The controversial theory that treatment to improve blood flow in the brain can improve the symptoms of multiple sclerosis has failed yet another test.

The theory, called Chronic Cerebro-Spinal Venous Insufficiency Therapy, involves using angioplasty to improve blood flow in the veins draining the central nervous system. Multiple sclerosis is caused by an inflammation of the myelin sheaths that surround nerve axons and protect them. In 2008 an Italian researcher, Paolo Zamboni, suggested that symptoms of the disease can be improved by restoring blood flow in the brain to alleviate inflammation. The theory generated excitement among some MS patients, but several studies have failed to replicate Zamboni's findings.

In the new study, researchers studied 18 patients with multiple sclerosis who were U.S. veterans. They were compared to 11 similar patients who did not have MS. All the participants had imaging tests to examine the veins for signs of blockage. The study found no difference between the two groups in impairment of the cerebral veins and blood outflow.

"We welcome new insights into the disease process and especially the promise of a single effective treatment," the study authors wrote. "However, our findings and those of other investigators call into question whether CCSVI plays a pathogenic role in a substantial fraction of patients with MS and whether it presents a valid therapeutic target."

The study was published online Monday in the Archives of Neurology.

http://www.latimes.com/health/boostershots/la-heb-multiple-sclerosis-20110811,0,6750398.story