Partial cavopulmonary assist from the inferior vena cava to the pulmonary artery improves hemodynamics in failing Fontan circulation: a theoretical analysis

Cavopulmonary assist (CPA) for failing Fontan patients remains a challenging issue in the clinical setting. To evaluate the effectiveness of a partial CPA from the inferior vena cava (IVC) to the pulmonary artery (PA), we performed a theoretical analysis using a computational model of the Fontan circulation. Cardiac chambers and vascular systems were described as the time-varying elastance model and the modified three-element Windkessel model, respectively. A rotational pump described as a non-linear function was inserted between the IVC and the PA. When pulmonary vascular resistance index varied from 2.1 to 5.9 Wood units m², the partial CPA maintained cardiac index as efficiently as total CPA and markedly reduced the IVC pressure compared with total CPA. However, the partial CPA increased the superior vena cava pressure substantially. The modification from total to partial CPA is potentially an effective alternative in failing Fontan patients suffering from high IVC pressure.