|Cardiologists at Emory are the first in the U.S. 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 the 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 is often 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 the plaque is accidentally dislodged and enters the brain during the journey, the patient could have a stroke or die.
Christopher Cates, MD, director of Vascular Intervention at Emory University Hospital and Emory Crawford Long Hospital, and his colleague, Anthony G. Gallagher, PhD, designed one of the first virtual reality programs to train physicians in carotid stenting. Using simulators that look like human mannequins, the physician threads a catheter through an artificial circulatory system while looking at a virtual angiogram. The simulator lets the physician know when he has manipulated the catheter incorrectly. At the end of each session, the physician gets a "report card" telling him how well he did in the exercise.
Dr. Cates has taken that technology one step further. He uses the non-invasive MRI scans of his patients, loading the data on the simulator, to do a rehearsal procedure. The simulator re-creates an exact virtual duplicate of the patient's own circulatory system for the physician to use as a guide while he manipulates the catheter. The "mission rehearsal" takes place in the operating room immediately before the patient's real live procedure.
"Although carotid stenting offers patients a less-invasive option than the traditional carotid endarterectomy," says Emory Heart Center's Dr. Cates. "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."
Being prepared also keeps health care costs down. The physician who does a "mission rehearsal" does not find himself in a situation where he has to use more than one piece of equipment because of an unexpected variation in the patient's anatomy. Even highly skilled doctors feel much more confidant when they know what to expect, and the patient spends less time on the operating table.
"Every person's anatomy is different and sometimes complications occur. Because the simulator lets us know when we have made a wrong turn, the rehearsal makes the actual procedure safer," says Dr. Cates. "A pilot would not wait until he has 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." Dr. Cates predicts that as technology continues to advance, it will become routine that high risk and complicated medical procedures will be mission rehearsed.