Differences in wait-list mortality: Temporary vs durable circulatory support devices

Background: In 2018, changes in the United Network for Organ Sharing (UNOS) allocation system led to a shift in practices, making durable left ventricular assist devices less desirable as a bridge to transplantation compared to temporary mechanical circulatory support. This study compares the composite outcome of waitlist mortality and delisting incidence at 1 year between these two support types. Methods: All actively listed adult patients on mechanical circulatory support listed for heart transplantation under the current UNOS system from October 2018 to October 2021 were included, excluding those with right ventricular devices, biventricular devices, total artificial hearts, and extracorporeal membrane oxygenators. The primary outcome was the composite of waitlist mortality and delisting due to clinical deterioration at 1 year. Survival analysis was conducted using Kaplan-Meier curves and multivariable Cox regression. Results: A total of 4,569 patients were included, with 1,877 on temporary mechanical circulatory support and 2,692 on left ventricular assist devices. Propensity-score matching was performed on 660 patients divided into two groups. The event rate was lower in the left ventricular assist device group compared to the temporary mechanical circulatory support group (15.9% vs 35.2%, p < 0.001). Temporary mechanical circulatory support had a significantly higher multivariable hazard ratio (HR) for outcome events (HR 3.37, p < 0.001). The HeartMate 3 (HM3) had the best outcomes compared to all other device types. Conclusion: In this propensity-score-matched analysis, durable mechanical circulatory support had better outcomes than temporary mechanical circulatory support. HM3 had the lowest risk of composite outcomes.