Utilization and Impact of Reduced Left Ventricular Ejection Fraction Donors on Outcomes of Heart Transplantation

Z. Whitten. Sollie¹, S. Katragadda², K. Shorbaji³, B. Welch⁴, A. Kilic^5
1Medical University of South Carolina, Wando, South Carolina ²Medical University of South Carolina, Charleston, South Carolina ³Medical University of South Carolina, Mount Pleasant, South Carolina ⁴Medical University of South Carolina (MUSC), Mount Pleasant, South Carolina ⁵MUSC, Charleston, South Carolina

Purpose: Heart transplants (HT) from donors with reduced left ventricular ejection fractions (LVEF) are generally associated with worse outcomes, although changes in practice with increasing utilization of ex-vivo technologies for higher risk donors is unknown. This study aimed to investigate trends and outcomes of HT recipients from donors with LVEF < 50%.

Methods: The United Network for Organ Sharing (UNOS) database was utilized to identify adult (≥ 18 years old) HT recipients between January 2010 and December 2022. Recipients were categorized into two groups based on donor LVEF: LVEF < 50% recipients and LVEF ≥ 50% recipients. The Mann-Kendall trend test was utilized to ascertain the statistical significance of the trend in transplants using donor LVEF < 50% over the study period. Pearson correlation was employed to examine the relationship between the annual center volume and the mean center LVEF. Kaplan-Meier analysis was used to estimate survival probability of LVEF < 50% recipients at 30-days, 1-year, and 5-years. Multivariable Cox regression models were built to measure the effect of donor LVEF on HT recipient mortality at these time intervals.

Results: A total of 30,677 recipients in 119 centers were included with 461 (1.5%) donor LVEF < 50% recipients. The proportion of donor LVEF < 50% recipients remained stable (1.72% in 2010 to 1.60% in 2022 (P=0.127)). Mean donor LVEF at the recipient center-level was 61.62% ± 5.8%. Mean recipient center donor LVEF was negatively correlated with center volume (Cor = -0.093, P= 0.001) [Figure 1]. In unadjusted analysis, HT survival rates were: [(30-days: LVEF < 50%: 95.8% vs LVEF ≥ 50%: 96.6%, log-rank p= 0.380), (1-year: LVEF < 50%: 89.8% vs LVEF ≥ 50%: 91.1%, log-rank p= 0.320), and (5-year: LVEF < 50%: 76.0% vs LVEF ≥ 50%: 78.9%, log-rank p= 0.150)]. After risk adjustment, Hazard Ratios (HR) of mortality for reduced donor LVEF recipients were: [30-days HR: 1.38 (0.86-2.20, p=0.178), 1-year HR: 1.38 (1.02-1.86, p=0.039), and 5-year HR: 1.17 (0.91-1.49, p=0.221)]. Recipients of reduced donor LVEF had similar morbidity rates compared to normal LVEF donors, respectively: [acute rejection: 22.8% vs 19.1%, p=0.057), stroke: (2.9% vs 3.2%, p=0.790), acute renal failure: (14.2% vs 12.5%, p=0.308), and need for pacemaker: (2.0% vs 2.6%, p=0.517)]

Conclusion: Despite acceptable outcomes, utilization of donors with LVEF < 50% remains very low in the US. With the introduction of newer ex-vivo technology that allows for diagnostic assessment of higher risk organs, this potential donor subset may be targeted for improved practice as a means to augment the limited donor supply.

Identify the source of the funding for this research project: There is no dedicated funding allocation for this research project.