Letter from the Editor

Unloading the Lodestones

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

There have been several inventions over the past two decades to minimize radiation exposure to patients, physicians, nurses, and staff in the EP laboratory. These include the Sensei® Robotic System (Hansen Medical), Amigo® Remote Catheter System (Catheter Robotics), Cathpax® radiation protection cabin (Lemerpax), MediGuide Technology (St. Jude Medical), and Niobe® magnetic navigation system (Stereotaxis).

Stereotaxis has long been a leader in this field. Since its inception 25 years ago, Stereotaxis has developed highly precise and safe robotic systems that use large powerful external magnets to navigate catheters in the cardiac chambers and have applications in the fields of EP and interventional cardiology. The Niobe system allows physicians to remotely control an ablation catheter in a patient while remaining outside of the radiation field generated by the EP lab x-ray equipment, reducing radiation exposure to the physician and avoiding the orthopedic complications associated with the use of lead aprons. Labs around the country felt compelled to be early adopters of magnetic navigation to remain competitive, and invested millions of dollars in the technology. 

Stereotaxis has also achieved many milestones. Their equipment has been installed in over 30 countries around the world, has been used for 80,000 procedures performed by more than 900 physicians, and has seen some recent increased adoption in Japan. There have been over 225 publications in peer-reviewed medical journals related to magnetic navigation, and the company has been awarded numerous patents including one as recently as September 1, 2015 for “Management of Live Remote Medical Display.” According to the company, this latest patent allows for the “future development of features within the Odyssey® Information Management Solution that optimize data transmission across a network to a high-resolution display facilitating the management of medical procedures.”

With such promise, why then is the Stereotaxis magnetic navigation system being dismantled and uninstalled in some EP labs? (Figure 1) Like most innovations, there are pros and cons, and in this case, the cons seem to outweigh the pros for many labs. Early obstacles to widespread adoption (e.g., the need to manually advance and retract the vascular sheaths, as well as ineffective ablation electrode contact force) have been addressed with a new device that can remotely advance the sheath at the vascular insertion site and has stronger magnets. However, negative experiences associated with use of early generation systems drove many away from the technology, and it has been hard to bring these physicians back. Other obstacles include no clear advantage to patients, the addition of complexity to already complex procedures, the large size of the magnets in rooms where space is limited, interference with patient throughput, high costs of equipment and disposables with no financial upside to the hospital, and incompatibility with some new EP technologies such as the cryoballoon ablation catheter. The workflow issues are not trivial in hospitals striving to utilize the EP labs to their fullest capacity. The large magnetic field in a Stereotaxis room makes it unsafe for some patients with metal objects such as brain clips and left ventricular assist devices to enter the lab, and requires that anesthesiologists use MRI-compatible anesthesia equipment. Furthermore, other advancements have been made since the introduction of magnetic navigation that allow physicians to navigate catheters with minimal fluoroscopy, such as the use of mapping systems and intracardiac echocardiography. So although a strong case can be made for the acquisition and use of the Stereotaxis system, there are also many drawbacks. 

Magnetic navigation needs a local champion for local success. It needs at least one physician in the hospital where it is installed who is invested in using the system for most, if not all, of his or her cases. In the absence of such a champion, it is challenging to reap the benefits of a system that at least initially is more complicated and less efficient than manual catheter manipulation. The Stereotaxis system shown in the figure is not the first to be permanently removed from an EP lab, and probably will not be the last.