Derivation and validation of the bridge to transplantation with left ventricular assist device score for 1 year mortality after heart transplantation. The BTT-LVAD score.

Background: To derive and validate a risk score that accurately predicts 1-year mortality after heart transplantation (HT) in patients bridged to transplant (BTT) with a left ventricular assist device (LVAD).
Methods: The UNOS database was queried to identify patients BTT with an LVAD between 2008 and 2018. Patients with ⩾1-year follow up were randomly divided into derivation (70%) and validation (30%) cohorts. The primary endpoint was 1-year mortality. A simple additive risk score was developed based on the odds of 1-year mortality after HT. Risk groups were created, and survival was estimated and compared.
Results: A total of 7759 patients were randomly assigned to derivation ( n  = 5431) and validation ( n  = 2328) cohorts. One-year post-transplant mortality was 9.8% ( n  = 760). A 33-point scoring was created from six recipient variables and two donor variables. Risk groups were classified as low (0-5), intermediate (6-10), and high (>10). In the validation cohort, the predicted 1-year mortality was significantly higher in the high-risk group than the intermediate and low-risk groups, 14.7% versus 9% versus 6.1% respectively (log-rank test: p  < 0.0001).
Conclusion: The BTT-LVAD Score can serve as a clinical decision tool to guide therapeutic decisions in advanced heart failure patients.