MS blocked vein theory disputed in Canadian study
Evidence mounts against Zamboni's multiple sclerosis idea
Three members of the research team at McMaster University in Hamilton travelled to Italy to observe the ultrasound technique at Paolo Zamboni's lab. Zamboni proposed the concept of blocked veins from the brain, which he coined chronic cerebrospinal venous insufficiency or CCSVI. Zamboni suggested clearing the blocked or narrow veins could relieve MS symptoms.
In Wednesday's issue of the journal PLOS One, professor emeritus Ian Rodger and his co-authors say they found no evidence of abnormalities in head or neck veins of 99 adults with MS compared with 100 healthy controls with no history of any neurological condition.
"This case-control study provides compelling evidence against the involvement of CCSVI in multiple sclerosis," the study's authors concluded.
The MS patients were randomly chosen from a list of clinic patients until there were 25 for each of the subtypes of the disease.
In the study, all participants received an ultrasound and MRI of the neck and deep cerebral veins on the same day to ensure their condition didn't change between measurements.
In the latest study, only one MS patient fulfilled Zamboni's ultrasound criteria for CCSVI. The MRIs showed no evidence of narrowing, blockages or vein abnormalities between cases and controls.
"The pendulum has swung dramatically away from the idea that CCSVI is a major player in MS," Rodgers said in an interview.
Since Zamboni's initial research found evidence of CCSVI in all MS patients, other studies have found it in just some or none.
As those studies were being done, some Canadians with MS rushed overseas for ballooning and stent procedures. Some people with milder forms of MS showed benefits, Rodger said, but there was no long-term followup on benefits. Two Canadians died following the procedure.
"I think that what happened here was that the movement jumped the gun before we truly appreciated whether CCSVI was a real phenomenon or not," Rodger said.
Mike Augustine of Mississauga, Ont., has secondary progressive MS and hopes to climb to the Mount Everest base camp next year in his wheelchair as a fundraiser. Augustine decided to wait before deciding to get Zamboni's treatment, but said he understands why others rushed for it.
"All I know is that there's no such thing as bad answers," Augustine said. "All answers are good. If we find out that CCSVI turns out to be a dead end, then it's just one more avenue that we don't have to waste our time going down."
The study was funded by private donations from the Harrison McCain Foundation, W. Garfield Weston Foundation, Charity Intelligence, St. Joseph's Healthcare Foundation and individuals in the community.
The federal government and MS societies in Canada and the U.S. are also funding trials of the vein-opening procedure.
Dr. Anthony Traboulsee, medical director of the UBC Hospital MS Clinic in Vancouver, is leading a federally funded clinical trial to test whether opening blocked veins in the neck of about 100 patients is safe and effective. Unlike in previous studies, Traboulsee is also using venography with a catheter to take a detailed look at veins.
"The only way to truly address whether or not this is worthwhile is to do a proper research study," Traboulsee said. "The Canadian study that is underway now will address that."
With files from CBC's Kelly Crowe