Controversial Treatment May Not Help MS Patients
Study appears to refute theory of blocked neck veins as cause of multiple sclerosis
"This was a big surprise to all of us. We were expecting to find many more people with this feature," Traboulsee said.
When they looked for a narrowing of more than 50 percent of the neck veins, they found 74 percent of MS patients had this narrowing.
"But again, to our surprise, we found very similar numbers of siblings, with 66 percent and with 70 percent of volunteers having these narrowings," Traboulsee said. "So, there weren't any significant differences between the three groups."
"Using the best methods available we were unable to confirm Dr. Zamboni's theory that MS was cause by CCSVI," he said. "Our conclusion was that the narrowing of the neck veins are common, and a normal finding in most people."
A U.S. expert said the new study provides significant insight into this theory.
"All of the studies to date have raised questions that CCSVI was a causal element of MS," said Timothy Coetzee, chief research officer at the National Multiple Sclerosis Society. "But we don't know to what degree the venous narrowing lead to the symptoms of MS. That's one of the open questions."
Coetzee isn't ready to completely discount CCSVI. He said the new findings need to be replicated before the theory is discarded.
Another expert, however, thinks these findings shut the door on the legitimacy of CCSVI both as a theory behind MS and as a treatment target.
Dr. Gary Birnbaum, director of the MS Treatment and Research Center at the Minneapolis Clinic of Neurology, said that "this is another in a series of papers, by a distinguished group of investigators, that persuasively refutes the contention that venous obstruction is a significant component of the pathogenic processes present in multiple sclerosis."
"Indeed, there are no persuasive data to suggest that treatment of venous narrowing in persons with MS offers any substantive therapeutic benefit," he said.
Traboulsee, however, has now embarked on a study to see why some MS patients who have undergone the liberation procedure say their conditions have improved.
In that study, MS patients are being randomly assigned to get the liberation procedure or a sham treatment. Based on the findings of this study, Traboulsee said he hopes to see if the reported improvements are the result of a placebo effect or real changes in the condition of the disease.
"It's possible the treatment effect is independent of the original theory," he said. "It is not unprecedented in medicine that a theory was disproven, but that it led to something beneficial for patients."