Centers of Excellence I Texas Cardiac Arrhythmia Institute I Austin, Texas
Enabling X-ray-free ablation procedures in the EP lab
Exposure to scatter radiation and orthopedic issues related to years of wearing lead aprons during long EP procedures has led electrophysiologists to seek out new ways to reduce the need for angiographic X-ray. The Texas Cardiac Arrhythmia Institute (TCAI) at St. David’s Medical Center in Austin has been a leader in leveraging new technologies such as intracardiac echo (ICE) and advanced EP mapping systems to enable fluoro-free procedures.
“The staff is getting bathed with scatter radiation for day after day, and those are not trivial risks to the staff,” says Rodney Horton, MD, researcher at the Texas Cardiac Arrhythmia Institute. “My journey for going from low-fluoro to zero-fluoro began really 15 years ago, and it was a very personal thing for me. If you look at the reasons that cardiologists and electrophysiologists retire prematurely, the vast majority of them are because of back injuries and neck injuries from the weight of the lead. I was one of those statistics. I was going home barely able to walk some days because of back pain. It took me about five years to teach myself how to put aside the X-ray, and I've been fluoro-less for all ablation procedures since 2013.”
He has become one of the biggest advocates for zero-fluoro ablation procedures and has taught other EPs how to do it.
This includes pairing ICE with newer versions of EP mapping systems that have eliminated latency issues that delayed motion seen on the overhead screen. Catheter movements can now be seen in near real time, and catheter information such as contact force, temperature sensing, and the angle of the catheter also can help visualize the procedure without the need for X-ray.
“Before we had really reliable 3D mapping systems, I think that doing procedures without fluoroscopy X-ray were a little reckless because I just don't think that we had enough feedback and information to be able to stop using the X-ray,” he says. “Most of us were trained with X-ray, and a lot of times it was only with X-ray. Sometimes it was with X-ray plus some sort of echo imaging. But now the 3D mapping systems have become so effective. I started my journey on fluoroless procedures largely because I became very confident in the capabilities and reliability of the mapping systems as well as the real-time information with the intracardiac echo. And so having those two really mastered, I think allowed me to set aside the X-ray without sacrificing safety to the patient.”
TCAI uses the newest version of the Johnson & Johnson MedTech CARTO™ 3 mapping system which recently became the first to gain U.S. FDA clearance to enable zero-fluoro ablation procedures.
“My journey for going from low-fluoro to zero-fluoro began really 15 years ago, and it was a very personal thing for me. If you look at the reasons that cardiologists and electrophysiologists retire prematurely, the vast majority of them are because of back injuries and neck injuries from the weight of the lead. I was one of those statistics.”
Rodney Horton, MD, Researcher, Texas Cardiac Arrythmia Institute
“CARTO has become so effective that my eyes have to look only in one direction,” Horton notes. “I can't look at the echo and the fluoro and the mapping system, I can only look at one of them at a time. So if you're going to rely on fluoroscopy, then you're not looking at the mapping system.”
The reliability of the mapping system is echoed by TCAI Executive Medical Director and National Medical Director of Cardiac Electrophysiology for HCA Healthcare Andrea Natale, MD.
The biggest benefit, he says, “is the integration with the three-dimensional mapping system, which has become critical together with intracardiac echo to make the procedure fluoroless, or with less fluoro. We can use the mapping system to create a geometry and deliver a lesion on the geometry without using fluoro all the time. Clearly, CARTO has been an important component of the evolution of catheter ablation because it gives us a geometry where we catalog all the information that is relevant.”
Natale cites the example of a focal arrhythmia. With CARTO, when the arrhythmia stops, the system can tag the location so the physician can ablate around the area to make sure the lesions are consolidated for good effect.
“This would not be possible with that degree of accuracy without the three-dimensional mapping system,” he says. “So it clearly is a critical part of the ablation procedure we do today.”
Advances in catheter technology aid zero-fluoro workflows
In addition to the 3D mapping system, catheter advances also have allowed physicians to eliminate X-ray use during ablations. Radiofrequency (RF) catheters added contact force sensing technology several years ago to show the operator they had good contact with the tissue to ensure good energy transfer for effective lesions. This allows operators to rely on the contact force information combined with the mapping system images, rather than angiographic imaging.
Temperature sensors also have been added to some RF catheters to gauge energy transfer level and to improve safety. The location of those sensors on the catheter can impact the accuracy and reliability of the information. The Texas Cardiac Arrhythmia Institute uses the latest RF technology available, which Natale and Horton agree has improved safety and the accuracy of the temperature information. The new QDOT MICRO™ RF catheter has three temperature sensors on the tip of the device. Paired with contact force sensing, it enables a new color-coded window on the mapping system to show not only the amount of contact force on the catheter tip, but also temperature and distribution of force and temperature so the operators can see if the catheter is coming in at a steep angle, which may not be ideal for creating a lesion.
Improved ICE catheter technology also has enhanced visualization inside the heart. Advances in 2D catheters have improved image quality and a new generation of 3D/4D catheter technology is now offering image quality similar to transesophegeal echo (TEE)—but with the EP operator in direct control of the catheter manipulation and view. Angiographic X-ray has issues clearly showing soft tissue, but ICE can clearly show devices, catheters, valves and walls of the heart.
Keeping EP procedures safe
Each EP needs to adjust how much fluoro they use in a procedure based on their comfort level. For example, Natale says when ablating in areas where there is a greater danger of complications, he uses the X-ray to increase safety. With 3D mapping system around the pulmonary vein, fluoroless procedures can be performed, or at least the use of fluoro can be reduced. This may mean a few minutes of fluoro time, but because they work using low dose mode, the exposure to radiation is minimal.
“If it's not sacrificing any safety to the patient, you're good at it and you've proven that you can do it, then I have no problem with using zero fluoro,” Horton adds. “I do think you should do these procedures with X-ray available, because in the case of an emergency, I do not want to sacrifice patient safety and my staff would feel the same way.”
Fluoroless labs are attractive to staff
One of the keys to moving to lower or zero-fluoro workflows, according to Horton, is training the EP staff well so they know what the physician needs to perform the procedure without X-ray. While there’s a learning curve for the staff, the benefits are very attractive. Reducing or eliminating the use of X-ray imaging not only helps patients, but also helps the physician and staff's wellbeing and it could help be a career extender by helping eliminate orthopedic issues caused by lead aprons.
Horton notes that the staff generally prefer his EP lab because they don't have to wear their lead—and fluoro-less also enables RF ablations on pregnant patients.
Thanks to innovative technology and plenty of training, EPs, patients and staff are benefitting from a fluoro-less workflow. Simply put, seeing better is treating better. And as Horton says: “It's nice to not be tethered to the X-ray, not to be forced to use the weight of the lead and not to expose all of the staff in the lab.”
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com