The US Food and Drug Administration cleared for marketing the Enroute Transcarotid Neuroprotection System (Enroute TNS), for use during a minimally invasive procedure to restore normal blood flow to narrowed carotid arteries. It is the first device designed to access the carotid arteries through an incision in the neck, instead of the groin, and uses a blood flow reversal system to capture pieces of the blockage dislodged during the procedure.

The carotid arteries are two large blood vessels on either side of the neck that supply oxygenated blood to the brain. Cholesterol or fatty substances can narrow one or both of the carotid arteries, causing carotid artery disease. If a piece of plaque breaks off, it can travel to arteries in the brain and cut off blood flow, resulting in a stroke. According to the National Heart Lung and Blood Institute, more than half of the strokes occurring in the United States each year are caused by carotid artery disease. A person with the disease may not experience any signs or symptoms until a stroke occurs.

A severe narrowing or blockage of the carotid artery may require a physician to perform a minimally-invasive balloon angioplasty procedure in which a balloon on a long flexible tube called a catheter is threaded through a patient’s vasculature from the groin to the site of the blockage, inflated to open the artery and then a small mesh tube called a stent is placed at the site to keep the artery open.

The Enroute TNS allows physicians to insert a catheter into the artery in the neck above the narrowed or blocked section of the artery rather than having to enter through the groin. During the stenting procedure, physicians typically use a filter or additional balloon to capture and remove small pieces of debris that might be dislodged and potentially travel to the brain.

The Enroute TNS captures debris by temporarily shunting blood flowing through the narrowed section of the artery away from the brain and into a filtering system outside the body. Blood is then returned to the body though a vein in the leg. Because the carotid artery branches into many interconnected smaller arteries, the brain still receives oxygenated blood during the procedure.

“Until today’s clearance, the only FDA-cleared systems to capture and remove debris and prevent them from reaching the brain during carotid angioplasty and stenting procedures required entry into the body through the femoral artery using an incision in the groin,” said William Maisel, MD, M.P.H., acting director of the Office of Device Evaluation at the FDA’s Center for Device and Radiological Health. “The Enroute TNS provides a minimally-invasive treatment for certain patients whose tortuous (twisted) or diseased vasculature does not permit access via the groin for treating their narrowed carotid arteries.”

The FDA reviewed the data for the Enroute TNS through a 510(k) submission, a regulatory pathway for low-to-moderate risk medical devices that are substantially equivalent to a legally marketed predicate device that is not subject to premarket approval. In this case, the FDA found the Enroute TNS to be substantially equivalent to a flow reversal system currently on the market that uses similar technology and has the same intended use but is designed to be introduced into the patient through the blood vessels in the groin.

Data supporting the FDA’s clearance included the results from a clinical trial sponsored by the manufacturer. The trial showed that the rate of stroke, heart attack, and death among the Enroute TNS patients was 3.5 per cent, significantly lower than the study performance goal of 11 per cent. At least one serious adverse event occurred in 14.2 per cent of patients, including excessive bleeding or injury at the device access site, low blood pressure due to the device or procedure, and blood clot formation within the placed stent. These events are consistent with the type and rate of serious adverse events associated with other carotid artery procedures.

The Enroute TNS is manufactured by Silk Road Medical of Sunnyvale, California.