CI-452769-2 PERFORMANCE OF LEADLESS PACEMAKERS IN EXTENDED FOLLOW-UP: 5 YEAR RESULTS FROM THE MICRA VR TRANSCATHETER PACING SYSTEM POST-APPROVAL REGISTRY

Abstract

Prior reports have demonstrated a favorable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. We report 5-year outcomes of the Micra VR leadless pacemaker from the worldwide post-approval registry (PAR). All Micra VR PAR patients (n=1809) undergoing implant attempt were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 patients implanted with a transvenous pacemaker using Fine-Gray competing risk models. Patients were followed for a median of 48.9 (IQR: 21.6-59.8) months with active patients followed for a median of 59.7 (IQR: 54.2-64.9) months. Median age was 79 (IQR: 71-84) years at implant and patients had multiple comorbidities, including renal dysfunction (21.5%) and heart failure (15.4%). The major complication rate at 60 months was 4.3% (95% CI: 3.4%-5.4%) and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: 0.47, 95% CI: 0.36-0.61; P<0.001; Figure). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (40.2%) or elevated thresholds (28.0%). The most frequent action was to program the device OOO (78.0%), while 10 devices were successfully explanted 2-1442 days post-implant. No infection requiring Micra removal was noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.3% vs 6.6%, P<0.001). Extended performance data of the Micra leadless pacemaker remains in-line with previously reported data with a 53% reduction in major complications through 36-months relative to transvenous pacemakers. The rate of system revisions was low through 5 years and importantly, no infections requiring Micra removal were observed. Performance will continue to be evaluated in this ongoing trial.