Examination with catheter venography and ultrasound shows narrowing of the internal jugular and azygous veins is not unique to MS patients.
Ultrasound and catheter venography demonstrate that venous narrowing is frequently present in the general population and not unique to patients with multiple sclerosis, according to a study published in The Lancet.
Since the publication of a paper in 2009 claiming that MS arises from chronic cerebrospinal venous insufficiency (CCSVI), proponents have been attempting to treat the disease with angioplasty treatments to widen the veins. To determine the validity of this claim, Canadian researchers from the University of British Columbia (UBC) in Vancouver and the University of Saskatchewan in Saskatoon undertook a series of research projects funded by the MS Society of Canada.
“Until now, most studies of venous narrowing have used ultrasound imaging to establish whether venous narrowing is present,” co-author Anthony Traboulsee, MD, said in a release. “We also used catheter venography – usually thought of as the gold standard of venous imaging – to measure whether any narrowing of the veins was present.”
Traboulsee is the MS Society of Canada Research Chair and an associate professor at UBC.
The researchers performed an assessor-blinded, case-controlled study of adults with multiple sclerosis (79), unaffected siblings (55), and unrelated healthy volunteers (43). Participants were enrolled between January 2011 and March 2012 and came from three centers in Canada. Using ultrasound and catheter venography, the researchers assessed narrowing of the internal jugular and azygous veins, which are criteria for CCSVI as proposed by Zamboni and colleagues in 2009. Catheter venography data were available for 149 participants and ultrasound data for 171 participants.
The results showed that at least two-thirds of each of the study groups had narrowing of the extracranial veins greater than 50 percent: 74 percent (48 of 65) of subjects with MS, 66 percent (31 of 47) of siblings, and 70 percent (26 of 37) of unrelated controls. Using the overall criteria for CCSVI proposed by Zamboni and colleagues, one subject (2 percent) with MS tested positive, but so did one of the siblings (2 percent) and one healthy volunteer (3 percent).
When looking at ultrasound findings alone, the researchers noted that the ultrasound criteria for CCSVI did not reliably pick up venous narrowing as shown by catheter venography. Ultrasound found only 42 percent of cases that were picked up by catheter venography.
“Our results confirm that venous narrowing is a frequent finding in the general population, and is not a unique anatomical feature associated with multiple sclerosis,” Traboulsee said. “This is the first study to find high rates of venous narrowing in a healthy control group, as well as the first to show that the ultrasound criteria usually used to ‘diagnose’ CCSVI are unreliable, so if there is a connection between venous narrowing and MS, it remains unknown, and it would certainly appear to be much more complicated than current theories suggest.”