First real-world assessment of the extravascular implantable cardioverter-defibrillator: periprocedural outcomes from the Enlighten post-market study and comparison to a pre-market cohort

Implantable cardioverter-defibrillators (ICDs) have been shown to reduce cardiac mortality, although transvenous ICDs cause lead-related complications over time. The extravascular ICD (EV-ICD) system was developed to address the need for a device similar in size to transvenous devices that avoids the vasculature and provides antitachycardia pacing. Pre-market clinical trials have shown the EV-ICD system to provide effective therapy with a low complication rate, but its performance in the real-world is unknown.

Report on the periprocedural safety and performance of the EV-ICD system from the post-market Enlighten study and compare results with a pooled pre-market cohort.

Enlighten is an ongoing, global, prospective, post-market registry study, enrolling patients with a class I or IIa indication for an ICD and a planned implantation of the EV-ICD system. A meta-analysis was performed to compare acute safety and efficacy outcomes between Enlighten patients and the pooled pre-market cohort that included patients from the EV-ICD Pilot, Pivotal, and Continued Access studies. Baseline characteristics, procedural details, defibrillation testing success, and rate of major complications through discharge were analyzed in both cohorts.

From SEP 2023 to JUN 2024 there were 228 Enlighten patients with an implant attempt performed by 81 implanters. For the pre-market studies, there were 370 implant attempts by 59 implanters. Compared to the pooled pre-market cohort, Enlighten patients were significantly younger (49.4 ± 15.4 vs 53.4 ± 13.2; P<0.001), had a higher mean left ventricular ejection fraction (43.5 ± 16.1 vs 39.5 ± 15.8; P=0.004), and had proportionally fewer patients with a cardiomyopathy, coronary artery disease, or hypertension (P<0.001 for all). Tunneling and substernal lead placement were successful in 227/228 (99.6%) Enlighten patients and 369/370 (99.7%) pre-market patients. After electrical testing, 221 (96.9%) and 347 (93.8%) patients remained implanted with the EV-ICD and proceeded to follow-up for Enlighten and pre-market cohorts, respectively. Defibrillation testing, if performed, was successful in 191/193 (99.0%) Enlighten patients compared to 346/354 (97.7%) pre-market patients according to study protocol. The rate of system- or procedure-related major complications at discharge was 3.9% for Enlighten and 2.4% for the pre-market group (P=0.329).

In a global, real-world cohort, the EV-ICD system demonstrated a high rate of success for terminating induced ventricular arrhythmias and a low rate of periprocedural major complications through discharge comparable to the pre-market experience.