Impact of age on patient selection in leadless pacemaker implant: experience with the micra transcatheter pacemaker

Background The safety and efficacy of the Micra AV leadless pacemaker has been demonstrated in the real-world setting. However, whether the patient profile and outcomes differ based upon patient age is not known. Purpose To report age-stratified peri-procedural outcomes and intermediate-term follow-up of patients undergoing Micra implant. Methods Patients (n=801) from the Micra AV Post-Approval Registry were included and divided into age groups: ≤40 (n=40), 41-<65 (n=110), 65-80 (n=332), and >80 (n=319). Baseline characteristics were summarized. A Fine-Gray competing risk model was used to compare risk for major complication through 12 months. Pacing burden and projected longevity were summarized. Results Among 801 included patients, 40 (5.0%) were ≤40 years of age with a mean age of 29.2 ± 6.6 years (range: 16-40) and 60.0% were female. Among patients ≤40, 20.0% had a prior CIED while 27.5% were precluded from transvenous pacing. Patients ≤40 had lower BMI and lower co-morbidity burden compared with older patients. The most common indication for implant was AV block in all age groups, however 35.0% of patients ≤40 had a syncope indication compared to ≤15.5% for older groups. Micra was successfully implanted in 100% of patients ≤40 years. The major complication rate at 12 months was 2.7% in patients ≤40 and did not significantly differ across age groups (P=0.82, Figure). Median pacing percentage was lowest in the ≤40 group (n=17, median= 1.0%) and was highest in the >80 group (n=127, median 88.0%). Median projected longevity across all patients was 10.9 years and was 14.8 years among patients ≤40 with 82.3% having longevity ≥10 years. Conclusion Micra was successfully implanted across a broad range of age groups. Younger patients tended to be healthier and had a low median percentage pacing. The rate of major complications was low and did not differ across age groups.