St. Michael’s physician-researcher appears before Senate committee
Toronto, November 6, 2012
By Leslie Shepherd
Dr. Andreas Laupacis
Dr. Andreas Laupacis, executive-director of the Li Ka Shing Knowledge Institute, appeared Nov. 1 before a Senate committee exploring whether there should be a national strategy for testing a controversial theory about the cause of multiple sclerosis.
Italian physician Dr. Paolo Zamboni has suggested that MS may be caused by blockages in the veins in the neck, which disrupt drainage of the brain and spinal cord. He calls this condition chronic cerebrospinal venous insufficiency or CCSVI.
Dr. Zamboni suggested in a 2008 research paper that CCSVI can be diagnosed using ultrasound, a non-invasive technique with no side effects, and that MS symptoms can be improved by mechanically widening and unblocking veins.
Dr. Laupacis is part of a group of 10 Canadian researchers funded by the Canadian Institutes of Health Research who have reviewed scientific evidence from around the world about MS and CCSVI.
He is also a palliative care physician at St. Michael’s Hospital in Toronto and a researcher with expertise is reviewing scientific literature to assess the benefits and harms of tests and treatments. He has advised health ministries in Canada about which tests and treatments should be paid for by the publicly funded health care system.
Dr. Laupacis told the Senate Social Affairs, Science and Technology Committee that at this time, he thinks that Canada’s public health care systems should not pay for the diagnosis or treatment of CSSVI. He said he does not think there is sufficient high-quality evidence to establish that the benefits of treatment outweigh the harms or that we can reliably diagnose CCSVI.
Dr. Laupacis said a number of studies have been unable to replicate Dr. Zamboni’s findings that all patients with MS had CCSVI and that he could find no CCSVI in people who did not have MS.
The CIHR-funded research group identified all of the published studies that diagnosed CCSVI with ultrasound and compared MS patients with healthy people. When the results from all 11 studies were combined, they found CCSVI was about eight times more likely to be found in people with MS than in healthy people.
However, there was a huge difference in results among the studies, which is unusual.
Dr. Laupacis said one explanation might be that ultrasound results can be affected by how much pressure is put on the neck with the ultrasound probe, the position in which the patient is scanned, how the patient is breathing and the experience of the person doing the ultrasound.
“It may well be that differences in ultrasound technique and in the interpretation of the test caused the marked difference in results of the studies, but we don’t know.” he said. “The bottom line is that the results of these studies are not conclusive.”
Dr. Laupacis said many people with MS report a dramatic improvement in symptoms after undergoing a venoplasty--dilating the narrowing in the veins with a balloon—although others report minor or no improvement. Renarrowing of the vein occurs within months in about 30-45 per cent of patients. Although venoplasty is safe in most people, between one-to-two per cent of patients suffer severe side effects including an abnormal heart rhythm, major bleeding from the blood thinners patients are prescribed around the time of the procedure, clots and even strokes.
Dr. Laupacis said the only way to establish whether CCSVI improves symptoms is to conduct a randomized trial in which some of the patients undergo venoplasty and others do not. No such trials have been reported, although six such trials are under way.