Time-dependent risk of post-transplant mortality in patients bridged with HeartMate 3: a UNOS database analysis
B Aboufrekha, O Khayat, A Zayed, H Itani, A Sena, M Amor, D KennethAbstract
Background
Under the 2018 UNOS allocation system, stable HeartMate 3 (HM3) patients often experience prolonged wait times at Status 4. We investigated whether the duration of durable mechanical support independently predicts post-transplant mortality in the contemporary era.
Methods
We analyzed the UNOS registry for adult primary heart transplant recipients bridged with HM3 between October 2018 and September 2025 (n = 2,969). Patients were stratified by support duration (0–6, 6–12 [ref], 12–18, 18–24, and >24 months). The primary endpoint was 1-year post-transplant mortality, adjusted for age, race, BMI, sensitization, PVR, and listing status using a Cox proportional hazards model.
Results
Median support duration was 371 days. Survival was comparable for patients transplanted within 0–18 months. However, a significant survival "cliff" emerged at the 18–24 month window (1-year survival 85.9% vs. 92.5% in reference; p < 0.001). In multivariable analysis, the 18–24 month duration was associated with an 87% increased risk of death (aHR 1.87; 95% CI 1.42–2.46; p < 0.001). This risk exceeded the hazard associated with Status 2 listing (aHR 1.64) and was independent of pre-transplant hemodynamics.
Conclusions
Duration of HM3 support is a robust, independent risk factor for post-transplant mortality. The 18–24 month window represents a period of physiological vulnerability, suggesting "time on device" should be considered a marker of hidden acuity in heart allocation policies.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.