MRIs for Patients With Pacemakers
Data from MagnaSafe suggest that MRIs for patients with pacemakers/ICDs can be performed safely.
MRI is an essential imaging modality for patients with genitourinary pathologies. In patients with CKD stage 3 or worse, it provides excellent renal anatomic detail without the risk of iodinated contrast. Additionally, in men screened for, or who have, prostate cancer, multiparametric MRI can assist in the performance of targeted biopsies as well as in cancer staging and management.
Nearly 2 million people in the United States have non–MRI-compatible pacemakers or implantable cardioverter defibrillator devices (ICD). At least half will have a clinical indication for MRI after device implantation. The current standard of care makes patients with pacemakers/ICDs ineligible for MRIs due to safety concerns, including cardiac lead heating, myocardial thermal injury, and adverse changes in pacing properties.
Results of the recently published prospective, multicenter MagnaSafe Registry study, however, suggest that MRIs for patients with pacemakers/ICDs can be performed safely. The study evaluated 1500 patients with non-MRI-compatible pacemakers/ICDs undergoing clinically indicated non-thoracic MRIs (1.5T). A multidisciplinary process was employed whereby physicians or extenders with cardiac device expertise and advanced training were in attendance for monitoring. They noted no deaths, no lead failures, no losses of capture, and no ventricular arrhythmias in 1500 MRIs. There were 6 cases of self-terminating atrial fibrillation/flutter and/or partial electrical reset. The authors concluded that device or lead failure did not occur in any patient with non–MRI “compatible” pacemakers/ICDs who underwent non-thoracic MRIs.1
Pacemakers were developed in the 1950s and MRI machines in the 1970s. For the last 35 years, clinicians have not used one in the presence of the other. The reasons for this are multifactorial, but may include the availability of imaging substitutes, limited knowledge, and a lack of multidisciplinary coordination and processes. The question now is: How long will it take to change culture and practice whereby patients with pacemakers/ICDs can safely undergo MRI at most hospitals?
As a profession, we excel at disseminating new knowledge, but are far less effective at implementing it. Implementation science is an emerging discipline within medical hierarchies to study the methods that increase integration of evidence-based interventions into practice settings. Translating research into practice is more complex that it may initially seem. Sustaining those changes requires a new level of cooperation, collective will, incentives, disincentives, and clinical champions. Physicians should lead these efforts. The data from MagnaSafe offer an easy place to start.
Robert G. Uzzo, MD, FACS, is a Professor and Chairman of the Department of Surgery and the G. Willing "Wing" Pepper Chair in Cancer Research at Fox Chase Cancer Center at Temple University School of Medicine in Philadelphia.
- Russo RJ et al: Assessing the Risks Associated with MRI in Patients with a Pacemaker or Defibrillator. N Engl J Med 2017;376:755-764.