October 24 , 2005
‘Rehearsal’ makes carotid stenting safer, more
BY Kathi Baker
Emory cardiologists are the first in the United States to combine the technology of a patient’s MRI (magnetic resonance imaging) scan with a training simulator to “rehearse” the high-risk carotid stenting procedure before actual surgery takes place. This innovative use of simulation technology helps the physician prepare for the procedure and reduces the risk of complications for the patient.
Carotid arteries are the primary blood vessels to the brain. When they become clogged with plaque, it often is necessary to open the vessels by implanting a wire mesh tube called a stent. While carotid stenting is a difficult procedure, it is the most effective way for doctors to prop open the artery and restore blood flow. Carotid stenting was approved by the U.S. Food and Drug Administration (FDA) in September 2004 as an alternative to carotid endarterectomy (surgically removing plaque from the carotid artery).
Carotid stenting requires a high-degree of technical skill. The surgeon makes a small incision in the groin, and while looking at a monitor, guides a catheter carrying the stent through the artery to the affected area. If plaque is accidentally dislodged and enters the brain during the journey, the patient could have a stroke or die.
Christopher Cates, director of vascular intervention at Emory and Crawford Long hospitals, and his colleague Anthony Gallagher designed one of the first virtual-reality programs to train physicians in carotid stenting. Using simulators that resemble human mannequins, the physician threads a catheter through an artificial circulatory system while looking at a virtual angiogram. The simulator lets physicians know when they have manipulated the catheter incorrectly. At the end of each session, physicians get a “report card” telling them how well they did.
Cates has taken the technology one step further. He uses noninvasive MRI scans of patients, loading the data on the simulator, to do a rehearsal procedure. The simulator creates an exact virtual duplicate of the patient’s own circulatory system for the physician to use as a guide while manipulating the catheter. The “mission rehearsal” takes place in the operating room immediately before the patient’s actual procedure.
“Although carotid stenting offers patients a less-invasive option than the traditional carotid endarterectomy,” Cates said, “it also makes the physician’s job more difficult because you can’t see or feel the tissues directly. ‘Mission rehearsal’ will make the complex procedure safer for patients.”
It also may keep down health care costs. Physicians who do mission rehearsals may not have to use more than one piece of equipment because of an unexpected variation in patients’ anatomies. Even highly skilled doctors feel much more confident when they know what to expect, and the patient spends less time on the operating table. As technology continues to advance, Cates predicted it will become routine that high-risk and complicated medical procedures will be mission rehearsed.
“Every person’s anatomy is different,” Cates said. “Sometimes complications occur, [but] because the simulator lets us know when we have made a wrong turn, the rehearsal makes the actual procedure safer. A pilot would not wait until he has to make an emergency landing to prepare for it—he learns how to react to certain situations by practicing with a simulator. Doctors should soon be able to do the same thing.”