Initial Implantation Research Articles

A new window on subcutaneous ICD system performance: Z-lead impedance change over time in devices with and without extracellular matrix envelope use

Abstract Background Device impedance for subcutaneous ICDs (S-ICDs) may rise over time reflecting changes in tissue electrical conduction due to fibrosis from the natural foreign body response, increasing the risk of defibrillation failure. A biologic envelope optimized for S-ICDs may mitigate fibrosis and encourages angiogenesis around the device possibly decreasing impedance rise over time. The S-ICD system performs routine low-voltage Z-lead (LVZ) impedance testing (impedance between shocking coil and can) that may provide insight into the impedance changes on device functionality and efficacy over time. Purpose Explore early and late impedance changes over time in S-ICDs implanted with and without envelopes using periodic LVZ measurements. Methods 30 patients received S-ICDs (15 with envelope) between 1/2017 and 3/2021, after excluding those with device complications, uncontrolled comorbidities, or recent cardiac surgery. Impedance data was recorded at initial implantation. LVZ impedance data was extracted from the wireless remote monitoring system, trended over 0–4 years post implant, and analyzed blinded to patient information. Results 24 patients (12 envelope) had evaluable implant and chronic data sets. Baseline clinical characteristics were similar between groups. Impedance in general was higher in the envelope group at initial implantation (LVZ mean 89 Ω vs 74 Ω) and throughout the first year. Comparing envelope to no envelope, the initial average shock impedance was 87.3±30.50 vs 66.7±10.40, followed by an average low-V impedance drop of 29 Ω vs 17 Ω during the first month, with a recovery to 109 Ω vs 91 Ω at 30 months post implant. After 30 months, impedance trends demonstrated a modest linear increase up to 48 months in the no envelope group in comparison with a modest decrease in the envelope group (sample sizes too small to determine significance) (Figure 1). Conclusion The results demonstrate periodic LVZ testing in the S-ICD monitoring system can reliably trend changes in system impedance over time. Impedance measurements within the first 6–7 months (and most markedly within the first 3 months) appear to be transiently lower than the values seen after this timepoint suggesting that early impedance measurements may not predict steady-state impedance. Further studies are needed to explore the impact of envelope use and the S-ICD impedance changes beyond 30 months. Funding Acknowledgement Type of funding sources: None.

Left ventricular dysfunction, heart failure, and mortality risk factors in de novo pacemaker recipients and those requiring pacemaker generator replacement

Abstract Background Pacing the right ventricle (RV) can lead to adverse remodelling of the left ventricle (LV), LV dysfunction, increased risk of heart failure hospitalisation (HFH) and mortality. Despite RV pacing avoidance programming becoming commonplace, pacemaker patients remain at risk of pacing-induced cardiomyopathy. New pacing strategies and cardiac resynchronisation therapy are available therapeutic options, but it is unclear which patients should be targeted, and when. Purpose This study examined the effects of RV pacing on LV function, the risk of heart failure requiring hospitalisation and all-cause mortality in patients during the first 12 months of pacemaker therapy, compared to those at pacemaker generator replacement (PGR). Methods Data were obtained from a cohort of patients who underwent de novo pacemaker implantation between 2014 and 2017, and patients requiring PGR between 2008 and 2011 at a single tertiary UK hospital, with follow-up from 12 months. Clinical, echocardiographic, and pacemaker variables, medication, and past medical history data were collected. Predictors of a combined endpoint of all-cause mortality or HFH were assessed using cox-regression analysis, with predictors of impaired LV function analysed using multivariable regression analysis. Results 514 newly implanted (NI) patients (mean age, 75 years; 66% male) were recruited, and 491 patients (mean age, 76 years; 56% male) requiring PGR. After a mean follow up of 887 days, 79 NI patients (16%) were deceased (n=27) or had been hospitalised for HF (n=52), whereas after a mean follow up of 668 days, 56 patients after PGR (12%) were deceased (n=34) or had been hospitalised (n=22) for HF. After 12 months of pacemaker therapy, 182 (35%) NI patients had a LV ejection fraction (LVEF) <50%, which had a higher incidence at PGR of 197 (40%). Age was the only significant predictor of mortality or HFH for both NI and PGR (hazard ratio (HR), 1.068; 95% confidence interval (CI), 1.039 to 1.098; p<0.001 vs 1.035; 95% CI, 1.007 to 1.064; p=0.014), respectively). Univariate analysis revealed baseline LVEF (2.439; 95 percent CI, 1.279 to 4.659; p=0.007), RV pacing burden, medication and blood chemistry were significant predictors of the combined outcome at PGR but not at NI (Table 2). Multivariable analysis of predictors of LV impairment (<50% LVEF) showed history of MI (odds ratio (OR), 0.47; 95% CI, 0.29 to 0.78; p=0.003), RV pacing burden (1.01; 95% CI, 1.01 to 1.02; p<0.001) and creatinine (1.06; 95% CI, 1.02 to 1.10; p=0.004) were independently associated in both cohorts. Conclusions Our data suggest that there remains a similar subgroup of people from initial implantation to PGR at risk of LV impairment that might benefit from medication optimisation or novel pacing strategies. Further research is required to better identifying these people to direct more complex therapies to those with the most to gain. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The research is supported by a National Institute for Health Research (NIHR) clinician scientist fellowship (NIHRCS-2012-032). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. This research was supported by the NIHR Leeds Clinical Research Facility.

Follow-up of hypertension after aortic coarctation stent implantation based on safe and effective re-intervention: a retrospective cohort study.

Stent implantation for aortic coarctation (CoA) is associated with anatomical and hemodynamic advantages. Although the anatomy is corrected after the intervention, patients often still suffer from hypertension during the follow-up. Its risk factors remain unclear. There are only a few studies on the long-term follow-up of hypertension after stenting. This study aimed to investigate the factors influencing systemic hypertension after CoA by transcatheter stent placement. A total of 82 patients (native CoA: 37; men: 53) who underwent stent implantation for CoA at a median age of 123 months (range, 40 days-44 years) between January 2004 and September 2012 were included in this study. Patients with native or recurrent CoA after surgery, simple CoA or complex CoA associated with other cardiac anomalies were recruited in this study. Only stents that were expandable to adult size were implanted. After the initial stent implantation, the patients were followed up for 76.7 months (range, 6-151 months). Those who met the indications for a re-intervention underwent a balloon dilatation or stent implantation to relieve restenosis and alleviate the hypertension caused by restenosis. Patients with hypertension were treated with anti-hypertensive agents. In the initial intervention, 87 stents were implanted in 82 patients. Seventy-two patients (87.8%) were diagnosed with hypertension before treatment, but only 23 (28.0%) patients had hypertension at the last follow-up, which is a number significantly lower than that before the intervention (P<0.001). Cox regression analysis showed that age at stent implantation was significantly correlated with the incidence of hypertension, which indicates that the younger the patient receiving the intervention, the lower the incidence of hypertension. Moreover, the incidence of hypertension in follow-up is related to the diagnosis. It was higher in the patients with simple CoA than those with complex CoA. There was no significant correlation between native CoA and recurrent CoA. The incidence of hypertension after CoA stent implantation was significantly lower than that before the intervention. Age at stent implantation is an essential influencing factor for paradoxical hypertension after CoA stent implantation. Complex CoA in patients was related to a significantly lower prevalence of follow-up hypertension.

Application-Based Early Interventions of Hardware-Related Infection After Invasive Neuromodulation Prevent Implant Removal

This study aimed to establish a mobile health application to diagnose and treat postdischarge hardware-related infections in a timely manner and prevent the complete removal of hardware or an implantable pulse generator (IPG). We conducted a retrospective and historical controlled study of all patients who had undergone initial hardware implantation at a single center. All participants were aggregated into 2 groups, A (between June 2005 and June 2014) and B (between July 2014 and May 2020). In group B, the Postdischarge Patient Aide was used for wound monitoring. Both groups received regular clinical follow-up. Cases and the range of hardware-related infections were compared. There was no significant difference in infection rate between the groups (1.8% vs. 1.4%, P= 0.413). After application of the Postdischarge Patient Aide, the proportion of patients with early interventions had increased significantly in group B compared with group A (83.3% vs. 20.0%, P < 0.001). The percentage of patients with IPG infection at the time of interventions in group B was significantly lower than that in group A (8.3% vs. 60.0%, P < 0.001). The IPG preservation rate in group B was significantly higher than that in group A (75% vs. 16%, P < 0.001). A mobile health application provides an efficient way to make an early diagnosis, treat a hardware-related infection, and prevent hardware removal. Information on wound healing should be transmitted to the surgery team in a convenient and fast way to prevent infection spreading, which helps to prevent the IPG from being abandoned.

Cochlear Reimplantation Rate and Cause: a 22-Year, Single-Center Experience, and a Meta-Analysis and Systematic Review.

In terms of cochlear reimplantation, there is no consensus on the definition, range, or calculation formulation for the reimplantation rate. This study aims to put forward a relatively standardized and more explicit definition based on a literature review, calculate the rate of cochlear reimplantation, and examine the classification and distribution of the reimplantation causes. A systematic review and retrospective study. A relatively clearer definition was used in this study: cochlear reimplantation is the implantation of new electrodes to reconstruct the auditory path, necessitated by the failure or abandonment of the initial implant. Seven English and Chinese databases were systematically searched for studies published before July 23, 2021 regarding patients who accepted cochlear reimplantation. Two researchers independently applied the inclusion and exclusion criteria to select studies and complete data extraction. As the effect size, the reimplantation rate was extracted and synthesized using a random-effects model, and subgroup and sensitivity analyses were performed to reduce heterogeneity. In addition, a retrospective study analyzed data on cochlear reimplantation in a tertiary hospital from April 1999 to August 2021. Kaplan-Meier survival analysis and the log-rank test were adopted to analyze the survival times of cochlear implants and compare them among different subgroups. A total of 144 articles were included, with 85,851 initial cochlear implantations and 4276 cochlear reimplantations. The pooled rate of cochlear reimplantation was 4.7% [95% CI (4.2% to 5.1%)] in 1989 to 2021, 6.8% [95% CI (4.5% to 9.2%)] before 2000, and 3.2% [95% CI (2.7% to 3.7%)] after 2000 ( P =0.003). Device failures accounted for the largest proportion of reimplantation (67.6% [95% CI (64.0% to 71.3%)], followed by medical reasons (28.9% [95% CI (25.7% to 32.0%)]). From April 1999 to August 2021, 1775 cochlear implants were performed in West China Hospital (1718 initial implantations and 57 reimplantations; reimplantation rate 3.3%). In total, 45 reimplantations (78.9%) were caused by device failure, 10 (17.5%) due to medical reasons, and 2 (3.5%) from unknown reasons. There was no difference in the survival time of implants between adults and children ( P = 0.558), while there existed a significant difference between patients receiving implants from different manufacturers ( P < 0.001). The cochlear reimplantation rate was relatively high, and more attention should be paid to formulating a standard definition, calculation formula, and effect assessment of cochlear reimplantation. It is necessary to establish a sound mechanism for long-term follow-up and rigorously conduct longitudinal cohort studies.

Lead and Pulse Generator Migration After Spinal Cord Stimulation Implantation: Insights From an Analysis of 7322 Patients

ObjectivesLead migration (LM) after spinal cord stimulation (SCS) implantation surgery is the most common device-related complication. Our study of lead and implantable pulse generator (IPG) migration using a large administrative claims data base aims to understand rates, risk factors, and outcomes after SCS implantation. Materials and MethodsThis retrospective cohort study used the IBM® MarketScan® (Armonk, NY) Commercial and Medicare Supplemental Databases from 2016 to 2018. Adult patients who underwent SCS surgical procedures with at least 90 days of follow-up were identified using Current Procedural Terminology (CPT®) codes. Patients with LM and IPG migration after SCS surgery were identified using the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10 CM) codes. Patients who underwent revision surgery after SCS implantation were identified using the CPT codes and ICD-10 CM codes. In addition, patient characteristics associated with LM or IPG migration, the temporal relationship of migration diagnosis, and revision surgery were evaluated in the cohort. Continuous outcomes were compared between groups using the two-sample Student t-test. The Fisher exact test was used to compare categorical outcomes between groups. ResultsA total of 7322 patients (64.4% percutaneous SCS) underwent SCS surgery during the study period. A total of 141 patients (1.9%) had LM or IPG migration. Of those, 116 patients (1.6%) had LM only; 18 patients (0.2%) had IPG migration; and seven patients (0.1%) had LM and IPG migration. The mean duration for migration diagnosis after initial SCS implantation was 168 (±163.1) days. The mean duration to revision surgery after the migration diagnosis was 12.3 (±35.2) days only. Most patients with migration (105, 74.5%) underwent revision surgery. Only younger age (p = 0.02) was associated with migration in this study. ConclusionsLM and pulse generator migration that required revision surgery occurred in a small proportion of patients who underwent SCS surgical procedures.

Phrenic nerve stimulation in an ovine model with temporary removable pacing leads.

BackgroundThe objective of this study was to assess the feasibility and safety of a novel, removable, surgically implanted, temporary neurostimulation approach involving the distal portion of the phrenic nerve.MethodsTemporary phrenic nerve pacing electrodes were implanted surgically using an ovine model (4 animals). The primary endpoint was the ability to successfully match the animal’s minute-ventilation upon implantation of both phrenic nerve pacers on day 1. Secondary endpoints were successful phrenic neurostimulation by both electrodes 15 and 30 days after initial implantation. We also assessed safe removal of the electrodes at 15 and 30 days after implementation.ResultsIn 3 of 4 animals, electrodes were successfully implanted in both right and left phrenic nerves. On day 1, median ventilation-minute induced by neurostimulation was not significantly different from baseline ventilation-minute [4.9 L·min−1 (4.4–5.5) vs. 4.4 L·min−1 (4.3–5.2); P=0.4] after 15 minutes. Neurostimulation was still possible 15 and 30 days after implementation in all left side phrenic nerves. On the right side, stimulation was possible at all times in 1 animal but not in the remaining 3 animals for at least one time point, possibly due to lead displacement. Analysis of pathology after percutaneous electrode removal showed integrity of the distal portion of all phrenic nerves.ConclusionsEfficient temporary neurostimulation through the distal portion of the phrenic nerve was possible at baseline. The main complication was the displacement of electrodes on the right phrenic nerve on two occasions, which was due to the anatomy of the ovine model. It compromised diaphragm pacing on day 15 and day 30. The electrodes could be safely removed percutaneously without damage to the phrenic nerves.

Trend in Age at the Initial Pacemaker Implantation in Patients With Bradyarrhythmia - A 50-Year Analysis (1970-2019) in Japan.

This study investigated whether the age of patients undergoing pacemaker implantation is increasing.Methods and Results: This study retrospectively reviewed the consecutive cases of 3,582 patients who underwent an initial pacemaker implantation at our hospitals because of symptomatic bradyarrhythmias between 1970 and 2019. The exclusion criteria were: patients with AV block due to cardiac surgery or AV junction ablation, and patients aged <20 years. The patients were divided into 5×10-year groups: those treated in the 1970s (1970-1979), 1980s (1980-1989), 1990s (1990-1999), 2000s (2000-2009), and 2010s (2010-2019). A total of 3,395 patients satisfied the study criteria. The average age at which the patients underwent a first pacemaker implantation increased across the 10-year periods: 63.7±13.2 years in the 1970s, 66.2±12.6 years (1980s), 69.1±12.4 years (1990s), 72.0±11.1 years (2000s), and 75.8±10.0 years (2010s) and advanced significantly in the 1990s, 2000s, and 2010s compared to the 1970s (all P<0.001). The ratio of patients aged ≥80 and ≥90 years increased from 10.6% and 0% in the 1970 s to 38.2% (P<0.001) and 5.2% (P= 0.017) in the 2010s, respectively. The average age at initial pacemaker implantation increased by 12.1 years over the last 50 years in Japan. In particular, the ratios of ≥80 and ≥90 years as the patients age increased significantly.

Trabecular metal augments in severe malignancy-associated acetabular bone loss.

Acetabular reconstruction is a challenging problem in orthopaedic oncology, especially in extended defects (Paprosky Type 3A and Type 3B). In revision total hip arthroplasty (THA), 1 option is trabecular metal (TM) augments with a porous metal acetabular component. This study evaluated the use of TM augments in periacetabular malignant bone disease. 15 patients were identified from our institutional database from 2000 to 2020 with either Paprosky Type 3A or Type 3B acetabular bone loss due to periacetabular malignancies that underwent at least 1 complex THA reconstruction with TM augments. Postoperative complications were documented, and clinical and radiographic outcomes were analysed. Radiological loosening or revision of the acetabular component were defined as endpoints. There were 7 primary and 8 metastatic cancer patients. 5 were Type 3A and 10 were Type 3B defects after tumour resection. The average follow-up time was 23.8 (range 1.5-47) months. 1 patient required revision for acetabular component loosening after 7 months from the initial implantation. An additional 4 patients required surgical intervention for infection, they had stable TM augments at latest follow-up. TM augments with a porous metal acetabular component may be an alternative to the traditional cemented constructs.

Nontuberculous Mycobacterial Infections Associated With Left Ventricular Assist Devices in 3 Patients.

Durable left ventricular assist devices (LVADs) provide circulatory support in patients with end-stage heart failure; however, complications include infection of the driveline exit site. Nontuberculous mycobacterial infections are rare in patients with LVADs, but they should be considered in those who have undergone device exchanges and have bacterial infections with driveline exit-site discharge but no fever or leukocytosis. We reviewed the charts of patients who had an LVAD implanted at our institution from January 2009 through December 2019, to identify those with a device-related nontuberculous mycobacterial infection. Collected data included patient demographics, premorbid conditions, infection type, previous device complications, treatment, and outcomes. We identified infections in 3 patients (mean age, 41 yr): Mycobacterium abscessus in 2 and M. chimaera in 1. All had a HeartMate II device and had undergone device exchanges for pump thrombosis or for driveline fault or infections. All presented with driveline exit-site discharge without fever or leukocytosis. The mean time between initial device implantation and diagnosis of a nontuberculous mycobacterial infection was 55 months. All 3 patients were treated with antibiotics and underwent localized surgical débridement; one underwent an additional device exchange. The M. abscessus infections disseminated, and both patients died; the patient with M. chimaera infection continued to take suppressive antibiotics. Nontuberculous mycobacterial infections are associated with high morbidity and mortality rates, warranting prompt diagnosis and treatment.

Use of a locking stem for reverse shoulder arthroplasty is a rare but reliable option.

RSA is widely used in the treatment of complex trauma or degenerative changes of the shoulder. Strong primary fixation of the stem is necessary to prevent any loosening of the stem and subsequent revision. Presently, cement fixation or press-fit fixation are two options for humeral fixation, though each has its own limitations and risks. The aim of the current study is to evaluate the effectiveness of an alternative option involving a distal screw interlocking system for fixation of the humeral stem from initial implantation. We performed a retrospective multicenter study of patients implanted with the Humelock Reversed® stem RSA that can be locked with distal humeral screws in cases of operative poor press fit or to modulate the lengthening of the arm via prosthetic humeral height. Seventy-two patients with a minimum two year follow-up were included, 13 for acute trauma, 42 for degenerative changes, and 17 for revision surgery. No difference was seen in radiological or clinical results for patients with or without interlocking screw primary stabilization. For non-trauma patients, the mean raw Constant score improved significantly from 31 (± 12) to 71 (± 12). For trauma patients, the mean raw Constant score for trauma (63.4) was significantly lower than for non-trauma cases (72.1) (p < 0.001). Analysis of the filling ratio demonstrated that interlocking screws were not used for lower filling ratios and that midterm fixation of the stem is not negatively impacted by distal interlocking screw fixation. Even if use of a distal interlocking screw fixation system is rare, it can be useful for patients with poor quality fixation of stemmed RSA. Use of an interlocking screw system to stabilize the stem in RSA provides good immediate and midterm stability of the implant allowing for clinical and radiological outcomes comparable to those obtained with press-fit fixation alone.

Lesser-Known Aspects of Deep Brain Stimulation for Parkinson's Disease: Programming Sessions, Hardware Surgeries, Residential Care Admissions, and Deaths

ObjectiveThe long-term treatment burden, duration of community living, and survival of patients with Parkinson's disease (PD) after deep brain stimulation (DBS) implantation are unclear. This study aims to determine the frequency of programming, repeat hardware surgeries (of the intracranial electrode, implantable pulse generator [IPG], and extension-cable), and the timings of residential care and death in patients with PD treated with DBS. Materials and MethodsIn this cross-sectional, population-based study, individual-level data were collected from the Australian government covering a 15-year period (2002–2016) on 1849 patients with PD followed from DBS implantation. ResultsThe mean DBS implantation age was 62.6 years and mean follow-up 5.0 years. Mean annual programming rates were 6.9 in the first year and 2.8 in subsequent years. 51.4% of patients required repeat hardware surgery. 11.3% of patients had repeat intracranial electrode surgery (including an overall 1.1% of patients who were completely explanted). 47.6% of patients had repeat IPG/extension-cable surgery including for presumed battery depletion. 6.2% of patients had early repeat IPG/extension-cable surgery (within one year of any previous such surgery). Thirty-day postoperative mortality was 0.3% after initial DBS implantation and 0.6% after any repeat hardware surgery. 25.3% of patients were admitted into residential care and 17.4% died. The median interval to residential care and death was 10.2 years and 11.4 years, respectively. Age more than 65 years was associated with fewer repeat hardware surgeries for presumed complications (any repeat surgery of electrodes, extension-cables, and early IPG surgery) and greater rates of residential care admission and death. ConclusionsData from a large cohort of patients with PD treated with DBS found that the median life span after surgery is ten years. Repeat hardware surgery, including of the intracranial electrodes, is common. These findings support development of technologies to reduce therapy burden such as enhanced surgical navigation, hardware miniaturization, and improved battery efficiency.

Spinal cord injury: the cost of mechanical ventilation versus phrenic nerve stimulation

Patients with respiratory insufficiency caused by tetraplegia at or above the level of cervical segment two can be treated with phrenic nerve stimulation instead of mechanical ventilation. An analysis of the annual invoices for single use airway equipment of 20 patients using phrenic nerve stimulation and 20 patients who were mechanically ventilated was conducted. The initial implantation of the phrenic nerve stimulation device costs considerably more than the mechanical ventilation device. However, this analysis found that the cost of running a phrenic nerve stimulator device is lower because of the reduced amount of airway nursing equipment needed. This analysis demonstrates that the cost of implanting a phrenic nerve stimulator device would be repaid within 4 years.

Implantable loop recorder as a strategy following cardiovascular implantable electronic device extraction without reimplantation.

Limited data exists for outcomes in patients undergoing cardiovascular implantable electronic device (CIED) transvenous lead extraction (TLE) without clear indications for device reimplantation. The implantable loop recorder (ILR) may be an effective strategy for continuous monitoring in select individuals. This retrospective analysis aims to investigate patients who have undergone ILR implant following TLE without CIED reimplantation. Clinical data from consecutive patients who have undergone TLE with ILR implant and without CIED reimplantation from October 2016 to May 2020 at a single center were collected. Among 380 patients undergoing TLE, 28 (7.7%) underwent ILR placement without CIED reimplantation. TLE indications were systemic infection (n=13, 46.4%), pain at the site (n=8, 28.6%), device/lead malfunction (n=4, 14.2%), and other. Devices extracted included: dual-chamber and single-chamber pacemaker (n=14, 50%; n=4, 14.2%), dual-chamber implantable cardiac defibrillator (n=10; 35.7%), and cardiac-resynchronization therapy with defibrillator (n=1, 3.5%). Reasons for no reimplantation included no longer meeting CIED criteria (n=14, 50%), patient preference (n=9, 32.1%), and no clear or inappropriate indication for initial CIED implantation (n=5, 18%). During an average of 12.3±13.1months of follow-up, there were no lethal arrhythmias, and four (13.3%) patients underwent permanent pacemaker reimplantation due to symptomatic sinus bradycardia and atrioventricular block with syncope as discovered on ILR. Three patients died due to unknown causes (n=1), noncardiac (n=1), and acute coronary syndrome (n=1). In patients undergoing TLE without reimplantation, an ILR may be an effective monitoring strategy in patients at low risk for cardiac arrhythmia.

Incidence and risk factors for acute kidney injury in patients with cardiac implantable electronic devices undergoing transvenous lead removal.

This study aimed to investigate the incidence and potentially modifiable risk factors of acute kidney injury (AKI) in patients with cardiac implantable electronic devices (CIED) admitted for removal of infected and non-infected transvenous leads. In this observational cohort study, data from 147 consecutive patients with CIED undergoing transvenous lead removal were analyzed. Study endpoint was AKI according to the KDIGO criteria. Multivariable logistic regression analysis was performed to identify independent risk factors for AKI. Lead removal was performed due to systemic infection (50.3%), isolated pocket infection (34.0%), pocket or lead perforation without infection (13.6%), and endocarditis (2.0%). Out of 147 patients, 34 (23.1%) developed AKI (82.4% stage 1, 8.8% stage 2, and 8.8% stage 3). There was no difference regarding incidence of AKI when separated by infectious vs. non-infectious lead status (25.5 vs. 25.0%) p = 0.605. Defibrillator lead type (HR 24.55, CI 2.41 - 249.97, p = 0.007), necessity to perform laser-assisted lead removal (HR 5.41, CI 1.12 - 26.13, p = 0.035), and time from initial implantation to lead removal (HR 1.01, CI 1.00 - 1.02, p = 0.013) were independent risk factors for AKI. Also, AKI was associated with in-hospital mortality (HR 8.44, CI 2.08 - 34.33, p = 0.003). Almost a quarter of patients undergoing transvenous lead removal developed AKI. Independent modifiable risk factors for AKI were identified. The role of procedure-related risk factors for AKI, such as lead type and use of laser, needs further evaluation in these patients.

Neurosurgical Team Acceptability of Brain–Computer Interfaces: A Two-Stage International Cross-Sectional Survey

Invasive brain-computer interfaces (BCIs) require neurosurgical implantation, which confers a range of risks. Despite this situation, no studies have assessed the acceptability of invasive BCIs among the neurosurgical team. This study aims to establish baseline knowledge of BCIs within the neurosurgical team and identify attitudes toward different applications of invasive BCI. A 2-stage cross-sectional international survey of the neurosurgical team (neurosurgeons, anesthetists, and operating room nurses) was conducted. Results from the first, qualitative, survey were used to guide the second-stage quantitative survey, which assessed acceptability of invasive BCI applications. Five-part Likert scales were used to collect quantitative data. Surveys were distributed internationally via social media and collaborators. A total of 108 qualitative responses were collected. Themes included the promise of BCIs positively affecting disease targets, concerns regarding stability, and an overall positive emotional reaction to BCI technology. The quantitative survey generated 538 responses from 32 countries. Baseline knowledge of BCI technology was poor, with 9% claiming to have a good or expert knowledge of BCIs. Acceptability of invasive BCI for rehabilitative purposes was >80%. Invasive BCI for augmentation in healthy populations divided opinion. The neurosurgical team's view of the acceptability of invasive BCI was divided across a range of indications. Some applications (e.g., stroke rehabilitation) were viewed as more appropriate than other applications (e.g., augmentation for military use). This range in views highlights the need for stakeholder consultation on acceptable use cases along with regulation and guidance to govern initial BCI implantations if patients are to realize the potential benefits.

Association between right ventricular dysfunction and appropriate icd therapy

Abstract Funding Acknowledgements Type of funding sources: None. Background Right ventricular fractional area change (RVFAC) as right ventricular function is recently referred as an independent predictor of sudden cardiac death (SCD). The purpose of this study was to evaluate the association of RVFAC and appropriate ICD therapy in order to determine the cut-off value of RVFAC. Methods Consecutive patients who underwent initial ICD implantation for any diseases except for non-dilated phase hypertrophic cardiomyopathy and channelopathy were retrospectively enrolled from 2012 to 2018. Primary endpoint was an initial appropriate ICD therapy. Transthoracic echocardiographic parameters before ICD implantation were evaluated by one physician and one echocardiologist to be validated. Right ventricular dimensions and function were also measured to be analyzed. Results In total, 172 patients (60.3±13.6 years, 131 males) including 63 ischemic cardiomyopathy were enrolled. Ninety patients received an ICD as a secondary prophylaxis. Mean LVEF and RVFAC were 38.3±14.3% and 35.8±8.82%, respectively. There was little correlation between RVFAC and LVEF (correlation coefficient =0.274). Regarding appropriate ICD therapy events, the best cut-off value of RVFAC was 34.8%. The odds ratio of low RVFAC was 2.731 (95%CI: 1.456-5.121, P=0.00174). Secondary prophylactic cohort with low RVFAC showed highest incidence of appropriate ICD therapy as shown in the figure. In multivariate analysis, only low RVFAC is an independent predictor of appropriate ICD therapy (HR: 3.53, 95%CI:1.78- 6.99, P=0.0003). Conclusion Low RVFAC seemed independently associated with increased appropriate ICD therapy.

Reasons for replacement and extraction of the subcutaneous implantable cardioverter-defibrillator in a large cohort

Abstract Funding Acknowledgements Type of funding sources: None. Background The subcutaneous implantable cardioverter-defibrillator (S-ICD) is proven to be a safe and effective alternative to the transvenous ICD. However, battery longevity is estimated to be shorter in the S-ICD, although newer generations S-ICD are thought to have an increased battery longevity compared to the first generation. In addition, the S-ICD lacks the option for pacing therapy and may therefore be extracted in patients who later develop an indication for bradycardia pacing, antitachycardia pacing or resynchronization therapy. In this analysis, we aim to evaluate occurrence and reasons for S-ICD replacement and extraction. Methods In this retrospective analysis, we collected data on S-ICD generator replacement and extraction from consecutive patients who were implanted with an S-ICD in our tertiary center between February 2009 and December 2021. Results A total of 408 patients received an S-ICD, with a median follow-up duration of 4.0 (IQR 1.5-6.8) years. Of the 168 implanted first generation S-ICDs, 123 (73.2%) were replaced after a mean of 5.9 ± 0.8 years, all due to battery depletion. A second generation S-ICD was replaced in 2/40 (5%) patients and a third generation S-ICD in 11/200 patients (5.5%), after a mean of 4.8 ± 0.12 and 3.6 ± 1.6 years, respectively. Two third generation S-ICDs were replaced due to device malfunction, all other replacements (134/136, 98.5%) were due to battery depletion. The S-ICD was extracted in 38/408 (9.3%) patients. The mean time from initial implantation to extraction was 3.7 ± 2.5 years. Reasons for extraction were a newly developed indication for pacing or resynchronization therapy (N = 14), an expired indication for ICD therapy (N = 8), heart transplantation or implantation of left ventricular assist device (N = 4), repeated inappropriate shocks (N = 4), pocket infection (N = 3), pocket erosion (N = 2), lead defect (N = 1), Twiddler syndrome (N = 1) and patient preference (N = 1). A new S-ICD could be re-implanted in 7 patients (18.4%), a cardiac resynchronization therapy defibrillator was implanted in 7 patients (18.4%) and there was a need for a transvenous ICD in 10 patients (26.3%). The remaining 14 patients (36.8%) were not re-implanted with any type of ICD. Reasons for end of S-ICD therapy are presented in the figure. Conclusion In this large cohort, a battery longevity of the first generation S-ICD of 5.9 years was reached. After a median follow-up duration of 4.0 years, 17/408 patients received a transvenous device, due to the need for bradycardia or antitachycardia pacing or resynchronization therapy. Importantly, 14/408 patients underwent an S-ICD extraction and were not re-implanted with any type of ICD. These patients may especially benefit from S-ICD therapy, as this device is less complicated to extract compared to a transvenous ICD.

Implementation of Minimally Invasive Brain Tumor Resection in Rodents for High Viability Tissue Collection.

The present protocol describes a standardized paradigm for rodent brain tumor resection and tissue preservation. In clinical practice, maximal tumor resection is the standard-of-care treatment for most brain tumors. However, most currently available preclinical brain tumor models either do not include resection, or utilize surgical resection models that are time-consuming and lead to significant postoperative morbidity, mortality, or experimental variability. In addition, performing resection in rodents can be daunting for several reasons, including a lack of clinically comparable surgical tools or protocols and the absence of an established platform for standardized tissue collection. This protocol highlights the use of a multi-functional, non-ablative resection device and an integrated tissue preservation system adapted from the clinical version of the device. The device applied in the present study combines tunable suction and a cylindrical blade at the aperture to precisely probe, cut, and suction tissue. The minimally invasive resection device performs its functions via the same burr hole used for the initial tumor implantation. This approach minimizes alterations to regional anatomy during biopsy or resection surgeries and reduces the risk of significant blood loss. These factors significantly reduced the operative time (<2 min/animal), improved postoperative animal survival, lower variability in experimental groups, and result in high viability of resected tissues and cells for future analyses. This process is facilitated by a blade speed of ~1,400 cycles/min, which allows the harvesting of tissues into a sterile closed system that can be filled with a physiologic solution of choice. Given the emerging importance of studying and accurately modeling the impact of surgery, preservation and rigorous comparative analysis of regionalized tumor resection specimens, and intra-cavity-delivered therapeutics, this unique protocol will expand opportunities to explore unanswered questions about perioperative management and therapeutic discovery for brain tumor patients.

The Port Delivery System with ranibizumab: a new paradigm for long-acting retinal drug delivery

The Port Delivery System with ranibizumab (PDS) is an innovative intraocular drug delivery system designed for the continuous delivery of ranibizumab into the vitreous for 6 months and beyond. The PDS includes an ocular implant, a customized formulation of ranibizumab, and four dedicated ancillary devices for initial fill, surgical implantation, refill-exchange, and explantation, if clinically indicated. Ranibizumab is an ideal candidate for the PDS on account of its unique physicochemical stability and high solubility. Controlled release is achieved via passive diffusion through the porous release control element, which is tuned to specific drug characteristics to accomplish a therapeutic level of ranibizumab in the vitreous. To characterize drug release from the implant, release rate was measured in vitro with starting concentrations of ranibizumab 10, 40, and 100 mg/mL, with release of ranibizumab 40 and 100 mg/mL found to remain quantifiable after 6 months. Using a starting concentration of 100 mg/mL, active release rate at approximately 6 months was consistent after the initial fill and first, second, and third refills, demonstrating reproducibility between implants and between multiple refill-exchanges of the same implant. A refill-exchange performed with a single 100-µL stroke using the refill needle was shown to replace over 95% of the implant contents with fresh drug. In vitro data support the use of the PDS with fixed refill-exchange intervals of at least 6 months in clinical trials.