The Food and Drug Administration approved the first MRI-compatible implantable cardioverter defibrillator on Sept. 14, starting a new era of convenience and flexibility when performing MRI scans on patients who carry this type of cardiac implant.
Eventually most, if not all, implantable cardioverter defibrillators (ICDs) will have MRI compatibility, electrophysiologists predicted, a change that’s already been occurring for pacemakers following FDA approval of the first MRI-compatible pacemaker in 2011.
“This is a major step forward and sets a new standard” for ICDs, commented Dr. Rod S. Passman, professor of medicine and electrophysiologist at Northwestern University, Chicago, who has not been involved in developing MRI-compatible ICDs. “If a patient has an ICD, they should be able to go to any community emergency room and get what could be a life-saving MRI. MRI scans of patients with ICDs should not be limited to experienced academic centers. Ultimately all [cardiac] devices will be MRI compatible,” Dr. Passman said in an interview.
“There is no downside” to the newly approved, MRI-compatible ICD, said Dr. Michael R. Gold, an electrophysiologist at the Medical University of South Carolina, Charleston, who led the pivotal study that showed the device’s safety and efficacy during and after MRI scanning. Dr. Gold first reported results from the Evera MRI Study at the Heart Rhythm Society annual meeting in May and in a concurrently published report (J Am Soc Cardiol. 2015;65[24]:2581-8). The study enrolled 275 patients at 42 centers. Medtronic, the company that makes the newly approved ICD, plans to begin U.S. sales the week of Sept. 20, a company spokesperson said.
“I’m not sure I’d use it in all patients” who need an ICD once it’s on the market, admitted Dr. Gold. For example, some patients already have ICD leads in place that are not MRI compatible, so placing an ICD capable of MRI exposure in such patients would be moot, he noted. In other cases, the patient might best receive an ICD model made by a different manufacturer because of other device features.
“Every physician will need to choose the ICD that is best for each patient, so I don’t think we’ll see immediate, wholesale adoption [of the MRI-compatible ICD], but I expect the field will move in this direction,” Dr. Passman said.
Dr. Gold agreed that, as time goes by, the ICD models sold for U.S. patients increasingly will be MRI compatible, although that might take several years to happen.
For example, the transition to pacemakers that are MRI compatible has been gradual and incomplete, even though the first of these came onto the U.S. market in 2011.
“Only two pacemaker manufacturers sell MRI-compatible devices in the United States,” noted Dr. Gold, professor of medicine and director of the division of adult cardiology at the university. Several other manufacturers produce MRI-compatible pacemakers, but so far they have not sought FDA approval for these and they only sell them outside the United States, he noted.
“Many physicians don’t think about a patient’s long-term needs [for MRI] and may instead focus on the device they are most comfortable with” or a device with other attractive features, Dr. Passman said.
The possibility of performing MRI on a patient with an ICD is not totally new. A relatively small number of sophisticated U.S. centers have been performing MRIs on patients with conventional ICDs or pacemakers for several years, especially in circumstances when the MRI was considered vitally needed. Some of these centers have participated in the MagnaSafe registry, which reported results documenting the safety and efficacy of the procedure at a cardiology meeting in 2013.
“If you take certain precautions, the risk from MRI appears to be quite low in the most experienced hands, although even in experienced hands adverse events have been reported,” said Dr. Passman. Performing an MRI on a patient with a conventional ICD or pacemaker is also a relatively labor-intensive process that requires temporarily reprogramming the device, closely monitoring the patient during the MRI scan, and then checking out the device thoroughly after the scan to make sure it is functioning correctly.
In addition to the extra labor and uncertainty about outcome, running an MRI scan on a conventional cardiac device is generally not reimbursed by insurers and creates medicolegal exposure, Dr. Gold noted. “Even though it can be done, it often is not done, and it clearly compromises patient care,” he said.
Although the Medtronic unit was the first to get FDA approval, a competitor model seems on track to also hit the U.S. market soon. Two different ICD models made by Biotronik showed safety and efficacy in a study with 153 patients (Heart Rhythm. 2015 doi. org/10.1016/j.hrthm.2015.06.002). Biotronik has submitted an application to the FDA to market these ICDs and associated leads as MRI compatible, and an agency decision is pending, a company spokeswoman said.
The Evera MRI Study was sponsored by Medtronic, which produces and will market the Evera ICD. Dr. Gold has been a consultant to and has received research and speaker funding from Medtronic as well as from Boston Scientific and St. Jude. Dr. Passman has received research support from Medtronic but not for work on ICDs.
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