Six-month safety and therapy efficacy of the extravascular implantable defibrillator in those 65 years or older: real-world results from the enlighten study post approval registry
D Duncker, A Amin, F Murgatroyd, M Sterlinski, I Crozier, J B Johansen, G Engel, C Wiggenhorn, L V A BoersmaAbstract
Background
The extravascular implantable cardioverter-defibrillator (EV-ICD) avoids vascular lead placement by implanting a lead in the substernal space. To date, implanters have often chosen the EV-ICD for younger patients, presumably to avoid the risks associated with long transvenous lead dwell times. Thus, an assessment of the EV-ICD in older patients is warranted.
Purpose
This analysis aims to examine outcomes of the EV-ICD in older patients (≥65) and compare to younger patients (<65) using data from a large, real-world, post-approval registry.
Methods
Enlighten is a global, prospective, post-market, registry study enrolling patients implanted with an EV-ICD system and following them for the life of the device. The primary endpoint of the Enlighten study is freedom from chronic (>30 days), system-related major complications at five years, excluding infections. Patients with an implant attempt were split into two groups based on their age at implant: those <65 years of age and those ≥65 years of age. Procedure outcomes, safety (including the primary endpoint at 6 months and infections), and characterization of appropriate and inappropriate therapy were assessed for each group.
Results
Patients aged ≥65 (N=135; mean age: 70.5±4.5 years) differed from those aged <65 (N=651; mean age: 44.6±12.6 years), with the older cohort having a lower proportion of women (20.7% vs 30.3% female), a lower mean LVEF (41.3±15.9% vs 45.5±16.0%), higher proportion of secondary prevention (37.0% vs 33.5%), and more likely to have a history of AF (28.9% vs 10.8%). Tunneling and lead placement success rate (100% vs 99.1%; P=0.60) and defibrillation testing success rate (100% vs 98.8%; P=0.60) were comparable in older and younger patients, respectively. The primary endpoint, evaluated at 6 months, did not differ: there was a 98.1% and 97.7% freedom from chronic, major system-related complications in older and younger patients, respectively (P=0.72). Of 11 major system- and/or procedure-related infections that occurred, 10 (1.5%) were in those <65 and one (0.7%) among those ≥65 through all follow-up. The older cohort also had statistically insignificant lower rates of appropriate therapy (2.1% vs 5.8%; P=0.31) and inappropriate shock (3.9% vs 5.8%; P=0.39) compared to the younger cohort, through 6 months.
Conclusions
In a large, real-world cohort through a mid-term observation period, the EV-ICD safety and efficacy was at least as good for older as it was for younger recipients of the system. These preliminary data indicate that the EV-ICD represents a clinically important option for all adults who are indicated for an ICD and do not require pacing.