Is it time for a cardiac allocation score? First results from the Eurotransplant pilot study on a survival benefit-based heart allocation

BACKGROUND: Patients awaiting heart transplantation in Eurotransplant are prioritized by waiting time and medical urgency. To reduce mortality, the introduction of post-transplant survival in an allocation model based on the concept of survival benefit might be more appropriate. The aim of this study was to assess the prognostic accuracy of the heart failure survival score (HFSS), the Seattle heart failure model (SHFM), the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) model, and the index for mortality prediction after cardiac transplantation (IMPACT) score for predicting mortality.

METHODS: The HFSS, SHFM, the adapted SHFM, and the INTERMACS model were evaluated for predicting waiting list mortality among heart transplant candidates, and the IMPACT score was tested for predicting post-transplant mortality in separate Cox regression models. Included were the 448 adult heart transplant candidates listed for an urgent status between October 2010 and June 2011 in Eurotransplant. A cardiac allocation score (CAS) was calculated based on the estimated survival times as predicted by the scores. All analyses were performed for the total cohort and separately for ventricular assist device (VAD) and non-VAD patients.

RESULTS: Mortality on the waiting list could significantly be predicted in the non-VAD cohort by HFSS (p = 0.005) and SHFM (p < 0.0001) and after transplant by IMPACT (p < 0.0001). None of the tested scores could predict mortality among VAD-supported patients.

CONCLUSIONS: In non-VAD patients, the HFSS, SHFM, and IMPACT provide accurate risk stratification. Further studies will reveal whether these models should be considered as the basis for a new heart allocation policy in Eurotransplant.