Wednesday, 30 November 2016

#ClinicSpeak & #ResearchSpeak: CCSVI a post-truism

Should we reframe the CCSVI meme as a post-truth phenomenon? #ClinicSpeak #MSBlog #ResearchSpeak

After much discussion, debate, and research, the Oxford Dictionaries Word of the Year 2016 is post-truth – an adjective defined as ‘relating to or denoting circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief’.


The MS community has had its share of 'post-truisms'. The most recent that comes to mind is CCSVI. No matter how much the traditional 'MS establishment' or 'MS intelligentsia' spoke out against the concept of CCSVI the more a small, but very vocal, group that are now known as the CCSVIers were able to drown out the 'truth'. 


Many years after the eye of the storm has passed the paper below comes out from the Canadian group showing that the prevalence of extracranial venous narrowing in pwMS is no different to that in siblings of pwMS and normal control subjects. It appears that these narrowings in the veins of pwMS are non-specific and therefore cannot be linked causally to MS. Will this be the last we hear of CCSVI? As a meme CCSVI, appears to have had its time in sun.




Purpose: The study sought to assess and compare the prevalence of narrowing of the major extracranial veins in subjects with multiple sclerosis and controls, and to assess the sensitivity and specificity of magnetic resonance venography (MRV) for describing extracranial venous narrowing as it applies to the chronic cerebrospinal venous insufficiency theory, using catheter venography (CV) as the gold standard.

Methods: The jugular and azygos veins were assessed with time-of-flight MRV in this assessor-blinded, case-control study of subjects with multiple sclerosis, their unaffected siblings, and unrelated controls. The veins were evaluated by diameter and area, and compared with CV. Collateral vessels were also analyzed for maximal diameter, as a potential indicator of compensatory flow.

Result: A high prevalence of extracranial venous narrowing was demonstrated in all study groups, collectively up to 84% by diameter criteria and 90% by area, with no significant difference between the groups when assessed independently (P = .34 and .63, respectively). There was high interobserver variability in the reporting of vessel narrowing (kappa = 0.32), and poor vessel per vessel correlation between narrowing on MRV and CV (kappa = 0.064). Collateral neck veins demonstrated no convincing difference in maximum size or correlation with jugular narrowing.

Conclusion: There is a high prevalence of narrowing of the major extracranial veins on MRV in all 3 study groups, with no significant difference between them. These findings do not support the chronic cerebrospinal venous insufficiency theory. Although MRV has shown a high sensitivity for identifying venous narrowing, time-of-flight imaging demonstrates poor interobserver agreement and poor specificity when compared with the gold standard CV.

3 comments:

  1. A brilliant post. I am in full agreement with you on this issue.

    ReplyDelete
  2. Where was this done , who were the Doctors , how many people were involved .
    This is bugas study

    ReplyDelete
    Replies
    1. It appears, there are still those out there who continue to hang on to this now completely discredited theory.
      Such is life.

      Delete

Please note that all comments are moderated and any personal or marketing-related submissions will not be shown.