A novel device that takes a simple approach to protecting the brain during procedures to improve blood flow through arteries in the neck appears to be safer and more effective than existing protection devices, according to a study presented today at the Society for Cardiovascular Angiography and Interventions (SCAI) 33rd Annual Scientific Sessions.
The ARMOUR study showed that when the MO.MA protection device was placed upstream of a cholesterol blockage in the carotid arteries, the one-month risk of heart attack, stroke or death was approximately 75 percent lower than would be typical with a downstream filter, the most common tool for catching bits of plaque and blood clot that can break loose during angioplasty and stenting.
"The MO.MA device protects the brain before we ever touch the lesion," said Robert M. Bersin, M.D., FSCAI, medical director of endovascular services for Seattle Cardiology and Swedish Medical Center, both in Seattle. "This is one of the best results ever observed for carotid stenting."
Angioplasty and stenting of the carotid arteries in the neck are not safe unless the brain is protected from particles that are knocked loose during the procedure. Filter devices positioned downstream of the blockage are often used to catch debris and prevent it from traveling to the brain or other organs. But pushing a filter across a tight blockage can itself dislodge small pieces of plaque and blood clot, and injure the brain.
The MO.MA device avoids this complication. It consists of two tiny balloons that are threaded into the neck arteries on a slender catheter and positioned forward of the blockage, one in the main carotid artery and one in the external carotid artery. Inflation of the balloons temporarily stops blood flow to the internal carotid artery, where the blockage is located. After the narrowed artery is widened with an angioplasty balloon and held open with an expandable metal stent, the interventional cardiologist uses a syringe to suction out any debris that has broken loose, repeating until no more particles are visible.
To evaluate the safety and effectiveness of the MO.MA protection device, researchers at 25 medical centers in the United States and Europe recruited 225 patients who were considered too high-risk for open surgery of the neck arteries, usually because of advanced age, other serious medical conditions, or challenging neck anatomy. The procedure was successful without major adverse cardiovascular or cerebrovascular events (MACCE) such as heart attack, stroke or death in 93 percent of patients. Within 30 days of stenting, the combined MACCE rate was 2.7 percent, far lower than the 13 percent that was predicted on the basis of experience with filter protection devices. The major stroke rate was less than 1 percent.
In addition, patients who were experiencing stroke-like symptoms at the time of the procedure had no higher MACCE rate than the overall group, whereas a doubling of the MACCE rate is typical in symptomatic patients treated with filter protection devices, Dr. Bersin said. Finally, among patients older than 75 years, the MACCE rate was just 2.3 percent.
"The idea that carotid stenting is not safe in the elderly no longer applies," Dr. Bersin said. "This device is a game-changer."
The ARMOUR study was funded by Invatec. Dr. Bersin reports no conflicts of interest.
Dr. Bersin will present the study "Use of the INVATEC MO.MA® proximal cerebral protection device during carotid stenting (The ARMOUR Trial)" at an oral abstract session on Thursday, May 6, 10:30 a.m. to 10:42 a.m. (Pacific Time).