Background on the Systematic Literature Review

The objective of this review was to provide the Scientific Expert Working Group with a high-quality knowledge synthesis and quarterly updates to the review (for one year). The review to support the work of the Scientific Expert Working Group focused on both diagnostic and therapeutic issues related to the proposed CCSVI condition in individuals with MS.

The systematic review questions were:

  1. What is the prevalence of extracranial venous malformation in individuals with MS compared to individuals without MS?
  2. What is the prevalence of abnormal cerebral venous drainage in individuals with MS compared to individuals without MS?
  3. What is the evidence that abnormal variation in extracranial venous anatomy is linked to abnormal cerebral venous drainage?
  4. What is the association between extracranial venous malformations and abnormal cerebral venous drainage with clinical outcomes of MS?
  5. What is the evidence regarding the reliability and validity of non-invasive testing to identify extracranial venous malformations and abnormal cerebral venous drainage (e.g. ultrasound, MR venography)?
  6. What is the evidence of the safety and efficacy of venoplasty of extracranial venous malformations to improve cerebral venous outflow?
  7. What is the evidence of the safety and efficacy of re-intervention for vein thrombosis (or restenosis) following venoplasty with or without concomitant stent placement (with respect to MS clinical outcomes, patency outcomes (for MS and general population), and other harms?)?

Results of this systematic literature review suggest a statistical relationship between CCSVI and MS. However, as the large variation in the results do not allow definitive conclusions to be drawn, the authors consider that more high-quality studies are needed to determine definitively whether CCSVI is more frequent in individuals with MS as compared to those without MS. This meta-analysis will need to be updated as the results of future studies become available.

Background of the Expedited Knowledge Synthesis Program

Expedited Knowledge Synthesis is a component of CIHR's Evidence on Tap program. The objective of Evidence on Tap is to produce high-quality, timely, and accessible evidence that is of immediate interest and use to knowledge-users. CIHR developed Evidence on Tap to amplify its capacity to engage with provincial and territorial ministries of health and to produce research that responds to their priorities. Syntheses are often cited as the preferred source of evidence to inform decision-making because they minimize bias and bring together the global evidence on a topic. They "render our vast libraries of scientific literature useful to knowledge-users – turning that knowledge into a form that is reliable, relevant and readable". The one drawback of syntheses, from the point of view of knowledge-users, is that they usually take too long to produce for them to be a useful response to urgent priorities. Knowledge-users have a narrow window for making decisions and therefore need their evidence to be available quickly.

Biography of Dr. Andreas Laupacis, MD, MSc, FRCPC

Dr. Laupacis is a General Internist. In September 2000, he was appointed President & CEO and Senior Adjunct Scientist at Institute for Clinical Evaluative Sciences (ICES), and a Professor in the Departments of Medicine and Health Policy Management and Evaluation at the University of Toronto. In October 2006, he moved to St. Michael's Hospital to assume the position of founding Executive Director of the Li Ka Shing Knowledge Institute. Dr. Laupacis continues to work with ICES, as an Adjunct Scientist.
His research training includes two years as a Medical Research Council of Canada (MRC) Research Fellow with Dr. Calvin Stiller at the University of Western Ontario studying the efficacy of cyclosporine as an immunosuppressant in transplantation and diabetes. He also has a Master’s degree in Design, Measurement and Evaluation from McMaster University.
Dr. Laupacis’ initial research interests were in the design and execution of multi-centre clinical trials, evaluating methods of presenting the results of clinical trials to patients and clinicians, and health care technology assessment. More recently, he has become involved in the areas of pharmacoeconomics, drug policy and the use of diagnostic tests.
Dr. Laupacis has published over 175 articles in peer-reviewed journals

For further details about the systematic review, please refer to the CMAJ publication entitled: Systematic review of the association between chronic cerebrospinal venous insufficiency and multiple sclerosis.

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