fox and colleagues reveals no association between CCSVI and MS, and suggests against a causal role of CCSVI in MS. They note that the use of different imaging tools and variation in the interpretation of data may explain the conflicting results that have been seen among CCSVI-related studies. As well, different approaches used for blinding of sonographers and radiologists may also explain some of the differences in outcomes. The MS Society of Canada continues to support the Canadian CCSVI trial, and is committed to funding research that will provide answers about CCSVI to people living with MS.
Fox RJ et al. No Association of Chronic Cerebrospinal Venous Insufficiency with Multiple Sclerosis. The Canadian Journal of Neurological Sciences Inc. 2015 August 2 [Epub ahead of print]