By Jim Knaub
A well-controlled blinded Canadian study strongly disputes the link between narrowed neck veins and multiple sclerosis (MS) by reporting similar rates of narrowing among MS patients and unrelated healthy controls
“The hypothesis that venous narrowings have a role in the cause of multiple sclerosis is unlikely, since the prevalence of venous narrowings is similar in people with the disease, unaffected siblings, and unrelated healthy controls on catheter venography,” wrote the authors of a study published this month in The Lancet. “Narrowing of more than 50% was recorded in almost 75% of the study population (cases and controls) on catheter venography, which supports the contention that venous narrowing is a common anatomical variant.”
The new study contradicts the theory first published by Italian vascular surgeon Paolo Zamboni, MD, that chronic cerebrospinal venous insufficiency (CCSVI), or reduced blood flow from veins leading out of the neck, may cause MS. Zamboni published initial findings on CCSVI and using angioplasty to treat MS patients—sometimes called the liberation treatment—in 2009.
Before The Lancet study, led by Anthony L. Traboulsee, MD, of the University of British Columbia, some follow-up research had shown evidence supporting the CCSVI theory while some did not. Zamboni began treating some patients with angioplasty and stents, and many of them saw improvement in their symptoms.
But the new study appears to break the link between CCSVI and MS by showing the vein narrowing is not unique to people with MS cases, but that does not explain why many patients have reported symptom improvement after angioplasty and stenting.
Interventional radiologists discussed their initial experience with patients during the Society of Interventional Radiology’s annual meetings in 2011 and 2012. At the time, there was concern that the small series of patients followed and the anecdotal evidence would provide false hope to the approximatey 400,000 people in America and 2.5 million worldwide who have MS. Those initial reports and discussion led to better controlled studies, such as the one published by Traboulsee et al.
The new study, “Prevalence of Extracranial Venous Narrowing on Catheter Venography in People with Multiple Sclerosis, Their Siblings, and Unrelated Healthy Controls: a Blinded, Case-Control Study,” also criticized the use of ultrasound to measure vein narrowing, noting that the gold standard method of catheter venography is a more reliable technique.
Since the study did not address whether the treatment has any beneficial effect—only that CCSVI is an unlikely cause for MS—a new study is enrolling patients in four Canadian cities to address that question, according to the Vancouver Sun. The initial results of that study are expected to be available in approximately two years and will provide some well-controlled data about the procedure’s benefits.
— Jim Knaub is editor of Radiology Today.