Subcutaneous implantable cardioverter-defibrillators: long-term results of the EFFORTLESS study

Abstract

Aims To report 5-year outcomes of EFFORTLESS registry patients with early generation subcutaneous implantable cardioverter-defibrillator (S-ICD) devices. Methods and results Kaplan–Meier, trend and multivariable analyses were performed for mortality and late (years 2–5) complications, appropriate shock (AS) and inappropriate shock (IAS) rates. Nine hundred and eighty-four of 994 enrolled patients with diverse diagnoses (28% female, 48 ± 17 years, body mass index 27 ± 6 kg/m2, ejection fraction 43 ± 18%) underwent S-ICD implantation. Median follow-up was 5.1 years (interquartile range 4.7–5.5 years). All-cause mortality was 9.3% (95% confidence interval 7.2–11.3%) at 5 years; 703 patients remained in follow-up on study completion, 171 withdrew including 87 (8.8%) with device explanted, and 65 (6.6%) lost to follow-up. Of the explants, only 20 (2.0%) patients needed a transvenous device for pacing indications. First and final shock efficacy for discrete ventricular arrhythmias was consistent at 90% and 98%, respectively, with storm episode final shock efficacy at 95.2%. Time to therapy remained unaltered. Overall 1- and 5-year complication rates were 8.9% and 15.2%, respectively. Early complications did not predict later complications. There were no structural lead failures. Inappropriate shock rates at 1 and 5 years were 8.7% and 16.9%, respectively. Self-terminating inappropriately sensed episodes predicted late IAS. Predictors of late AS included self-terminating appropriately sensed episodes and earlier AS. Conclusion In this diverse S-ICD registry population, spontaneous shock efficacy was consistently high over 5 years. Very few patients underwent S-ICD replacement with a transvenous device for pacing indications. Treated and self-terminating arrhythmic episodes predict future shock events, which should encourage more personalized device optimization. Key question Is subcutaneous implantable cardioverter-defibrillator (S-ICD) shock efficacy maintained over time? Key finding Subcutaneous implantable cardioverter-defibrillator shock efficacy remains high for discrete and storm episodes. For discrete episodes first and final shock efficacy do not change over time or by rhythm type. Take-home message The EFFORTLESS study 5-year results provide the longest follow up of a large patient cohort implanted with the S-ICD. For 984 patients with a median follow-up of 5.1 years, the S-ICD maintains a high level of shock efficacy of 98%.

Advantages, limitations and new perspectives on the implantation of subcutaneous cardioverter-defibrillator

“…In a 5-year registry the surgical site infections were rarely reported (3.2%), along with erosions (2.3%) and haematomas (0.9%). Lead damage were not observed in this registry [9]. Occasional damage were observed in the third-generation SQ leads.…”

Clinical outcomes of subcutaneous vs. transvenous implantable defibrillator therapy in a polymorbid patient cohort

“…The EFFORTLESS S-ICD registry was designed to obtain clinical outcome data in S-ICD patients implanted with early generation devices ( 10 ). Recently, long-term results have been published and demonstrate an encouraging 5-year survival rate of 90.7% ( 37 ). The UNTOUCHED trial was designed to evaluate the inappropriate shock rate in a more typical, contemporary S-ICD cohort (14% having chronic kidney disease) ( 14 ).…”

Response by van der Stuijt et al to Letter Regarding Article, “Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial”

“…The UNTOUCHED registry (Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction) and EFFORTLESS registry (Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the S-ICD) already demonstrated an apparent reduction in inappropriate shocks with the newest algorithms available in the S-ICD. 3,4 Patients with heart failure or end-stage renal failure undergoing hemodialysis are at greater risk for fluid shifts, which may affect QRS complexes and might therefore provoke inappropriate shocks. However, to date, these changes have not been shown to increase inappropriate shock rates in the S-ICD.…”

“…The UNTOUCHED registry (Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction) and EFFORTLESS registry (Evaluation of Factors Impacting Clinical Outcome and Cost Effectiveness of the S-ICD) already demonstrated an apparent reduction in inappropriate shocks with the newest algorithms available in the S-ICD. 3,4…”