Elsevier

International Journal of Cardiology

Volume 222, 1 November 2016, Pages 764-768
International Journal of Cardiology

Influence of remote monitoring on long-term cardiovascular outcomes after cardioverter-defibrillator implantation

https://doi.org/10.1016/j.ijcard.2016.07.157Get rights and content

Abstract

Aims

Device-based remote monitoring (RM) has been linked to improved clinical outcomes at short to medium-term follow-up. Whether this benefit extends to long-term follow-up is unknown. We sought to assess the effect of device-based RM on long-term clinical outcomes in recipients of implantable cardioverter-defibrillators (ICD).

Methods

We performed a retrospective cohort study of consecutive patients who underwent ICD implantation for primary prevention. RM was initiated with patient consent according to availability of RM hardware at implantation. Patients with concomitant cardiac resynchronization therapy were excluded. Data on hospitalizations, mortality and cause of death were systematically assessed using a nationwide healthcare platform. A Cox proportional hazards model was employed to estimate the effect of RM on mortality and a composite endpoint of cardiovascular mortality and hospital admission due to heart failure (HF).

Results

312 patients were included with a median follow-up of 37.7 months (range 1 to 146). 121 patients (38.2%) were under RM since the first outpatient visit post-ICD and 191 were in conventional follow-up. No differences were found regarding age, left ventricular ejection fraction, heart failure etiology or NYHA class at implantation. Patients under RM had higher long-term survival (hazard ratio [HR] 0.50, CI 0.27–0.93, p = 0.029) and lower incidence of the composite outcome (HR 0.47, CI 0.27–0.82, p = 0.008). After multivariate survival analysis, overall survival was independently associated with younger age, higher LVEF, NYHA class lower than 3 and RM.

Conclusion

RM was independently associated with increased long-term survival and a lower incidence of a composite endpoint of hospitalization for HF or cardiovascular mortality.

Introduction

Technological developments and expanded indications have translated into a large population of recipients of implantable electronic cardiac devices. There has been a significant increase in the number of patients submitted to implantation of cardioverter-defibrillators (ICD). This growing population represents a unique challenge regarding their follow-up, requiring an experienced team with in-depth knowledge of device programming and potential complications [1]. To this date, optimal clinical resource allocation regarding adequate follow-up to these patients is not yet established.

In this setting, remote monitoring (RM) is poised as an optimal tool in the intensive and continuous follow-up of ICD patients. Published data supports the safety and efficacy of this intervention [1]. However, data regarding potential clinical benefits has been scarce, with a short duration of follow-up and mainly limited to specific ICD brands.

In this study we aimed to assess the long-term clinical benefits of RM in a population of patients with ICD for primary prevention of sudden cardiac death. As such, we sought to investigate the effect of RM on hospital admissions for heart failure (HF), cardiovascular death and all-cause death.

Section snippets

Methods

We performed a retrospective cohort study in patients who underwent ICD implantation for primary prevention and compared a group followed with use of RM (RM +) versus a group on conventional outpatient clinic follow-up (RM −). Consecutive patients referred to a tertiary center for implantation of an ICD between December 2002 and October 2014 were included. The study population was divided in two groups, according to the modality of follow-up: RM + versus RM −. The protocol was approved by the

Statistical analysis

Continuous variables were displayed as mean and standard deviation where they followed a normal distribution, and in terms of their median and interquartile range where they did not. Qualitative variables were expressed in terms of frequency and percentage. Baseline comparisons were performed using the chi-square test for qualitative data and the t-student test for continuous variables.

The analysis of main outcome of time to admission for HF and mortality was performed by Kaplan–Meier curves,

Study population

A total of 923 patients received an ICD during this period. Of these, 611 patients were excluded on the basis of concomitant CRT (473 patients) or implantation in the setting of secondary prevention (138 patients). After exclusion, a total of 312 patients underwent further analysis.

Patient characteristics at implantation are described in Table 1. Most patients had an indication for ICD in primary prevention in the setting of left ventricular systolic dysfunction (85.6%). The etiology was

Discussion

The main finding of our study was a significantly lower incidence of unplanned hospital admissions for HF and overall mortality at very-long follow-up in patients under RM. This reduction in mortality was mainly driven by a reduction in cardiovascular mortality.

To further validate our findings and adjust for the potential confounding effect of other baseline characteristics, we used a stepwise approach to calculate a multivariate Cox regression model performed a multivariate regression

Limitations

This was a single center non-randomized study, thus the generalizability of our results is limited. As this is a retrospective cohort trial, we cannot exclude the effect of unmeasured confounders or some degree of bias; in particular, despite there being no significant differences between both groups at baseline, we cannot exclude the effect of potential selection bias. In addition, since patients had to agree to the use of RM, we could hypothesize that some of those who refused RM had also

Conclusions

In this very long-term retrospective cohort study, the use of RM in patients submitted to implantation of an ICD for primary prevention was independently associated with increased survival. RM was also associated with a lower incidence of a composite endpoint of hospitalization for HF or cardiovascular mortality. Larger, adequately powered randomized clinical trials are warranted to definitely establish whether device-based remote monitoring can lead to improved outcomes in this high-risk

Conflict of interest

The authors report no relationships that could be construed as a conflict of interest.

References (12)

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This author takes responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation

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