Remote follow-up and monitoring of patients implanted with cardiac implantable electronic devices (CIEDs) has been introduced over a decade ago, and is now indicated according to European (class IIa indication1) and American (class I indication2) guidelines. There have been high expectations that this technology will improve patient outcome, as it significantly shortens response to actionable events (e.g. AF) compared with standard in-office follow-up.3,4 However, several randomised trials have failed to meet this promise.5,6
The remote management of heart failure using implanted devices and formalised follow-up procedures (REM-HF) study has been published recently.7 This trial, conducted at nine centres in England, randomised 1650 patients implanted with an ICD, cardiac resynchronisation therapy defibrillator or cardiac resynchronisation therapy pacemaker to either remote management with weekly transmissions or to usual care. After a median follow-up of 2.8 years, there were no differences in the primary outcome of mortality or cardiovascular admissions, nor in any of the secondary endpoints (although there was a trend in reduced mortality). This study is remarkable in that it is – as yet – the largest study in this field, with the longest follow-up, few exclusion criteria (e.g. AF was admissible and there was no age limit), and included devices from three major manufacturers. The results were disappointing: there were no differences in the primary endpoint of total mortality or cardiovascular hospitalisation, nor in any of the secondary endpoints. However, there are a number of points that need to be discussed.
First, the study was performed in tertiary expert centres where specialised heart failure clinics already manage these complex patients to a high level of quality of care. Therefore, incremental benefit of any intervention is likely to be more difficult to achieve, and results may not be extrapolated to other less specialised settings.
Second, this was not a study randomising remote device management with standard in-office care, as patients in the control group could be remotely monitored (except to manage heart failure). Third, the active group required weekly transmissions to be actively performed by the patients, with almost 40 % of patients transmitting <75 % of the time at 2 years. This is in contrast to automatic pre-defined alerts, which are the usual form of remote management, and that achieve successful transmissions in >90 % of the time.4,8 Remote monitoring by automatic alerts, using devices not included in REM-HF (Biotronik), has been shown in the TRUECOIN patient-level meta-analysis to reduce mortality compared with standard care.9
Last, but not least, the patients in the remote management group generated 79,325 transmissions. This means that each centre received on average 10–15 transmissions/day to process (this number was certainly higher towards the end of patient enrolment). Only 226 (0.3 %) transmissions resulted in medication change by the monitor and only 910 (1.1 %) resulted in the patient being advised to seek medical attention. Therefore, very few actions resulted from transmissions in the remote management group.
In any process aiming to improve patient outcome, three fundamental factors are implicated: 1) availability of good data, 2) proper interpretation of these data and 3) generation of meaningful action. In the case of REM-HF, there was most probably data overload, with parameters that are sometimes difficult to interpret individually (e.g. transthoracic impedance, heart rate variability etc.). This is probably one of the reasons why so little action was taken. For the reasons detailed above, it is not surprising that the study was negative.
The key to improving outcome with remote CIED management lies most probably in data management. Triage of alerts into risk categories enables healthcare personnel to focus attention on those patients who are most likely to require medical intervention, thereby avoiding clinical deterioration. Cowie (who is also the last author of REM-HF) and collaborators devised the Medtronic “Heart Failure Risk Status” score based on an automatic algorithm that combines data extracted from remote monitoring transmissions (on intrathoracic impedance, nocturnal heart rate, heart rate variability, daily activity and arrhythmic events), to stratify patients into high, medium and low risk.10 Patients with a high risk score had a significant six-fold increased likelihood of being admitted for heart failure in the following month compared with those with a low risk score. These findings were later confirmed in independent cohorts from the Resynchronization-Defibrillation for Ambulatory Heart Failure Trial (RAFT)11 and Monitoring Resynchronization Devices And Cardiac Patients (MORE-CARE) trials.12 Of note, the proportion of high-risk alerts was 10 % in all three reports, underlining the potential not only for improving data interpretation using integrated diagnostics, but also for facilitating data triage. Other devices companies are also working on risk stratification tools. In the Multisensor Chronic Evaluation In Ambulatory Heart Failure Patients (MultiSENSE) study, an algorithm by Boston Scientific combining different parameters (heart sounds, respiration, thoracic impedance, heart rate, and activity) showed promising results for predicting heart failure events.13 Algorithms from other companies using fewer parameters such as transthoracic impedance only14 or minute ventilation combined with daily activity15 were less predictive, and response to data that are non-specific may even result in inappropriate treatment that is harmful.16 It nevertheless remains to be proven by randomised trials that the use of risk-stratification algorithms leads to improved patient outcome.
Beyond improvement in patient outcome, remote CIED management is a matter of convenience, both for patients as well as for caregivers.17 It allows improved adherence to follow-up,18 reduces healthcare utilisation8,19 and is invaluable for monitoring device function.20 Furthermore, it allows generation of large amounts of data for scientific research21 and quality control (e.g. lead survival and device longevity for manufacturer product performance reports).
In conclusion, the results of REM-HF merely show that remote CIED management should not be performed by weekly manual transmissions, which are cumbersome for the patient and lead to data overflow for device clinics, without any improvement in patient outcome. Modern-day technology allows more streamlined solutions, which continue to evolve. Without any doubt, remote CIED patient management is not only here to stay, but will continue to grow.