Studies Defy Taboo of MR Imaging of Abandoned Cardiac Leads

Patrice Wendling

May 25, 2017

CHICAGO, IL — Two new studies support the safety of MRI in patients with cardiac implantable electronic devices (CIEDs) and abandoned leads, a longstanding contraindication to MRI.

The first study[1] found no clinical or electrical evidence of CIED dysfunction and no arrhythmias or pain among 56 patients with 63 abandoned leads undergoing 69 MRIs at the Mayo Clinic in Rochester, MN.

In the second study[2], there were no acute changes in device function and one report of a transient burning sensation among 36 patients with abandoned leads or lead fragments undergoing 57 MRIs at the University of Pennsylvania, PA.

"Usually abandoned leads are an absolute contraindication, so while a few places do it, no one discusses it," Tamara Brunker (University of Pennsylvania) lead author of the UPenn study, said in an interview.

"Sites need to start disclosing that they're doing it, so we can have more useful discussions with our patients about what the risk is based on numbers of patients and data."

 

Dr Deepak Padmanabhan

Dr Deepak Padmanabhan (Mayo Clinic) lead author of the Mayo Clinic study, told heartwire  from Medscape that the problem is more that "an extremely low number of centers across the world are even prepared to do this. These patients are just getting told, 'why don't you get a CT done?' " when an MRI scan would be optimal.

He noted that there have been two major lead recalls over the past 15 years, and many of these leads have not been extracted. Moreover, "this population is getting older, and 50% of patients who've had a device implanted are going to need an MRI."

Both studies were presented here at the Heart Rhythm Society (HRS) Scientific Sessions 2017 , during which the HRS published a consensus statement on MRI and radiation exposure in patients with CIEDs[3].

Consensus statement coauthor Dr Rachel Lampert (Yale School of Medicine, New Haven, CT) said there's an increasing body of evidence supporting the safety of MRI in patients with standard MRI-nonconditional devices including the "enormous" 1500-patient MagnaSafe registry study , but it did not include abandoned leads.

"So to now have these data in addition, it's really time these scans start getting reimbursed by CMS because right now CMS doesn't reimburse MRIs in patients with devices" unless they're part of a data-gathering study. "It needs to change," she told heartwire .

UPenn Experience

 

Tamara Brunker

Brunker and colleagues have conducted close to 1400 MRIs in patients with CIEDs over the past 4 years, so far all on a 1.5-T scanner. The 57 MRIs in the present study included 32 brain scans using a transmit-receive head coil when possible, 15 spinal scans, eight cardiac scans, one pelvis scan, and one face scan.

The 36 patients had both FDA-approved MRI-conditional and nonconditional CIEDs, though the presence of an abandoned lead makes any system nonconditional, she noted.

The one report of a burning sensation occurred 6 minutes into a cardiac MRI in a patient with an abandoned subcutaneous array electrode, and the scan was stopped. The symptoms abated after a few minutes and were thought possibly related to the patient's sternal wires rather than heating of the abandoned array because the burning sensation was in the anterior chest and the array was located posterolateral. The patient's vital signs remained normal and his 12-lead ECG was unchanged.

No symptoms or changes in vital signs occurred in any other patients. Brunker noted that one patient with an abandoned ICD lead had undergone eight brain MRIs to date with no apparent complications.

"I get to know my patients; some of them are young patients with brain tumors who come back multiple times. I really feel like I'm helping them, but I'd like this to be more accessible to patients so that they don't have to drive for hours and hours," she said.

MRI Troponin Values

Mayo Clinic also has a long experience using its previously detailed MRI protocol , including 1292 scans with CIEDs in situ in 873 patients now in its prospective database. For the present study, troponin I (TNI) assessments were added to screen for myocardial damage in 38 of 56 patients with abandoned leads who were matched based on age, sex, and site of MRI to a cohort with CIEDs without abandoned leads.

There are concerns that the radiofrequency energy may heat up abandoned leads and damage the heart, but there was no significant difference between pre- and post-MRI TNI values (mean 0.025 vs 0.023 ng/mL; P=0.07).

Further, TNI values did not differ based on type of CIED (pacemaker, ICD/CRT-D, abandoned leads only), number of defibrillation coils (0–4 coils), or area scanned (head, chest, lumbar, limb). "You would think that there would be a difference, but again, absolutely no difference," Padmanabhan said.

In the matched analysis, there were no deaths, generator failures, lead failures, loss of capture, or atrial or ventricular arrhythmias in either group, although electrical resets were needed in six controls vs no cases.

Brunker and Padmanabhan both stressed the need for close monitoring and use of a multidisciplinary protocol when scanning patients with a cardiac device but added that the current data should provide reassurance on the use of MRI in those with abandoned leads.

"Maybe data accumulating from all the centers will help us change guidelines. I think this is strong enough data to at least give them a good nudge," Padmanabhan said.

The University of Pennsylvania study was supported by the Murray and Susan Bloom EP Research Fund. Brunker and Padmanabhan report no relevant financial relationships. Lampert reports consulting for/participating in advisory boards/receiving honoraria from Medtronic, and receiving research grants from Boston Scientific, Medtronic, and St Jude Medical. Disclosures for the coauthors are listed in the paper.

Follow Patrice Wendling on Twitter: @pwendl. For more from theheart.org, follow us on Twitter and Facebook.

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