Some researchers believe that CCSVI, which is characterized by a narrowing (stenosis) of veins in the neck and chest, may cause multiple sclerosis (MS) or may contribute to the progression of the disease by impairing blood drainage from the brain and upper spinal cord. However, studies exploring a link between MS and CCSVI are inconclusive, and the criteria used to diagnose CCSVI have not been adequately established.
"Because there is no reliable evidence from controlled clinical trials that this procedure is effective in treating MS, FDA encourages rigorously-conducted, properly-targeted research to evaluate the relationship between CCSVI and MS," said William Maisel, M.D., M.P.H., chief scientist and deputy director for science in the FDA's Center for Devices and Radiological Health. "Patients are encouraged to discuss the potential risks and benefits of this procedure with a neurologist or other physician who is familiar with MS and CCSVI, including the CCSVI procedures and their outcomes."
The experimental procedure uses balloon angioplasty devices or stents to widen narrowed veins in the chest and neck. However, the FDA has learned of death, stroke, detachment and migration of the stents, damage to the treated vein, blood clots, cranial nerve damage and abdominal bleeding associated with the experimental procedure. Balloon angioplasty devices and stents have not been approved by the FDA for use in treating CCSVI.
MS is a progressive, immune-mediated disorder of the brain and spinal cord. In MS, the lining around nerve fibers, and often the nerve fibers themselves, in the brain and spinal cord are injured, resulting in significant and disabling neurological symptoms. The underlying cause of MS is not known.
Complications following CCSVI treatment can be reported through MedWatch, the FDA Safety Information and Adverse Event Reporting program.
The FDA also is notifying physicians and clinical investigators who are planning or conducting clinical trials using medical devices to treat CCSVI that they must comply with FDA regulations for investigational devices. Any procedures conducted are considered significant risk clinical studies and require FDA approval, called an investigational device exemption.
In February 2012, the FDA sent a warning letter to a sponsor/investigator who was conducting a clinical study of CCSVI treatment without the necessary approval. The sponsor/investigator voluntarily closed the study.
The FDA will continue to monitor reports of adverse events associated with "liberation therapy" or the "liberation procedure" and keep the public informed as new safety information becomes available.
The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation's food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.