New research on MS
We rely on our brains and nervous system for everything, and the effects of neurodegenerative diseases like multiple sclerosis can be widespread and devastating. When a new option like the Liberation Treatment offers new hope, it’s easy to wonder why it can’t be offered to everyone who wants it — and lament about the seemingly slow progress of medical science.
Indeed, the treatment has been mired in controversy, thanks in part to conflicting research regarding the theory behind it: chronic cerebrospinal venous insufficiency (or CCSVI for short). Named by Italian doctor Paolo Zamboni in 2009, the theory posits that veins in the neck and head of MS patients may be narrowed or blocked, which creates problems with blood flow and drainage in the brain and spinal cord. These abnormalities can be detected by ultrasound, and Zamboni and his colleges’ work found that CCSVI was much more common in people suffering from multiple sclerosis than in people without the disease.
Sound too good to be true? Unfortunately, other researchers weren’t able to replicate his success — leading to a lot of confusion about CCSVI, not to mention the treatment designed to combat it. However, a new meta-analysis of research conducted by Canadian experts recently published in the Canadian Medical Association Journal (CMAJ) found that Zamboni was on the right track after all.
During this review, researchers from St. Michael’s Hospital, University of Toronto, Sunnybrook Health Sciences Centre in Toronto and the University of Calgary examined all eight published studies conducted in Italy, Germany, Jordan and the United States which compared the incidence of CCSVI in patients with and without multiple sclerosis. The results among individual studies showed a lot of variation: some studies found there was little difference between patients with MS and those without the disease, while others showed a marked difference.
However, when reviewers considered the statistics as a whole — including 664 patients with multiple sclerosis and an equal number of participants in the control groups — the data does suggest an association between CCVSI and MS.
However, because some of the studies had small sample sizes and possible differences in quality control, the reviewers couldn’t say there was a definitive link. For instance, how ultrasound staff were trained and which techniques they used could have influenced the results, as could potential bias from the “blinding” process.
“We found a strong and statistically significant association between chronic cerebrospinal venous insufficiency and multiple sclerosis. However, the large amount of heterogeneity among the study results prevents a definitive conclusion,” writes Dr. Andreas Laupacis, Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, with coauthors. “The source of the heterogeneity is not clear. It is not obviously caused by differences in the definition of chronic cerebrospinal venous insufficiency, patient characteristics or the methodologic quality of the studies.”
It’s also important to keep in mind that an association between CCVSI and MS doesn’t mean one condition causes the other. Researchers note it’s possible that CCSVI could be more common in MS patients without causing the disease. (After all, the studies did find cases where CCVSI was present in patients who didn’t have MS.)
Perhaps this conclusion didn’t surprise you, but there are other lessons to be learned here. By looking at the studies collectively, researchers can spot potential faults that can be corrected in future studies. The authors conclude that “further high-quality studies, using identical ultrasound protocols, are needed to definitively determine whether chronic cerebrospinal venous insufficiency is more frequent among patients with multiple sclerosis than among those without it.”
In the meantime, it’s too early to say whether CCVSI will revolutionize the treatment of MS.
“The meta-analysis by Laupacis and colleagues is a good starting point,” says Dr. Robert Fox from the Mellen Center for Multiple Sclerosis Treatment and Research at the Cleveland Clinic, Cleveland, Ohio, in a related commentary. “However, much work remains to be done before we can be certain whether chronic cerebrospinal venous insufficiency is a paradigm shift in the classic sense … or just another fad.”
(Read more about the review on the CMAJ website.)
The impact of MS in Canada
– Canada has one of the highest rates of MS in the world. An estimated 55,000 to 75,000 Canadians have MS, according to the Public Health Agency of Canada. (A new Multiple Sclerosis Monitoring System was announced in March 2011 to help keep tabs on incidence and patterns.)
– Every day, three Canadians are diagnosed with MS. It’s the most common neurological disease affecting younger adults, and is often first detected between the ages of 15 and 40.
– MS affects three times as many women as men.
– Currently, clinical trials investigating CCSVI are still in the planning stages in Canada. In June 2011, our Minister of Health announced that Phase I/II clinical trials would proceed in Canada. (Read the press release from Health Canada.)
ON THE WEB
For more information about MS and CCSVI, see our previous article, Multiple Sclerosis: a primer, and these sources: