Sensitivity analysis of a mathematical model simulating the post-hepatectomy hemodynamics response

Recently a lumped-parameter model of the cardiovascular system was proposed to simulate the hemodynamics response to partial hepatectomy and evaluate the risk of portal hypertension due to this surgery. Model parameters are tuned based on each patient data. This work focuses on a global sensitivity analysis study of such model to better understand the main drivers of the clinical outputs of interest. The analysis suggests which parameters should be considered patient-specific and which can be assumed constant without losing in accuracy in the predictions. While performing the sensitivity analysis, model outputs need to be constrained to physiological ranges. We employ an innovative approach exploiting the features of the polynomial chaos expansion method to reduce the overall computation cost. The computed results give new insights on how to improve the calibration of some model parameters. Moreover the final parameter distributions enable the creation of a virtual population that can be then used in future works. Although this work is focused on partial hepatectomy, the pipeline can be applied to other cardiovascular hemodynamics models to gain insights for patient-specific parameterization and to define a physiologically relevant virtual population.