  Impaired cardiac function has been described as a frequent complication of
COVID-19-related pneumonia. To investigate possible underlying mechanisms, we
represented the cardiovascular system by means of a lumped-parameter 0D
mathematical model. The model was calibrated using clinical data, recorded in
58 patients hospitalized for COVID-19-related pneumonia, to make it
patient-specific and to compute model outputs of clinical interest related to
the cardiocirculatory system. We assessed, for each patient with a successful
calibration, the statistical reliability of model outputs estimating the
uncertainty intervals. Then, we performed a statistical analysis to compare
healthy ranges and mean values (over patients) of reliable model outputs to
determine which were significantly altered in COVID-19-related pneumonia. Our
results showed significant increases in right ventricular systolic pressure,
diastolic and mean pulmonary arterial pressure, and capillary wedge pressure.
Instead, physical quantities related to the systemic circulation were not
significantly altered. Remarkably, statistical analyses made on raw clinical
data, without the support of a mathematical model, were unable to detect the
effects of COVID-19-related pneumonia, thus suggesting that the use of a
calibrated 0D mathematical model to describe the cardiocirculatory system is an
effective tool to investigate the impairments of the cardiocirculatory system
associated with COVID-19.
