Temporary Mechanical Circulatory Support with Axillary IABP or Impella 5.5 Versus Durable LVAD as Bridge to Heart Transplantation: A Strategy-Level Analysis in the Contemporary Allocation Era

Introduction: The 2018 revision of the United Network for Organ Sharing (UNOS) heart allocation system has shifted clinical practice toward increased use of temporary mechanical circulatory support (tMCS) as a bridge to transplantation (BTT). However, comparative outcomes between temporary and durable MCS strategies remain incompletely defined, particularly from a strategy-level perspective. We aim to compare clinical and peri-transplant outcomes between temporary and durable mechanical circulatory support strategies in patients undergoing heart transplantation. Methods: We conducted a single-center retrospective cohort study of consecutive adult patients who underwent orthotopic heart transplantation between October 2018 and October 2020. Patients were categorized according to MCS strategy as temporary (Impella 5.5 or axillary intra-aortic balloon pump) or durable left ventricular assist device (LVAD). Primary outcomes included device-to-transplant time, cardiopulmonary bypass time, and post-transplant ICU length of stay (LOS). Kaplan–Meier analysis and multivariable linear regression were used to evaluate outcomes and predictors. Results: A total of 26 patients were included, of whom 17 (65.4%) received tMCS and 9 (34.6%) durable LVAD support. Temporary MCS was associated with significantly shorter waitlist time (median 27.5–34 vs. 606 days, p = 0.002) and device-to-transplant time (7–13 vs. 572 days, p = 0.001). Kaplan–Meier analysis demonstrated significantly shorter time to transplantation with tMCS (log-rank χ2 = 18.98, p < 0.001). In multivariable analysis, tMCS remained independently associated with shorter device-to-transplant time (B = −495.23; 95% CI −714.38 to −276.08; p = 0.001) and shorter cardiopulmonary bypass time (B = −88.85; 95% CI −126.32 to −51.38; p = 0.001). No statistically significant differences in post-transplant ICU LOS or other early post-transplant outcomes were detected between groups. Conclusions: In this single-center cohort, temporary MCS was associated with significantly shorter time to transplantation and shorter cardiopulmonary bypass times compared with durable LVAD support, while no statistically significant differences in early post-transplant outcomes were detected between groups.