Safety of magnetic resonance imaging in patients with cardiac implantable electronic devices and abandoned transvenous leads – a systematic review

There is concern about performing magnetic resonance imaging (MRI) in patients with so-called abandoned leads, i.e. electrodes that are no longer attached to a device generator, because of the fear of tip heating reported in in vitro studies. As the patient population eligible for MRI continues to expand, there is a clear need for the collection and dissemination of empirical safety data.

The electronic databases Medline and CINAHL were searched to identify relevant literature in Englisch language by applying the key terms “magnetic resonance imaging” AND “abandoned leads”. The primary outcome of interest in the selected studies were safety-relevant events defined as (1) MACE. Secondary outcome measures included (2) major change in the CIED parameter, (3) device- or patient-related dysfunction, (4) signs of myocardial injury and/ or laboratory measurement of myocardial tissue damage with biomarker. The Newcastle-Ottawa Scale (NOS) for cohort studies was used to assess study quality and potential bias.

13 publications with a total of 410 abandoned leads and 459 MRI scans of different anatomical regions were included. No scan-related MACE was documented. Furthermore, no severe device dysfunction or severe arrhythmia was reported. Transient atrial sensing reduction in patients with an additional functional lead occurred in only 3 cases (0.68%) and no other parameter chances were documented. As a possible correlate of myocardial injury, subjective sensations such as heating occurred also in only 3 patients (0.68%), but no change in myocardial biomarkers was observed.

For abandoned CIED leads in MRI, the guidelines provide no or only limited recommendations due to a lack of data, as such patients were primarily not included in prospective studies for fear of tip heating. It is noteworthy that the common theoretical concerns do not match what we see in the published literature of real-world experience. The idea that feeling heat during an MRI inevitably predicts tissue damage is debatable, because people often feel warmth due to the radiofrequency pulses used in MRI, and peripheral nerve stimulation can also cause this sensation. In addition, no increase in cardiac biomarkers was observed. In general, heating-related issues in patients without CIED were reported in in literature up to 1.5 % of routine MRI scans, which is twice as much, compared to our present data (0.68 %). Another marker for cardiomyocyte death could be a deterioration of the measured CIED parameter. Transient atrial sensing decrease was 0.68 % in our population with an additional functional lead, compared to 1.5% parameter change in a large previous meta-analysis. We believe this is an acceptable risk in relation to the diagnostic information that is gained from a clinically indicated MRI scan in case of missing appropriate alternative imaging modalities.

No serious adverse effects were found in patients with abandoned leads. Compared to the results of other studies with non-conditional CIEDs, there is no significant increased risk regarding parameter change or subjective heating. Based on our data, a clinically indicated and carefully performed MRI study can be safely performed in patients with abandoned transvenous leads if other alternative imaging modalities for the respective clinical question are not appropriate.