MRI pacemaker article

• by WYknitter
• 2014-08-01 01:08:48
• General Posting
• 3459 views
• 4 comments

I found an interesting article on Medscape, entitled Cardiology's Biggest Lie: No MRI for Your Device Patient by Melissa Walton-Shirley - July 29, 2014

http://www.medscape.com/viewarticle/829046

You will need to subscribe (it's free) to see the article online, but I've copied it below.

After you read the article, please share your thoughts about this information.

Nancy

Here's the article:

Cardiology's Biggest Lie: No MRI for Your Device Patient by Melissa Walton-Shirley - July 29, 2014

She's been a good friend for 23 years and an integral part of a team of healthcare providers. But now, she stands
disheveled in a hospital room with one sock on and one sock off. She greets the nurse twice within five minutes of entering
the room, tells the same joke over and over, and at sundown, morphs from Dr Jekyll to Mr Hyde. After a predictably
nonspecific head CT, she desperately needs an MRI, but by the end of the day, two tertiary centers, one regional center,
and her local hospital radiology department refused to place her in the MRI scanner because she has a pacemaker. It's
not their fault, really.

If this patient's home address were Baltimore, for instance, her cardiologist would have dialed the radiology department at
Johns Hopkins Hospital and heard a friendly but mechanical female voice invite her to "press 3 to order an MRI for a
patient with a device." Instead, in a country where the latticework of web-based information rivals the neuronal complexity
of the human brain, most hospitals still can't move forward on the MRI-device issue. Johns Hopkins Hospital has. It is part
of a registry that opened a floodgate of diagnostic opportunity for cardiologists, orthopedists, and neurologists. With well
over 1000 MRIs performed on device-laden individuals and no clinically adverse outcomes, it should be lauded as one of
the country's leaders in MR imaging; but you can't be a leader in the US unless you have followers who can get past
governmental constraints.

Dr Carsten Zobel (now at Marien Hospital Euskirchen, Germany) and colleagues from the University Hospital of Cologne,
Germany, are also leaders. They published an excellent review on the history of MRI scanning in device patients in the
April 2012 issue of Deutsches Ärzteblatt International [1]. It references another overview of MRI from Europace that
revisited 10 deaths in the 1980s that were "poorly characterized with no ECG records for review"[2,3]. From 1992 to 2001,
there were six deaths during or following MRI scanning in Germany, but no ECG records were available, and autopsy
reports were unrevealing. The authors "guessed" the cause was "[ventricular fibrillation] due to inadequate asynchronous
pacing on activation of magnetic function."

Things are different now. In Germany, there have been no deaths reported with MRI scanning in the past decade. Johns
Hopkins Hospital, following the lead of physicians like Dr Robert Russo at the Scripps Institute, who championed the
MagnaSafe registry, joined a handful of other facilities in the US that now scan frequently. It too has deciphered the
formula for safety: sometimes resetting the device and performing an exit device interrogation and then a few follow-up
interrogations over the coming weeks and months. There is beauty in the simplicity of those protocols, but to ignore the
historic and complex mechanical, thermal, and electromagnetic concerns of scanning would do the topic a great injustice.
Modern Devices, Modern Scanners
Modern MRI scanners, for instance, create an electromagnetic field of only 1 to 3 T, far less than older scanners. The
more recent legacy pacer components are far less magnetic, including both generators and lead tips.
Dog studies found no greater increase in lead tip temperature than a piddling 0.2°C. Pigs, however, demonstrate a 20°
increase in temperature at the lead tip, "approaching ablation-range" thermal energy, but histological studies demonstrate
no necrosis at the endocardium and little clinical implication for adverse outcomes[4].
The electromechanical jargon that generates the most concern is the issue of "reed switch activation," which can lead to
asynchronous pacing "at an unpredictable rate." The reed switch trigger can inactivate ICDs as well.

The German review states, "There have been a few reports of a pacemaker reset, leading to activation of the device's
standard configuration. The latter is generally a VVI (ventricular pacing, ventricular sensing, and inhibition of a sensed
ventricular event) mode; therefore, pacer-dependent patients may be at risk of asystole from inhibition of pacing owing to
misinterpretation of artifacts induced by the gradient fields.
"Furthermore, the standard parameters may not always suffice for effective stimulation in patients who need high initial
energy. The main dangers are thus asystole from inhibition of pacing and induction of tachycardia by inadequate
asynchronous pacing."
Pooling their data with published papers, the German authors found that 1043 patients with devices (including ICDs) had
undergone MRI safely. "No life-threatening complications have been observed," they concluded. In addition, "in just 11
cases (1%), electrical resetting of the device was necessary, and a significant increase in pacing threshold (>1.0 mV) was
seen in 16 cases (1.5%)." While they acknowledge that the study conditions varied widely, including differences in
localization, field strength of the scanner, device, sensors, etc, their review provides a good estimation of how frequently
complications can be expected.
A Q&A on the Johns Hopkins Experience
I reached out to Dr Saman Nazarian, an electrophysiologist at Johns Hopkins who has published on the institution's
experience with MRI scanning of device patients[5]. Here is a review of that conversation.
Walton-Shirley: Do you agree that it's time to make MRI available to more patients with devices?
Nazarian: I agree. MRI is the imaging modality of choice for many disorders, and most patients who are currently denied
an MRI due to a cardiac device could safely undergo imaging if a simple protocol such as ours were followed. We now
have somewhere over 1000 who have undergone imaging safely and are analyzing the data.
Walton-Shirley: Why the slow uptake of imaging protocols?
Nazarian: In many cases, the main hindrance is a personnel issue. It does take resources from the division of cardiology
to appoint someone to do the interrogations and monitoring during the scans. Additionally, that person should not be a
device tech. That someone used to be me, but now we feel much safer and the number of scans has greatly increased.
Ideally, someone who is [Advanced Cardiovascular Life Support] ACLS trained would be needed so he/she can act in
case of an emergency. We designate a research nurse who is ACLS certified. We keep a cardiologist nearby and would
not want a rep to be unsupported by a cardiologist.
Walton-Shirley: What are the obstacles to offering MRI to device patients?
Nazarian: Some radiologists and electrophysiologist are unconvinced of the overall safety and would not scan anyone
unless the device were FDA approved with MRI labeling. Another issue is that [the Centers for Medicare & Medicaid
Services] CMS pays for the MRI scan only if the scan in a device recipient is performed under an [institutional review
board] IRB/CMS-approved protocol. Therefore, institutions without the research infrastructure would be unable to perform
the scan for Medicare recipients.
[In March of 2011, Russo received approval from the CMS for payment for MRI scans if a facility agreed to participate in
the MagnaSafe trial. Previously reported by heartwire , the trial was originally set to enroll 1500 participants and excluded
pacer-dependent patients who have ICDs, abandoned leads, and abdominal implants. It also excluded those patients with
any device with an FDA MRI-friendly label. According to Clinicaltrials.gov, there are 21 facilities in 14 states that are
participating. The study is ongoing but not recruiting.]

Walton-Shirley: Could you get around the issue of scheduling by designating a "device" day per week or month in the
MRI area?
Nazarian: That is an efficient way of setting up a program. We currently have appointed device MRI days. But as I
mentioned before, it would not solve all the potential hurdles.
Walton-Shirley: Are there difficulties with obtaining MRI-compatible ECG monitoring equipment?
Nazarian: Scanners often have monitoring equipment that is filtered to minimize the noise. This is necessary for the
scanners that perform cardiac MRI to synchronize image acquisition to cardiac motion. However, even such filtered ECGs
can have noise during certain scans. We have learned to rely heavily on the pulse-oximetry signal. It almost never has
noise (unless it's coming off the patient's finger or ear) and can give a reliable surrogate of the heart rate during the
periods when the ECG signal is affected by artifact.
Walton-Shirley: Are there liability issues because there are no recently updated guidelines on MRI in device patients?
Nazarian: I think that is a possibility. However, if the patient and referring physicians are well-informed of the minute but
possible risks and the patient signs an informed consent, the liability issues should be no different from any other
procedure in medicine. We weigh the risks/benefits in each case and proceed only if we believe the risks for that patient
are smaller than the potential diagnostic benefit of MRI. In most patients, this is the case, but we do turn certain patients
away. There is a problem with viability studies. We can't evaluate the anterior-wall viability in patients with a device due to
artifact.
Walton-Shirley: How often do you offer MRI for patients with devices?
Nazarian: At this point we are scanning approximately 20 to 30 patients per month.
Walton-Shirley: Do you have a protocol you'd feel comfortable sharing for device patients?
Nazarian: Sure. The protocol is published in Heart Rhythm [6].
Walton-Shirley: What about patients with capped tips? The German review article stated this was a contraindication.
Nazarian: There are some patients that have been reported to demonstrate superheating, but we've done five or six
patients with capped leads who have had no difficulties. Additionally, we do scan patients with Medtronic MR-conditional
devices, but the majority of patients scanned at Hopkins have legacy devices that we have found to be safe based upon
prior in vitro/in vivo tests.
Walton-Shirley: Have there been any problems?
Nazarian: We've done experimental work with devices developed prior to the year 2000, and they did fry in the scanner.
We were unable to communicate with them. This has not happened in devices developed after the year 2000.
What Will It Take for Things to Change in the US?
Despite the opportunity for entering patients in a scanning registry and the experience at European sites like University
Hospital of Cologne in Germany, roughly 50% of US patients with devices who will need an MRI scan in the next year
won't get one. Even at some of the registry sites, there is a reluctance to scan, and it's viewed as a hassle or a burden to
the department staff. "What if I just mention your name as a perk for your hospital?" I asked one MRI director. "It would be
great PR for your department to let folks know that you can perform an MRI in patients with devices."

"We don't need that kind of publicity," she said. "I won't scan a patient unless they have a doctor on our staff," but she
confessed that they did scan a patient with a spinal-cord emergency once without a consult at the insistence of the
neurosurgeon, who said the patient would otherwise die. They previously scanned patients with pain-control units at the
insistence of a neurologist but stopped because the leads heated up and burned the patients. "I won't do things like a torn
meniscus; I make all of them see our electrophysiologist," she added.
I wondered if she might feel differently if she was the one with a torn meniscus, where every single step is a painful
navigation between gravity and locomotion, but I appreciated her concern for her patients nonetheless.
As I write this piece, all over the world, there are patients with headaches, paresthesias, and presumptive and
unconfirmed diagnoses of MS, brain tumors, stroke, and multi-infarct dementia who still wait for an MRI because they
have a device. For some, the progress made in this field will not reach their facility in time to help them.
My patient and my friend still waits. With thousands of safe scans documented, it's time to open the floodgate of diagnostic
opportunities for all of these individuals even if scanning them is a bit of a hassle. Unfortunately, those of us outside the
reach of a registry are still firmly stuck in that black hole that exists between knowledge and implementation.
It's high time to crawl out and expose cardiology's biggest lie, so here goes: Most of our device patients really can have an
MRI safely after all.

© 2014 WebMD, LLC
Cite this article: Cardiology's Biggest Lie: No MRI for Your Device Patient. Medscape. Jul 29, 2014.
References
1. Bovenschulte H, Schluter-Brust K, Liebig T, et al. MRI in patients with pacemakers: overview and procedural
management. Dtsch Arztebl Int 2012; 109:270-275. Article
2. Roguin A, Schwitter J, Vahlhaus C, et al. Magnetic resonance imaging in individuals with cardiovascular
implantable electronic devices. Europace 2008; 10:336-346. Article
3. Irnich W, Irnich B, Bartsch C, et al. Do we need pacemakers resistant to magnetic resonance imaging? Europace
2005; 7:353-365. Article
4. Roguin A, Zviman MM, Meininger GR, et al. Modern pacemaker and implantable cardioverter/defibrillator systems
can be magnetic resonance imaging safe: In vitro and in vivo assessment of safety and function at 1.5 T.
Circulation 2004; 110:475-482. Article
5. Nazarian S, Hansford R, Roguin A, et al. A prospective evaluation of a protocol for magnetic resonance imaging of
patients with implanted cardiac devices. Ann Intern Med 2011; 155:415-424. Abstract
6. Nazarian S, Halperin HR. How to perform magnetic resonance imaging on patients with implantable cardiac
arrhythmia devices. Heart Rhythm 2009; 6:138-143. Abstract

Here are the comments that were posted about the article:

Dr. D O| Cardiology, General 13 hours ago
Part of the reluctance to scan these patients is lack of familiarity. Europe is far ahead of the US when it comes to cardiac MRI. Centres that perform lots of cardiac scans are used to patients with devices. They are familiar with the protocol and have cardiac techs that can assess the pacemakers, and switch them to VVI mode is required. It is still quite common to hear of centres not scanning patients because they have stents, or artificial valves - all of which can be safely scannen

Apart from litigation, another US issue is reimbursement. Who will pay the cardiac techs, or EP docs to look at the pacemaker setup?


Tobias Gilk| Other Healthcare Provider 2 days ago
While the underlying message of this piece is valid, that there is a need for safe MR scanning of cardiac device patients, I believe that there are a few points raised in the article that need some clarification:

"Modern MRI scanners, for instance, create an electromagnetic field of only 1 to 3 T, far less than older scanners."

While the first part of the statement is true, that most contemporary MRI scanners use magnetic fields of between 1.0 and 3.0 Tesla. Though I don't know that it's appropriate to characterize a magnetic field that's 20,000 to 60,000 times the strength of the average Earth's magnetic field (as we experience it) as being *only* this strong. The second statement, that this is "far less than older scanners" is actually the exact opposite of the technological progression of the MRI scanners in clinical use. In fact 3.0 Tesla MRI scanners were only a few years ago relegated to only research settings, but now are the single fastest growing segment of the clinical MRI equipment market.

After stating that some studies show a 20º C increase in temperatures at the lead tip, temperatures which are "approaching ablation-range", the very next paragraph states that the greatest concern is reed switch activation. I don't know about anyone else, but I would be extremely concerned about ablating viable cardiac muscle.

In fact, shortly after this, the author reports the reported rates of adverse events from the study, with 1.5% of participants seeing a post-MRI "significant increase in pacing threshold." One of the leading theories of the cause of the need of the pacer to send greater voltage to the heart in order to effectively pace it after an MRI exam is because of lead heating damaging or destroying cells in direct contact with the lead tips. This essentially creates an electrically-insulating barrier between the lead tip and the cardiac tissues, requiring the pulse generator to expend more energy to accomplish the job.

The American College of Radiology, in their 2013 Guidance Document on MR Safety Practices, offers the following list of potential risks associated with imaging pacing devices not specifically approved for use in MRI:

"Potential Complications: Unexpected programming changes, inhibition of pacemaker output, failure to pace, transient asynchronous pacing, rapid cardiac pacing, the induction of ventricular fibrillation, heating of the tissue adjacent to the pacing or ICD system and especially cardiac tissue near the lead tip, early battery depletion, and outright device failure requiring replacement may occur during MRI of patients with pacemakers or ICDs (18,29–31). Multiple deaths have been documented to occur under poorly and incompletely characterized circumstances when CIED patients underwent MRI (32–34). These deaths may have occurred as a result of pacemaker inhibition, failure to capture or device failure (resulting in prolonged asystole) and or rapid cardiac pacing or asynchronous pacing (resulting in the initiation of ventricular tachycardia or fibrillation)." -- http://onlinelibrary.wiley.com/doi/10.1002/jmri.24011/pdf

In the piece, Dr. Nazarian is quoted as saying that CMS will only reimburse for MR exams of pacemaker patients when performed under an IRB/CMS-approved protocol. This fails to acknowledge the fact that CMS does reimburse for MR exams of patients with FDA-approved MR Conditional pacing devices. In fact, the entire article on MRI for pacemaker patients, there are only oblique mentions of the fact that there even are FDA-approved MR Conditional pacing devices which greatly diminish both the risks to the patient and the burden to the provider when scanning.

In an industry where there are few regulatory, licensure, or accreditation requirements for any MRI safety standards at the point of care, and where supervising / reading radiologists are directly responsible for the safe administration of an exam, whether he or she is present or not, and where providers won't be reimbursed by insurance providers for MR studies of patients without MR Conditional devices, it's a bit more multifaceted than claiming that pacemaker patients have been 'lied to' about the safety and efficacy of scanning their non-MR Conditional implants.


Dr. MIGUEL LÓPEZ HIDALGO| Cardiology, Interventional 2 days ago
Until you don´t get this Knowledge in a Guideline it will be very difficult to spread this info and make most of the physicians more confortable and confident in ordering an MRI in a device patient


Dr. john mandrola| Cardiology, General 2 days ago
Thank you MWS. This is an important topic, and one that inflames me greatly. You did a terrific job covering it. Great interview.

Yes, of course, it's a lie. And any informed professional knows it. Yet the problem persists. No MRIs in patients with non-conditional devices. End of story. Don't even think about it.

Therein lies a metaphor for much of what is wrong in today's medical culture--fast thinking predominates over slow thinking.

I would ask your readers to consider two other "big picture" aspects of this story:

One is the power of misinformation and fear and dogma. The data from the MagnaSafe registry has been out since 2012. There are other publications as well. I wrote about this topic last year at ESC (http://www.medscape.com/viewarticle/810310). As you point out, it's quite safe to do an MRI in most legacy devices. The utter lack of probabilistic medical decision-making inherent in this issue makes the medical community look dumb. Such systemic misthink and lack of courage is a blemish on our profession.

The second aspect of this story is the influence of industry. Namely, the marketing power of one big medical device company--the one with the head start on MRI-conditional devices. I'm often asked by referring colleagues to implant this company's "MRI-safe" device. This happens because marketing works. No, the company isn't breaking any rules in promoting their MRI-safe devices; they just leave out the part about almost all devices being MRI-safe, and, most importantly, that the MRI-safe device comes with tradeoffs. Clunky leads, less battery longevity, and lack of wireless monitoring, for instance.

It's time that we engage our slow-thinking minds and muster the courage to fix this issue. For our patients. And because it is obvious and correct to do so.

JMM