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Page 6 of 11 Tredway et al. Mini-invasive Surg 2020;4:78 I http://dx.doi.org/10.20517/2574-1225.2020.77

Another technically challenging percutaneous intervention that has the potential to be enhanced by
patient-specific 3D printed models is endovascular stenting of the aorta in cases of aortic hypoplasia
or coarctation. Placement of a stent within the aorta can result in many complications including stent
[19]
migration, stroke, and occlusion of head and neck vessels by the stent itself. Valverde et al. presented
a case in which a 3D model of a hypoplastic transverse aortic arch was created that closely mimicked
the distensibility of the native vasculature and its response to stent delivery. In the case described, the
endovascular stenting procedure was simulated on the printed model under fluoroscopic guidance prior
to the percutaneous intervention. This simulation provided the proceduralists the opportunity to devise an
optimal interventional approach, as well as determine the appropriate stent size, length, and position within
[19]
the aorta .
3D printed models have recently been described for use in patients undergoing left atrial appendage (LAA)
closure. Occlusion of the LAA in patients with atrial fibrillation significantly reduces thromboembolic risk
[20]
in those who have contraindications to systemic anticoagulation . Given the variable dimensions and
morphology of the LAA, accurately sizing and positioning an occluder device in the orifice of the LAA
can be challenging. Additionally, implanting a sub-optimally sized device to occlude the orifice can result
in complications such as peri-device leakage, thrombus formation, device migration, and cardiac injury.
[20]
Fan et al. conducted a study assessing the utility of 3D printed models created from 3D trans-esophageal
echocardiography to aid in the selection of an appropriately sized device [Figure 4]. They found that device
sizing based on 3D-printed models was associated with higher implantation success, shorter procedural
[21]
times, and fewer complications. Iriart et al. described their technique of printing the entire left atrium
and atrial septum in addition to the LAA in order to determine the optimal orientation for transseptal
puncture during device placement. They also found that the models are invaluable in training physicians
[21]
and fellows and augmenting communication with patients .

Percutaneous closure of patent ductus arteriosus (PDA) is another intervention that has the potential to
benefit from the use of 3D printed models. Particularly in adult cases, the PDA can be long, tortuous, and
calcified, which makes catheter-based device placement challenging. Matsubara and colleagues presented a
case in which patient-specific 3D printed models were created to detail the precise anatomy of the proximal
[22]
aorta, aortic arch, PDA, and pulmonary artery . These models allowed for selection of a particular device
and exact size. They also allowed the interventionalists to simulate and practice device deployment within
the models themselves, thereby decreasing fluoroscopic and procedural times .
[22]
3D models can be instrumental in decision making to determine feasibility of transcatheter intervention. A
recent case at our center involved a 78-year-old patient with a sinus venosus atrial septal defect with partial
anomalous pulmonary venous return of the right upper pulmonary vein (RUPV) to the superior vena
cava. A 3D model was created from a cardiac CT to demonstrate the relationship between the anomalous
pulmonary venous return, atrial communication, and left atrium for potential use of a covered stent to
reroute the RUPV flow. Although the cross-sectional imaging was helpful in delineating the pulmonary
venous anatomy, the 3D model provided a much clearer picture of the spatial relationship among the
RUPV, superior vena cava, and the left atrium. It was determined that use of a covered stent would result in
occlusion of the RUPV in the position needed to ensure stent stability and avoid embolization. The patient
will undergo surgical intervention for this congenital heart defect.

Finally, We described a case in which a large fistula, arising from the left coronary artery to the right
atrium, was modeled in order to devise an approach for interventional closure [Figure 5A and B]. The
3D printed model enabled the interventionalists to consider several different approaches to transcatheter
closure of the fistula [Figure 6]. Practicing the device closure on the 3D model demonstrated the feasibility
of using a venous approach to access the fistula and provided insight on the optimal device to use for the
[23]
procedure, with the goal of ultimately limiting procedure time and thereby reducing radiation exposure .