Generator replacement is associated with an increased rate of ICD lead alerts

Risk of Appropriate Implantable Cardioverter-Defibrillator Therapies and Sudden Cardiac Death in Patients With Heart Failure With Improved Left Ventricular Ejection Fraction

BACKGROUND

The benefit of implantable cardioverter-defibrillator (ICD) therapy is controversial in patients who have heart failure with improved left ventricular ejection fraction (EF) to >35% after implantation (HFimpEF).

METHODS

Databases (Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar) were queried for studies in patients with ICD that reported the association between HFimpEF and arrhythmic events (AEs), defined as the combined incidence of ventricular arrhythmias, appropriate ICD intervention, and sudden cardiac death (primary composite end point).

RESULTS

A total of 41 studies and 38,572 patients (11,135 with HFimpEF, 27,437 with persistent EF ≤35%) were included; mean follow-up was 43 months. HFimpEF was associated with decreased AEs (odds ratio [OR] 0.39, 95% confidence interval [CI] 0.32 to 0.47; annual rate [AR] 4.1% vs 8%, p <0.01). Super-responders (EF ≥50%) had less risk of AEs than did patients with more modest reverse remodeling (EF >35% and <50%, OR 0.25, 95% CI 0.14 to 0.46, AR 2.7% vs 6.2%, p <0.01). Patients with HFimpEF who had an initial primary-prevention indication had less risk of AEs (OR 0.43, 95% CI 0.3 to 0.61, AR 5.1% vs 10.3%, p <0.01). Among patients with primary prevention who had never received appropriate ICD therapy at the time of generator change, HFimpEF was associated with decreased subsequent AEs (OR 0.26, 95% CI 0.12 to 0.59, AR 1.6% vs 4.8%, p <0.01). In conclusion, HFimpEF is associated with reduced, but not eliminated, risk for AEs in patients with ICDs. The decision to replace an ICD in subgroups at less risk should incorporate shared decision making based on risks for subsequent AEs and procedural complications.

First Demonstration of Cardiac Resynchronization Therapy Defibrillator Service Life Exceeding Patient Survival in a Heart Failure with Reduced Ejection Fraction Cohort

The occurrence of patient longevity exceeding implantable cardioverter-defibrillator (ICD) service life has important implications for patient outcomes and the cost of care. Battery capacity as measured in ampere-hours (Ah) is a strong predictor of survival to an elective replacement indicator (ERI) point and 2.1 Ah is the largest-capacity ICD battery in use at our facility. This was a long-term study of ICDs out of service (OOS) in patients with heart failure with reduced ejection fraction who received a 2.1-Ah cardiac resynchronization therapy defibrillator (CRT-D). All 2.1-Ah CRT-D systems implanted (n = 418) from August 1, 2008 through August 31, 2016 were included in this retrospective chart review. The primary endpoint was device OOS due to the battery reaching an ERI point, patient death, infection/erosion, advisory/recall, heart transplant, or unspecified. The maximum follow-up period was 10.3 years, with a mean follow-up length of 4.7 years. The most common reason for device OOS was patient death (65.6%), with only 5.7% of devices reaching the ERI point during the study. There was a period of OOS acceleration driven numerically by patient death in the sixth to ninth years of follow-up. Male sex, ischemic cardiomyopathy, elevated creatinine level, advanced age, and reduced ejection fraction were associated with OOS (p < 0.05). To our knowledge, this is the first study to report ICD battery life exceeding patient survival in a chronic heart failure cohort. During an accelerated time of CRT-D OOS (when it is expected that ~98% of 1.0-Ah and 1.4-Ah CRT-D systems reach an ERI point), patient death resulted in substantially more device OOS than battery replacement and avoided costs of complications and generator changes. These results help to explain the elevated risks of CRT-D generator changes in shorter-longevity devices.

Predicted longevity of contemporary cardiac implantable electronic devices: A call for industry-wide "standardized" reporting

BACKGROUND

Battery longevity is an important factor that may influence the selection of cardiac implantable electronic devices (CIEDs). However, there remains a lack of industry-wide standardized reporting of predicted CIED longevity to facilitate informed decision-making for implanting physicians and payers.

OBJECTIVE

The purpose of this study was to compare the predicted longevity of current generation CIEDs using best-matched CIEDs settings to assess differences between brands and models.

METHODS

Data were extracted for current model pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronization therapy-defibrillators (CRT-Ds) from product manuals and, where absent, by communication with the manufacturers. Pacemaker longevity estimations were based on standardized pacing outputs (2.5V, 0.40-ms pulse width, 500-Ω impedance) and pacing loads of 50% or 100% at 60 bpm. ICD and CRT-D longevity were estimated at 0% pacing and 15% atrial plus 100% biventricular pacing, with essential capacitor reforms and zero clinical shocks.

RESULTS

Mean maximum predicted longevity of single- and dual-chamber pacemakers was 12.0 ± 2.1 and 9.8 ± 1.9 years, respectively. Use of advanced features such as remote monitoring, prearrhythmia electrogram storage, and rate response can result in ∼1.4 years of reduction in longevity. Mean maximum predicted longevity of ICDs and CRT-Ds was 12.4 ± 3.0 and 8.8 ± 2.1 years, respectively. Of note, there were significant variations in predicted CIED longevity according to device manufacturers, with up to 44%, 42%, and 44% difference for pacemakers, ICDs, and CRT-Ds, respectively.

CONCLUSION

Contemporary CIEDs demonstrate highly variable predicted longevity according to device manufacturers. This may impact on health care costs and long-term clinical outcomes.

ENDURALIFE-Powered Cardiac Resynchronisation Therapy Defibrillator Devices for Treating Heart Failure: A NICE Medical Technology Guidance

ENDURALIFE™-powered cardiac resynchronisation therapy defibrillator (CRT-D) devices were the subject of an evaluation by the National Institute for Health and Care Excellence, through its Medical Technologies Evaluation Programme, for the treatment of heart failure. Boston Scientific (manufacturer) submitted a case for the adoption of the technology, claiming that it has a longer battery life resulting in a longer time to CRT-D replacement. Other claimed benefits were fewer complications associated with replacement procedures, fewer hospital admissions, less time spent in hospital and reduced demand on cardiology device implantation rooms. The submission was critiqued by Cedar, an external assessment centre. The submitted clinical evidence showed that ENDURALIFE-powered devices implanted during the period 2008-2010 were superior, in terms of longevity, to other devices at that time. Submitted economic evidence indicated that, because of a reduction in the need for replacement procedures, ENDURALIFE-powered devices were cost saving when compared to comparator devices. Cedar highlighted uncertainty of the applicability of the clinical evidence to devices marketed today. The Medical Technologies Advisory Committee noted that this was unavoidable due to the follow-up time required to study battery life. Clinical experts noted that increased battery life is an important patient benefit. However, centres use devices from multiple manufacturers to negate pressure on clinical services in the event of a major device recall. The clinical and economic evidence showed benefits to the patient, and further analysis requested by the committee suggested that ENDURALIFE-powered CRT-Ds may save between £2120 and £5627 per patient over 15 years through a reduction in the need for replacement procedures. ENDURALIFE-powered CRT-D devices received a positive recommendation in Medical Technologies Guidance 33.

Technologies for Prolonging Cardiac Implantable Electronic Device Longevity

Prolonged longevity of cardiac implantable electronic devices (CIEDs) is needed not only as a passive response to match the prolonging life expectancy of patient recipients, but will also actively prolong their life expectancy by avoiding/deferring the risks (and costs) associated with device replacement. CIEDs are still exclusively powered by nonrechargeable primary batteries, and energy exhaustion is the dominant and an inevitable cause of device replacement. The longevity of a CIED is thus determined by the attrition rate of its finite energy reserve. The energy available from a battery depends on its capacity (total amount of electric charge), chemistry (anode, cathode, and electrolyte), and internal architecture (stacked plate, folded plate, and spiral wound). The energy uses of a CIED vary and include a background current for running electronic circuitry, periodic radiofrequency telemetry, high-voltage capacitor reformation, constant ventricular pacing, and sporadic shocks for the cardiac resynchronization therapy defibrillators. The energy use by a CIED is primarily determined by the patient recipient's clinical needs, but the energy stored in the device battery is entirely under the manufacturer's control. A larger battery capacity generally results in a longer-lasting device, but improved battery chemistry and architecture may allow more space-efficient designs. Armed with the necessary technical knowledge, healthcare professionals and purchasers will be empowered to make judicious selection on device models and maximize the utilization of all their energy-saving features, to prolong device longevity for the benefits of their patients and healthcare systems.