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

Impact of Immunosuppressive Therapy on Lead Dislodgement After Cardiac Implantable Electronic Device Implantation

BACKGROUNDS

Lead dislodgement is a severe complication in cardiac implantable electronic device (CIED) implantation. Inflammation after CIED implantation results in the development of adhesions between lead and tissues, resulting in the lead becoming fixed in the body. In patients with immunosuppressive therapy, however, adhesion is inhibited by anti-inflammatory effects. However, the association between lead dislodgement and immunosuppressive therapy has not been clarified. The purpose of this study was to investigate the association between lead dislodgement and immunosuppressive therapy.

HYPOTHESIS

We hypothesized that lead dislodgement more frequently occur in patients with immunosuppressive therapy than those without.

METHODS

In total, 651 consecutive patients who underwent CIED implantation or lead addition (age, 76 ± 11 years; and males, 374 [58%], high voltage device, 121 [19%], lead addition 23 [4%]) were retrospectively enrolled. Immunosuppressive therapy was with regular steroids or immunosuppressants. Lead placement was guided by fluoroscopy, and active fixation leads were used. Restraint of the upper limb by chest tape was performed for 1 week after the procedure. Lead dislodgement was defined as a change in lead position and/or lead failure requiring reoperation.

RESULTS

Twenty (3.1%) patients received immunosuppressive therapy. Among these, 15 (2.3%) patients regularly took steroids and 8 (1.2%) took immunosuppressants. Lead dislodgement occurred in 10 (1.5%) patients. Lead dislodgement was more frequent in patients with immunosuppressive therapy than in those without (3 [15%] vs. 7 [1%], p = 0.003).

CONCLUSION

In patients with CIED implantation or lead addition, lead dislodgement is more frequent in patients with immunosuppressive therapy than in those without.

Next-Generation Cardiac Interfacing Technologies Using Nanomaterial-Based Soft Bioelectronics

Cardiac interfacing devices are essential components for the management of cardiovascular diseases, particularly in terms of electrophysiological monitoring and implementation of therapies. However, conventional cardiac devices are typically composed of rigid and bulky materials and thus pose significant challenges for effective long-term interfacing with the curvilinear surface of a dynamically beating heart. In this regard, the recent development of intrinsically soft bioelectronic devices using nanocomposites, which are fabricated by blending conductive nanofillers in polymeric and elastomeric matrices, has shown great promise. The intrinsically soft bioelectronics not only endure the dynamic beating motion of the heart and maintain stable performance but also enable conformal, reliable, and large-area interfacing with the target cardiac tissue, allowing for high-quality electrophysiological mapping, feedback electrical stimulations, and even mechanical assistance. Here, we explore next-generation cardiac interfacing strategies based on soft bioelectronic devices that utilize elastic conductive nanocomposites. We first discuss the conventional cardiac devices used to manage cardiovascular diseases and explain their undesired limitations. Then, we introduce intrinsically soft polymeric materials and mechanical restraint devices utilizing soft polymeric materials. After the discussion of the fabrication and functionalization of conductive nanomaterials, the introduction of intrinsically soft bioelectronics using nanocomposites and their application to cardiac monitoring and feedback therapy follow. Finally, comments on the future prospects of soft bioelectronics for cardiac interfacing technologies are discussed.

Lead Management in Patients with Congenital Heart Disease

Pediatric patients with congenital heart disease present unique challenges when it comes to cardiac implantable electronic devices. Pacing strategy is often determined by patient size/weight and operator experience. Anatomic considerations, including residual shunts, anatomic obstructions and barriers, and abnormalities in the native conduction system, will affect the type of CIED implanted. Given the young age of patients, it is important to have an "eye on the future" when making pacemaker/defibrillator decisions, as one can expect several generator changes, lead revisions, and potential lead extractions during their lifetime.

Procedural outcome & risk prediction in young patients undergoing transvenous lead extraction-a GALLERY subgroup analysis

Background

The prevalence of young patients with cardiac implantable electronic devices (CIED) is steadily increasing, accompanied by a rise in the occurrence of complications related to CIEDs. Consequently, transvenous lead extraction (TLE) has become a crucial treatment approach for such individuals.

Objective

The purpose of this study was to examine the characteristics and procedural outcomes of young patients who undergo TLE, with a specific focus on identifying independent risk factors associated with adverse events.

Methods

All patients in the GALLERY (GermAn Laser Lead Extraction RegistrY) were categorized into two groups based on their age at the time of enrollment: 45 years or younger, and over 45 years. A subgroup analysis was conducted specifically for the younger population. In this analysis, predictor variables for all-cause mortality, procedural complications, and procedural failure were evaluated using multivariable analyses.

Results

We identified 160 patients aged 45 years or younger with a mean age of 35.3 ± 7.6 years and 42.5% (n = 68) female patients. Leading extraction indication was lead dysfunction in 51.3% of cases, followed by local infections in 20.6% and systemic infections in 16.9%. The most common device to be extracted were implantable cardioverter-defibrillators (ICD) with 52.5%. Mean number of leads per patient was 2.2 ± 1.0. Median age of the oldest indwelling lead was 91.5 [54.75-137.5] months. Overall complication rate was 3.8% with 1.9% minor and 1.9% major complications. Complete procedural success was achieved in 90.6% of cases. Clinical procedural success rate was 98.1%. Procedure-related mortality was 0.0%. The all-cause in-hospital mortality rate was 2.5%, with septic shock identified as the primary cause of mortality. Multivariable analysis revealed CKD (OR: 19.0; 95% CI: 1.84-194.9; p = 0.018) and systemic infection (OR: 12.7; 95% CI: 1.14-142.8; p = 0.039) as independent predictor for all-cause mortality. Lead age ≥ 10 years (OR: 14.58, 95% CI: 1.36-156.2; p = 0.027) was identified as sole independent risk factor for procedural complication.

Conclusion

TLE in young patients is safe and effective with a procedure-related mortality rate of 0.0%. CKD and systemic infection are predictors for all-cause mortality, whereas lead age ≥ 10 years was identified as independent risk factor for procedural complications in young patients undergoing TLE.

Safety and Efficacy of Excimer Laser Powered Lead Extractions in Obese Patients: A GALLERY Subgroup Analysis

BACKGROUND

The incidence of cardiac implantable electronic device (CIED)-related complications, as well as the prevalence of obesity, is rising worldwide. Transvenous laser lead extraction (LLE) has grown into a crucial therapeutic option for patients with CIED-related complications but the impact of obesity on LLE is not well understood.

METHODS AND RESULTS

All patients (n = 2524) from the GermAn Laser Lead Extraction RegistrY (GALLERY) were stratified into five groups according to their body mass index (BMI, <18.5; 18.5-24.9; 25-29.9; 30-34.9; ≥35 kg/m²). Patients with a BMI ≥ 35.0 kg/m² had the highest prevalence of arterial hypertension (84.2%, p < 0.001), chronic kidney disease (36.8%, p = 0.020) and diabetes mellitus (51.1%, p < 0.001). The rates for procedural minor (p = 0.684) and major complications (p = 0.498), as well as procedural success (p = 0.437), procedure-related (p = 0.533) and all-cause mortality (p = 0.333) were not different between groups. In obese patients (BMI ≥ 30 kg/m²), lead age ≥10 years was identified as a predictor of procedural failure (OR: 2.99; 95% CI: 1.06-8.45; p = 0.038). Lead age ≥10 years (OR: 3.25; 95% CI: 1,31-8.10; p = 0.011) and abandoned leads (OR: 3.08; 95% CI: 1.03-9.22; p = 0.044) were predictors of procedural complications, while patient age ≥75 years seemed protective (OR: 0.27; 95% CI: 0.08-0.93; p = 0.039). Systemic infection was the only predictor for all-cause mortality (OR: 17.68; 95% CI: 4.03-77.49; p < 0.001).

CONCLUSIONS

LLE in obese patients is as safe and effective as in other weight classes, if performed in experienced high-volume centers. Systemic infection remains the main cause of in-hospital mortality in obese patients.

A Large-Diameter Vascular Graft Replacing Animal-Derived Sealants With an Elastomeric Polymer

INTRODUCTION

To assess the safety and efficacy of an experimental large-diameter vascular graft externally sealed with an elastomeric polymer when used as an interposition graft in the descending aorta of sheep.

METHODS

The experimental vascular grafts as well as control gelatin sealed interposition grafts were inserted into the descending aorta of juvenile sheep. The grafts were assessed by time to hemostasis and blood loss during surgery and hematology and biochemistry panels at distinct time points. Magnetic resonance imaging (MRI) was performed at 3 and at 6 mo after surgery, after which the animals were euthanized and necropsies were carried out including macroscopic and microscopic examination of the grafts, anastomoses, and distal organs.

RESULTS

All animals survived the study period. There was no perceivable difference in the surgical handling of the grafts. The median intraoperative blood loss was 27.5 mL (range 10.0-125.0 mL) in the experimental group and 50.0 mL (range 10.0-75.0 mL) in the control group. The median time to hemostasis was 5.0 min (range 2.0-16.0 min) minutes in the experimental group versus 6.0 min (range 4.0-6.0 min) in the control group. MRI showed normal flow and graft patency in both groups. Healing and perianastomotic endothelialization was similar in both groups.

CONCLUSIONS

The experimental graft has a similar safety and performance profile and largely comparable necropsy results, in comparison to a commonly used prosthetic vascular graft, with the experimental grafts eliciting a nonadherent external fibrous capsule as the major difference compared to the control grafts that were incorporated into the periadventitia. Survival, hemostatic sealing, and hematologic and radiologic results were comparable between the study groups.

"Ghost", a Well-Known but Not Fully Explained Echocardiographic Finding during Transvenous Lead Extraction: Clinical Significance

"Ghosts" are fibrinous remnants that become visible during transvenous lead extraction (TLE).

METHODS

Data from transoesophageal echocardiography-guided TLE procedures performed in 1103 patients were analysed to identify predisposing risk factors for the development of so-called disappearing ghosts-flying ghosts (FG), or attached to the cardiovascular wall-stable ghosts (SG), and to find out whether the presence of ghosts affected patient prognosis after TLE.

RESULTS

Ghosts were detected in 44.67% of patients (FG 15.5%, SG 29.2%). The occurrence of ghosts was associated with patient age at first system implantation [FG (OR = 0.984; p = 0.019), SG (OR = 0.989; p = 0.030)], scar tissue around the lead (s) [FG (OR = 7.106; p < 0.001, OR = 1.372; p = 0.011), SG (OR = 1.940; p < 0.001)], adherence of the lead to the cardiovascular wall [FG (OR = 0.517; p = 0.034)] and the number of leads [SG (OR = 1.450; p < 0.002). The presence of ghosts had no impact on long-term survival after TLE in the whole study group [FG HR = 0.927, 95% CI (0.742-1.159); p = 0.505; SG HR = 0.845, 95% CI (0.638-1.132); p = 0.265].

CONCLUSIONS

The degree of growth and maturation of scar tissue surrounding the lead was the strongest factor leading to the development of both types of ghosts. The presence of either form of ghost did not affect long-term survival even after TLE indicated for infection.

Advanced Strategies to Thwart Foreign Body Response to Implantable Devices

Mitigating the foreign body response (FBR) to implantable medical devices (IMDs) is critical for successful long‐term clinical deployment. The FBR is an inevitable immunological reaction to IMDs, resulting in inflammation and subsequent fibrotic encapsulation. Excessive fibrosis may impair IMDs function, eventually necessitating retrieval or replacement for continued therapy. Therefore, understanding the implant design parameters and their degree of influence on FBR is pivotal to effective and long lasting IMDs. This review gives an overview of FBR as well as anti‐FBR strategies. Furthermore, we highlight recent advances in biomimetic approaches to resist FBR, focusing on their characteristics and potential biomedical applications.

Tissues attached to retrieved leadless pacemakers: Histopathological evaluation of tissue composition in relation to implantation time and complications

BACKGROUND

Leadless pacemakers (LPs) have proven safe and effective, but device revisions remain necessary. Either replacing the LP or implanting a new adjacent LP is feasible. Replacement seems more appealing, but encapsulation and tissue adhesions may hamper the safety and efficacy of LP retrieval.

OBJECTIVE

We determined the incidence and cellular characteristics of tissue adherent to retrieved LPs and the potential implications for end-of-life strategy.

METHODS

All 15 consecutive successful Nanostim LP retrievals in a tertiary center were included. We assessed the histopathology of adherent tissue and obtained clinical characteristics.

RESULTS

Adherent tissue was present in 14 of 15 retrievals (93%; median implantation duration 36 months; range 0-96 months). The tissue consisted of fibrosis (n = 2), fibrosis and thrombus (n = 9), or thrombus only (n = 3). In short-term retrievals (<1 year), mostly fresh thrombi without fibrosis were seen. In later retrievals, the tissue consisted of fibrosis often with organizing or lytic thrombi. Fibrosis showed different stages of organization, notably early fibrocellular and later fibrosclerotic tissue. Inflammatory cells were seen (n = 4) without signs of infection. Tricuspid valve material was retrieved in 1 patient after 36 months, resulting in increased tricuspid regurgitation.

CONCLUSION

Our results suggest that fibrosis and thrombus adherent to LPs are common and encapsulate the LP as seen in transvenous pacemakers. LPs may adhere to the tricuspid valve or subvalvular apparatus affecting retrieval safety. The end-of-life strategy should be optimized by incorporating risk stratification for excessive fibrotic encapsulation and adhesions.

Morphometric Characterization of Human Coronary Veins and Subvenous Epicardial Adipose Tissue-Implications for Cardiac Resynchronization Therapy Leads

Subvenous epicardial fat tissue (SEAT), which acts as an electrical insulation, and the venous diameter (VD) both constitute histomorphological challenges for optimal application and lead design in cardiac synchronization therapy (CRT). In this study, we characterized the morphology of human coronary veins to improve the technical design of future CRT systems and to optimize the application of CRT leads. We retrospectively analyzed data from cardiac computed tomography (CT) of 53 patients and did studies of 14 human hearts using the postmortem freeze section technique and micro CT. Morphometric parameters (tributary distances, offspring angles, luminal VD, and SEAT thickness) were assessed. The left posterior ventricular vein (VVSP) had a mean proximal VD of 4.0 ± 1.4 mm, the left marginal vein (VMS) of 3.2 ± 1.5 mm and the anterior interventricular vein (VIA) of 3.9 ± 1.3 mm. More distally (5 cm), VDs decreased to 2.4 ± 0.6 mm, 2.3 ± 0.7 mm, and 2.4 ± 0.6 mm, respectively. In their proximal portions (15 mm), veins possessed mean SEAT thicknesses of 3.2 ± 2.4 (VVSP), 3.4 ± 2.4 mm (VMS), and 4.2 ± 2.8 mm (VIA), respectively. More distally (20-70 mm), mean SEAT thicknesses decreased to alternating low levels of 1.3 ± 1.1 mm (VVSP), 1.7 ± 1.1 mm (VMS), and 4.3 ± 2.6 mm (VIA), respectively. In contrast to the VD, SEAT thicknesses alternated along the further distal vein course and did not display a continuous decrease. Besides the CRT responsiveness of different areas of the LV myocardium, SEAT is a relevant electrophysiological factor in CRT, potentially interfering with sensing and pacing. A sufficient VD is crucial for successful CRT lead placement. Measurements revealed a trend toward greater SEAT thickness for the VIA compared to VVSP and VMS, suggesting a superior signal-to-noise-ratio in VVSP and VMS.