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Regarding “A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency”

      In the article “A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency,” by Zamboni et al,
      • Zamboni P.
      • Galeotti R.
      • Menegatti E.
      • Malagoni A.M.
      • Gianesini S.
      • Bartolomei I.
      • et al.
      A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency.
      the authors compared pre- and post-therapy outcomes with two-sample statistical analyses as though the outcomes arose from independent groups of patients (page 1351 of the article). They did not present within-patient results or use paired statistical tests for change in venous pressure or neurologic outcomes. Their reported use of Fisher exact test to analyze annualized relapse rates is not appropriate because those data are not proportions or numbers of patients. Tables IV and V fail to state the number of patients included in these results. One might suspect that not all 35 relapsing remitting patients contribute to Table IV, as no counts yield percentages of 27% (9: 26%, 10: 29%) or 50% (17: 49%, 18: 51%), for example.
      Given the attention that Dr Zamboni's results have received, the reader would welcome an addendum with clarification and information that is more complete. It is possible that the appropriate paired testing would provide similar or greater degrees of statistical significance, bolstering hope for the effectiveness of percutaneous transluminal angioplasty in treating multiple sclerosis patients.

      Reference

        • Zamboni P.
        • Galeotti R.
        • Menegatti E.
        • Malagoni A.M.
        • Gianesini S.
        • Bartolomei I.
        • et al.
        A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency.
        J Vasc Surg. 2009; 50: 1348-1358

      Linked Article

      • A prospective open-label study of endovascular treatment of chronic cerebrospinal venous insufficiency
        Journal of Vascular SurgeryVol. 50Issue 6
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          Chronic cerebrospinal venous insufficiency (CCSVI) is characterized by combined stenoses of the principal pathways of extracranial venous drainage, including the internal jugular veins (IJVs) and the azygous (AZY) vein, with development of collateral circles and insufficient drainage shown by increased mean transit time in cerebral magnetic resonance (MR) perfusion studies. CCSVI is strongly associated with multiple sclerosis (MS). This study evaluated the safety of CCSVI endovascular treatment and its influence on the clinical outcome of the associated MS.
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        Journal of Vascular SurgeryVol. 52Issue 6
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          Our study is a pilot study with promising results. It shows two main shortcomings: the lack of a control group and blinded clinical assessors. We chose to use statistical tests to underestimate rather than exalt our findings, precisely because of the above limitations. The tests suggested by you, as you noted at the end of your letter, provide even greater degrees of statistical significance. Our policy is to be as prudent as we can, waiting for randomized control trial angioplasty results. The main message of our study is the safety and the feasibility of venous angioplasty in patients affected by chronic cerebrospinal venous insufficiency associated with multiple sclerosis (CCSVI-MS).
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