(RxWiki News) Studies have shown a possible connection between blocked veins and multiple sclerosis (MS). But these studies may have been designed poorly, leaving this topic in need of more research.
Studies that looked at the link between vein blockages and MS have conflicting results. More research is needed before a solid association can be made.
"Don't rely on treating blocked veins to improve MS."
Andreas Laupacis, M.D., M.Sc., of St. Michael's Hospital in Toronto, and his colleagues reviewed eight studies that examined the link between MS and a type of vein blockage called chronic cerebrospinal venous insufficiency (CCSVI).
CCSVI is a condition in which people have blocked blood flow in the veins that drain the brain and spinal cord. The association between this condition and MS is controversial, as different researchers have come to very different conclusions.
According to Dr. Laupacis, people on both sides of this controversy tend to pay attention to the research that supports their view while disregarding the other. For this reason, the team of Canadian researchers conducted a review of these studies.
In their review, the researchers found that some studies showed no difference in the rate of CCSVI between patients with MS and those without the disease. At the same time, they saw studies that found huge differences.
These inconsistent results may be due to the quality of the studies.
All eight of the studies used ultrasound (the use of sound waves to produce pictures of inside the body) to diagnose CCSVI and compare MS patients to non-MS patients. However, most of the studies were not clear about the training of those who did the ultrasounds.
The studies were also unclear about how much the people doing the ultrasounds knew about the MS-status of participants.
When the findings of all the studies were calculated together, MS patients were more likely to have CCSVI than those without MS.
Dr. Laupacis says these overall findings suggest a link between the two conditions. Be that as it may, the different results and poor quality of certain studies means that more research is needed, Dr. Laupacis concludes.
This analysis of studies - which is published in the Canadian Medical Association Journal - received financial support from the Canadian Institutes of Health Research.