Repeated procedures at the generator pocket are a determinant of implantable cardioverter-defibrillator infection

A comparison of different methods to maximise signal extraction when using central venous pressure to optimise atrioventricular delay after cardiac surgery

Objective

Our group has shown that central venous pressure (CVP) can optimise atrioventricular (AV) delay in temporary pacing (TP) after cardiac surgery. However, the signal-to-noise ratio (SNR) is influenced both by the methods used to mitigate the pressure effects of respiration and the number of heartbeats analysed. This paper systematically studies the effect of different analysis methods on SNR to maximise the accuracy of this technique.

Methods

We optimised AV delay in 16 patients with TP after cardiac surgery. Transitioning rapidly and repeatedly from a reference AV delay to different tested AV delays, we measured pressure differences before and after each transition. We analysed the resultant signals in different ways with the aim of maximising the SNR: (1) adjusting averaging window location (around versus after transition), (2) modifying window length (heartbeats analysed), and (3) applying different signal filtering methods to correct respiratory artefact.

Results

(1) The SNR was 27 % higher for averaging windows around the transition versus post-transition windows. (2) The optimal window length for CVP analysis was two respiratory cycle lengths versus one respiratory cycle length for optimising SNR for arterial blood pressure (ABP) signals. (3) Filtering with discrete wavelet transform improved SNR by 62 % for CVP measurements. When applying the optimal window length and filtering techniques, the correlation between ABP and CVP peak optima exceeded that of a single cycle length (R = 0.71 vs. R = 0.50, p < 0.001).

Conclusion

We demonstrated that utilising a specific set of techniques maximises the signal-to-noise ratio and hence the utility of this technique.

Infection remediation after septic device extractions: analysis of three treatment strategies including a 1-year follow-up

Introduction

In CIED infections, all device material needs to be removed. But, especially in pacemaker-dependent patients it is often not possible to realize a device-free interval for infection remediation. In those patients, different treatment options are available, however the ideal solution needs still to be defined.

Methods

This retrospective analysis includes 190 patients undergoing CIED extractions due to infection. Three different treatment algorithms were analyzed: Group 1 included 89 patients with system removal only (System removal group). In Group 2, 28 patients received an epicardial electrode during extraction procedure (Epicardial lead group) while 78 patients in group 3 (contralateral reimplantation group) received implantation of a new system contralaterally during extraction procedure. We analyzed peri- and postoperative data as well as 1-year outcomes of the three groups.

Results

Patients in the system removal and epicardial lead groups were significantly older, had more comorbidities, and suffered more frequently from systemic infections than those in contralateral reimplantation group. Lead extraction procedures had comparable success rates: 95.5%, 96.4%, and 93.2% of complete lead removal in the System removal, Epicardial Lead, Contralateral re-implantation group respectively. Device reimplantation was performed in all patients in Epicardial lead and Contralateral reimplantation group, whereas only 49.4% in System removal group received device re-implantation. At 1-year follow-up, freedom from infection and absence of pocket irritation were comparable for all groups (94.7% Contralateral reimplantation group and Epicardial lead group, 100% System removal group). No procedure-related mortality was observed, whereas 1-year mortality was 3.4% in System removal group, 4.1% in Contralateral re-implantation group and 21.4% in Epicardial lead group (p < 0.001).

Conclusion

In patients with CIED infection, systems should be removed completely and reimplanted after infection remediation. In pacemaker-dependent patients, simultaneous contralateral CIED re-implantation or epicardial lead placement may be performed, depending on route, severity and location of infection.

Chlorhexidine gluconate pocket lavage to prevent cardiac implantable electronic device infection in high-risk procedures

BACKGROUND

Infection is the most dreaded complication of cardiac implantable electronic devices (CIEDs), particularly in patients undergoing high-risk procedures (eg, generator change, device upgrade, lead/pocket revision).

OBJECTIVE

The purpose of this study was to describe the impact of chlorhexidine gluconate (CHG) pocket lavage in high-risk procedures.

METHODS

Patients from a prospective multicenter registry undergoing high-risk procedures were included. CHG lavage was performed by irrigating the generator pocket with 20 cc of 2% CHG without alcohol followed by and normal saline (NS) irrigation. Only NS irrigation was performed in the comparison group. The primary efficacy outcome was CIED-related infection at 12 months. The primary safety outcome was any CHG-associated adverse event. The secondary outcome was CIED infection during long-term follow-up. Propensity score matching (PSM) analysis was performed for the primary efficacy outcome.

RESULTS

A total of 1504 patients were included. At 12-month follow-up, the primary efficacy outcome occurred in 4 of 904 CHG (0.4%) and 14 of 600 NS (2.3%) subjects (log-rank P = .005). On multivariate analysis, the use of CHG irrigation was associated with a lower risk of infection at 1-year follow-up (Cox proportional hazard ratio [HR] 0.138; 95% confidence interval [CI] 0.04-0.45; P = .001). This effect persisted during long-term follow-up. PSM demonstrated a significant reduction in CIED-related infection for the CHG group (0.2% vs 2.5%; Cox proportional HR 0.08; 95% CI 0.01-0.59; P = .014). No adverse events were associated with the use of CHG.

CONCLUSION

CHG lavage during high-risk procedures was associated with a reduction in CIED-related infections without any adverse events reported. The benefits of CHG lavage were observed even during long-term follow up and in PSM analysis.

Pocket histology at cardiac implantable electronic device replacement: What's new?

BACKGROUND

Repeated procedures involving the cardiac implantable electronic device (CIED) pocket increase the infection risk, and the extent of pocket adhesions may prolong the procedure time. Few data on pocket histology at the time of CIED replacement are available.

OBJECTIVE

The purpose of this study was to describe CIED pocket histology in a cohort of patients undergoing CIED replacement or upgrade.

METHODS

All consecutive patients undergoing CIED replacement or upgrade at our center between November 2019 and May 2020 were enrolled. Subclinical pocket infection was ruled out by physical inspection and laboratory parameters before the procedure. Pocket tissue specimens from the anterior and posterior pockets were obtained intraoperatively. A systematic histological analysis of capsular thickness, fibrous connective tissue, neovascularization, inflammation, and calcifications was performed.

RESULTS

Thirty patients (6 women, 20%) were enrolled. The mean capsular thickness was 0.8 ± 0.3 mm in the anterior wall and 1.1 ± 0.4 mm in the posterior wall. Subcapsular fibrosis was mild and multifocal in the anterior wall and moderate and focal in the posterior wall. Neovascularization was focal in most cases, and vessel remodeling mainly involved the tunica media. Chronic inflammation was usually mild and nongranulomatous, and in a quarter of cases, subacute exudative fibrous inflammation was detected in the posterior pocket wall.

CONCLUSION

The CIED pocket is a histopathologically dynamic environment, given the coexistence of both a subacute foreign body response and fibrous tissue growth, implying continuous remodeling due to an injury-repair mechanism. Strategies to interact with foreign body response might minimize inflammatory pocket activity, especially device encapsulation by tight fibrous tissue, and possibly complications related to repeated CIED procedures.

Should they stay, or should they go: do we need to remove the old cardiac implantable electronic device if a new system is required on the contralateral side?

Background

Ipsilateral approach in patients requiring cardiac implantable electronic device (CIED) revision or upgrade may not be feasible, primarily due to vascular occlusion. If a new CIED is implanted on the contralateral side, a common practice is to explant the old CIED to avoid device interaction.

Objective

The purpose of this study was to assess a conservative approach of abandoning the old CIED after implanting a new contralateral device.

Methods

We used an artificial intelligence algorithm to analyze postimplant chest radiographs to identify those with multiple CIEDs. Outcomes of interest included device interaction, abandoned CIED elective replacement indicator (ERI) behavior, subsequent programming changes, and explant of abandoned CIED. Theoretical risk of infection with removal of abandoned CIED was estimated using a validated scoring system.

Results

Among 12,045 patients, we identified 40 patients with multiple CIEDs. Occluded veins were the most common indication for contralateral implantation (n = 27 [67.5%]). Fifteen abandoned CIEDs reached ERI, with 4 reverting to VVI 65. One patient underwent explant due to device interaction, and 2 required device reprogramming. Of 32 patients with an implantable cardioverter-defibrillator, 8 (25%) had treated ventricular arrhythmia. There were no failed or inappropriate therapies due to interaction. Eighteen patients (45%) had hypothetical >1% annual risk of hospitalization for device infection if the abandoned CIED had been explanted.

Conclusion

In patients requiring new CIED implant on the contralateral side, abandoning the old device is feasible. This approach may reduce the risk of infection and concerns regarding abandoned leads and magnetic resonance imaging scans. Knowledge of ERI behavior is essential to avoid device interactions.

Postimplantation pocket hematoma increases risk of cardiac implantable electronic device infection: A meta-analysis

INTRODUCTION

 Several studies have shown an inconsistent relationship between postimplantation pocket hematoma and cardiac implantable electronic device (CIED) infection. In this study, we performed a systematic review and meta-analysis to explore the effect of postimplantation hematoma and the risk of CIED infection.

METHODS

 We searched the databases of MEDLINE and EMBASE from inception to March 2020. Included studies were cohort studies, case-control studies, cross-sectional studies, and randomized controlled trials that reported incidence of postimplantation pocket hematoma and CIED infection during the follow-up period. CIED infection was defined as either a device-related local or systemic infection. Data from each study were combined using the random effects, generic inverse variance method of Der Simonian and Laird to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Fourteen studies were included in final analysis, involving a total of 28 319 participants. In random-effect model, we found that postimplantation pocket hematoma significantly increases the risk of overall CIED infection (OR = 6.30, 95% CI: 3.87-10.24, I 2 = 49.3%). There was no publication bias observed in the funnel plot as well as no small-study effect observed in Egger's test.

CONCLUSIONS

Our meta-analysis demonstrated that postimplantation pocket hematoma significantly increases the risk of CIED infection. Precaution should be taken during device implantation to reduce postimplantation hematoma and subsequent CIED infection.

Strategies to Prevent Cardiac Implantable Electronic Device Infection

The association between the risk of mortality and cardiovascular implantable electronic device (CIED) infections has been well-established in the literature. As CIED implantations have increased in frequency in the past few decades, the incidence of CIED-related infections has also risen. Given the morbidity, mortality, and health-care costs associated with CIED infections, the prevention of device-related infection is a critical goal. Risk factors for developing CIED infections can be categorized as patient-, procedure-, or device-related. Numerous studies have highlighted different strategies for preventing CIED-related infections, which include patient optimization, device selection, and periprocedural preparation and treatment. Nonetheless, as the comorbidity burden of patients undergoing CIED implantation continues to increase, significant challenges in the successful elimination of CIED-related infections remain. This review provides a comprehensive overview of available evidence-based approaches and strategies to reduce the risk of CIED infections.

Timing of device reimplantation and reinfection rates following cardiac implantable electronic device infection: a systematic review and meta-analysis

OBJECTIVES

Initial management of cardiac implantable electronic device (CIED) infection requires removal of the infected CIED system and treatment with systemic antibiotics. However, the optimal timing to device reimplantation is unknown. The aim of this study was to quantify the incidence of reinfection after initial management of CIED infection, and to assess the effect of timing to reimplantation on reinfection rates.

DESIGN

Systematic review and meta-analysis.

INTERVENTIONS

A systematic review and meta-analysis was performed of studies published up to February 2018. Inclusion criteria were: (a) documented CIED infection, (b) studies that reported the timing to device reimplantation and (c) studies that reported the proportion of participants with device reinfection. A meta-analysis of proportions using a random effects model was performed to estimate the pooled device reinfection rate.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the rate of CIED reinfection. The secondary outcome was all-cause mortality.

RESULTS

Of the 280 screened studies, 8 met inclusion criteria with an average of 96 participants per study (range 15-220 participants). The pooled incidence rate of device reinfection was 0.45% (95% CI, 0.02% to 1.23%) per person year. A longer time to device reimplantation >72 hours was associated with a trend towards higher rates of reinfection (unadjusted incident rate ratio 4.8; 95% CI 0.9 to 24.3, p=0.06); however, the meta-regression analysis was unable to adjust for important clinical covariates. There did not appear to be a difference in reinfection rates when time to reimplantation was stratified at 1 week. Heterogeneity was moderate (I²=61%).

CONCLUSIONS

The incident rate of reinfection following initial management of CIED infection is not insignificant. Time to reimplantation may affect subsequent rates of device reinfection. Our findings are considered exploratory and significant heterogeneity limits interpretation.

PROSERO REGISTRATION NUMBER

CRD4201810960.

The never-ending story of CIED infection prevention: Shall we WRAP-IT and go?

CIED infection is perceived as substantial, ranging from 1% to 4% in literature depending on different studies and on the population profile, and can appear either as surgical site or endovascular infection or both. Several factors have been found to be associated to CIED infection, that can be summarized as patient-related (clinical profile, associated comorbidities, ongoing treatment as anticoagulants and immunosuppressants), Procedure-related (complexity of CIED surgery, type of surgery, previous pocket exploration), and center-/operator-related (center/operator volume). Thus, it is difficult to disentangle the extent of benefit that any intervention may offer to decrease this threatened complication, owing to its multifaceted complexity. The recently completed PADIT and WRAP-IT trials have significantly improved our knowledge in this field (nearly 20 000 patients enrolled), reporting an infection rate of 1% to 1.2% in control-arm patients and a 20% to 67% infection decrease when incremental antibiotic prophylaxis is added on top of optimized preventative strategies. Observational registries highlighted that participation in a prospective survey of CIED infection dramatically decrease infection rate by optimization of antisepsis protocols and operator awareness, that explains the low event rate observed in PADIT and WRAP-IT. While this consideration prompts each center to engage into a proactive infection prevention program, it makes a point in favor of antibiotic prophylaxis delivered locally in 7 days or more, as enabled by TYRX in the WRAP-IT trial. However, care sustainability (the number needed to treat in the most favorable WRAP-IT scenario is 100) suggests further analysis to understand the settings (patient- or procedure-related) most likely to benefit by such an enhanced prevention strategy.

Real-life outcome of implantable cardioverter-defibrillator and cardiac resynchronization defibrillator replacement/upgrade in a contemporary population: observations from the multicentre DECODE registry

Aims

The benefit of prolonged implantable cardioverter-defibrillator (ICD)/cardiac resynchronization therapy defibrillator (CRT-D) therapy following device replacement is hindered by clinical and procedure-related adverse events (AEs). Adverse events rate is highest in more complex devices and at upgrades, as per the REPLACE registry experience, but is changing owing to the improvement in device technology and medical care. We aimed at understanding the extent and type of AEs in a contemporary Italian population.

Methods and results

Detect long-term complications after ICD replacement (DECODE) was a prospective, single-arm, multicentre cohort study aimed at estimating medium- to long-term AEs in a large population of patients undergoing ICD/cardiac resynchronization defibrillator replacement/upgrade from 2013 to 2015. We prospectively analysed all clinical and device-related AEs at 12-month follow-up (FU) of 983 consecutive patients (median age 71 years, 76% male, 55% ischaemic, 47% CRT-D) followed for 353 ± 49 days. Seven percent of the patients died (60.6% for cardiovascular reasons), whereas 104 AEs occurred; 43 (4.4%) patients needed at least one surgical action to treat the AE. Adverse events rates were 3.3/100 years lead-related, 3.4/100 years bleedings, and 1.6/100 years infective. The primary endpoint was predicted by hospitalization in the month prior to the procedure [hazard ratio (HR) = 2.23, 1.16–4.29; 0.0169] and by upgrade (HR = 1.75, 1.02–2.99, 0.0441). One hundred and twelve (11.4%) patients met the combined endpoint of death from any cause, cardiac implantable electronic device (CIED)-related infection, and surgical action/hospitalization required to treat the AE. Hospitalization within 30 days prior to the procedure (HR = 2.07, 1.13–3.81; 0.0199), anticoagulation (HR = 1.97, 1.26–3.07; 0.003), and ischaemic cardiomyopathy (HR = 1.67, 95% confidence interval 1.06–2.63; P = 0.0276) were associated with the combined endpoint during FU.

Conclusions

Adverse events following CIED replacement/upgrade are lower than previously reported, possibly owing to improved patients care. Hospitalization in the month prior to the procedure, upgrade, and clinical profile (anticoagulation, ischaemic cardiomyopathy) hint to increased risk, suggesting an individualized planning of the procedure to minimize overall AEs.

Clinical trial registration

URL: http://clinicaltrials.gov/ Identifier: NCT02076789.

Successful defibrillation verification in subcutaneous implantable cardioverter-defibrillator recipients by low-energy shocks

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (S-ICD) is an effective alternative to the transvenous one. Defibrillation efficacy depends on maximum device output and on the optimal device location at device implantation.

HYPOTHESIS

We sought to investigate the defibrillation safety margin in real life clinical practice.

METHODS

We sought to understand what is the efficacy of induced ventricular fibrillation (VF) termination at S-ICD implantation using lower energies than the recommended 65 J.

RESULTS

Sixty-four consecutive S-ICD recipients underwent VF termination attempts at implantation with energies ranging from 20 to 50 J. Overall, VF termination occurred in 84% of patients with ≤40 J, in 88% with 45 J, and in 100% with 60 J. Intermuscular S-ICD placement was associated with 94% VF termination at ≤40 J. An ejection fraction <35% was associated to higher energy requirement for defibrillation; however, an intermuscular S-ICD placement conferred 90% defibrillation efficacy at 31 ± 5 J in this patients subset.

CONCLUSIONS

This is a hypothesis-generating observation that prompts a methodologically correct investigation to prove that a 60 J output S-ICD can provide an adequate safety margin to terminate VF in clinical practice. This would enable superior device longevity and/or device downsizing for pediatric/small size patients.

Repeated procedures at the generator pocket are a determinant of implantable cardioverter-defibrillator infection

BACKGROUND

Rates of cardiac-device infections have increased in recent years, but the current incidence and risk factors for infection in patients with implantable cardioverter-defibrillators (ICDs) are not well known.

HYPOTHESIS

The increasing number of ICD infections is related to accumulated pocket manipulations over time.

METHODS

This single-center, prospective study included patients that underwent ICD implantation from 2008 to 2015. The endpoint was time to infection. Multivariate analysis was performed to identify independent risk factors related to infection.

RESULTS

The study included a total of 570 patients, of whom 419 (73.5%) underwent a first implantation. Mean age was 59 ± 14 years, and 80% were male. During a median follow-up of 36 months (interquartile range, 18-61 months; 1887 patient-years), infection was identified in 26 patients (4.56%), an incidence of 14.9 × 1000 patient-years. Median time to infection was 9.7 months (interquartile range, 1.35-23.4 months), and 38.5% were late infections (beyond 12 months of follow-up). In patients with replacement implants, the incidence was 3-fold higher than in first implantations (27.7 vs 9.1 × 1000 patient-years; P = 0.002). Cox regression identified 2 independent predictors of ICD infection: cumulative number of interventions at the generator pocket (hazard ratio: 1.92, 95% confidence interval: 1.42-2.6, P < 0.001) and pocket hematoma (hazard ratio: 7.0, 95% confidence interval: 2.7-17.9, P < 0.0001).

CONCLUSIONS

The incidence of infection in ICD patients is greater than previously reported, largely due to late infections. Each new cumulative intervention at the same generator pocket nearly doubles the risk of infection.