The adapted Heart Donor Score

Abstract

The Heart Donor Score (HDS) predicts donor organ discard for medical reasons and survival after heart transplantation (HTX) in the Eurotransplant allocation system. Our aim was to adapt the HDS for application in the United Network for Organ Sharing (UNOS) registry. To adjust for differences between the Eurotransplant and UNOS registries, the "adapted HDS" was created (aHDS) by exclusion of the covariates "valve function," "left-ventricular hypertrophy," and exclusion of "drug abuse" from the variable "compromised history." Two datasets were analyzed to evaluate associations of the aHDS with donor organ discard (n = 70 948) and survival (n = 19 279). The aHDS was significantly associated with donor organ discard [odds ratio 2.72, 95% confidence interval (CI) 2.68-2.76, P < 0.001; c-statistic: 0.937). The score performed comparably in donors <60 and ≥60 years of age. The aHDS was a significant predictor of survival as evaluated by univariate Cox proportional hazards analysis (hazard ratio 1.04, 95% CI 1.01-1.07, P = 0.023), although the association lost significance in a multivariable model. The aHDS predicts donor organ discard. Negative effects of most aHDS components on survival are likely eliminated by highly accurate donor selection processes.

Keywords: Eurotransplant; United Network for Organ Sharing; donor; heart transplantation.

Figure 1

Distribution of the aHDS. The mean aHDS was 3.62 (±1.36) for accepted organs and 8.67 (±2.84) for discarded organs, while the median aHDS values amounted to 3.59 (2.97–4.06) and 8.59 (6.76–11.11), respectively.

Figure 2

Prediction of donor organ discard. The receiver operating characteristic curve of the aHDS is visualized. The area under the receiver operating characteristic curve (c‐statistic) amounts to 0.937.

Figure 3

Donors <60 years of age. In donors <60 years of age, the mean aHDS value was 3.61 (±1.35) for accepted organs and 7.72 (±2.50) for discarded organs, while the median aHDS values amounted to 3.58 (2.97–4.05) and 7.71 (5.88–9.83), respectively.

Figure 4

Donors ≥60 years of age. Donors ≥60 years of age presented with substantially higher aHDS values for both accepted organs (mean: 5.91 ± 1.72; median 5.58, 4.60–6.85) and discarded organs (mean: 11.63 ± 1.46; median: 12.09, 11.13–12.35).

Figure 5

Prediction of Survival after HTX. Kaplan–Meier survival curves of transplanted patients stratified along the median donor aHDS value of 3.53 (2.92–4.00) are visualized. Survival at 1 year after HTX amounted to 88.9% in recipients of a donor with an aHDS value ≥3.53 and 89.9% in those with an aHDS value <3.53 (log‐rank test, P = 0.021).