Researchers test alternative approach to ranking US heart transplant candidates

Editor's Note

The current method for identifying heart transplant candidates with the most urgent need might not be the best one. In a study published February 13 in Jama Network, a candidate risk score incorporating the latest clinical, laboratory, and hemodynamic data out-performed the current treatment-based categorical allocation system.  

The US heart allocation system prioritizes medically urgent candidates with a high risk of dying without transplant. However, the current therapy-based, six-status categorical allocation system “is susceptible to manipulation and has limited rank ordering ability,” the study authors write.

To develop a US candidate risk score (US-CRS) model, the researchers added a predefined set of predictors to the current French Candidate Risk Score (French-CRS) model. “Performance of the US-CRS model, French-CRS model, and 6-status model in the test dataset was evaluated by time-dependent area under the receiver operating characteristic curve (AUC) for death without transplant within 6 weeks and overall survival concordance (c-index) with integrated AUC,” they write.

The registry-based observational study included 16,905 adult heart transplant candidates from the US heart allocation system listed between January 1, 2019, and December 31, 2022. The AUC for death within 6 weeks of listing was 0.79 for the US-CRS model, 0.72 for the French-CRS model, and 0.68 for the 6-status model. Overall c-index was 0.76 for the US-CRS model, 0.69 for the French-CRS model, and 0.67 for the 6-status model.

“A continuous multivariable allocation score outperformed the 6-status system in rank ordering heart transplant candidates by medical urgency and may be useful for the medical urgency component of heart allocation,” the researchers conclude.