Venous narrowing may not be significant in MS

Chronic cerebrospinal venous insufficiency may not be associated with multiple sclerosis (MS), contrary to a widely held belief. A study published online Oct. 9 in The Lancet found chronic cerebrospinal venous insufficiency in very small percentages of people with MS, their healthy siblings and unrelated people who do not have MS.

Previous studies conducted by Paolo Zamboni, MD, of the University of Ferrara in Italy and colleagues in 2009 reported a significant association between MS and chronic cerebrospinal venous insufficiency and researchers believed treating venous blockages with venoplasty would improve the disease. Subsequent treatment with venoplasty did lead to better quality of life outcomes and the procedure was in great demand.

However, later studies could not replicate those findings, which led some experts to doubt the existence of chronic cerebrospinal venous insufficiency.

“Until now, most studies of venous narrowing have used ultrasound imaging to establish whether venous narrowing is present,” lead author Anthony Traboulsee, MD, of the University of British Columbia, said in a press release. “While ultrasound is a relatively simple and inexpensive way of looking at veins, it’s not necessarily the most accurate imaging technique, so in our study, 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.”

The researchers looked at the narrowing of the internal jugular and azygous veins in 177 adults—79 had MS, 55 were their healthy siblings and 43 were unaffected controls. They used catheter venography and ultrasound with the same criteria for chronic cerebrospinal venous insufficiency used by Zamboni et al.

Only one of the 65 participants (2 percent) with MS who remained at the end of the study period had chronic cerebrospinal venous insufficiency based on Zamboni et al’s criteria. The narrowing was also seen in only one of the 46 remaining siblings (2 percent) and one of 32 remaining controls (3 percent).

Additionally, 44 percent of the participants with MS, 31 percent of the siblings and 45 percent of the controls met the ultrasound criteria for chronic cerebrospinal venous insufficiency. Ultrasound criteria sensitivity for detecting more than 50 percent narrowing on catheter venography was 0.406.

More than 75 percent of participants had more than 50 percent narrowing, suggesting it is relatively common.

“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 controls on catheter venography,” the authors concluded.