LATITUDE NXT Patient Management System for monitoring cardiac devices at home

Study component

Description

Objectives/hypotheses

To estimate and compare the event-free rate at 1 year following ICD implantation using 4 different remote monitoring systems and to investigate the effects of the frequency of data transmissions on the early detection of clinical and device-related events.

Study design

Prospective, single centre, non-randomised cohort study with 1 year follow-up.

Setting

Policlinico Casilino Hospital, Rome, Italy. Patients were enrolled between January 2009 and January 2011. One year post-implant follow-up.

Inclusion/exclusion criteria

Included patients had a standard indication for implantable cardiac devices, with or without cardiac synchronisation therapy. No exclusion criteria were noted.

Primary outcomes

The primary endpoint was time to investigator's first evaluation of a true-positive clinical or device-related event during the first year after implant, whichever was first observed during a remote follow-up (whether or not it was triggered by an automatic alert) or during an in-person visit. Episodes were classified as false-positive if they did not trigger medical intervention other than device reprogramming. The number of RM transmissions, alerts, and the mean intervals between consecutive RM transmissions were also registered and compared.

Statistical methods

Sample distributions of continuous variables were tested for normality with the Shapiro-Wilk test. Categorical variables were reported as percentages. Comparisons among RM groups were performed with the Kruskal-Wallis rank test for continuous variables using Bonferroni's correction for pair-wise multiple comparisons. Chi-squared test was used for comparison of baseline categorical variables. Event-free rates were estimated with the product-limit method and Kaplan–Meier plots generated: comparisons among groups were performed with the log-rank test. Areas under Kaplan–Meier curves were calculated using the restricted mean method. To investigate the association between event-free rate and frequency of RM transmissions, uni- and multivariate Cox proportional hazard models were used.

Patients included

211 patients (mean age 69 years; 75% male) with implanted cardiac devices were included in the analysis (49 with Boston LATITUDE, 65 with Medtronic CareLink, 61 with BIOTRONIK, and 36 with St Jude Merlin).

Results

In total, 95 patients (45%) experienced at least 1 clinical or device-related event.

Conclusions

Although the rates of remotely detected events were similar in all systems, the time to first event evaluation was about 56 days longer in patients with quarterly compared to daily transmissions.

Abbreviations: RM, remote monitoring.

^a Incorrectly reported as 12 people in the study.

LATITUDE

CareLink

BIOTRONIK

Merlin

Analysis

Efficacy

n=49

n=65

n=61

n=36

-

Primary outcome: Clinical or device-related event-free rate at 1 year following implant.

37/49 (76%)

37/65 (57%)

30/61 (49%)

25/36 (69%)

Log-rank test p=0.23

Selected secondary outcomes:

Cumulative rate of actionable events

45%

22%

37%

16%

Log-rank test p=0.005

False positive alerts

4

11

1

0

-

False negative alerts

1

0

7

2

-

Median maximum interval between transmissions (IQR) in days

70 (63–96)

93 (82–126)

9 (3–25)

86 (58–93)

The max expected duration of unmonitored periods was significantly shorter in the BIOTRONIK system (p<0.0001)

Abbreviations: IQR, interquartile range.

Study component

Description

Objectives/hypotheses

To examine the association between the use of remote patient monitoring of implantable cardioverter defibrillators and all-cause mortality and hospital admissions among patients undergoing initial implant.

Study design

Retrospective observational cohort study. Patients were divided into 2 groups; those who had at least 1 remote transmission in the first year following implantation, and those with no remote transmissions.

Setting

A data set was constructed from Boston Scientific ALTITUDE Registry and the American College of Cardiology National Cardiovascular Data Registry ICD Registry between January 2006 and March 2010. Patients were followed up for 3 years.

Inclusion/exclusion criteria

Patients were eligible for inclusion if they had a remote patient monitoring compatible device and had first-time device implantation between January 2006 and March 2010.

Patients were excluded if they had missing data linking fields, used devices from manufacturers other than Boston Scientific, used a non-wireless device, underwent implantation at an institute that did not participate in the ALTITUDE database, had a pacemaker or implanted cardiac device previously, died during their initial hospital stay, were under 21 or over 89 years old, had a history of cardiac transplant or an epicardial lead, were in a hospital not reporting all of its implants to the ICD registry, or had unknown vital status.

Primary outcomes

All-cause mortality and re-admission to hospital during the 3‑year follow-up.

Statistical methods

A multi-variate time-dependant Cox model was used to examine the association between remote monitoring and survival up to 3 years after implantation.

Patients included

After employing the exclusion criteria to the ICD registry and linking to the ALTITUDE data set, 37,742 patients were included in the cohort for mortality. For analysis of hospital admissions, this cohort was further restricted to 15,258 by including only those patients at least 65 years old enrolled in Medicare fee-for-service.

Results

Patients who used remote monitoring had statistically significantly lower risk of mortality compared with patients who did not (HR 0.67, 95% CI 0.64 to 0.71, p<0.0001).

Patients who used remote monitoring had statistically significantly lower risk of hospital admission compared with patients who did not (HR 0.82, 95% CI 0.80 to 0.84, p<0.0001).

Conclusions

Among patients undergoing initial ICD implantation, remote monitoring is associated with a statistically significantly lower risk of adverse outcomes.

Abbreviations: CI, confidence interval; HR, hazard ratio; ICD, implantable cardiac device.

Remote Monitoring

No remote monitoring

Analysis

Cohort for mortality analysis

n=20,852

n=16,890

-

Cohort for hospital admission analysis

n=9,150

n=6,104

-

Primary outcome: All-cause mortality at 1 and 3 years

Not reported

Not reported

Median follow-up was 822 days (IQR: 623 to 1126).

Overall cohort mortality:

1 year, 9.4%.

3 year, 20.9%.

Remote monitoring was associated with a lower risk of mortality HR : 0.67, 95% CI: 0.64 to 0.71, p<0.0001

Primary outcome:

Hospital re-admission

Not reported

Not reported

The 3 year all-cause hospital re-admission rate was 63.9%with a median follow-up of 922 days (IQR: 662 to 1195).

Remote monitoring was associated with a lower risk of hospital re-admission HR: 0.82, 95% CI: 0.80 to 0.84, p<0.0001.

Abbreviations: CI, confidence interval; IQR, interquartile range; HR, hazard ratio; n, number of patients.

Study component

Description

Objectives/hypotheses

To assess the influence of remote monitoring on long-term mortality following the implantation of ICD and CRT-D devices.

Study design

Retrospective non-randomised observational cohort study comparing patients with an ICD or CRT-D followed remotely or in-clinic.

Setting

Data in the Boston scientific ALTITUDE database from 2,096 participating clinics in the USA. Patients were followed up for 5 years.

Inclusion/exclusion criteria

Patients were included following the implantation of an ICD or CRT-D at a participating centre.

The decision to place a patient in the remote follow-up group was made by the implanting physician at the time of device implantation or at the post-implantation clinic visit.

No exclusion criteria were noted.

Primary outcomes

One- and 5‑year survival rates following device implantation.

Statistical methods

Kaplan–Meier curves and multivariate Cox proportional hazard models adjusting for baseline covariates of age, gender, implantation year, and device type were used to calculate cumulative mortality and to assess the relationship between mortality risk and the following:

Patients included

A total of 194,006 patients were included in the survival analysis; 69,556 were followed on the network, and 124,450 were followed in clinic only (116,222 ICD and CRT-D devices and 8228 CRT-only devices).

Results

Compared with in-clinic monitoring, patients having remote monitoring using both ICDs and CRT-Ds showed statistically significant survival improvements (hazard ratio 0.56 and 0.45 respectively, p<0.0001).

Conclusions

Observed survival rates compared favourably with those reported in clinical trials. Remote follow-up of device data is associated with excellent survival.

Abbreviations: CRT-D, cardiac resynchronisation therapy defibrillators; ICD, implantable cardioverter defibrillators.

Remote monitoring

In-clinic monitoring

Analysis

Efficacy

n=69,556

n=124,450

-

Primary outcome: Comparative survival at 5 years following implant.

Not reported

Not reported

10,272 matched patients implanted with ICD and CRT-D devices on and off the remote follow up network.

ICD: HR 0.558, 95% CI 0.467 to 0.867

p<0.0001.

CRT-D: HR 0.454, 95% CI 0.388 to 0.532

p<0.0001.

Abbreviations: CI, confidence interval; HR, hazard ratio; n, number of patients.