Study suggests CCSVI could be symptom of MS
CTV.ca News Staff
Published Thursday, April 14, 2011 10:13PM EDT
A new study suggests that those suffering from severe cases of multiple sclerosis have greater problems draining blood from their brain, and raises questions about whether that condition is a cause or a symptom of MS.
Researchers at the University of Buffalo performed ultrasound scans on nearly 500 people, more than half of whom had MS. The results were published Wednesday in the journal Neurology.
Among participants who were suspected of having MS because they had one initial attack, 38 per cent also had a narrowing of veins that restricts normal outflow of blood from the brain, a condition known by the acronym CCSVI.
Fifty-six per cent of those diagnosed with MS and 89 per cent of participants with severe cases of the disease also had the blood-flow condition.
The researchers also found that 22 per cent of healthy controls had CCSVI. Some in this group were family members of patients with MS – a disease that sometimes has a genetic link.
"I think there are two key messages of the study," said Dr. Robert Zivadinov, a professor of neurology at the University of Buffalo and the study's lead researcher.
"One is certainly that CCSVI is associated with MS," he told CTV News Channel by phone from Honolulu, Hawaii, on Thursday afternoon.
"On the other hand, the fact that almost one in four (subjects) has CCSVI and has no MS, and the fact that almost 45 per cent of our subjects who had other neurologic diseases had CCSVI, clearly puts a question whether CCSVI is the cause of this disease," he said.
Since restricted blood-flow was found to be more common among those with "advanced phases" of MS, Zivadinov said the study's results suggest that CCSVI could be a symptom of MS.
"Do not misunderstand me -- we clearly believe the CCSVI research should continue," he said. "We need to understand, if more progressive patients have more CCSVI, what does that mean for them, and what is the real association?"
Given the uncertainties of the relationship between CCSVI and MS and the potential risks of intervention, the researchers advised that balloon venoplasty should be used to open restricted neck veins only in "a blinded, controlled clinical trial."
The study also included 10 children with MS, and found that half had CCSVI.
"Although the sample size was too small to draw any firm conclusions, these results suggest that CCSVI is also present in children and is not the result of aging," Dr. Ann Yeh, an assistant professor of neurology at the University of Buffalo, said in a press release.
The term CCSVI, or chronic cerebrospinal venous insufficiency, was coined by Italian vascular surgeon Dr. Paolo Zamboni. It refers to a narrowing of the veins in the neck and chest that restrict normal blood flow out from the brain.
"The Buffalo data is very clear," Zamboni told CTV News by phone. "(CCSVI) is found in normal people… but the prevalence in MS is higher, significantly higher."
Some news reports suggested that lower rates of prevalence cast doubt on the CCSVI theory, and on the venoplasty therapy some clinics offer to open narrowed veins in MS patients.
Zamboni established five ultrasound criteria for the definition of CCSVI and says patients with two of the five criteria meet the standard for having the condition. He has reported finding the condition in over 90 per cent of patients with MS.
Patients like Michelle Walsh refuse to be drawn into the scientific debate. Walsh was treated twice for three blocked veins in her neck and chest and now reports having more energy and control of her bladder.
"I just want to tell patients that you know that this study doesn't have a lot of relevance, in my opinion, that this is maybe a small indication," she said from Winnipeg. "The rest of the world is showing great correlations in their studies and it's being done properly by endovascular specialists, not neurologists."
Walsh is currently "on tour" with a physician from California who treated her the second time. Dr. Joseph Hewitt is an interventional radiologist who says he is finding CCSVI in over 90 per cent of patients with MS, using a venogram, which is considered the gold standard for diagnosis. It threads a wire into the veins to look for blockages.
Hewitt says the Buffalo study he says has "flaws" because it relied on ultrasound tests, which depend on a technician's skills to perform and interpret them properly.
Meanwhile, researchers at the University of British Columbia are in the midst of a study comparing prevalence rates of CCSVI in those with MS twins, and healthy controls. They are using ultrasound MRV and venograms.
One of the researchers with the UBC study, Dr. Lindsay Machan, says the University of Buffalo research is of limited value.
"I don't think the study either proves or disproves it. The definitive gold standard of diagnosing venous disease is putting a catheter inside the vein and injecting x-ray die," he said. "In those studies that were reported, that wasn't done."
Machan expects the UBC study will be complete in the fall.
"It's going to take a collective body of evidence from many facets and many different researchers for us to really get an idea of what the role of CCSVI is in MS," he said.
With a report from CTV's Medical Specialist Avis Favaro