Table 1.

Study characteristics of randomized controlled trials and multi- and single-center studies.

Authors	Study Design	Sample Size and Participants	Types of CHD	Key Findings
Loke et al. 2017 [22]	RCT: study group was presented with 3D printed models, while control group with 2D images	35 pediatric residents:18 in study group and 17 in control group	Tetralogy of Fallot (ToF)	3D printed models resulted in significantly higher satisfaction scores than 2D images (p = 0.03). 3D printed models improved residents’ self-efficacy scores in managing ToF, although this did not reach significant difference when compared to 2D images (p = 0.39).
Su et al., 2018 [23]	RCT: study group participated in teaching seminar including 3D printed models, while control group only attended teaching seminar without having 3D models	63 medical students: 32 in study group and 31 in control group	Ventricular septal defect (VSD)	Significant improvement in VSD learning and structure conceptualization in the study group compared to the control group (p < 0.05).
White et al., 2018 [24]	RCT: study group was given 3D printed models in addition to lectures, while control group received only the lectures	60 pediatric residents:31 in study group and 29 in control group	VSD and ToF	3D printed models of CHD improved residents’ knowledge and confidence in managing complex CHD such as ToF but did not seem to improve simple CHD such as VSD.
Olivieri et al., 2016 [26]	Single-center report of 3D printed models for training and simulation	10 3D printed models, 70 clinicians participated in the training sessions	Cardiac and vascular anomalies	3D printed models can be used as a simulation training tool for multidisciplinary intensive care providers by enhancing their anatomic knowledge and clinical management of CHD patients.
Hoashi et al., 2018 [27]	Single-center experience	20 cases	DORV and other cardiac anomalies	3D printed heart models improved understanding of the relationship between intraventricular communications and great vessels. Further, 3D printed models allowed simulation of cardiac surgeries by creating intracardiac pathways, thus providing benefits to inexperienced cardiac surgeons.
Valverde et al., 2017 [21]	Multi-center study consisting of 10 international centers	40 patients with complex CHD	DORV (50%) and other cardiac anomalies	3D models were accurate in replicating anatomy. 3D models refined the surgical approach in nearly 50% cases. 3D models resulted in significant change in the surgical plan in 24% of cases.
Zhao et al., 2018 [28]	Single-center experience	25 patients with 8 in 3D printing group and 17 in control group	DORV	3D printed models showed high accuracy in measurements of aortic diameters and the size of VSD when compared to original CT data. 3D printed models significantly reduced ICU time and mechanical ventilation time (p < 0.05).
Ryan et al., 2018 [29]	Single-center experience	Of 928 cardiothoracic surgeries, 164 3D models were printed for various purposes	DORV, ToF and other cardiac anomalies	3D printed models reduced mean time in the operating room and 30-day readmission and mortality rates when compared to the standard of care.

CHD—congenital heart disease, DORV—double outlet right ventricle, ICU—intensive care unit, RCT—randomized controlled trial.