Is less always more? A prospective two-centre study addressing clinical outcomes in leadless versus transvenous single-chamber pacemaker recipients

Background

Transvenous (TV) pacemakers are a well established treatment of bradyarrhythmias yet their complications, namely bleeding, infection and pneumothorax, still pose challenges to modern cardiology. This applies particularly to the older patient subgroup requiring single-chamber pacing due to comorbid atrial fibrillation (AF). Furthermore, conditions such as superior venous access issues, high infectious, or bleeding risk may complicate or preclude transvenous lead implantation. While VVIR leadless (LL) pacemakers aim to tackle these shortcomings, a comparison with contemporary single-chamber TV cohorts is currently lacking thus hindering a clear definition of the scope of LL pacing in clinical practice.

Purpose

To prospectively analyse survival and complication rates in leadless versus transvenous single-chamber pacemaker recipients.

Methods

This is a prospective analysis of 344 consecutive patients who received single-chamber TV or LL pacemakers between June 2015 and May 2021 in two tertiary cardiology centres. Indications for single-chamber pacing were “slow” AF, atrio-ventricular block with comorbid AF (either permanent or accepted as “destination rhythm”) or with sinus rhythm in bedridden cognitively impaired patients. LL indications were ongoing or expected chronic haemodialysis (6.9%), superior venous access issues such as occlusion (11.1%) or need for its preservation (9.7%), active lifestyle with low amount of pacing expected (22.2%), frailty causing high bleeding and infectious risk (23.6%), as well as recent valvular endocarditis (2.8%) or implantable electronic device infection requiring extraction (5.6%).

Results

72 patients (20.9%) received LL and 272 (79.1%) TV single-chamber pacemakers. In keeping with LL indications, diabetes and ongoing haemodialysis were more prevalent in the LL population. No significant difference in overall complication rate was observed between LL and TV patients (5.6% vs. 5.1%, p=0.33) apart from haematomas, which occurred more frequently in the LL population. Only 1 haematoma in the TV group required surgical reintervention. TV recipients survival was lower with greater cardiovascular mortality, likely due to selection of significantly older patients.

Conclusions

Given the limited complication rate observed in this contemporary single-chamber TV cohort and low life expectancy of this particular population, extending LL indications to all VVIR candidates is unlikely to provide a clearcut survival advantage. Considering the higher costs of LL technology, these data prompt a careful selection of those cases where LL approach does indeed provide an advantage. In addition to the setting of vascular access issues and high bleeding or infectious risk, these may include patients with sufficient life expectancy where lead-related risks may indeed adversely affect prognosis. Based on our patient selection criteria, LL might account for approximately 20% of VVIR pacing recipients.

Funding Acknowledgement

Type of funding sources: None.

Predicting long-term mortality following transvenous lead extraction using the lead extraction difficulty (LED) index score

Funding Acknowledgements

Type of funding sources: None.

Background

Transvenous Lead Extraction (TLE) scoring systems have proven to be a reliable method to predict TLE difficulty, thus improving procedure safety and efficacy. Nevertheless, TLE has shown a significant mortality rate during the subsequent follow-up, up to 33% at 10 years, with historical data showing several procedural and clinical characteristics associate with this poor outcome.

Purpose

We aimed to investigate the association between difficult TLE procedures and long-term mortality, using a specific scoring system [Lead Extraction Difficulty (LED)] to identify difficult/simple procedures.

Methods

Consecutive patients underwent TLE procedures between January 2014 and January 2016 at Spedali Civili Hospital, Brescia, Italy, were prospectively considered to receive a follow-up during 2021. TLE difficulty was retrospectively assessed in all patients using the LED index score (number of leads to extract + years from implant of the oldest lead to remove + 1 [for a dual-coil implantable cardioverter defibrillator lead] – 1 [in case of confirmed vegetations along the lead]). According to the score, "high-difficult" procedures were defined for a LED >10. Patient long-term follow-up was obtained by review of medical records from patient surveys or from the referring institution/family practitioner. Univariate analysis and multivariate logistic regression were used to identify factors associated with long-term mortality. Kaplan-Meier estimates were used to investigate survival during the follow-up. Two-sided P<.05 was considered significant.

Results

A total of 466 permanent leads were removed in 249 patients with a clinical success rate of 99.1%, and without major acute complications. The mean time follow-up was 6.7 (5.9-7.1) years, with a cumulative all-cause mortality rate of 17.7%. Clinical characteristics, indication for TLE, and mortality during follow-up are reported in the Table. Among all variable associated with mortality at univariate analysis, only LED index >10 independently predicted the mortality during the follow-up at logistic regression (OR 2.98; 95% CI: 0.081-1.4; p=0.028). Survival plots for individuals underwent high/low difficult TLE are shown in the Figure. Mortality at 1, 3, and 5 years following TLE was highest among patients with LED index >10 (1.1%, 12.6%, and 26.3%, respectively).

Conclusions

Cumulative long-term mortality following TLE was confirmed to be high. Of interest it resulted highest among patients following high-difficult TLE procedure. LED index score resulted a useful tool to predict long-term mortality after procedure. This finding should be considered when approaching TLE procedures in order to estimate the risk/benefit ratio over the time.

The subcutaneous defibrillator in patients with low BMI - insights from a large European multicenter registry

Funding Acknowledgements

Type of funding sources: None.

Background

The subcutaneous implantable cardioverter defibrillator (S-ICD) has become an alternative to transvenous ICDs (tv-ICD), especially in young patients without a need for pacing. One of the current limitations of the S-ICD is the relatively large size of the generator compared to tv-ICDs. There is little evidence whether the size of the current S-ICD generator is associated with an elevated risk of device-related complications in patients with a low body mass index (BMI).

Purpose

To compare the device-related complications and long-term outcomes in a large real world cohort of S-ICD recipients in patients with a BMI <18 kg/m2 compared to patients with a BMI >18 kg/m2.

Methods

The iSuSI registry is a European, multi-center, open-label, independent, and physician-initiated observational registry. A total of twenty-two Public and Private Healthcare Institutions from 4 different countries in Europe were involved in the registry. All consecutive patients meeting current guideline indications for ICD implantation and undergoing implantation of a S-ICD device (Boston Scientific, Marlborough, Massachusetts, USA) at 21 European institutions enrolled in the registry were used for the current analysis. Patients were classified into two cohorts, depending on the BMI at the time of device implantations: BMI < 18 kg/m2 versus > 18 kg/m2.

Results

Out of a total of 1497 pts, 58 pts (3.9%) had a BMI < 18 kg/m2. Patients with BMI <18 kg/m2 were younger (44.6±2.4 vs 50.8±0.4; p=0.004) and more frequently female (58.6% vs 22.3%, p<0.001). No differences in any of the other baseline characteristic were observed. Implantation techniques resulted comparable between the groups (Rates of 2-incision technique: 87.8% vs 91.9%; p=0.256; inter-muscular placement: 89.7% vs 83.3%; p=0.198). Of note, the mean PRAETORIAN score at implantation of patients with BMI <18 kg/m2 was significantly lower (33.8±9.1 vs 54.1±47.3; p=0.035), although the vast majority of pts in both cohorts qualify as at low risk of conversion failure (100% vs 91.4%; p=0.436).

Over a median follow up time of 22.4 [11.6–36.8] months, both overall device-related complications (5.2% vs 7.4%) and rates of inappropriate shocks (12.0% vs 8.8%) resulted comparable between the two groups (p =0.517 and p=0.385, respectively). Figure1 reports Kaplan-Meier curves reporting the combined incidence of device-related complications and inappropriate shocks in the two groups (log-rank p = 0.576).

Conclusion

No difference in device-related complications and long-term outcomes after S-ICD implantation were observed in patients with BMI <18 kg/m2 compared to the remaining recipients from a large, multi-centered S-ICD registry.

Figure 1: Kaplan-Meier-survival curve for the combined endpoint of inappropriate shocks (IAS) and device-related complications (DRC)

S-ICD in heart failure patients: real-world data from a multicenter, european analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Data on patients with heart failure (HF) and subcutaneous implantable cardioverter defibrillator (S-ICD) are very scarce and limited to a single prospective analysis from the UNTOUCHED trial.

Purpose

Aim of this study was to assess clinical outcomes of the S-ICD in HF patients, comparing them with a no-HF population, in a real-world analysis from the largest European retrospective S-ICD registry (ELISIR registry).

Methods

All consecutive patients undergoing S-ICD implantation at 20 European institutions enrolled in the ELISIR registry were used for the current analysis. According to European Guidelines, the registry population was classified into two groups: the HF cohort (further classified as HF with reduced and mid-range ejection fraction – HFrEF and HFmrEF) vs the no-HF group. The primary outcome of the study was the inappropriate shock (IS) rate across the two cohorts. As secondary outcomes, appropriate shocks, cardiovascular mortality and device-related complications during follow-up were assessed.

Results

A total of 1409 patients from the ELISIR registry were included in this analysis; HF patients represented 57.3% of the entire cohort (n=701, 86.9% HFrEF; n=106,13.1% HFmrEF). As expected, the HF cohort showed significantly higher rates of cardiovascular risk factors and comorbidities when compared to the no-HF cohort. Over a median follow-up of approximately 2 years, a total of 133 inappropriate shocks were observed in the entire cohort, without significant differences among the two groups (9.2% vs 9.8%, p=0.689). 133 complex ventricular arrhythmias were adequately recognized and treated in the overall cohort, showing similar rates of appropriate shocks (9.2% vs 9.8%, p=0.689). Inappropriate and effective shocks-free survival has been represented in Figure 1, showing Kaplan-Meier estimates comparing HF vs no-HF patients, also stratified by left ventricular ejection fraction (LVEF). The impact of baseline and procedural characteristics on the primary outcome was tested through univariable and multivariable Cox regression analysis in HF patients; at multivariate analysis, only age (HR=0.974 [0.955–0.992], p=0.005), LVEF (HR=0.954 [0.926-0.984], p=0.003), ARVC (HR=3.364 [1.206-9.384], p=0.020) and smart pass algorithm "on" (HR=0.321 [0.184-0.560], p<0.001) remained associated with inappropriate shocks (Figure 2). A low number of patients (n=76) experienced device-related complications, more frequently in the HF cohort (6.2% vs 3.8%, p=0.031) with no significant differences regarding any specific outcome of interest: lead infection (1.1% vs 0.7%, p=0.381), pocket infection (1.9% vs 0.8%, p=0.107), pocket hematoma (3.2% vs 2.8%, p=0.668).

Conclusion

The rate of inappropriate shocks seems to be comparable in both HF and non-HF patients implanted with S-ICD. However, the rate of device-related complications was slightly more frequent in HF patients.

Age-related differences and associated outcomes of S-ICD: insights from a large, european, multicenter, real-world registry

Funding Acknowledgements

Type of funding sources: None.

Background

Young patients often represent the most suitable candidates for an entirely subcutaenous implantable cardioverter defibrillator (S-ICD) system, since they have to face a lifetime of device therapy and they rarely have a pre-existing or concurrent pacing or cardiac resynchronization therapy (CRT) indication. Moreover, S-ICD offers lower rate and a safer management of lead and major procedure-related complications. To date, a few limited case series and experiences with S-ICD in teenagers and young adults have shown that the S-ICD system is safe and feasible in this population, with a rate of inappropriate shocks (IS) comparable to transvenous (TV) ICD, but focused analysis on a large scale are currently lacking in this setting.

Purpose

The aim of the current study was to compare the age-related differences observed in patient selection, baseline characteristics, and device long-term associated outcomes in a large real world cohort of S-ICD recipients. The primary outcome of the study was defined as the comparisons of the IS rate observed during the entirety of follow up in the teenagers/young adult vs the adult populations. Rate of complications, freedom from sustained ventricular arrhythmic events, overall and cardiovascular mortality were also assessed in the two cohorts and assessed as secondary outcomes.

Methods

All S-ICD recipients in the ELISIR project were enrolled in the current study. Patients were classified into teenagers + young adults (≤ 30 years old) vs adults (> 30 years old), depending from patient age at device implantation (Figure 1). Rates of device-related complications and IS were compared between the cohorts.

Results

A total of 1349 patients were extracted from the ELISIR project. Teenagers and young adults represented 12.4% of the registry (n=56 teenagers; n=112 young adults). Patients were followed-up for a median of 23.1 [12.6–37.9] months. Overall, 117 (8.7%) patients experienced inappropriate S-ICD shocks and 100 (7.4%) device related complications were observed, with no age-related differences. IS resulted more frequent in the teenager and young adult cohort (14.3% vs 7.9%; p=0.006). Figure 2 reports Kaplan Meier curves for the occurrence of IS. At univariate analysis, young age was associated with IS, but after correcting for differences in arrhythmic substrate, this association resulted non-significant (aHR: 1.428 [0.883–2.331]; p=0.146). The use of SMART pass algorithm was instead associated to a strong reduction in IS (aHR 0.367 [0.245–0.548]; p<0.001).

Conclusion

The use of S-ICD in teenagers/young adults resulted safe and effective. Indeed, the rate of complications between teenagers/young adults and adults was not significantly different. Although a higher rate of IS was observed in the teenagers/young adults, when accounting for differences in baseline substrate and comorbidities, young age did not result associated with an increased risk of IS.

C9 SUBCUTANEOUS IMPLANTABLE CARDIOVERTER DEFIBRILLATOR IN PATIENTS WITH LOW BMI: REAL–WORLD DATA FROM A EUROPEAN MULTICENTER ANALYSIS

Background

One of the current limitations of the S–ICD is the relatively large size of the generator compared to the TV (transvenous) ICD. There is little evidence whether the size of the current S–ICD generator is associated with an elevated risk of device–related complications in patients with a low body mass index (BMI).

Purpose

Aim of this study was to compare the device–related complications and long–term outcomes in a large real world cohort of S–ICD recipients in patients with a BMI <18 kg/m2 compared to patients with a BMI >18 kg/m2.

Methods

All consecutive patients meeting current guideline indications for ICD implantation and undergoing implantation of a S–ICD device (Boston Scientific, Marlborough, Massachusetts, USA) at 21 European institutions enrolled in the extended ELISIR registry were used for the current analysis. Patients were classified into two cohorts, depending on the BMI at the time of device implantations: BMI < 18 kg/m2 versus > 18 kg/m2.

Results

Out of a total of 1497 pts, 58 pts (3.9%) had a BMI < 18 kg/m2. Patients with BMI <18 kg/m2 were younger (44.6±2.4 vs 50.8±0.4; p = 0.004) and more frequently female (58.6% vs 22.3%, p < 0.001). No differences in any of the other baseline characteristic were observed. Implantation techniques resulted comparable between the groups (rates of 2–incision technique: 87.8% vs 91.9%; p = 0.256; inter–muscular placement: 89.7% vs 83.3%; p = 0.198). Of note, the mean PRAETORIAN score at implantation of patients with BMI <18 kg/m2 was significantly lower (33.8±9.1 vs 54.1±47.3; p = 0.035), although the vast majority of patients in both cohorts qualified as at low risk of conversion failure (100% vs 91.4%; p = 0.436). Over a median follow up time of 22.4 [11.6–36.8] months, both overall device–related complications (5.2% vs 7.4%) and rates of inappropriate shocks (12.0% vs 8.8%) resulted comparable between the two groups (p = 0.517 and p = 0.385, respectively). Figure 1 reports Kaplan–Meier curves showing the combined incidence of device–related complications and inappropriate shocks in the two groups (log–rank p = 0.576).

Conclusion

No differences in device–related complications and long–term outcomes after S–ICD implantation were observed in patients with BMI <18 kg/m2 compared to the remaining recipients in a large multicentered real–world analysis.

P21 AGE–RELATED DIFFERENCES AND ASSOCIATED OUTCOMES OF S–ICD: INSIGHTS FROM A LARGE, EUROPEAN, MULTICENTER REGISTRY

Background

The subcutaneous implantable cardioverter defibrillator (S–ICD) has become an alternative to transvenous ICDs (TV–ICD) in patients who do not need pacing. To date, there is little evidence directly comparing the rates of inappropriate shocks (IAS) in young vs old S–ICD recipients.

Purpose

Aim of our study was to assess differences in device–related complications and inappropriate shocks (IS) between teenagers/young adults and adult recipients of a subcutabeous implantable cardioverter defibrillator (S–ICD) device.

Methods

Two propensity–matched cohorts of teenagers + young adults (≤ 30–year–old) and adults (> 30–year–old) were retrieved from the ELISIR registry. The primary outcome was the comparison of the inappropriate shock (IAS) rate; complications, freedom from sustained ventricular arrhythmic events, overall and cardiovascular mortality were deemed secondary outcomes.

Results

A total of 1491 patients were extracted from the ELISIR project. Teenagers + young adults represented 11.0% of the entire cohort. Two propensity–matched groups of 161 patients each were used for the analysis (Figure 1); median follow–up was 23.1 [13.2–40.5] months. 15.2% patients experienced inappropriate S–ICD shocks and 9.3% device related complications were observed with no age–related differences in IAS (16.1% vs 14.3%; p = 0.642) and complication rates (9.9% vs 8.7%; p = 0.701); Figure 2 shows a survival analysis from inappropriate shocks in the teen–ager/young adult cohort (red) and in the adult cohort (blue). At univariate analysis, young age was not associated with increased rates of IAS (HR 1.204 [0.675–2.148]: p = 0.529). At multivariate analysis (Figure 3), the use of SMART pass algorithm was associated to a strong reduction in IAS (aHR 0.292 [0.161–0.525]; p < 0.001), while ARVC was associated with higher rates of IAS (aHR 2.380 [1.205–4.697]; p = 0.012).

Conclusion

In a large multicentered European registry of patients with S–ICD, 11.0% of all recipients were teenagers or young adults. The use of S–ICD in teenagers/young adults resulted safe and effective, and the rates of complications and IAS between teenagers/young adults and adults were not significantly different. The only predictor of increased IAS was a diagnosis of ARVC.

P25 SUBCUTANEOUS–ICD IN PATIENTS WITH HEART FAILURE: RESULTS FROM A MULTICENTER, EUROPEAN ANALYSIS

Background

Data on patients with heart failure (HF) with a subcutaneous implantable cardioverter defibrillator (S–ICD) are scarce.

Objective

Aim of this study was to assess clinical outcomes of the S–ICD in HF patients in a real–world analysis from the largest European retrospective S–ICD registry (ELISIR).

Methods

All consecutive patients undergoing S–ICD implantation at several European institutions were used for the current analysis. The population was classified into two groups: the HF (classified as HF with reduced and mid–range ejection fraction – HFrEF and HFmrEF) vs the no–HF cohort. The primary outcome of the study was the inappropriate shock (IS) rate across the two cohorts. As secondary outcomes, appropriate shocks, cardiovascular mortality and device–related complications during follow–up were assessed

Results

A total of 1409 patients from the ELISIR registry were included; HF patients represented 57.3% of the entire cohort (n = 701, 86.9% HFrEF; n = 106,13.1% HFmrEF). Over a median follow–up of approximately 2 years, a total of 133 inappropriate shocks were observed in the entire cohort, without significant differences among the two groups (9.2% vs 9.8%, p = 0.689). 133 complex ventricular arrhythmias were adequately recognized and treated, with similar rates of appropriate shocks (9.2% vs 9.8%, p = 0.689). Inappropriate and effective shocks–free survival has been represented in Figure 1 (Kaplan–Meier estimates). At multivariate analysis (Figure 2), age (HR = 0.974 [0.955–0.992], p = 0.005), LVEF (HR = 0.954 [0.926–0.984], p = 0.003), arrhythmogenic right ventricular cardiomyopathy – ARVC (HR = 3.364 [1.206–9.384], p = 0.020) and smart pass + (HR = 0.321 [0.184–0.560], p < 0.001) remained associated with inappropriate shocks. Moreover, a low number of patients (n = 76) experienced device–related complications, more frequently in the HF cohort (6.2% vs 3.8%, p = 0.031) with no significant differences regarding any specific outcome of interest: lead infection (1.1% vs 0.7%, p = 0.381), pocket infection (1.9% vs 0.8%, p = 0.107), pocket hematoma (3.2% vs 2.8%, p = 0.668).

Conclusion

The use of S–ICD in HF patients did not result in a higher rate of inappropriate shocks when compared to no–HF patients, even when stratifying for LVEF. Only age, LVEF, ARVC e Smart Pass algorithm were predictors of the primary outcome at multivariate analysis. Despite a lower overall rate of complications in the entire cohort, HF patients experienced device–related complications more frequently.