CCSVI – Part 2
There was a great deal of excitement in the MS community when Dr. Zamboni’s paper was published in 2009. Using a form of ultrasound, Zamboni investigated abnormal blood flow using five different criteria. Most of the 65 people with MS (relapsing-remitting, secondary-progressive and primary-progressive) had evidence of an abnormality on four of five criteria (although on different criteria depending on whether they were RRMS, SPMS or PPMS). None of the 235 people without MS met more than one of the criteria.
The second part of the study was more invasive. Everyone in the MS group and 48 people in the non-MS group underwent venography, which involves inserting a catheter into a vein and looking directly at the inside of the blood vessel. (The controls were healthy older people already scheduled for venography.) A stenosis (narrowing of the blood vessel) was defined as at least a 50% reduction in the inside diameter of the vein. What Zamboni found was the 91% of people with MS had narrowing of the jugular vein, and 86% had narrowing of the azygous vein (although this vein isn’t directly involved in blood flow from the brain). None of the healthy controls showed this pattern of narrowed blood vessels.
As a result of these preliminary findings, Zamboni asked two questions. 1) Does CCSVI influence the clinical course of MS? and 2) Are venous stenoses the cause or products of MS? (This is the chicken/egg question: Is narrowing of the veins the cause of MS, or does it develop because of MS?) He also raised the further possibility that MS treatments may alter venous blood flow. This was a bit of a red herring, however, since this study found that narrowing was no different in people treated with a disease-modifying therapy or immunosuppressants.
If people with MS had narrow blood vessels, the obvious step would be to open them with angioplasty. This involves inserting a catheter into the vein and inflating a small balloon to expand the inside of the blood vessel. When this was done in a pilot study involving 65 people with MS meeting the Zamboni criteria for CCSVI (Zamboni and colleagues. J Vasc Surg 2009;50:1348-1358). Following the procedure, about one-half of the jugular veins restenosed (got narrow again). Despite this, angioplasty appeared to increase the number of people who were free of relapses 18 months later (from 27% to 50%), and reduced the number of people with inflammatory lesions on their MRI (from 50% to 12%).
In an unfortunate bit of hype, Dr. Zamboni called his angioplasty surgery the Liberation procedure. Although he later explained that he meant that angioplasty liberated the flow of blood, there was a whiff of snake oil to the term: Liberation will set you free.
In Part 3 we’ll look at the studies that challenged CCSVI as a treatment for MS.
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