Rationale and Design of the Lead EvaluAtion for Defibrillation and Reliability (LEADR) Study: Safety and Efficacy of a Novel ICD Lead Design

Background: Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small diameter, lumenless, catheter delivered, defibrillator lead was developed with the aim to improve long term reliability. Methods and Results: The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi-center, single-arm, Bayesian, adaptive design, pre-market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre-hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients will participate for a minimum of 18 months to approximately 3 years. Fracture-free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in-vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow-up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. Conclusion: The LEADR Clinical Study was designed to efficiently provide evidence for short- and long-term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach.

Long-Term Follow-up of Standard and Small Diameter Implantable Cardioverter Leads

Background: Small-diameter implantable cardioverter-defibrillator (ICD) leads have been introduced into clinical practice to facilitate the implantation procedure. Despite their expected benefits, the reliability of these leads has proven to be questionable. The main purpose of our study is to investigate the impact of ICD lead diameter (≤8 F versus >8 F) on long-term lead durability. Methods: Overall, 206 consecutive patients implanted with a right ventricular ICD lead in the Electrophysiology and Cardiac Pacing Unit of our department from January 2008 to December 2013 were included in this analysis. ICD leads were defined, according to their diameter, as small (≤8 F) and standard (>8 F).The small-diameter leads (n=106) included Linox (Biotronik; n=58) and Durata (St. Jude Medical/Abbot; n=48). The standard-diameter ICD leads (n=100) consisted of Sprint Quattro (Medtronic; n=64) and Endotak (Boston Scientific; n=36). Results: After a median follow-up of 7.3 years, lead failure rate was significantly increased for small-diameter leads compared with standard-diameter leads (6.6% vs 1%; P=0.035). No difference in lead survival probability has been observed between Linox and Durata small-diameter leads (93% vs 92.7%; P=0.71). The majority of lead failures presented as noise (87.5%), without detectable abnormalities on fluoroscopic evaluation. Conclusion: Our single-centre study showed that both Linox and Durata small-diameter ICD are associated to be more susceptible to a greater risk of lead failure as compared to standard-diameter ICD leads. In this perspective, a comprehensive vigilance strategy including home monitoring is warranted for early detection of lead failure.

Three-Dimensional Analysis of the In Vivo Motion of Implantable Cardioverter Defibrillator Leads

Better understanding of the lead curvature, movement and their spatial distribution may be beneficial in developing lead testing methods, guiding implantations and improving life expectancy of implanted leads. Objective The aim of this two-phase study was to develop and test a novel biplane cine-fluoroscopy-based method to evaluate input parameters for bending stress in leads based on their in vivo 3D motion using precisely determined spatial distributions of lead curvatures. Potential tensile, compressive or torque forces were not subjects of this study. Methods A method to measure lead curvature and curvature evolution was initially tested in a phantom study. In the second phase using this model 51 patients with implanted ICD leads were included. A biplane cine-fluoroscopy recording of the intracardiac region of the lead was performed. The lead centerline and its motion were reconstructed in 3D and used to define lead curvature and curvature changes. The maximum absolute curvature Cmax during a cardiac cycle, the maximum curvature amplitude Camp and the maximum curvature Cmax@amp at the location of Camp were calculated. These parameters can be used to characterize fatigue stress in a lead under cyclical bending. Results The medians of Camp and Cmax@amp were 0.18 cm−1 and 0.42 cm−1, respectively. The median location of Cmax was in the atrium whereas the median location of Camp occurred close to where the transit through the tricuspid valve can be assumed. Increased curvatures were found for higher slack grades. Conclusion Our results suggest that reconstruction of 3D ICD lead motion is feasible using biplane cine-fluoroscopy. Lead curvatures can be computed with high accuracy and the results can be implemented to improve lead design and testing.

Predictors of success and complications in laser lead extraction

Funding Acknowledgements Type of funding sources: None. Background Extraction of cardiac implantable electronic device (CIED) leads using excimer laser is in use since > 20 years, but the predictors of success, all-cause complications and mortality are not yet sufficiently statistically evaluated. Method All consecutive laser extractions performed at our institution between September 2011 and March 2020 with lead age > 12 months were included and retrospectively analysed. Results 792 leads (mean age 75 months) were extracted during 335 procedures. The indication for extraction was pocket infection in 59%, CIED endocarditis in 25%, lead dysfunction or upgrade in 14% and others in 2%. 94.6% of leads were extracted complete, 4.2% partial (< 4 cm rest) and the extraction failed in 1.3% of the leads (retention of ≥ 4 cm rest). Multivariable analysis identified lead age > 7.5 years (odds ratio [OR] 6.5; p = 0.0281), broken leads (OR 28.0; p = 0.0009) and implantable cardioverter-defibrillator (ICD) leads (OR 6.5; p = 0.0010) as independent predictors of failed extraction. CIED-endocarditis was independently associated with complete extraction (OR 3.3; p = 0.0218). Complete procedural success or clinical success was achieved in 330 of 335 procedures (98.6%). The lead extraction failed in five cases (1.5%). Major procedure-associated adverse events (injuries of the great vessels or heart) occurred in four cases (1.2%). Two patients died perioperatively (0.6%). Minor complications occurred in 13 cases (3.9%). Major adverse events (MAE) causally not related to the procedure occurred in 18 (5.4%) of the patients. The most frequent MAE was postoperative aggravation of the sepsis (10 patients; 3.0%). Independent predictors of major adverse events were CIED-endocarditis (OR 6.0; p = 0.0175), preoperative C-reactive-protein (CRP) > 35 mg/l (OR 3.8; p = 0.0412) and body mass index (BMI) ≥ 25 kg/m2 (OR 5.0; p = 0.0489). Ten patients (3%) died during the hospital stay. CIED-endocarditis with preoperative CRP > 35 mg/l was independently associated with hospital mortality in multivariable analysis (OR 10.7; p = 0.0020). The Kaplan-Meyer analysis of 30-day mortality showed a significantly worse survival of patients with endocarditis (Log-Rank p = 0.0102). Conclusion Leads > 7.5 years, broken leads and ICD leads are independent predictors of failed extraction. CIED endocarditis, CRP > 35 and BMI ≥ 25 are associated with MAE. CIED endocarditis is related to higher short-term mortality despite successful lead extraction. Abstract Figure. Predictors of major adverse events

Analysis of the Movement of ICD Leads During Cardiac Contraction as Determinant of Intracardiac Impedance

Intracardiac impedance (ICI) has been proposed as an indicator of cardiac status in heart failure patients. We introduce a biophysical model of the measurement setup and apply it to the movement of ICD leads reconstructed from clinical-routine X-ray recordings in a study population of 12 patients. Tilting of the right ventricular lead is found to be a major determinant of ICI changes during cardiac contraction with a mean contribution of 42±23%. The relative position between right and left ventricular lead is the second major contributor (40±22%). However, the contributions of the components of movement strongly differ between the patients. The proposed method provides means for a better interpretation of ICI measurements and for an improvement of its performance for monitoring heart failure status.<br>

Analysis of the Movement of ICD Leads During Cardiac Contraction as Determinant of Intracardiac Impedance

Intracardiac impedance (ICI) has been proposed as an indicator of cardiac status in heart failure patients. We introduce a biophysical model of the measurement setup and apply it to the movement of ICD leads reconstructed from clinical-routine X-ray recordings in a study population of 12 patients. Tilting of the right ventricular lead is found to be a major determinant of ICI changes during cardiac contraction with a mean contribution of 42±23%. The relative position between right and left ventricular lead is the second major contributor (40±22%). However, the contributions of the components of movement strongly differ between the patients. The proposed method provides means for a better interpretation of ICI measurements and for an improvement of its performance for monitoring heart failure status.<br>

Quantitative and Qualitative Assessment of Adhesive Thrombo-Fibrotic Lead Encapsulations (TFLE) of Pacemaker and ICD Leads in Arrhythmia Patients—A Post Mortem Study

The demand for cardiac implantable electronic devices for arrhythmia therapy is still unabated and rising. Despite onward optimizations, lead-related problems such as infections or fractures often necessitate lead extraction. Due to adhesive thrombo-fibrotic lead encapsulations (TFLE) transvenous lead extraction is challenging and risky. However, knowledge on TFLEs and possible correlations with technical lead parameters and dwelling time (DT) were hitherto insufficiently studied. Therefore, we analyzed TFLEs of 62 lead from 35 body donor corpses to gain information for a potential lead design optimization. We examined both TFLE topography on the basis on anatomical landmarks and histo-morphological TFLE characteristics by means of histological paraffin sections and scanning electron microscopy of decellularized samples. The macroscopic analysis revealed that all leads were affected by TFLEs, mainly in the lead bearing veins. Half (47.2%) of the right-ventricular leads possessed adhesions to the tricuspid valve. On average, 49.9 ± 21.8% of the intravascular lead length was covered by TFLE of which 82.8 ± 16.2% were adhesive wall bindings (WB). The discrete TFLEs with at least one WB portion had a mean length of 95.0 ± 64.3 mm and a maximum of 200 mm. Neither sex, DT nor certain technical lead parameters showed distinct tendencies to promote or prevent TFLE. TFLE formation seems to start early in the first 1–2 weeks after implantation. The degree of fibrotization of the TFLE, starting with a thrombus, was reflected by the amount of compacted collagenous fibers and likewise largely independent from DT. TFLE thickness often reached several hundred micrometers. Calcifications were occasionally seen and appeared irregularly along the TFLE sheath. Leadless pacemaker systems have the advantage to overcome the problem with TFLEs but hold their own specific risks and limitations which are not fully known yet.

Abstract 15748: Failure of Subcutaneous Implantable Cardioverter Defibrillator in a Patient With Arrhythmogenic Right Ventricular Cardiomyopathy

Introduction: The subcutaneous ICD is an attractive option in ARVC patients as they rarely require pacing, it preserves vascular access, and it avoids the long-term morbidity related to intravascular lead placement. However, the limitations of the S ICD have not been fully demarcated by clinical trials. Case: After her father presented with a cardiac arrest, a 16-year-old female was diagnosed with ARVC on MRI after initially presenting with palpitations. This was corroborated via genetic testing, and an S ICD was placed after she passed pre-implant screening. Initially she did well, but she suffered inappropriate shocks approximately seven months after implant, in the setting of “hugging her boyfriend”. Interrogation revealed apparent noise, which was felt to be most likely due to lead fracture or possibly generator malfunction. At reoperation, first her lead was replaced, but continued noise was demonstrated intra-operatively, and thus her generator was also replaced. However, she was found again to have noise in each vector causing recurrent inappropriate shocks. Further testing ultimately determined that the noise was due to myopotentials, which were present in all vectors and unable to be programmed around. Ultimately, the S ICD was removed and replaced with a transvenous device. Discussion: While the S ICD is an attractive option in ARVC patients, the limitations of the technology must be acknowledged. The far-field nature of the sensing algorithm in the S ICD leads to a risk of myopotential oversensing. If this occurs, sometimes the system cannot be salvaged and the patient must be converted to a transvenous system. Recognizing this at the initial presentation with inappropriate shocks can avoid unsuccessful attempts at S ICD system modification and morbidity from future inappropriate shock events.

Abstract 14091: Outcomes of Patients With Recalled Defibrillator Leads: Results From the NCDR-ICD Registry

Introduction: Whether to reuse, abandon, or extract functioning, recalled ICD leads at the time of generator replacement is an area of uncertainty as lead failure is more common following generator replacement, and long term failure rates of recalled ICD leads are unknown. We sought to evaluate outcomes following various lead management strategies at the time of generator replacement. Hypothesis: Functional St. Jude Riata and Medtronic Sprint Fidelis leads at the time of elective generator replacement are more frequently reused than replaced, and extracting them poses significant procedural risk. Methods: We queried the NCDR ICD Registry for Medicare patients undergoing elective generator replacement with a normal Fidelis or Riata lead from 2010-2016 and categorized patients based on the fate of the recalled lead: reused, abandoned, or extracted. We report pre-discharge complications by group. Results: There were 9937 generator replacement patients between 2010-2016 with a functioning Riata or Fidelis lead in which lead management was reported. The lead was reused in 9806 (98%) patients, extracted in 55 (0.6%), and abandoned in 76 (0.8%). Compared with the reused group, extracted patients were >10 years younger, had less heart failure and fewer comorbidities. In-hospital death occurred in 4 (7.3%) patients in the extracted group and 7 (0.07%) in the reused group (P<0.0001). The combination of death or any pre-discharge event occurred in 11% of extracted patients compared with 0.3% and 0% in the reused and abandoned groups, respectively.(Table) Conclusions: At the time of generator replacement, a small percentage of functional Riata and Fidelis leads were extracted. Even in this highly selected extraction population, extraction posed significant risk of in-hospital mortality and severe complications. Future work will help clarify whether these peri-procedural risks may be justified by improved medium and long term outcomes.