Potential applications of ultrasound-derived 3D printed ASD
models in ASD occlusion
AS an established alternative to surgical repair, closure surgery of
secundum ASD still remains some challenges. The appropriate device can’t
always be predicted accurately in advance. Replacement of the occluder
occurs occasionally during the operation if the estimated one is too
large or too small. Furthermore, in patients with multiple defects, the
identification of appropriate candidates for closure and the selection
of surgical approach are important. Though single device in the largest
defect to occlude the entire defect remains optimal
strategy25, it is still technically challenging
because of inability to determine the target defect for catheter passage
and occluder selection pre-operation, which highlight the necessity of
comprehensive evaluation of the ASD parameters and preoperative
simulation operation for successful device closure. This study showed a
high correlation between the ASD parameters measured from the 3D printed
ASD models and the size parameters of intraoperative occluders, among
which the circumference of 3D printed models resulted to be most
relevant to the occluder device size. 3D printed ASD models can mimics
the “en face” view for evaluating the morphological characteristics of
an ASD comprehensively and provide reference for determine
individualized plans in ASD occlusion 26.
In this preliminary study, the rubber-like material was used to make the
3D models, it can mimics the deformation of ASD structure after device
implantation well. On this basis, the ASD 3D printed models were
utilized as an intuitive tool for selection of desired occluder during
the experiments in vitro. The device size was adjusted based on the
parameter measured from 3D printed models and changes of morphological
of ASD after the ASO implantation. As a result, the size of ASO selected
according to the simulation operation was consistent with the one that
actually applied in individualized ASD occlusion. In this simulation
operation, if only taking the maximal diameters into consideration, the
devices would be undersized or oversized. Associated with the
correlation analysis results, other parameters as the minimum diameter
and circumference were also taken into account. As a result, the desired
occluders were implanted in the 3D printed models successfully, which
had the same size as the one utilized in actual operation. In biforate
ASD case, the whole size and shape of the two holes were the reference
to the determination of appropriate occlude, the optimal target defect
and device size was selected through several experiments in vitro in the
tangible-patient specific model. The simulation operation indicated that
the 3D printed ASD model based on echocardiography has a great potential
for integration into clinical practice to assist with device selection
and decision-making.