Background
Right ventricular failure (RVF) continues to be a major adverse event following left ventricular assist device (LVAD) implantation. This study investigates the use of a Bayesian statistical model to address the limited predictive capacity of existing risk scores derived from multivariate analyses. This is based on the hypothesis that it is necessary to consider the inter-relationships and conditional probabilities amongst independent variables to achieve sufficient statistical accuracy.
Methods
The data used for this study was derived from 10,909 adult patients from INTERMACS who had a primary LVAD from December 2006 – March 2014. An initial set of 176 pre-implant variables were considered. RVF post-implant was categorized as acute (<48 hours), early (48 hours–14 days) and late (>14 days) in onset. For each of these endpoints, a separate tree-augmented Naïve Bayes model was constructed using the most predictive variables using an open source Bayesian inference engine (SMILE.)
Results
The acute RVF model consisted of 33 variables, including: systolic pulmonary artery pressure (PAP), white blood cell count, left ventricular ejection fraction, cardiac index, sodium levels, and lymphocyte percentage. The early RVF model consisted of 34 variables, including systolic PAP, pre-albumin, LDH, INTERMACS profile, right ventricular ejection fraction, pro-B-type natriuretic peptide, age, heart rate, tricuspid regurgitation and BMI. The late RVF model included 33 variables and was mostly predicted by peripheral vascular resistance, MELD score, albumin, lymphocyte percentage, mean PAP and diastolic PAP. The accuracies of all the Bayesian models were between 91–97%, AUC between 0.83–0.90 sensitivity of 90% and specificity between 98–99%, significantly outperforming previously published risk scores.
Conclusion
A Bayesian prognostic model of RVF, based on the large, multi-center INTERMACS registry provided highly accurate predictions of acute, early, and late RVF based on preoperative variables. These models may facilitate clinical decision-making while screening candidates for LVAD therapy.