麻豆传媒

Magnetic resonance scans appeared safe for people retaining unused cardiac implantable electronic device (CIED) leads, according to a study that may help persuade CMS to remove its MRI coverage restriction in this population.

Among 139 consecutive CIED recipients with at least one abandoned lead who underwent MRIs -- including MRIs of the thorax -- there were no abnormal vital signs or sustained tachyarrhythmias, nor any changes in battery voltage, power-on reset events, or changes of pacing rate when MRI was performed under special safety protocols, said a group led by Robert Schaller, DO, of the Hospital of the University of Pennsylvania in Philadelphia.

There were six adverse MRI-related events related to concomitant active CIED leads:

• Four patients showed decreased right atrial sensing (mean decrease of 57.8%). Sensing returned to normal in all four patients after reprogramming.
• One patient had left ventricular R-wave sensing of a coronary sinus lead drop from 6.0 to 3.1 mV, which improved to 5.0 mV the following day.
• One patient with an abandoned subcutaneous array experienced sternal heating that subsided on premature cessation of the study.

"The growing aggregate of data calls into question current institutional and CMS reimbursement policies concerning MRI in patients with abandoned CIED leads," Schaller and colleagues wrote in their report .

CIED recipients have gained access to MRIs in recent years: newer MRI-conditional devices have made it easier for patients to receive imaging, and guidelines and CMS reimbursement policies also acknowledge the safety of MRIs for people with legacy devices.

"However, abandoned leads, which are theoretically associated with higher risk to adjacent structures including functional leads due to greater lead tip heating compared with leads attached to a generator, remain a contraindication to MRI examination in many institutions and are excluded from CMS reimbursement due to a paucity of safety data," Schaller and colleagues noted.

As a result, people with abandoned leads usually have to consider non-MRI imaging modalities or face a risky transvenous lead extraction.

"It is hoped that future registry data will be sufficiently compelling to prompt CMS to further modify the NCD [National Coverage Determination] and to remove the coverage restriction for patients with an abandoned lead undergoing MRI with or without a pacemaker or defibrillator generator," commented Robert Russo, MD, PhD, of the Scripps Research Institute in La Jolla, California.

In an , he reasoned that the literature "has clearly demonstrated that no patient with a non-MRI-conditional system or an abandoned pacing lead should ever be exposed to the risks associated with pacing lead extraction, nor should access or coverage be denied to clinically indicated MRI for these patients, owing to an overestimation of risk of an appropriately performed and monitored scan."

The cohort study included 139 consecutive people (mean age 65.6 years, 79% men) undergoing 1.5-T MRI. There were 200 scans, performed in 2013-2020 at Schaller's institution, of various anatomic regions including the thorax.

Each patient averaged 1.22 abandoned CIED leads and 2.04 active leads at the time of MRI. Under half of the cohort were pacemaker-dependent.

Study authors emphasized safety measures such as the use of a transmit-receive radiofrequency coil in patients undergoing MRI of the brain or extremities; such a coil was used in 20.5% of patients in the study (all undergoing MRI of the brain).

Physicians and mid-level healthcare professionals oversaw the safety of the MRI environment and all CIED-related issues. Additionally, an external defibrillator was kept at the ready, close to the MRI control room while the patient was in the scanner, according to Schaller's team.

The investigators cautioned that theirs was a single-center, observational study, and that findings may not be extrapolated to different MRI field strengths.

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