PARIS – Results of two randomized controlled trials appear to solidify the safety of remote monitoring of implantable cardioverter defibrillators, and one of the studies showed a significant decrease in the number of patients receiving inappropriate shocks in the remote-monitoring group.
Manufacturers of ICDs currently recommend in-clinic follow-up every 3 months to detect clinical events or device malfunctions. With increasing numbers of people receiving ICDs to prevent sudden cardiac death from rhythm disturbances, investigators are testing ways to avoid the time constraints of so many in-clinic visits by remotely transmitting information from the device via telephone from the patient’s home. Most ICDs now have this capability.
The two randomized controlled trials support findings from patient registries in Europe and in the United States, where remote monitoring is common.
In the yearlong Evaluation of Tele Follow-up (EVATEL) trial, 1,501 patients at 30 French centers were randomized to in-clinic follow-up at the implant center every 3 months or to remote transmission of data to the implant center every 3 months. The study included four types of ICDs.
Results showed no significant difference between groups in the time to first major cardiovascular event or in the rates of major cardiovascular events (death from all causes, cardiovascular-related hospitalization, or inappropriate or ineffective shocks), Dr. Philippe Mabo and his associates reported at the annual congress of the European Society of Cardiology .
Rates of this composite end point were 28% in the remote-monitoring group and 29% in the control group in an intent-to-treat analysis, showing that home monitoring was not inferior to in-office monitoring. In a per-protocol analysis, the primary end points were seen in 28% and 30% of the groups, respectively, but the confidence interval was too wide to claim that there was no significant difference between groups, said Dr. Mabo of Rennes (France) University Hospital.
Dr. Philippe Mabo
The trial could not demonstrate an impact on preventing major clinical events, but it did reinforce the safety of remote monitoring, he said.
The study also found a significant 27% reduction in the number of inappropriate shocks delivered by the ICDs, from approximately 8% in the control group to 5% in the remote-monitoring group.
Among several weaknesses of the study, there were no interventions planned in response to monitoring, said Dr. Angelo Auricchio, who commented on the study in the presentation session. Using the data to intervene in problems with ICDs is "the greatest advantage" of the technology, so it is not surprising that the EVATEL study did not show a major impact on cardiovascular end points, said Dr. Auricchio of the Fondazione Cardiocentro Ticino, Lugano, Switzerland.
In addition, the number of patients in the study did not quite reach the calculated sample size required to demonstrate noninferiority of home ICD monitoring.
The separate Effectiveness and Cost of ICD Follow-up Schedule with Telecardiology (ECOST) study randomized 433 patients in 43 French centers to daily remote monitoring using the Biotronik Home Monitoring system or quarterly in-clinic follow-up for 27 months.
Rates of a combined end point of mortality, major cardiovascular events, or major device-related adverse events did not differ significantly between groups, affecting 38% of the remote-monitoring group and 42% of the control group, Dr. Salem Kacet and his associates reported.
Dr. Salem Kacet
Among secondary outcomes, the remote monitoring group showed a significant 52% reduction in the number of patients receiving inappropriate shocks (5% in the remote-monitoring group and 10% in the control group), said Dr. Kacet of the University of Lille, France.
The number of patients hospitalized because of inappropriate shocks also was significantly lower in the remote-monitoring group (3) compared with the control group (11).
A significant 76% decrease in the total number of charged shocks in the remote-monitoring group (499 shocks), compared with the control group (2,081 shocks) translated into a significant impact on battery longevity. Among patients with more than one charged shock during the study, ICD battery capacity depleted 0.07% per day in the remote-monitoring group and 0.18% per day in the control group, so that 3 patients in the remote-monitoring group and 11 in the control group had ICDs left with less than 50% of battery capacity.
The number of delivered shocks was significantly lower in the remote-monitoring group (193) than in the control group (657), a significant 71% difference.
Quality-of-life scores on the Short Form-36 were similar between groups.
The relatively long-term follow-up of the ECOST study supports the safety and noninferiority of remote monitoring of ICDs, and shows that home monitoring could reduce inappropriate shocks, charged shocks and delivered shocks, thus prolonging battery longevity and potentially delaying the need for battery replacement surgery, as well as decreasing associated risks.