Pacemaker Implantation following Heart Transplantation: Analysis of a Nation-Wide Database

Background: The 2018 United-Network-for-Organ-Sharing (UNOS) allocation-system changes resulted in greater recognition of mechanical circulatory support (MCS), leading to more heart transplantations (HTx) in patients with MCS. We aimed to investigate the effect of the new UNOS allocation system on the need for a permanent pacemaker and associated complications following HTx. Methods: The UNOS Registry was questioned, to identify patients that received HTx in the US between 2000 and 2021. The primary objectives were to identify risk factors for the need for a pacemaker implantation following HTx. Results: 49,529 HTx patients were identified, 1421 (2.9%) requiring a pacemaker post-HTx. Patients who required a pacemaker were older (53.9 +/- 11.5 vs. 52.6 +/- 12.8 years, p < 0.001), more frequently white (73% vs. 67%; p < 0.001) and less frequently black (18% vs. 20%; p < 0.001). In the pacemaker group, UNOS status 1A (46% vs. 41%; p < 0.001) and 1B (31% vs. 27%; p < 0.001) were more prevalent, and donor age was higher (34.4 +/- 12.4 vs. 31.8 +/- 11.5 years; p < 0.001). One-year survival was no different between the groups (HR: 1.08; 95% CI: 0.85, 1.37; p = 0.515). An era effect was observed (per year: OR: 0.97; 95% CI: 0.96, 0.98; p = 0.003), while ECMO pre-transplant was associated with lower risk of a pacemaker (OR: 0.41; 95% CI: 0.19, 0.86; p < 0.001). Conclusions: While associated with various patient and transplant characteristics, pacemaker implantation does not seem to impact one-year survival after HTx. The need for pacemaker implantation was lower in the more recent era and in patients who required ECMO pre-transplant, a finding explained by recent advances in perioperative care.

Automated summary

The changes in the 2018 UNOS allocation system led to an increase in heart transplantations in patients with mechanical circulatory support (MCS). This study aimed to investigate the impact of the new UNOS allocation system on the need for pacemaker implantation and associated complications after heart transplantation. Analysis of the UNOS Registry data showed that 2.9% of heart transplant patients required a pacemaker post-transplantation. There was an era effect and a correlation with pre-transplant ECMO in the need for a pacemaker.