Effects of systemic ventricular assist combined with fenestration in failing Fontan: A theoretical analysis

Biventricular assist for failing Fontan circulation remains challenging. Because fenestration effectively reduces stressed blood volume and central venous pressure in Fontan patients with increased pulmonary vascular resistance (PVR), systemic ventricular assist device (VAD) combined with fenestration may improve hemodynamics in failing Fontan patients with increased PVR who would require biventricular assist. To validate this hypothesis, we performed a computational hemodynamic simulation of the failing Fontan circulation using a lumped parameter model. We compared hemodynamic variables between the models with and without fenestration while the PVR index was increased sequentially from 3.01 to 6.81 Wood Units m². Following VAD initiation and stressed blood volume reduction, central venous pressure was maintained at a lower level in the fenestration models. This positive effect was greater in the model with larger fenestration diameter. However, excessive fenestration caused significant desaturation. In failing Fontan circulation with elevated PVR, systemic VAD combined with fenestration significantly improved hemodynamics.