Reduced Adverse Events Without Survival Benefit With HeartMate 3 vs. HeartMate II in Japan

HeartMate 3 (Abbott Laboratories), a fully magnetically levitated left ventricular assist device (LVAD), has shown improved hemocompatibility vs. previous devices, but nationwide real-world data in Japan remain limited.

Using the Japanese nationwide registry for Mechanically Assisted Circulatory Support (J-MACS), we analyzed patients who underwent de novo implantation of HeartMate 3 or HeartMate II between 2013 and 2025. The primary outcome was a composite of all-cause death, stroke, and device dysfunction requiring exchange or explantation within 2 years. In all, 978 patients were included in the study (HeartMate 3, n=486; HeartMate II, n=492). The 2-year cumulative incidence of the primary outcome was significantly lower in the HeartMate 3 group than in the HeartMate II group (9% vs. 23%; P<0.001). HeartMate 3 was independently associated with a lower risk of the primary outcome (adjusted hazard ratio 0.35; 95% confidence interval 0.23-0.51; P<0.001), which remained consistent in competing-risk and several statistically matched analyses. The incidence of hemocompatibility-related adverse events, including major bleeding, stroke, and device dysfunction, was significantly lower in the HeartMate 3 group. In contrast, 2- and 5-year overall mortality did not differ significantly between groups (<10% for both devices).

In this nationwide Japanese registry, HeartMate 3 reduced major LVAD-related complications without improving survival, supporting its clinical advantages in contemporary LVAD management.