Predicting the right! Validation of right heart failure predictive risk models after primary durable ventricular assist device implantation.

OBJECTIVES: Perioperative right heart failure remains a severe complication after durable left ventricular assist device implantation. Accurate preoperative risk assessment is crucial to identify patients requiring advanced medical or mechanical biventricular support. Existing predictive risk models show limited comparability and lack consistent external validation. We aimed to validate commonly used right heart failure risk models using a standardized definition and, as a secondary exploratory analysis, to evaluate a parsimonious Firth-penalized model in our cohort. METHODS: We performed a single-center, retrospective observational study of 105 patients undergoing durable left ventricular assist device implantation from April 2015 to February 2023. Right heart failure was defined according to the Interagency Registry for Mechanically Assisted Circulatory Support definition. Preoperative EUROMACS, Michigan, CRITT, BiVAD, Utah, and a modified Utah score were calculated. The postoperative EUROMACS score, which includes cardiopulmonary bypass time, was analyzed separately as an early perioperative risk marker. Discrimination was assessed using receiver-operating characteristic analysis. The exploratory five-variable Firth model was internally validated by bootstrap optimism correction and calibration analysis. RESULTS: Moderate-severe right heart failure occurred in 21 patients (20.4%). Among established scores, AUC values ranged from 0.394 (Utah) to 0.729 (postoperative EUROMACS). The exploratory five-variable Firth model, including INTERMACS profile, total bilirubin, aspartate aminotransferase, diastolic pulmonary artery pressure, and pulmonary vascular resistance, showed an apparent AUC of 0.854. After 2,000 bootstrap resamples, the optimism-corrected AUC was 0.773, with an optimism-corrected Brier score of 0.149 and calibration slope of 0.586, indicating relevant optimism and potential overfitting. CONCLUSIONS: Established right heart failure risk scores showed limited-to-moderate discrimination in this cohort. Postoperative EUROMACS achieved the highest AUC but should not be interpreted as a purely preoperative prediction tool. The exploratory Firth model identified a potentially informative combination of clinical status, hepatic laboratory markers, and pulmonary hemodynamics, but remains hypothesis-generating and requires external validation before clinical implementation.