Development and Validation of a Novel Pediatric Mechanical Circulatory Support Risk Stratification Tool: The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) Ventricular Assist Device Score

We sought to develop and validate a new risk stratification score for mortality for children supported with a ventricular assist device (VAD). This retrospective, multicenter study used data from patients undergoing VAD implantation between April 2018 and February 2023 at 44 participating institutions in the Advanced Cardiac Therapies Improving Outcomes (ACTION) network. Multivariable Cox proportional-hazards modeled mortality after VAD implantation. A total of 1,022 patients were enrolled. The 1 year mortality was 19% (95% confidence interval [CI]: 16-23). The multivariable model was used to build the ACTION VADs risk stratification score with four components: ventilation, advanced organ support (dialysis or ECMO), diagnosis, and size (weight ≤5 kg). One point is added for each risk factor. Based on the sum of the risk factors, patients were classified into four classes: class 0-green (4% mortality at 1 year), class 1-yellow (16% mortality at 1 year), class 2-orange (21% mortality at 1 year), and class 3 or higher-red (42% mortality at 1 year). The score performed well, with area under the curve (AUC) of 0.72 and excellent calibration. The ACTION VADs score for mortality can be calculated easily and offers risk stratification and prognostic information for pediatric VAD candidates. This is the first validated risk assessment tool for pediatric mechanical circulatory support.