Development of a Transplantation Risk Index in Patients With Mechanical Circulatory Support. A Decision Support Tool

Objectives: The aim of this study was to develop a risk index specific to patients on mechanical circulatory support that accurately predicts 1-year mortality after orthotopic heart transplantation using the United Network for Organ Sharing database. Background: Few clinical tools are available to aid in the decision between continuing long-term device support and performing transplantation in patients bridging with mechanical circulatory support. Methods: Using a prospectively collected, open cohort, 6,036 patients receiving mechanical circulatory support who underwent orthotopic heart transplantation between 2000 and 2013 were evaluated and randomly separated into derivation (80%) and validation (20%) groups. Multivariate logistic regression models were constructed using variables that improved the explanatory power of the model, which was determined using multiple methods. Points for a simple additive risk index were apportioned on the basis of relative effect on odds of 1-year mortality. Results: A 75-point scoring system was created from 9 recipient and 4 donor variables. The average score in the validation cohort was 14.4 ± 7.7, and scores ranged from 0 to 57; these values were similar to those in the derivation cohort. Each 1-point increase predicted an 8.3% increase in the odds of 1-year mortality (odds ratio: 1.08; 95% confidence interval: 1.06 to 1.11). Low (0 to 10), intermediate (11 to 20), and high (>20) risk score cohorts were created, with predicted average 1-year mortalities of 8.6%, 12.8%, and 31%, respectively, in the validation cohort. Conclusions: The investigators present a novel, internally cross-validated risk index that accurately predicts mortality in bridge-to-transplantation patients.