Looking Beyond: Long-Term Post-Transplant Outcomes Stratified by STS-PEDIMACS Mechanical Circulatory Support Category

Background The STS-PEDIMACS classifies pediatric MCS as PP, PC, IC, and Percutaneous. While the STS-PEDIMACS provides outcomes of these devices such as bridge to cardiac transplantation, it does not provide long-term outcomes of cardiac transplantation in the transplanted patients. We used the UNOS database to study the long-term outcomes of cardiac transplantation in patients bridged with MCS as per STS-PEDIMACS classification. Methods Pediatric heart transplant recipients (2004–2025) receiving pre-transplant MCS were identified from the OPTN registry and classified according to the STS-PEDIMACS system as PP (n=1,181), PC (n=234), IC (n=660), or percutaneous support (n=57). Waitlist outcomes were additionally evaluated in 1,552 registrations with MCS recorded at listing. Kaplan-Meier, restricted mean survival time (RMST), and multivariable Cox proportional hazards analyses were performed. Results IC and percutaneous recipients were older, whereas PP and PC recipients had greater pre-transplant illness severity. Among recipients with both listing and transplant MCS data available, 95.0% had the same MCS category recorded at listing and transplantation. PC support was associated with higher post-transplant morbidity and the lowest unadjusted survival. RMST analysis demonstrated a significant 5-year survival advantage for IC compared with PP (+3.0 months; p=0.017). On multivariable Cox regression, PC remained independently associated with increased post-transplant mortality compared with PP (HR 1.97, 95% CI 1.19–3.26), whereas IC and percutaneous support demonstrated comparable adjusted risk. Conclusion Post-heart transplant outcomes are largely comparable across pediatric MCS strategies; however, PC support is associated with inferior long-term survival.