"The computer-controlled magnetic system is useful to steer guide wires and navigate turns in tortuous coronary arteries that would otherwise be impossible to negotiate," said study co-author Neal S. Kleiman, M.D., director of cardiac catheterization laboratories at the Methodist DeBakey Heart Center and associate professor of medicine at Baylor College of Medicine in Houston, Texas.
The magnetic-assisted intervention is being introduced in the United States and Europe, with fewer than 15 systems installed at institutions worldwide. Developed by Stereotaxis, Inc., a St. Louis firm, the system was approved by the U.S. Food and Drug Administration in 2003.
The researchers presented a study of the first 26 patients who underwent 31 magnetic-assisted interventions (MAI) at the Methodist DeBakey Heart Center, leading to a high success rate.
The three-dimensional system is installed in the center's catherization laboratory.
The system consists of two permanent magnets that generate a magnetic field over the heart and a magnet-tipped coronary guide wire. The magnetic navigation involves interaction between the magnetic field of specified direction and magnitude, positioned externally to the patient, and a tiny magnet in the tip of the interventional device. An automatic advancement system controls the catheter advancement and retraction.
Kleiman said the magnetic system is useful in patients with difficult lesions who are undergoing a coronary intervention, such as balloon angioplasty. He said the more tortuous the vessel, the more difficult it is to place the wire manually.
"About 20 percent of patients treated with the magnetic system were poor candidates for standard angioplasty or had already failed the standard procedure,"
Contact: Carole Bullock
American Heart Association