Background
Preliminary, unpublished results from a placebo-controlled, double-blind phase I/II pan-Canadian CCSVI clinical trial were presented at the Society for Interventional Radiology annual scientific meeting in Washington, D.C. on March 8th, 2017. Jointly funded by the MS Society of Canada and the Canadian Institutes of Health Research (CIHR), with additional funding from the Provinces of British Columbia, Manitoba and Quebec, the trial was led by MS neurologist and researcher Dr. Anthony Traboulsee from the University of British Columbia and involved an extensive network of neurologists, radiologists, statisticians, clinical trialists, and trainees from across Canada. The primary purpose of the clinical trial was to evaluate the safety of venoplasty (a procedure that involves inserting a balloon that widens the veins and improve blood flow) versus placebo in people with multiple sclerosis who displayed signs of chronic cerebrospinal venous insufficiency (CCSVI) as described by Dr. Paolo Zamboni. Additionally the trial was conducted to ascertain the efficacy of this procedure in treating MS both in the short and long term.
About the study
The clinical trial was launched in 2012 when Dr. Traboulsee received a grant from the MS Society and CIHR. Recruitment of MS participants occurred over two years, and those who displayed signs of CCSVI as determined by ultrasound and venography were randomized to receive either venoplasty or a sham procedure (placebo). A total of 104 participants from Vancouver, Winnipeg, Montreal and Quebec City were randomized: 49 participants received venoplasty and 55 received the sham procedure. Participants crossed over to the treatment or placebo arm at 48 weeks, for an additional 48-week treatment period. Preliminary results at 48 weeks were presented by interventional radiologist Dr. Lindsay Machan from UBC. They showed no statistical difference in outcomes between the two study groups in terms of MRI measures, clinical assessments of MS symptoms and patient self-assessments. The research team concluded that venoplasty is ineffective as a treatment for people living with multiple sclerosis.
About Chronic cerebrospinal venous insufficiency (CCSVI)
Chronic cerebrospinal venous insufficiency (CCSVI) is a term coined by Dr. Paolo Zamboni of the University of Ferrara in Italy. CCSVI describes a theory in which the veins in the head and neck are narrowed or blocked, and therefore unable to efficiently remove blood from the central nervous system. More specifically, 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 suggested that because these compensatory blood vessels don't have the same structural integrity as larger veins, they tend to leak blood into the surrounding tissue, depositing iron in the central nervous system and thereby triggering an immune response associated with multiple sclerosis. Dr. Zamboni published results from a study which demonstrated that CCSVI was present in all the individuals with MS that he examined. Following the release of Dr. Zamboni’s findings, additional studies have been conducted world-wide, including 7 research projects jointly funded by the MS Society of Canada and the National MS Society (U.S.) that focused on the relationship between CCSVI and MS.
Comment
The MS Society has heard from many Canadians living with MS who have undergone venous dilation procedures to treat their MS, who have reported a range of health outcomes. These preliminary results provide a critical first glance at the efficacy and safety of venoplasty, which provide more clarity around whether or not this is a viable treatment option and whether CCSVI is unique to MS. The MS Society of Canada respects and honours an individual’s right to make decisions for the benefit of their own health and encourage those who want to explore venoplasty as treatment for MS to visit Risks and Safety with CCSVI-Related Procedures and Accessing Treatments Outside of Canada. Publication of the results of the pan-Canadian CCSVI clinical trial will provide the MS community a clear and deeper understanding of the effects of this procedure for MS, and will ultimately provide the information that people living with MS need to make safe and informed decisions about their health.