Canadian researchers were unable to duplicate Paolo Zamboni’s finding that CCSVI plays a significant role in MS.

Canadian researchers at McMaster University have found no evidence of compromised veins in the heads or necks of multiple sclerosis (MS) patients. This contradicts a theory developed by Italian researcher Paolo Zamboni that chronic cerebrospinal venous insufficiency (CCSVI) is a primary contributing factor in MS.

The term CCSVI was coined by Zamboni, of the University of Ferrara, Italy in 2008. He proposed that veins in the heads and necks of those with MS are either blocked, malformed, or narrowed, impeding the flow of blood and drainage from the central nervous system (CNS).

In Zamboni’s study, published in 2008, 65 patients with diagnosed MS and 235 patients who were either healthy or suffering from neurological conditions other than MS took part.

Zamboni concluded that MS “…is strongly associated with CCSVI, a scenario that has not previously been described, characterized by abnormal venous [blood movement] determined by extracranial multiple venous strictures of unknown origin. The location of venous obstructions plays a key role in determining the clinical course of the disease.”

Thrilled by Zamboni’s findings, many MS patients asked for an angioplasty, a blockage clearing procedure, to open the obstructed veins.

In the medical camp, however, Zamboni’s revelations were met with skepticism, sparking a heated debate over the validity of his study and methods. The fact that Zamboni is a vascular surgeon by training caused some to speculate this was the reason he found a connection between MS and malformed veins.

Zamboni is also affiliated with the company Esoate, makers of the imaging equipment used to examine patients in his study. Some see this as a conflict of interest that further taints the study results.

Patients who were treated for CCSVI with angioplasty shortly after Zamboni’s study have not all fared well. There are risks associated with any surgery, and this is no exception.

Citing that, “CCSVI procedures have been associated with serious, even fatal, complications,” the U.S. Food and Drug Administration (FDA), alerted the public in a 2012 safety publication.

If Zamboni’s theory that CCSVI causes MS is correct, other researchers should be able to make the same observations.

In the McMaster University study published last week, however, Zamboni’s methods were replicated, but not his results. Researchers found no concrete correlation between vein drainage and MS in 100 MS patients and 100 healthy control subjects.

“This is the first Canadian study to provide compelling evidence against the involvement of CCSVI in MS,” said principal investigator Ian Rodger, a professor emeritus of medicine in the Michael G. DeGroote School of Medicine, in a press release. “Our findings bring a much-needed perspective to the debate surrounding venous angioplasty for MS patients.”

Within hours of the release of the McMaster study, Zamboni issued a formal response suggesting that because the McMaster researchers did not use the same imaging equipment—which Zamboni helped to develop and market—and failed to capture images using his techniques, it would not be possible for them to replicate the same results he found in his earlier study.

Neither party responded to interview requests from Healthline.

While the CCSVI debate is certain to continue, patients who want to learn more about the theory and recommended treatments should study up before undergoing any medical procedure.

The National Multiple Sclerosis Society (NMSS) has published information regarding CCSVI, taking no stance on its validity. They have funded research to explore the theory, including a study at the University of Texas Health Science Center. The NMSS summarized the study by saying, “…their findings do not indicate altered vein flow in people with MS, and do not support a significant role for CCSVI in MS.”