Donor Utilization in the Recent Era: Effect of Sex, Drugs, and Increased Risk

Single-center experience of extended brain-death donor heart preservation with the organ care system

BACKGROUND

The Organ Care System (OCS) (Transmedics, Andover, MA) reduces cold ischemic time of donor hearts by producing a normothermic beating state during ex vivo perfusion, enabling extended ex situ intervals, which potentially increases donor pool. We aimed to compare outcomes in utilization of OCS and conventional cold storage technique.

METHODS

Consecutive heart transplants following brain death at our institution between May 2022 and July 2023 were analyzed. Recipients were divided into those receiving hearts preserved with OCS [N = 15] and those with conventional cold storage (Control, N = 27), with OCS utilization when anticipated ischemic time was more than 4 h. Pre-transplant characteristics and transplant outcomes were compared.

RESULTS

OCS utilization allowed a significant increase in distance traveled for heart retrieval (OCS, 624 ± 269 vs. Control, 153 ± 128 miles, p < 0.001), with longer mean total preservation times (6.2 ± 1.1 vs 2.6 ± 0.6 h, p < 0.001). All but one patient displayed a general decrease or plateau in lactate throughout perfusion time by OCS. Both groups experienced similar rates of severe primary graft dysfunction (OCS, 6.7% [N = 1] vs. Control, 11.1% [N = 3], p = 0.63), with 100% in-hospital survival in the OCS group compared to 96.3% in the Control group (p = 0.34). Kaplan-Meier survival analysis showed that estimated one-year survival were comparable (OCS, 93.3 ± 6.4% vs. Control, 88.9 ± 6.0%, p = 0.61).

CONCLUSION

With a mean preservation time of around 6 h and distance covered of over 600 miles, our results using OCS indicate a potential to safely increase the quantity and viability of accessible organs, thus broadening the donor pool without negatively affecting outcomes.

Machine Perfusion for Recovery of Brain Death Donor Hearts from Extended Distances

The emerging ex vivo machine perfusion (MP) enables the extension of ex situ intervals, potentially expanding the heart transplant (OHT) donor pool. From October 18, 2018, to June 30, 2023, isolated OHT using donation after brain death (DBD) from extended distances (>500 miles) were identified in the United Network for Organ Sharing database, and categorized into cold storage (non-MP, N = 1,212) and MP group (N = 152). The MP utilization rate for DBD hearts from extended distances surged from 0% in 2018 to 27.7% in 2023. Recipient characteristics including listing status were similar except for history of cardiac surgery (non-MP, 32% vs. MP, 41%, p = 0.019). The travel distance was longer in MP group (696 vs. 894 miles, p < 0.001), as was donor organ preservation time (4.42 vs. 6.27 hours, p < 0.001). One-year survival was similar between groups (non-MP, 93.0 ± 0.8% vs. MP, 90.5 ± 2.9%, p = 0.23). In multivariable Cox hazards models, MP was not associated with mortality (hazard ratio, 1.19; p = 0.60). Among MP cohort, survival was comparable between hearts transported between 500-999 miles (N = 112) and those over 1,000 miles (N = 40). The utilization of MP for DBD heart recovery allows for safe DBD recovery from extended distance with comparable survival to cold storage.

Cardiac transplantation with increased-risk donors: Trends and clinical outcomes

BACKGROUND

Orthotopic Heart transplantation (OHT) is a definitive treatment for patients with advanced heart failure. Despite available evidence, recipients and some clinicians remain hesitant to accept organs from Increased Risk Donors (IRD). This study aims to report trends in acceptance of donors from IRD donors and long-term outcomes.

METHODS

This study is an analysis of OHT recipients captured in the United Network of Organ Sharing (UNOS) registry from 2004 to 2021. OHT recipients were dichotomized by IRD status. Primary objectives were to report survival following OHT and trends in IRD use. Secondary objectives included all-cause hospitalizations, hospitalizations for infection, treated rejection, and graft failure.

RESULTS

Of the 36,989 OHT recipients within the study period, 7779 (21%) were identified as recipients of IRD. Recipients of IRD were older (57 years vs 56 years, p ≤0.001), more likely to be African American (23% vs 21%, p = 0.006), blood group O (40% vs 38%, p = 0.02), have public insurance (52% vs 50%, p = 0.02), and have a BMI >30 (30% vs 29%, p = 0.003). IRD recipients had shorter waitlist time (69 days vs 76 days, p = 0.009) and similar long-term survival. IRD recipients also had lower odds of rehospitalization due to infection (OR 0.893, CI 0.842-0.947; p = 0.0002) and lower odds of rehospitalization due to rejection (OR 0.849, CI 0.782-0.921; p ≤0.001).

CONCLUSIONS

In this large multicenter study, we report that recipients of IRD had similar long-term survival and incidence of graft failure as recipients of standard risk donors. Further analysis is needed to understand observed differences in outcomes of hospitalizations for infection and treated rejection.

Longitudinal analysis of social and community factors effective in increasing the number of liver donors in the United States

In this research, it was aimed to evaluate of social and community factors effective in increasing the number of liver donors. Descriptive and relational scanning models were used to conduct the research. Data on liver donors was gathered from the USA Health Resources & Services Administration's Organ Procurement and Transplantation Network between 1988 and 2023. The United States (USA) World Bank Country Reports provided the mortality rates. The data was analyzed using Spearman rho correlation, year-controlled partial correlation, and Generalized Linear Model-Logit analysis. Deceased donor numbers were significantly and negatively correlated with government health expenditure (r = -0.816; P < .01), current health expenditure (r = -0.768; P < .01), female education attainment (r = -0.804; P < .01) and Gini index (r = 0.434; P < .05). Living donor numbers were significantly and negatively correlated with government health expenditure (r = -0.731; P < .01), current health expenditure (r = -0.781; P < .01), male percentage (r = -0.786; P < .01), female education attainment (r = -0.640; P < .05), employment (r = 0.751; P < .01), GDP (r = -0.792; P < .01) and Gini index (r = -0.486; P < .01). Living donor numbers were significantly and positively correlated with age dependency (r = 0.815; P < .01). Generalized Linear Model-Logit (GLM-L) results showed that effect of female education attainment had significant contribution on deceased liver donor (B = -3290.605; P < .01). Effects of significantly correlated community factors on living liver donor numbers were found to be statistically insignificant (P > .05). Research findings reveal that among community factors, especially women's participation in education has a statistically significant effect on liver donors. These results show that the health expenditures made over the years do not provide any added value for liver donors, and role of women on liver donor is significantly dominant.

Donor Pericardial Interleukin and Apolipoprotein Levels May Predict the Outcome after Human Orthotopic Heart Transplantation

The proinflammatory cascade that is activated at the time of brain death plays a crucial role in organ procurement. Our aim of this study was to explore the relationship between the clinical outcome of orthotopic heart transplantation, as well as cytokine and apolipoprotein profiles of the pericardial fluid obtained at donation. Interleukin, adipokine and lipoprotein levels in the pericardial fluid, as well as clinical data of twenty donors after brain death, were investigated. Outcome variables included primary graft dysfunction, the need for posttransplantation mechanical cardiac support and International Society for Heart and Lung Transplantation grade ≥ 2R rejection. Hormone management and donor risk scores were also investigated. Lower levels of IL-6 were observed in primary graft dysfunction (median: 36.72 [IQR: 19.47–62.90] versus 183.67 [41.21–452.56]; p = 0.029) and in the need for mechanical cardiac support (44.12 [20.12–85.70] versus 247.13 [38.51–510.38]; p = 0.043). Rejection was associated with lower ApoAII (p = 0.021), ApoB100 (p = 0.032) and ApoM levels (p = 0.025). Lower adipsin levels were detected in those patients receiving desmopressin (p = 0.037); moreover, lower leptin levels were found in those patients receiving glucocorticoid therapy (p = 0.045), and higher T3 levels were found in those patients treated with L-thyroxine (p = 0.047) compared to those patients not receiving these hormone replacement therapies. IL-5 levels were significantly associated with UNOS-D score (p = 0.004), Heart Donor Score (HDS) and Adapted HDS (p < 0.001). The monitoring of immunological and metabolic changes in donors after brain death may help in the prediction of potential complications after heart transplantation, thus potentially optimizing donor heart allocation.