Trends and In-Hospital Outcomes Associated With Adoption of the Subcutaneous Implantable Cardioverter Defibrillator in the United States

Subcutaneous versus transvenous implantable defibrillator: An updated meta-analysis

BACKGROUND

Implantable cardioverter-defibrillator (ICD) placement is a well-established therapy for prevention of sudden cardiac death. The subcutaneous implantable cardioverter-defibrillator (S-ICD) was specifically designed to overcome some of the complications related to the transvenous implantable cardioverter-defibrillator (TV-ICD), such as lead complications and systemic infections. Evidence on the comparison of S-ICD vs TV-ICD are limited.

OBJECTIVE

The purpose of this study was to conduct an updated meta-analysis comparing S-ICD vs TV-ICD.

METHODS

Electronic databases were searched for studies directly comparing clinical outcomes and complications between S-ICD and TV-ICD. The primary outcome was the composite of clinically relevant complications (lead, pocket, major procedural complications; device-related infections) and inappropriate shocks. Secondary outcomes included death and the individual components of the primary outcome.

RESULTS

Thirteen studies comprising 9073 patients were included in the analysis. Mean left ventricular ejection fraction was 40% ± 10%; 30% of patients were female; and 73% had an ICD implanted for primary prevention. There was no statistically significant difference in the risk of the primary outcome between S-ICD and TV-ICD (odds ratio [OR] 0.80; 95% confidence interval [CI] 0.53-1.19). Patients with S-ICD had lower risk of lead complications (OR 0.14; 95% CI 0.06-0.29; P <.00001) and major procedural complications (OR 0.18; 95% CI 0.06-0.57; P = .003) but higher risk of pocket complications (OR 2.18; 95% CI 1.30-3.66; P = .003) compared to those with TV-ICD. No significant differences were found for the other outcomes.

CONCLUSION

In patients with an indication for ICD without the need for pacing, TV-ICD and S-ICD are overall comparable in terms of the composite of clinically relevant device-related complications and inappropriate shock.

Trends in Use and In-Hospital Outcomes of Subcutaneous Implantable Cardioverter Defibrillators in Patients Undergoing Long-Term Dialysis

BACKGROUND AND OBJECTIVES

Patients on dialysis are at high risk of complications related to implantable cardioverter defibrillator (ICD) implantation; use of subcutaneous ICDs may be preferred over transvenous devices due to lower risk of bloodstream infection and interference with vascular access sites. We evaluated trends in use and in-hospital outcomes of subcutaneous compared with transvenous ICDs among patients on dialysis in the United States.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Retrospective analysis of ICD implants from 2012 to 2018 among patients on dialysis reported to the National Cardiovascular Data Registry ICD Registry, a nationally representative US ICD Registry. We examined overall trends in subcutaneous ICD adoption as a proportion of all eligible ICD implants among patients on dialysis and then compared in-hospital outcomes between eligible subcutaneous ICD and transvenous ICD recipients using inverse probability of treatment weighting.

RESULTS

Of the 23,136 total ICD implants in patients on dialysis during the study period, 3195 (14%) were subcutaneous ICDs. Among eligible first-time ICD recipients on dialysis, the proportion of subcutaneous ICDs used increased yearly from 10% in 2012 to 69% in 2018. In propensity score-weighted analysis of 3327 patients, compared with transvenous ICDs, patients on dialysis receiving subcutaneous ICDs had a higher rate of in-hospital cardiac arrest (2% versus 0.4%, P=0.002), but there was no significant difference in total in-hospital complications (2% versus 1%, P=0.08), all-cause death, or length of hospital stay.

CONCLUSIONS

The utilization of subcutaneous ICDs among US patients on dialysis has been steadily increasing. The overall risk of short-term complications is low and comparable with transvenous ICDs, but higher risks of in-hospital cardiac arrest merits closer monitoring and further investigation.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2020_09_23_CJN07920520.mp3.

The subcutaneous ICD for prevention of sudden cardiac death: Current evidence and future directions

Despite major advances in medical therapy, sudden cardiac death remains an important cause of cardiovascular mortality. In order to improve the risk-benefit balance of transvenous implantable cardioverter-defibrillator (ICD) systems, a totally subcutaneous ICD (S-ICD) system was developed and approved for use in Europe in 2009. The currently available S-ICD system has undergone several important hardware- and software-related modifications and improvements over the last 10 years aimed at further improving its efficacy and safety. The results of the PRAETORIAN trial, that is, the first randomized comparison of S-ICD versus transvenous ICDs, of the prospective UNTOUCHED study, and the overall consistent observational data underline that current generation S-ICD systems may be a valid alternative in patients with an ICD indication in whom bradycardia pacing or cardiac resynchronization therapy is not required due to a lower risk of system-related problems. This review summarizes the key differences between the two systems, improvements in hardware components and algorithms over time, as well as most recent clinical evidence regarding the efficacy and safety of the S-ICD.

Defibrillation testing during implantation of the subcutaneous implantable cardioverter-defibrillator: a necessary standard or becoming redundant?

Since the publication of the SIMPLE and NORDIC trials, defibrillation testing (DFT) is rarely performed during routine implantation of transvenous implantable cardioverter-defibrillators (ICD). However, the results of these trials cannot be extrapolated to the later introduced subcutaneous ICD (S-ICD) and a class I recommendation to perform DFT during the implantation of these devices remains in the current guidelines. Due to the high conversion success rate of DFT on one hand, and the risk of complications on the other, a significant number of physicians omit DFT in S‑ICD recipients. Several retrospective analyses have assessed the safety of the omission of DFT and report contradicting results and recommendations. It is known that implant position, as well as device factors and patient characteristics, influence defibrillation success. A better comprehension of these factors and their relationship could lead to more reliable and safer alternatives to DFT. An ongoing randomised clinical trial, which is expected to end in 2023, is the first study to implement a method that assesses implant position to identify patients who are likely to fail their DFT.

His bundle pacing for newly acquired pacing needs in patients implanted with a subcutaneous implantable cardioverter defibrillator: A feasibility study based on the automated screening score and clinical cases

INTRODUCTION

Management of subcutaneous implantable cardioverter defibrillator (S-ICD) patients with newly acquired pacing needs remains problematic. His bundle pacing (HBP) allows for cardiac pacing without significant changes in the QRS morphology. We hypothesized that HBP does not alter S-ICD sensing and functions.

METHODS

Twenty consecutive patients were implanted with a HB pacemaker. Among them, 17 demonstrated successful His recruitment and were prospectively screened with the automated screening tool (AST). Results of screenings performed immediately after implant and during follow-up, during intrinsic rhythm and while pacing from all available pacing configurations, were compared using the AST score. Positive-screening tests were defined by greater than or equal to 1 positive vector.

RESULTS

Among the 17 patients successfully implanted (male: 41%; mean age: 73), 13 presented an indication of ventricular pacing and four of cardiac resynchronization. Absolute AST scores during both HBP (all configurations) and intrinsic rhythm were similar (p: NS). Due to left bundle branch block correction, HBP resulted in higher number of positive vectors (AST ≥ 100). AST scores were higher during HBP when compared with right ventricular pacing (RVP) (primary vector: 272 [16; 648] vs 4.6 [0.8; 16.2]; P = .003; secondary vector: 569 [183; 1186] vs 1.5 [0.7; 8.3]; P < .0001; alternate vector: 44 [2;125] vs 4.8 [0.9; 9.3]; P = .02) and resulted in a much higher number of positive vectors. Up to 90% of the patients had a positive-screening test during HBP. This passing rate was higher when compared RVP (17%; P < .0001).

CONCLUSION

HBP restores normal intrinsic conduction and minimally modifies the surface electrocardiograph and subcutaneous electrograms. When ventricular pacing is needed, HBP might represent an ideal pacing option for patients implanted with a S-ICD.

Ventricular tachycardia in cardiolaminopathy: Characteristics and considerations for device programming

BACKGROUND

Mutations in LMNA cause an arrhythmogenic cardiomyopathy (cardiolaminopathy) with high risk of ventricular tachycardia (VT). The natural history of VT among patients with cardiolaminopathy is incompletely understood.

OBJECTIVE

The purpose of this study was to determine the longitudinal burden and progression of VT, including change in tachycardia cycle length (TCL), response to antitachycardia pacing (ATP), and prognostic significance of high-burden VT (>5 episodes of VT at any device interrogation) in cardiolaminopathy patients.

METHODS

Patients with cardiolaminopathy and an implantable cardioverter-defibrillator (ICD) were identified from a single-center database. Serial device interrogations and medical records were used to collect data on VT burden, TCL, and response to ATP.

RESULTS

Cardiolaminopathy patients with primary (n = 27) or secondary prevention (n = 16) ICDs were followed for 2 years (interquartile range [IQR] 1-5). VT burden was substantially higher in patients receiving secondary prevention ICDs (28 ± 40.9 vs 3.6 ± 7.3 episodes per 100 patient-years; P <.001). ATP was highly effective (94%) at terminating VT except for short TCL (<250 ms), for which ATP failed in 60%. Among patients with recurrent VT, TCL increased by 112 ± 93.6 ms during follow-up. Inappropriate shocks were rare (0.4% of all therapies). Median time to transplantation, ventricular assist device, or death was 18 months (IQR 0.7-27.1) in patients with high-burden VT.

CONCLUSION

In patients with cardiolaminopathy, VT is recurrent and highly responsive to ATP, which supports the use of transvenous ICDs iteratively programmed to manage VT of various TCLs. Onset of high-burden VT indicates poor prognosis and should warrant referral to a heart failure specialist.

Ultrasound-guided serratus anterior plane block combined with parasternal block in subcutaneous implantable cardioverter defibrillator implantation: Results of a pilot study

BACKGROUND

The standard approach to subcutaneous defibrillator (S-ICD) implantation often requires general anesthesia or anesthesiologist-delivered deep sedation. Ultrasound-guided serratus anterior plane block (SAPB) combined with parasternal block (PSB) has been proposed in order to provide anesthesia/analgesia and to reduce the need for sedation during S-ICD implantation. In this pilot study, we compared the double-block approach (SAPB + PSB) with the single-block approach (SAPB only) and with the standard approach involving local anesthesia and sedation.

METHODS

We prospectively enrolled 22 patients undergoing S-ICD implantation: in 10, the single-block approach was adopted; in 12, the double-block approach. As a control group, we retrospectively enrolled 14 consecutive patients who had undergone S-ICD implantation under standard local anesthesia and sedation in the previous 6 months. Intra- and postprocedural data, including patient-reported pain intensity, were collected and compared in the three study groups.

RESULTS

The double-block approach was associated with a shorter procedure duration than the single-block and standard approaches (63.3 ± 7.9 vs 70.1 ± 6.8 vs 76.9 ± 7.8 min; P < .05) and with a lower dose of local an aesthetic for infiltration (18.9 ± 1.7 vs 27.5 ± 4.6 vs 44.6 ± 4.0 cc; P < .001). Both the double- and single-block approaches were associated with lower pain intensity at the device pocket and the lateral tunneling site (P < .05). The double-block approach proved superior to the other two approaches in controlling intraoperative pain at the parasternal tunneling site (P < .05).

CONCLUSIONS

In our study, SAPB combined with PSB was superior to SAPB alone and to the standard approach in controlling intraoperative pain during S-ICD implantation. In addition, this approach resulted in shorter procedure durations.

Feasibility and safety of same day subcutaneous defibrillator implantation and send home (DASH) strategy

PURPOSE

To assess the feasibility and safety of same-day discharge after S-ICD implantation by implementing a specific analgesia protocol and phone follow-up.

METHODS

Consecutive patients presenting for outpatient S-ICD implantation were enrolled between 1/1/2018 and 4/30/2019. An analgesia protocol included pre-operative acetaminophen and oxycodone, intraoperative local bupivacaine, and limited use of oxycodone-acetaminophen at discharge. The primary outcome was successful same-day discharge. Numerical Pain Rating Scale (NPRS) on postoperative day (POD) 1, 3, 14, and 30 and any unplanned health care visits during the 1-month follow-up period were assessed.

RESULTS

Out of 53 potentially eligible S-ICD patients, 49 patients (92.5%) were enrolled and successfully discharged on the same day. Mean age of these 49 patients was 47 ± 14 years. There were no acute procedural complications. Severe pain (NPRS ≥ 8) on POD 0, 1, and 3 was present in 14.3%, 14.3%, and 8.2% of patients, respectively. The total in-hospital stay was 534 ± 80 min. Four unplanned visits (8%) due to cardiac or device-related issues occurred during 1-month follow-up, including 2 patients with heart failure exacerbation, one patient with an incisional infection, and one patient with inappropriate shocks.

CONCLUSIONS

With the appropriate institutional protocol including specific analgesics and phone follow-up, same-day discharge after outpatient S-ICD implantation is feasible and appears safe for most patients.. Device-related pain can be severe in the first 3 days post-implantation and can be successfully treated with limited supply of narcotic medications.

Patient characteristics and in-hospital complications of subcutaneous implantable cardioverter-defibrillator for Brugada syndrome in Japan

BACKGROUND

Clinical features and complications of subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation for Brugada syndrome have not been well studied.

METHODS

We used the Japanese Diagnosis Procedure Combination database to retrospectively investigate patients who had undergone ICD implantation between April 2016 and March 2017. We compared the characteristics and in-hospital complications of patients with Brugada syndrome implanted with S-ICD or transvenous (TV)-ICD.

RESULTS

We extracted 3090 patients who received ICD implantation. Among them, we identified 278 Brugada patients. The mean age was 43 ± 14.4 years and 262 (94%) were male. Of these 278 patients, 136 (49%) received S-ICD and 142 (51%) received TV-ICD. TV-ICD recipients had a history of atrial fibrillation more frequently compared with S-ICD recipients. The median (interquartile range) of length of hospital stay was not significantly different between patients with S-ICD and TV-ICD (13 days [10-20.5] vs 12 days [10-18], respectively). The prevalence of in-hospital complications after ICD implantation was similar between the two groups. There were no patients with cardiac tamponade, hemothorax, pneumothorax, cardiovascular event, stroke, and death following the procedure during hospitalization in either group.

CONCLUSIONS

Short-term safety of S-ICD implantation may be identical to that of TV-ICD. Large prospective studies are warranted to compare the effects and long-term safety of S-ICD compared with TV-ICD.

The role of implantable cardioverter-defibrillators and sudden cardiac death prevention: indications, device selection, and outcome

Multiple randomized multicentre clinical trials have established the role of the implantable cardioverter-defibrillator (ICD) as the mainstay in the treatment of ventricular tachyarrhythmias and sudden cardiac death (SCD) prevention. These trials have focused mainly on heart failure patients with advanced left ventricular dysfunction and were mostly conducted two decades ago, whereas a more recent trial has provided conflicting results. Therefore, much remains to be determined on how best to balance the identification of patients at high risk of SCD together with who would benefit most from ICD implantation in a contemporary setting. Implantable cardioverter-defibrillators have also evolved from the simple, defibrillation-only devices implanted surgically to more advanced technologies of multi-chamber devices, with physiologic bradycardic pacing, including cardiac resynchronization therapy, atrial and ventricular therapeutic pacing algorithms, and subcutaneous ICDs. These multiple options necessitate individualized approach to device selection and programming. This review will focus on the current knowledge on selection of patients for ICD treatment, device selection and programming, and future directions of implantable device therapy for SCD prevention.

Collapse

The subcutaneous implantable cardioverter-defibrillator in review

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a completely extrathoracic device that has recently been FDA approved for the prevention of sudden cardiac death in select populations. Although the transvenous implantable cardioverter defibrillator (TV-ICD) has a proven mortality benefit in multiple patient populations, there are significant risks both with implantation and years after its placement. The S-ICD may help prevent some of these complications. Currently, the S-ICD is typically implanted in patients with prior device infection or at an increased risk for an infection, younger patients with difficult venous access related to either hemodialysis or difficult cardiac anatomy, patients who live active lifestyles, and those who may outlive the TV-ICD leads. There is an absolute contraindication for S-ICD implantations for patients who need pacing either for ventricular tachycardia or bradycardia because this device cannot perform these functions. To date, there are no randomized controlled trial (RCT) data evaluating the safety and efficacy of this relatively new device. Observational studies of both the S-ICD alone and in comparison with the TV-ICD have showed promising results, including a decrease in lead-related and periprocedural complications as well as a high level of effectiveness at terminating ventricular arrhythmias. These analyses over time may have contributed to the evolution and comfortability with the S-ICD system, as physicians are more often referring for and/or implanting this device for patients with appropriate indications. Furthermore, inappropriate shock rates with the S-ICD have decreased over time especially with dual zone programming. This review summarizes the results of a multitude of observational studies with respect to patient selection for the S-ICD, complication rates, appropriate and inappropriate shock rates, and programming. This review also tackles current ongoing randomized trials. Although the results of ongoing trials will be helpful, there is still a continued need to evaluate the efficacy of the S-ICD in broader patient populations including patients with several comorbidities and older patients so that more patients can be considered for this potentially lifesaving device.

Subcutaneous implantable cardioverter-defibrillator in primary and secondary prevention of sudden cardiac death: A meta-analysis

BACKGROUND

Subcutaneous implantable cardioverter-defibrillator (S-ICD) is gaining in popularity for primary and secondary prevention of sudden cardiac death. The objective was to evaluate the safety and clinical effectiveness of the S-ICD for prevention of sudden cardiac death compared to transvenous cardioverter-defibrillator (TV-ICD).

METHODS

A systematic review with meta-analyses was performed. The electronic databases MEDLINE, EMBASE, SCI, and Cochrane Central Register of Controlled Trials were consulted in March 2018 with no restrictions on publication date. Predefined criteria were used to determine inclusion of studies and to assess their methodologic quality.

RESULTS

Ten longitudinal-observational studies with comparison group presenting moderate methodologic flaws were included (N = 7820). The combination of results indicates that health-related quality of life is not significantly different between S-ICD and TV-ICD groups (Physical health: MD = 2.90; 95% CI = -3.88, 9.68/Mental health: MD = 0.13; 95% CI = -2.11, 2.37). Mortality occurred in 4.4% of S-ICD patients and 5.9% of TV-ICD patients died (OR = 0.79; 95% CI = 0.50, 1.24). The incidence of infections (OR = 1.79; 95% CI = 0.93, 3.43) and inappropriate shocks (OR = 1.28, 95% CI = 0.91, 1.78) is not significantly different between both groups. The S-ICD reduces complications related to electrodes/leads (OR = 0.13, 95% CI = 0.05, 0.29) and has lower electrodes/leads movement compared with TV-ICD (OR = 0.26; 95% CI 0.10, 0.67). In contrast, pneumothorax is more likely in TV-ICD than S-ICD (OR = 0.17; 95% CI = 0.03, 0.97).

CONCLUSIONS

S-ICD reduces electrodes/leads movement, electrodes/leads related complications, and pneumothorax. Our study did not demonstrate a statistically significant difference in mortality, health-related quality of life, and infection rate between S-ICD and TV-ICD.

Subcutaneous ICD: Current standards and future perspective

The subcutaneous implantable cardioverter-defibrillator (S-ICD) system is an established therapy for prevention of sudden cardiac death (SCD) and an alternative to a transvenous implantable cardioverter-defibrillator (ICD) system in selected patients. Since introduction of S-ICD in 2010, the device has undergone further development. Based on the unique feature of an entirely extracardiac implantation, S-ICD is able to reduce the known common perioperative and long-term complications of conventional transvenous implanted ICD systems. Especially for patients with a complex anatomy and no option of an endovascular lead implantation, the S-ICD offers a potential alternative. Initial uncertainty existed, questioning whether this ICD approach would be reliable in detecting and terminating ventricular arrhythmias. Multiple clinical studies, however, provided evidence for an effective treatment. Based on obvious advantages compared to conventional ICD systems, the question arises whether the S-ICD should actually be the first choice in the majority of all primary prevention patients in the future. Recent data from large registries show that S-ICD indications are also expanding in secondary prevention patients. As a consequence, the S-ICD was listed in the 2015 ESC guidelines as an alternative therapeutic option with a class-IIa recommendation in patients with an ICD indication not requiring pacing for bradycardia, cardiac resynchronization therapy or anti-tachycardia pacing (ATP). In addition, the American Heart Association guidelines refer to class-I recommendation for patients with a complex anatomy and venous access problems or at a high risk for infections who need ICD therapy. Limitations with respect to the not available pacing option of S-ICD might be also overcome by a potential combination with a leadless pacemaker in the near future. This article provides an overview of recent developments of S-ICD and reviews the most recent literature and ongoing studies.

Rationale and design of the PRAETORIAN-DFT trial: A prospective randomized CompArative trial of SubcutanEous ImplanTable CardiOverter-DefibrillatoR ImplANtation with and without DeFibrillation testing

In transvenous implantable cardioverter-defibrillator (TV-ICD) implants, routine defibrillation testing (DFT) does not improve shock efficacy or reduce arrhythmic death but patients are exposed to the risk of complications related to DFT. The conversion rate of DFT in subcutaneous ICD (S-ICD) is high and first shock efficacy is similar to TV-ICD efficacy rates. STUDY DESIGN: The PRAETORIAN-DFT trial is an investigator-initiated, randomized, controlled, multicenter, prospective two-arm trial designed to demonstrate non-inferiority of omitting DFT in patients undergoing S-ICD implantation in which the S-ICD system components are optimally positioned. Positioning of the S-ICD will be assessed with the PRAETORIAN score. The PRAETORIAN score is developed to systematically evaluate implant position of the S-ICD system components which determine the defibrillation threshold on post-operative chest X-ray. A total of 965 patients, scheduled to undergo a de novo S-ICD implantation without contra-indications for either DFT strategy, will be randomized to either standard of care S-ICD implantation with DFT, or S-ICD implantation without DFT but with evaluation of the implant position using the PRAETORIAN score. The study is powered to claim non-inferiority of S-ICD implantation without DFT in de novo S-ICD patients in respect to the primary endpoint of first shock efficacy in spontaneous arrhythmia episodes. Patients with a high PRAETORIAN score (≥90) in the interventional arm of this study will undergo DFT according to the same DFT protocol as in the control arm. CONCLUSION: The PRAETORIAN-DFT trial is a randomized trial that aims to gain scientific evidence to safely omit a routine DFT after S-ICD implantation in patients with correct device positioning.

The subcutaneous implantable cardioverter-defibrillator: Current trends in clinical practice between guidelines and technology progress

The subcutaneous implantable cardioverter defibrillator (S-ICD) is a valuable alternative to the conventional trans-venous ICD (TV-ICD) for the prevention of sudden cardiac death (SCD). Prospective registries showed that the S-ICD is safe and effective in treating ventricular tachyarrhythmias in high-risk patients without pacing indications. While in earlier studies patients implanted with S-ICDs were young and mostly affected by channelopathies, contemporary S-ICD cohorts include patients with severely impaired left ventricular function and significant comorbidities. This review focuses on S-ICD evidence-based use and highlights current gaps between guidelines recommendations and real-world clinical practice.

Iatrogeniа in internist practice

The article presents the history of the issue, the concept of iatrogenia, possible negative consequences of the interaction of the doctor and the patient in modern conditions. The main forms of iatrogenic (psychogenic, hospital, iatrogenic diagnostic procedures, medicinal, etc.) are given. An important place is occupied by implantation of iatrogenic (patients with artificial heart valves, cardio-implanted electronic devices, coronary stents, articular endoprostheses). The most vulnerable to the development of iatrogenic are elderly and senile patients. The interdisciplinarity of the iatrogenic problem and its educational significance for therapists, general practitioners, clinical pharmacologists, pathologists. Keywords: iatrogeniа, iatrogenic events, undesirable drug reactions, мedical error.

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.

Efficacy, safety, and in-hospital outcomes of subcutaneous versus transvenous implantable defibrillator therapy: A meta-analysis and systematic review

BACKGROUND

Lead-related complication is an important drawback of trans-venous implantable cardioverter-defibrillators (TV-ICD). The subcutaneous ICD (S-ICD) was developed to overcome ICD lead associated complications; however, whether the S-ICD confers enhanced clinical benefits compared with TV-ICD remains unclear. The present systematic review and meta-analysis aimed to assess TV-ICD and S-ICD for safety, efficacy, and in-hospital outcomes in the prevention of sudden cardiac death (SCD) in patients not requiring pacing.

METHODS

The Medline, PubMed, EmBase, and Cochrane Library databases were searched for studies comparing TV-ICD and S-ICD.

RESULTS

A total of 9 eligible studies, including 5 propensity-matched case-control, 3 retrospective, and 1 cross-sectional studies were identified, assessing 7361 patients in all. Pool analyses demonstrated that SICD were associated with lower lead-related complication rates [odds ratio (OR) = 0.13; 95% confidence interval [CI] 0.05-0.33; I = 0%], and S-ICD was more beneficial in terms of reducing ICD shocks [OR = 0.48; 95% CI 0.32-0.72, I = 4%]. In addition, the patients administered S-ICD tend to have shorter length of hospital stay after implantation (SMD = -0.06; 95% CI -0.11 to 0.00, I = 0%) and reduce total complication rates (OR = 0.72; 95% CI 0.50-1.03; I = 18%), non-decreased quality of life (QoL). Moreover, both devices appeared to perform equally well with respect to infection rate and death.

CONCLUSIONS

Available overall data suggested that S-ICD is associated with reducing lead-related complications, ICD shocks. In addition, S-ICD has tendency to shorten hospitalization and reduce total complications, although the difference is no significant. Equivalent death rate, infection, and QoL were found between 2 groups. Therefore, S-ICD could be considered an alternative approach to TV-ICD in appropriate patients for SCD prevention.

Spotlight on S-ICD™ therapy: 10 years of clinical experience and innovation

Subcutaneous ICD (S-ICD™) therapy has been established in initial clinical trials and current international guideline recommendations for patients without demand for pacing, cardiac resynchronization, or antitachycardia pacing. The promising experience in ‘ideal’ S-ICD™ candidates increasingly encourages physicians to provide the benefits of S-ICD™ therapy to patients in clinical constellations beyond ‘classical’ indications of S-ICD™ therapy, which has led to a broadening of S-ICD™ indications in many centres. However, the decision for S-ICD™ implantation is still not covered by controlled randomized trials but rather relies on patient series or observational studies. Thus, this review intends to give a contemporary update on available empirical evidence data and technical advancements of S-ICD™ technology and sheds a spotlight on S-ICD™ therapy in recently discovered fields of indication beyond ideal preconditions. We discuss the eligibility for S-ICD™ therapy in Brugada syndrome as an example for an adverse and dynamic electrocardiographic pattern that challenges the S-ICD™ sensing and detection algorithms. Besides, the S-ICD™ performance and defibrillation efficacy in conditions of adverse structural remodelling as exemplified for hypertrophic cardiomyopathy is discussed. In addition, we review recent data on potential device interactions between S-ICD™ systems and other implantable cardio-active systems (e.g. pacemakers) including specific recommendations, how these could be prevented. Finally, we evaluate limitations of S-ICD™ therapy in adverse patient constitutions, like distinct obesity, and present contemporary strategies to assure proper S-ICD™ performance in these patients. Overall, the S-ICD™ performance is promising even for many patients, who may not be ‘classical’ candidates for this technology.

Determinants of outcomes following outpatient placement of implantable cardioverter defibrillators in a Medicare Advantage population

BACKGROUND

Recipients of ICD are likely to have several risk factors that could interfere with successful use of implantable cardioverter defibrillators (ICDs).

HYPOTHESIS

Age, sex, and factors indicated in claims are associated with one-year mortality and complications after ICD placement.

METHODS

Adult Medicare Advantage patients who underwent outpatient ICD implantation from January 2014 to September 2015 were included. Age, sex, Charlson Comorbidity Index (CCI), prior year hospitalization and emergency department (ED) visit, diabetes, heart failure, ischemic heart disease, and indicators of the need for pacing were evaluated as risk factors. Mortality and device-related complications (lead and nonlead) were assessed at one-year post-procedure using Kaplan-Meier and Cox Proportional Hazard analysis.

RESULTS

Among 8450 patients who underwent implantation, 1-year event-free survival was 80.1%, based on an overall composite measure of complications and mortality. Adjusted survival analysis showed that age ≥ 65, male sex, incremental increase in CCI, heart failure, prior year hospitalization, ED visit, and prior year pacing procedure were significant predictors of mortality. Age ≥ 65, male sex, and prior year hospitalization were significant predictors of a composite measure of device-related complications. CCI and prior hospitalization were significant predictors of a composite measure of any adverse outcome.

CONCLUSIONS

Results suggest most patients in an older population do not experience adverse outcomes in the year following ICD implantation. The risk of mortality may be greater in men, patients over the age of 65, and patients with greater general morbidity, heart failure, or a history of a pacing procedure.

An Overview of Clinical Outcomes in Transvenous and Subcutaneous ICD Patients

PURPOSE OF REVIEW

Clear guidelines on when to select a subcutaneous ICD (S-ICD) over a transvenous ICD (TV-ICD) are lacking. This review will provide an overview of the most recent clinical data on S-ICD and TV-ICD therapy by pooling comparison studies in order to aid clinical decision making.

RECENT FINDINGS

Pooling of observational-matched studies demonstrated an incidence rate ratio (IRR) for device-related complication of 0.90 (95% CI 0.58-1.42) and IRR for lead-related complications of 0.15 (95% CI 0.06-0.39) in favor of S-ICD. The IRR for device infections was 2.00 (95% CI 0.95-4.22) in favor of TV-ICD. Both appropriate shocks (IRR 0.67 (95% CI 0.42-1.06)) and inappropriate shocks (IRR 1.17 (95% CI 0.77-1.79)) did not differ significantly between both groups. With randomized data underway, the observational data demonstrate that the S-ICD is associated with reduced lead complications, but this has not yet resulted in a significant reduction in total number of complications compared to TV-ICDs. New technologies are expected to make the S-ICD a more attractive alternative.

Quality and Safety in Health Care, Part XLII: Introduction to the Implantable Cardioverter Defibrillator Registry

Implantable cardioverter defibrillators for both primary and secondary prevention have been successful in decreasing sudden cardiac death. The Implantable Cardioverter Defibrillator Registry was established partly for reimbursement for primary prevention. However, the registry also has been helpful in better understanding the risks and appropriate selection of patients to receive these devices, serving as an impetus for quality improvement by giving outcome information to the contributing institutions regarding their performance relative to the national results, and increasing research. It is also expected to be helpful to compare results from different devices and provide information to the public.

Effect of defibrillation threshold testing on effectiveness of the subcutaneous implantable cardioverter defibrillator

BACKGROUND

Defibrillation threshold (DFT) testing is recommended with the subcutaneous implantable cardioverter defibrillator (SICD).

OBJECTIVE

To describe first shock efficacy for appropriate SICD therapies stratified by the presence of implant DFT testing.

METHODS

We reviewed all patients receiving SICDs at our institution and stratified them based on whether implant DFT testing was performed. Appropriate shocks were reviewed to see if ventricular tachycardia/ventricular fibrillation (VT/VF) terminated with a single shock. First shock efficacy was stratified by implant DFT status.

RESULTS

178 patients implanted with SICDs and followed in our center were included in this study. Of these, 135 (76%) underwent DFT testing (DFT (+) group). In the DFT (+), 80 appropriate shocks were needed to treat 69 episodes of VT/VF. The first shock was effective in 61 out of 69 episodes (88.4%), whereas multiple shocks were required to terminate VT/VF in the remaining eight episodes. Among 43 patients without implant DFT testing (DFT (-) group), 20 appropriate shocks to treat 17 episodes of VT/VF occurred in seven patients. VT/VF was successfully terminated with the first shock in 16 out of 17 episodes (first shock efficacy 94.1 %). There was no significant difference in first shock effectiveness between those with and without implant DFT testing (P  =  0.97).

CONCLUSION

A strategy that omits DFT testing at implant did not appear to compromise the effectiveness of the SICD. These data suggest that routine DFT testing at SICD implant might not be necessary. Randomized trials are needed to confirm this finding.

[Journey of the S‑ICD to first-line therapy]

The subcutaneous implantable cardioverter-defibrillator (S-ICD®, Boston Scientific, Marlborough, MA, USA, previously Cameron Health, San Clemente, CA, USA) represents an important milestone in ICD therapy for prevention of sudden cardiac death (SCD). Since the introduction of the S‑ICD in 2010, the device has undergone further development. Based on the unique feature of an entirely extracardiac implantation, the S‑ICD is able to reduce the common perioperative and long-term complications of the usual endovascular implanted ICD systems. Especially for patients with a complex anatomy and no option of an endovascular lead implantation, the S‑ICD offers a potential alternative. Regarding the initial uncertainty if this innovative ICD approach is actually reliable in detecting and terminating ventricular arrhythmias has been resolved by multiple clinical studies and trials providing evidence for an effective treatment. Based on the obvious advantages compared to conventional ICD systems, the question arises if the S‑ICD should actually be the first choice in the majority of all primary prevention patients in the future. Furthermore, recent data from large registries show that S‑ICD indications are also expanding in secondary prevention patients. As a consequence the S‑ICD was listed in the 2015 ESC guidelines as an alternative therapeutic option with a class IIa recommendation in patients with an ICD indication not requiring pacing for bradycardia, cardiac resynchronization therapy or anti-tachycardia pacing (ATP). In addition, the American Heart Association guidelines refer to class I recommendation for patients with a complex anatomy and venous access problems or at a high risk for infections who need ICD therapy. Limitations with respect to the not available pacing option of S‑ICD might be also overcome by a potential combination with a leadless pacemaker in the near future. This article provides an overview of recent developments of the S‑ICD and reviews the most recent literature and ongoing studies.

Risk Factors and Temporal Trends of Complications Associated With Transvenous Implantable Cardiac Defibrillator Leads

Background

The transvenous implantable cardioverter‐defibrillator (ICD) lead is the most common source of complications in a traditional ICD system. This investigation aims to determine the incidence, predictors, and costs associated with these complications using a large insurance database.

Methods and Results

Data from the OptumLabs™ Data Warehouse, which include diagnosis, physician and procedure codes, and claims from patient hospitalizations, were analyzed. Patients with a de novo ICD or cardiac resynchronization therapy defibrillator implanted from January 1, 2003, through June 30, 2015, were included; those who did not have continuous coverage beginning 1 year before implantation were excluded, resulting in 40 837 patients followed up over an average of 2.3±2.1 years. Patients were followed up until they had the procedure or their last active date in the database. Of 20 580 device procedures, 2165 (5.3%) and 771 (1.9%) had mechanical and infectious complications, respectively. The 5‐year rate of freedom from mechanical complication was 92.0% and 89.3% for ICDs and cardiac resynchronization therapy defibrillators, respectively. Infectious complications were more likely in patients with a history of atrial fibrillation, diabetes mellitus, and renal disease, and the risk increased with subsequent device procedures. Younger age, female sex, lack of comorbidities, and implantations between 2003 and 2008 were associated with more mechanical complications.

Conclusions

Incidence of mechanical and infectious complications of transvenous ICD leads over long‐term follow‐up is much higher in the real world than in clinical studies. In our study cohort, 1 of 4 transvenous ICD leads had mechanical complications when followed up to 10 years. The high rate of reintervention leads to additional complications.

The subcutaneous implantable cardioverter-defibrillator: A tertiary center experience

BACKGROUND

The aim of the study was to evaluate subcutaneous implantable cardioverter-defibrillator (S-ICD) patients with regard to underlying etiology, peri-procedural outcome, appropriate/inappropriate shocks, and complications during follow-up.

METHODS

All patients who underwent S-ICD implantation from February 2013 to March 2017 at an academic hospital in Vienna were included. Medical records were examined and follow-up interrogations of devices were conducted.

RESULTS

A total of 79 S-ICD patients (58.2% males) with a mean age of 44.5 ± 17.2 years were followed for a mean duration of 12.8 ± 13.7 months. A majority of patients (58.2%) had S-ICD for primary prevention of sudden cardiac death. The most common of the 16 underlying etiologies were ischemic cardiomyopathy, non-ischemic cardiomyopathy, and idiopathic ventricular fibrillation. The lead was implanted to the left sternal border in 96.2% of cases, between muscular layers in 72.2%. Mean implant time was 45 min, 3 patients were induced, and all patients except one were programmed to two zones. Six (7.6%) patients experienced at least one appropriate therapy for ventricular arrhythmias and the time to first event ranged from 1 to 52 months. Seven patients experienced inappropriate shocks due to T-wave oversensing, atrial tachycardia with rapid atrioventricular conduction, external electromagnetic interference, and/or baseline oversensing due to lead movement. Four patients underwent revision for lead repositioning (n = 1), loose device suture (n = 1), and infection (n = 2).

CONCLUSIONS

While S-ICDs are a feasible and effective treatment, issues remain with inappropriate shock and infection.

Initial experience with the subcutaneous implantable cardioverter-defibrillator with the real costs of hospitalization analysis in a single Polish center

BACKGROUND

The recent introduction of an entirely subcutaneous implantable cardioverter-defibril-lator (S-ICD) represents an important progress in the defibrillation technology towards a less invasive approach. This is a single-center observational study of S-ICD implantations in Poland.

METHODS

The S-ICD was implanted in 11 patients with standard indications for an ICD. Patients in whom the device was implanted were evaluated for adverse events and device function at hospital discharge. All hospitalization costs were calculated and summed up for all patients. Costs were divided into following categories: medical materials, pharmaceuticals, operating theatre staff, cardiology depart-ment staff, laboratory tests, non-laboratory tests and additional non-medical costs.

RESULTS

The mean age of patients was 51.6 ± 16.4 years, 9 were men and 2 were women. Four pa-tients had atrial fibrillation as the basal rhythm, 1 patient had atrial flutter and 6 patients had sinus rhythm. All patients had at least one condition that precluded the use of a traditional ICD system or the S-ICD was preferred due to other conditions, i.e. a history complicated transvenous ICD therapy (18%), anticipated higher risk of infection (27%), lack or difficult vascular access (18%), young age and anticipated high cumulated risk of lifetime device therapy (36%). The mean duration of the im-plantation procedure was 2 h. One patient developed a postoperative pocket hematoma. Mean total time of hospitalization was 28 (6-92) days. Average cost of hospitalization per patient was 21,014.29 EUR (minimal = 19,332.71 EUR and maximal = 24,824.14 EUR).

CONCLUSIONS

S-ICD implantation appears to provide a viable alternative to transvenous ICD, espe-cially for patients without pacing requirements.