The Cleveland Clinic PediPump: anatomic modeling and virtual fitting studies in a lamb model

Implantation of ventricular assist devices (VADs) is challenging in small patients with limited space in the chest. We created three-dimensional models of lambs to facilitate fitting of the PediPump, a pediatric VAD currently under development. Serial computed tomography (CT) scans were acquired at multiple time points (n = 8) for three lambs. Digital models were created using these CT datasets and three-dimensional image processing software (Mimics, Materialise). Pixels representing the heart and chest wall were rendered as three-dimensional models. Using three-dimensional model manipulation software (Magics RP, Materialise), on-screen models of extravascular and intravascular VADs were placed in right, left and biventricular support configurations to determine optimal placement. A cannulation strategy was established and in some cases three-dimensional models of the inflow and outflow grafts were created. After the final CT study, an open-chest fitting study was performed using rapid prototype models of the pediatric VAD and cannulas. The pump location and orientation predictions from the virtual fitting studies matched those determined at the time of the open-chest fitting studies. Using three-dimensional modeling, we have established a fitting protocol that facilitates animal implantations; the same modeling techniques may be useful for device fitting in humans.