Safety of leadless versus transvenous pacemakers in patients with low body surface area: a matched-pair analysis.

BACKGROUND: Leadless pacemakers (LPs) avoid lead- and pocket-related issues but require large venous access, which raises safety concerns in patients with a small body surface area (BSA), particularly in Asian populations. We defined low BSA as < 1.46 m², based on validated 3D-derived anthropometric standards for Chinese adults. OBJECTIVE: To assess procedural complication rates of LP implantation in patients with low BSA. METHODS: We analyzed LP implantations from 2016 to 2025 at a single center in Thailand. Of 59 patients, 25 (42.4%) had low BSA. We conducted two comparisons: (1) low- vs. normal/high-BSA LP patients and (2) low-BSA LP patients with a 1:2 age-, sex-, and BSA-matched transvenous pacemaker (TVP) cohort. The primary outcome was major device-related complications. RESULTS: LP patients were elderly (median 79 years) with high comorbidity (median Charlson Comorbidity Index [CCI], 7.0). In the matched analysis, low-BSA LP patients had a significantly higher comorbidity burden than TVP controls (median CCI, 7.0 vs. 5.0; P = 0.002). The 3.8-year cumulative incidence of major complications did not differ between low- vs. normal/high-BSA LP patients (8.0% vs. 8.8%, P = 0.39) and between low-BSA LP patients vs. matched TVP controls (8.0% vs. 14.0%, P = 0.91). Adjusted analyses revealed no significant association between device type and complications, although the confidence intervals were wide. CONCLUSION: In this exploratory analysis, patients with low-BSA showed no increased risk of major complications following LP implantation. However, given the small sample size and pronounced selection bias, these findings should be interpreted with caution.