3D-Printed Models for Surgical Planning in Complex Congenital Heart Diseases: A Systematic Review

Pathogenesis and Surgical Treatment of Congenitally Corrected Transposition of the Great Arteries (ccTGA): Part III

Congenitally corrected transposition of the great arteries (ccTGA) is an infrequent and complex congenital malformation, which accounts for approximately 0.5% of all congenital heart defects. This defect is characterized by both atrioventricular and ventriculoarterial discordance, with the right atrium connected to the morphological left ventricle (LV), ejecting blood into the pulmonary artery, while the left atrium is connected to the morphological right ventricle (RV), ejecting blood into the aorta. Due to this double discordance, the blood flow is physiologically normal. Most patients have coexisting cardiac abnormalities that require further treatment. Untreated natural course is often associated with progressive failure of the systemic right ventricle (RV), tricuspid valve (TV) regurgitation, arrhythmia, and sudden cardiac death, which occurs in approximately 50% of patients below the age of 40. Some patients do not require surgical intervention, but most undergo physiological repair leaving the right ventricle in the systemic position, anatomical surgery which restores the left ventricle as the systemic ventricle, or univentricular palliation. Various types of anatomic repair have been proposed for the correction of double discordance. They combine an atrial switch (Senning or Mustard procedure) with either an arterial switch operation (ASO) as a double-switch operation or, in the cases of relevant left ventricular outflow tract obstruction (LVOTO) and ventricular septal defect (VSD), intra-ventricular rerouting by a Rastelli procedure. More recently implemented procedures, variations of aortic root translocations such as the Nikaidoh or the half-turned truncal switch/en bloc rotation, improve left ventricular outflow tract (LVOT) geometry and supposedly prevent the recurrence of LVOTO. Anatomic repair for congenitally corrected ccTGA has been shown to enable patients to survive into adulthood.

The Course of the Trochlear Nerve Presented via a 3-Dimensional Photorealistic Anatomic Model

OBJECTIVES

Several factors contribute to the anatomical complexity of the trochlear nerve, including small diameter, complex and longest intracranial course, deep location, and numerous neurovascular relationships. A 3-dimensional (3D) photorealistic model of the cranial nerves provides a detailed and immersive representation of the anatomy, enabling one to improve surgical planning, advanced surgical research, and training. The purpose of this work is to present a 3D photogrammetric study for a more intuitive and interactive way to explore and describe the entire course of trochlear nerve.

METHODS

Two injected-fixed head human specimens (4 sides) were examined. The dissection protocol was divided into the following steps: 1) brain hemisphere exposure; 2) hemispherectomy dissecting all cranial nerves and partial removal of the free edge of the tentorium; 3) middle fossa and lateral wall of cavernous sinus exposure; and 4) orbital exposure. A detailed 3D photogrammetric model was generated for each dissection step.

RESULTS

Four main volumetric models were generated during a step-by-step layered dissection of the entire nerve pathway highlighting its different segments. Finally, a full and integrated model of the entire course of the nerve was created. The models are available for visualization on monoscopic display, virtual, and augmented reality environment.

CONCLUSIONS

The present photogrammetric model provides a more comprehensive understanding of the nerve's anatomy in its different segments, allows for customizable views thus simulating different perspectives, and can be a valuable alternative to traditional dissections. It is an advanced tool for surgical planning and surgical simulation as well as virtual reality representation of the anatomy.

3D-Printed Cardiac Models for Fetal Counseling: A Pilot Study and Novel Approach to Improve Communication

A fetal cardiology consultation involves using two-dimensional drawings to explain the cardiac anatomy which can result in inherent variation in how the congenital heart disease (CHD) is conveyed. In this pilot study, we incorporated three-dimensional printed (3DP) models into fetal counseling to demonstrate feasibility and evaluate the impact on parental knowledge, understanding, and anxiety. Parents with a prenatal diagnosis of a muscular ventricular septal defect (VSD) and/or coarctation of aorta were enrolled. Providers were randomized into a Model or Drawing Group and crossed after six months. Parents completed a survey after the consultation which evaluated knowledge of the CHD lesion, expectant surgical management, self-rated understanding, attitude towards the visualization tool, and anxiety. Twenty-nine patients enrolled over a 12 month period. Twelve consultations were done for coarctation of aorta, 13 for VSD, and four for coarctation with a VSD. Both Model and Drawing groups scored similarly in self-reported understanding and confidence, helpfulness of and improvement in communication with the visualization tool. The Model group had higher scores on questions related to the CHD anatomy and surgical intervention [5 [4-5] versus 4 [3.5-5]], p = 0.23 although this didn't reach statistical significance. For the majority (83%) of consultations, the cardiologist agreed that the 3D model improved communication. In this pilot study, we demonstrate the use of 3DP cardiac models during prenatal CHD counseling is feasible and produces results related to parental understanding and knowledge that are equal to and possibly better than the current standard of care.

Optimized preoperative planning of double outlet right ventricle patients by 3D printing and virtual reality: a pilot study

OBJECTIVES

In complex double outlet right ventricle (DORV) patients, the optimal surgical approach may be difficult to assess based on conventional 2-dimensional (2D) ultrasound (US) and computed tomography (CT) imaging. The aim of this study is to assess the added value of 3-dimensional (3D) printed and 3D virtual reality (3D-VR) models of the heart used for surgical planning in DORV patients, supplementary to the gold standard 2D imaging modalities.

METHODS

Five patients with different DORV subtypes and high-quality CT scans were selected retrospectively. 3D prints and 3D-VR models were created. Twelve congenital cardiac surgeons and paediatric cardiologists, from 3 different hospitals, were shown 2D-CT first, after which they assessed the 3D print and 3D-VR models in random order. After each imaging method, a questionnaire was filled in on the visibility of essential structures and the surgical plan.

RESULTS

Spatial relationships were generally better visualized using 3D methods (3D printing/3D-VR) than in 2D. The feasibility of ventricular septum defect patch closure could be determined best using 3D-VR reconstructions (3D-VR 92%, 3D print 66% and US/CT 46%, P < 0.01). The percentage of proposed surgical plans corresponding to the performed surgical approach was 66% for plans based on US/CT, 78% for plans based on 3D printing and 80% for plans based on 3D-VR visualization.

CONCLUSIONS

This study shows that both 3D printing and 3D-VR have additional value for cardiac surgeons and cardiologists over 2D imaging, because of better visualization of spatial relationships. As a result, the proposed surgical plans based on the 3D visualizations matched the actual performed surgery to a greater extent.

Trends and Challenges in the Development of 3D-Printed Heart Valves and Other Cardiac Implants: A Review of Current Advances

This article provides a comprehensive review of the current trends and challenges in the development of 3D-printed heart valves and other cardiac implants. By providing personalized solutions and pushing the limits of regenerative medicine, 3D printing technology has revolutionized the field of cardiac healthcare. The use of several organic and synthetic polymers in 3D printing heart valves is explored in this article, with emphasis on both their benefits and drawbacks. In cardiac tissue engineering, stem cells are essential, and their potential to lessen immunological rejection and thrombogenic consequences is highlighted. In the clinical applications section, the article emphasizes the importance of 3D printing in preoperative planning. Surgery results are enhanced when surgeons can visualize and assess the size and placement of implants using patient-specific anatomical models. Customized implants that are designed to match the anatomy of a particular patient reduce the likelihood of complications and enhance postoperative results. The development of physiologically active cardiac implants, made possible by 3D bioprinting, shows promise by eliminating the need for artificial valves. In conclusion, this paper highlights cutting-edge research and the promise of 3D-printed cardiac implants to improve patient outcomes and revolutionize cardiac treatment.

Case report: Use of three-dimensional technology in criss-cross heart with double outlet right ventricle

Background

In this case report, we utilized a three-dimensional printing model to replicate the complex anatomy of a criss-cross heart with double outlet right ventricle-an extremely rare congenital cardiac abnormality. This approach facilitated our understanding of the patient's unique condition and enabled us to plan the surgical procedure with greater precision.

Case presentation

Our department received a 13-year-old female patient who presented with a pronounced heart murmur and a decrease in exercise capacity. Subsequent two-dimensional imaging revealed the presence of a criss-cross heart with double outlet right ventricle-an intricate and uncommon cardiac malformation that poses challenges for accurate visualization through conventional two-dimensional modalities. To address this challenge, we constructed and printed a three-dimensional model using computed tomography data, which enabled us to visualize and understand the complex intracardiac structures and plan surgical interventions with greater precision. Using this approach, we successfully performed a right ventricular double outlet repair, and the patient made a full recovery following the procedure.

Conclusion

The criss-cross heart with double outlet right ventricle constitutes a complex and uncommon cardiac anomaly that poses considerable challenges in terms of diagnosis and surgical intervention. Employing three-dimensional modeling and printing represents a promising approach, given its potential to enhance the precision and comprehensiveness of the anatomical evaluation of the heart. As a result, this method holds significant promise in facilitating accurate diagnosis, meticulous surgical planning, and ultimately improving clinical outcomes for patients affected by this condition.

Applications of Three-Dimensional Printing in the Management of Complex Aortic Diseases

The use of three-dimensional (3D) printing is gaining considerable success in many medical fields, including surgery; however, the spread of this innovation in cardiac and vascular surgery is still limited. This article reports our pilot experience with this technology, applied as an additional tool for 20 patients treated for complex vascular or cardiac surgical diseases. We have analyzed the feasibility of a "3D printing and aortic diseases project," which helps to obtain a more complete approach to these conditions. 3D models have been used as a resource to improve preoperative planning and simulation, both for open and endovascular procedures; furthermore, real 3D aortic models were used to develop doctor-patients communication, allowing better knowledge and awareness of their disease and of the planned surgical procedure. A 3D printing project seems feasible and applicable as an adjunctive tool in the diagnostic-therapeutic path of complex aortic diseases, with the need for future studies to verify the results.

Three-dimensional printing and virtual reconstruction in surgical planning of double-outlet right ventricle repair

Objectives

For more than a decade, 3-dimensional (3D) printing has been identified as an innovative tool for the surgical planning of double-outlet right ventricle (DORV). Nevertheless, lack of evidence concerning its benefits encourages us to identify valuable criteria for future prospective trials.

Methods

We conducted a retrospective study involving 10 patients with DORV operated between 2015 and 2019 in our center. During a preoperative multidisciplinary heart team meeting, we harvested surgical decisions following a 3-increment step process: (1) multimodal imaging; (2) 3D virtual valvular reconstruction (3DVVR); and (3) 3D-printed heart model (3DPHM). The primary outcome was the proportion of predicted surgical strategy following each of the 3 steps, compared with the institutional retrospective surgical strategy. The secondary outcome was the change of surgical strategy through 3D modalities compared with multimodal imaging. The incremental benefit of the 3DVVR and 3DPHM over multimodal imaging was then assessed.

Results

The operative strategy was predicted in 5 cases after multimodal imaging, in 9 cases after 3DVVR, and the 10 cases after 3DPHM. Compared with multimodal imaging, 3DVVR modified the strategy for 4 cases. One case was correctly predicted only after 3DPHM inspection.

Conclusions

3DVVR and 3DPHM improved multimodal imaging in the surgical planning of patients with DORV. 3DVVR allowed a better appreciation of the relationships between great vessels, valves, and ventricular septal defects. 3DPHM offers a realistic preoperative view at patient scale and enhances the evaluation of outflow tract obstruction. Our retrospective study demonstrates benefits of preoperative 3D modalities and supports future prospective trials to assess their impact on postoperative outcomes.

In vivo visualization and molecular targeting of the cardiac conduction system

Accidental injury to the cardiac conduction system (CCS), a network of specialized cells embedded within the heart and indistinguishable from the surrounding heart muscle tissue, is a major complication in cardiac surgeries. Here, we addressed this unmet need by engineering targeted antibody-dye conjugates directed against the CCS, allowing for the visualization of the CCS in vivo following a single intravenous injection in mice. These optical imaging tools showed high sensitivity, specificity, and resolution, with no adverse effects on CCS function. Further, with the goal of creating a viable prototype for human use, we generated a fully human monoclonal Fab that similarly targets the CCS with high specificity. We demonstrate that, when conjugated to an alternative cargo, this Fab can also be used to modulate CCS biology in vivo, providing a proof of principle for targeted cardiac therapeutics. Finally, in performing differential gene expression analyses of the entire murine CCS at single-cell resolution, we uncovered and validated a suite of additional cell surface markers that can be used to molecularly target the distinct subcomponents of the CCS, each prone to distinct life-threatening arrhythmias. These findings lay the foundation for translational approaches targeting the CCS for visualization and therapy in cardiothoracic surgery, cardiac imaging, and arrhythmia management.

Invited commentary for: Essential role of cardiac computed tomography for surgical decision making in children with total anomalous pulmonary venous connection and single ventricle

Thousands of neonates are born each year with complex congenital heart defects, such as total anomalous pulmonary venous connection combined with single ventricle physiology. This dual diagnosis with significant vessel and ventricular complexity requires alternative additional imaging to fully visualize the anatomical challenge and devise the appropriate treatment strategy for the patient.

3D-printed heart models for hands-on training in pediatric cardiology - the future of modern learning and teaching?

BACKGROUND

This project aims to develop a new concept in training pediatric cardiologists to meet the requirements of interventional cardiac catheterizations today in terms of complexity and importance. This newly developed hands-on training program is supposed to enable the acquisition of certain skills which are necessary when investigating and treating patients in a catheter laboratory.

METHODS

Based on anonymous CT-scans of pediatric patients' digital 3D heart models with or without cardiac defects were developed and printed three-dimensionally in a flexible material visible under X-ray. Hands-on training courses were offered using models of a healthy heart and the most common congenital heart defects (CHD). An evaluation was performed by quantifying fluoroscopy times (FL-time) and a questionnaire.

RESULTS

The acceptance of theoretical and practical contents within the hands-on training was very positive. It was demonstrated that it is possible to master various steps of a diagnostic procedure and an intervention as well as to practice and repeat them independently which significantly reduced FL-time. The participants stated that the hands-on training led to more confidence in interventions on real patients.

CONCLUSION

With the development of a training module using 3D-printed heart models, basic and advanced training in the field of diagnostic cardiac examinations as well as interventional therapies of CHD is possible. The learning effect for both, practical skills and theoretical understanding, was significant which underlines the importance of integrating such hands-on trainings on 3D heart models in education and practical training.

Virtual Reality in the Preoperative Planning of Adult Aortic Surgery: A Feasibility Study

Background: Complex aortic anatomy needs careful preoperative planning in which a patient-tailored approach with novel immersive techniques could serve as a valuable addition to current preoperative imaging. This pilot study aimed to investigate the technical feasibility of virtual reality (VR) as an additional imaging tool for preoperative planning in ascending aortic surgery. Methods: Ten cardiothoracic surgeons were presented with six patients who had each undergone a recent repair of the ascending aorta. Two-dimensional computed tomography images of each patient were assessed prior to the VR session. After three-dimensional (3D) VR rendering and 3D segmentation of the ascending aorta and aortic arch, the reconstructions were analyzed by each surgeon in VR via a head-mounted display. Each cardiothoracic surgeon completed a questionnaire after each planning procedure. The results of their assessments were compared to the performed operations. The primary endpoint of the present study was a change of surgical approach from open to clamped distal anastomosis, and vice versa. Results: Compared with conventional imaging, 80% of surgeons found that VR prepared them better for surgery. In 33% of cases (two out of six), the preoperative decision was adjusted due to the 3D VR-based evaluation of the anatomy. Surgeons rated CardioVR usefulness, user-friendliness, and satisfaction with median scores of 3.8 (IQR: 3.5-4.1), 4.2 (IQR: 3.8-4.6,) and 4.1 (IQR: 3.8-4.7) on a five-point Likert scale, respectively. Conclusions: Three-dimensional VR imaging was associated with improved anatomical understanding among surgeons and could be helpful in the future preoperative planning of ascending aortic surgery.

Three-dimensional printed moulds to obtain silicone hearts with congenital defects for paediatric heart-surgeon training

OBJECTIVES

Many types of congenital heart disease are amenable to surgical repair or palliation. The procedures are often challenging and require specific surgical training, with limited real-life exposure and often costly simulation options. Our objective was to create realistic and affordable 3D simulation models of the heart and vessels to improve training.

METHODS

We created moulded vessel models using several materials, to identify the material that best replicated human vascular tissue. This material was then used to make more vessels to train residents in cannulation procedures. Magnetic resonance imaging views of a 23-month-old patient with double-outlet right ventricle were segmented using free open-source software. Re-usable moulds produced by 3D printing served to create a silicone model of the heart, with the same material as the vessels, which was used by a heart surgeon to simulate a Rastelli procedure.

RESULTS

The best material was a soft elastic silicone (Shore A hardness 8). Training on the vessel models decreased the residents' procedural time and improved their grades on a performance rating scale. The surgeon evaluated the moulded heart model as realistic and was able to perform the Rastelli procedure on it. Even if the valves were poorly represented, it was found to be useful for preintervention training.

CONCLUSIONS

By using free segmentation software, a relatively low-cost silicone and a technique based on re-usable moulds, the cost of obtaining heart models suitable for training in congenital heart defect surgery can be substantially decreased.

Feasibility and accuracy of printed models of complex cardiac defects in small infants from cardiac computed tomography

BACKGROUND

Three-dimensional (3-D) printed models are increasingly used to enhance understanding of complex anatomy in congenital heart disease.

OBJECTIVE

To assess feasibility and accuracy of 3-D printed models obtained from cardiac CT scans in young children with complex congenital heart diseases.

MATERIALS AND METHODS

We included children with conotruncal heart anomalies who were younger than 2 years and had a cardiac CT scan in the course of their follow-up. We used cardiac CT scan datasets to generate 3-D models. To assess the models' accuracy, we compared four diameters for each child between the CT images and the printed models, including the largest diameters (D_max) of ventricular septal defects and aortic annulus and their minimal diameters (D_min).

RESULTS

We obtained images from 14 children with a mean age of 5.5 months (range 1-24 months) and a mean weight of 6.7 kg (range 3.4-14.5 kg). We generated 3-D models for all children. Mean measurement difference between CT images and 3-D models was 0.13 mm for D_min and 0.12 mm for D_max for ventricular septal defect diameters, and it was 0.16 mm for D_min and -0.13 mm for D_max for aortic annulus diameter, indicating a non-clinically significant difference.

CONCLUSION

Three-dimensional printed models could be feasibly generated from cardiac CT scans in a small pediatric population with complex congenital heart diseases. This technique is highly accurate and reliably reflects the same structural dimensions when compared to CT source images.

Use of rotational angiography in congenital cardiac catheterisations to generate three-dimensional-printed models

BACKGROUND

Three-dimensional printing is increasingly utilised for congenital heart defect procedural planning. CT or MR datasets are typically used for printing, but similar datasets can be obtained from three-dimensional rotational angiography. We sought to assess the feasibility and accuracy of printing three-dimensional models of CHD from rotational angiography datasets.

METHODS

Retrospective review of CHD catheterisations using rotational angiography was performed, and patient and procedural details were collected. Imaging data from rotational angiography were segmented, cleaned, and printed with polylactic acid on a Dremel® 3D Idea Builder (Dremel, Mount Prospect, IL, USA). Printing time and materials' costs were captured. CT scans of printed models were compared objectively to the original virtual models. Two independent, non-interventional paediatric cardiologists provided subjective ratings of the quality and accuracy of the printed models.

RESULTS

Rotational angiography data from 15 catheterisations on vascular structures were printed. Median print time was 3.83 hours, and material costs were $2.84. The CT scans of the printed models highly matched with the original digital models (root mean square for Hausdorff distance 0.013 ± 0.003 mesh units). Independent reviewers correctly described 80 and 87% of the models (p = 0.334) and reported high quality and accuracy (5 versus 5, p = NS; κ = 0.615).

CONCLUSION

Imaging data from rotational angiography can be converted into accurate three-dimensional-printed models of CHD. The cost of printing the models was negligible, but the print time was prohibitive for real-time use. As the speed of three-dimensional printing technology increases, novel future applications may allow for printing patient-specific devices based on rotational angiography datasets.

3D Printing-A Cutting Edge Technology for Treating Post-Infarction Patients

The increasing complexity of cardiovascular interventions requires advanced peri-procedural imaging and tailored treatment. Three-dimensional printing technology represents one of the most significant advances in the field of cardiac imaging, interventional cardiology or cardiovascular surgery. Patient-specific models may provide substantial information on intervention planning in complex cardiovascular diseases, and volumetric medical imaging from CT or MRI can be translated into patient-specific 3D models using advanced post-processing applications. 3D printing and additive manufacturing have a great variety of clinical applications targeting anatomy, implants and devices, assisting optimal interventional treatment and post-interventional evaluation. Although the 3D printing technology still lacks scientific evidence, its benefits have been shown in structural heart diseases as well as for treatment of complex arrhythmias and corrective surgery interventions. Recent development has enabled transformation of conventional 3D printing into complex 3D functional living tissues contributing to regenerative medicine through engineered bionic materials such hydrogels, cell suspensions or matrix components. This review aims to present the most recent clinical applications of 3D printing in cardiovascular medicine, highlighting also the potential for future development of this revolutionary technology in the medical field.

Evaluation of 3D-printer settings for producing personal protective equipment

Aim: COVID-19 resulted in a shortage of personal protective equipment. Community members united to 3D-print face shield headbands to support local healthcare workers. This study examined factors altering print time and strength. Materials & methods: Combinations of infill density (50%, 100%), shell thickness (0.8, 1.2 mm), line width (0.2 mm, 0.4 mm), and layer height (0.1 mm, 0.2 mm) were evaluated through tensile testing, finite element analysis, and printing time. Results: Strength increased with increased infill (p < 0.001) and shell thickness (p < 0.001). Layer height had no effect on strength. Increasing line width increased strength (p < 0.001). Discussion: Increasing layer height and line width decreased print time by 50 and 39%, respectively. Increased shell thickness did not alter print time. These changes are recommended for printing.

A three-dimensional printed model in preoperative consent for ventricular septal defect repair

Background

The 3D printing technology in congenital cardiac surgery has been widely utilized to improve patients’ understanding of their disease. However, there has been no randomized controlled study on its usefulness in surgical consent for congenital heart disease repair.

Methods

A randomized controlled study was performed during consent process in which guardians of candidates for ventricular septal defect repair were given detailed explanation of the anatomy, indication for surgery and potential complication and risks using 3D print ventricular septal defect model (n = 20) versus a conventional 2D diagram (n = 20). A questionnaire was finished by each guardian of the patients. Data collected from questionnaires as well as medical records were statistically analyzed.

Results

Statistically significant improvements in ratings of understanding of ventricular septal defect anatomy (p = 0.02), and of the surgical procedure and potential complications (p = 0.02) were noted in the group that used the 3D model, though there was no difference in overall ratings of the consent process (p = 0.09). There was no difference in questionnaire score between subjects with different education levels. The clinical outcomes, as represented by the duration of intensive care unit stay, intubation duration was comparable between the two groups.

Conclusions

The results indicated that it was an effective tool which may be used to consent for congenital heart surgery. Different education levels do not affect guardians’ understanding in consent. The impact of 3D printing used in this scenario on long term outcomes remains to be defined.

3D Printing in Modern Cardiology

BACKGROUND

3D printing represents an emerging technology in the field of cardiovascular medicine. 3D printing can help to perform a better analysis of complex anatomies to optimize intervention planning.

METHODS

A systematic review was performed to illustrate the 3D printing technology and to describe the workflow to obtain 3D printed models from patient-specific images. Examples from our laboratory of the benefit of 3D printing in planning interventions were also reported.

RESULTS

3D printing technique is reliable when applied to high-quality 3D image data (CTA, CMR, 3D echography), but it still needs the involvement of expert operators for image segmentation and mesh refinement. 3D printed models could be useful in interventional planning, although prospective studies with comprehensive and clinically meaningful endpoints are required to demonstrate the clinical utility.

CONCLUSION

3D printing can be used to improve anatomy understanding and surgical planning.

Single-center experience with routine clinical use of 3D technologies in surgical planning for pediatric patients with complex congenital heart disease

PURPOSE

This study was planned to assess the application of three-dimensional (3D) cardiac modeling in preoperative evaluation for complex congenital heart surgeries.

METHODS

From July 2015 to September 2019, 18 children diagnosed with complex congenital heart diseases (CHDs) were enrolled in this study (double outlet right ventricle in nine patients, complex types of transposition of the great arteries in six patients, congenitally corrected transposition of the great arteries in two patients, and univentricular heart in one patient). The patients' age ranged from 7 months to 19 years (median age, 14 months). Before the operation, 3D patient-specific cardiac models were created based on computed tomography (CT) data. Using each patient's data, a virtual computer model (3D mesh) and stereolithographic (SLA) file that would be printed as a 3D model were generated. These 3D cardiac models were used to gather additional data about cardiac anatomy for presurgical decision-making.

RESULTS

All 18 patients successfully underwent surgeries, and there were no mortalities. The 3D patient-specific cardiac models led to a change from the initial surgical plans in 6 of 18 cases (33%), and biventricular repair was considered feasible. Moreover, the models helped to modify the planned biventricular repair in five cases, for left ventricular outflow tract obstruction removal and ventricular septal defect enlargement. 3D cardiac models enable pediatric cardiologists to better understand the spatial relationships between the ventricular septal defect and great vessels, and they help surgeons identify risk structures more clearly for detailed planning of surgery. There was a strong correlation between the models of the patients and the anatomy encountered during the operation.

CONCLUSION

3D cardiac models accurately reveal the patient's anatomy in detail and are therefore beneficial for planning surgery in patients with complex intracardiac anatomy.

Virtual reality three-dimensional echocardiographic imaging for planning surgical atrioventricular valve repair

OBJECTIVES

To investigate how virtual reality (VR) imaging impacts decision-making in atrioventricular valve surgery.

METHODS

This was a single-center retrospective study involving 15 children and adolescents, median age 6 years (range, 0.33-16) requiring surgical repair of the atrioventricular valves between the years 2016 and 2019. The patients' preoperative 3-dimesnional (3D) echocardiographic data were used to create 3D visualization in a VR application. Five pediatric cardiothoracic surgeons completed a questionnaire formulated to compare their surgical decisions regarding the cases after reviewing conventionally presented 2-dimesnional and 3D echocardiographic images and again after visualization of 3D echocardiograms using the VR platform. Finally, intraoperative findings were shared with surgeons to confirm assessment of the pathology.

RESULTS

In 67% of cases presented with VR, surgeons reported having "more" or "much more" confidence in their understanding of each patient's pathology and their surgical approach. In all but one case, surgeons were at least as confident after reviewing the VR compared with standard imaging. The case where surgeons reported to be least confident on VR had the worst technical quality of data used. After viewing patient cases on VR, surgeons reported that they would have made minor modifications to surgical approach in 53% and major modifications in 7% of cases.

CONCLUSIONS

The main impact of viewing imaging on VR is the improved clarity of the anatomical structures. Surgeons reported that this would have impacted the surgical approach in the majority of cases. Poor-quality 3D echocardiographic data were associated with a negative impact of VR visualization; thus. quality assessment of imaging is necessary before projecting in a VR format.

Computed Tomography-Derived 3D Modeling to Guide Sizing and Planning of Transcatheter Mitral Valve Interventions

A plethora of catheter-based strategies have been developed to treat mitral valve disease. Evolving 3-dimensional (3D) multidetector computed tomography (MDCT) technology can accurately reconstruct the mitral valve by means of 3-dimensional computational modeling (3DCM) to allow virtual implantation of catheter-based devices. 3D printing complements computational modeling and offers implanting physician teams the opportunity to evaluate devices in life-size replicas of patient-specific cardiac anatomy. MDCT-derived 3D computational and 3D-printed modeling provides unprecedented insights to facilitate hands-on procedural planning, device training, and retrospective procedural evaluation. This overview summarizes current concepts and provides insight into the application of MDCT-derived 3DCM and 3D printing for the planning of transcatheter mitral valve replacement and closure of paravalvular leaks. Additionally, future directions in the development of 3DCM will be discussed.

[Impact of 3D printing in surgical planning of congenital heart disease]

Introducción

Los defectos cardíacos congénitos constituyen el 30% de todas las anomalías congénitas. La prevalencia es de 8/1,000 recién nacidos vivos, sin predominio de género. Para una planificación quirúrgica óptima es esencial una evaluación precisa de la anatomía en los defectos cardíacos congénitos. Las modalidades de imagen como el ecocardiograma, la angiografía por cateterismo cardíaco, la tomografía computarizada (TC) o la resonancia magnética (RM) se utilizan de forma regular para el diagnóstico de las cardiopatías congénitas. Estos métodos pueden proporcionar reconstrucciones virtuales en reconstrucción volumétrica o 3D, pero no réplicas táctiles reales de la anatomía cardíaca.

Objetivo

Realizar modelos de corazón impresos en 3D con la finalidad de proporcionar réplicas táctiles 3D reales de la anatomía cardíaca para visualizar de forma detallada todas las perspectivas posibles de las estructuras extracardíacas o intracardíacas.

Métodos

Los datos de la imagen se obtuvieron en formato DICOM, se editaron en el paquete de software "3D slicer 4.3" y se exportaron para la impresión en formato de archivo (.stl).

Resultados y conclusiones

Con la impresión 3D se puede evaluar de forma detallada la anatomía intracardíaca y extracardíaca con modelos cardíacos en tiempo real. Esta técnica es de gran utilidad, sobre todo en los defectos cardíacos congénitos complejos, ya que permite hacer una planificación precisa del procedimiento quirúrgico.

Introduction

Congenital heart disease makes up for 30% of all congenital anomalies. The prevalence is 8/1,000 live newborns, without predominance of gender. Imaging methods such as echocardiography, angiography, computed tomography or magnetic resonance imaging must be routinely used in congenital heart disease. The mentioned methods can provide virtual reconstructions in volumetric reconstruction or in three dimensional (3D), but only 3D-printed heart models can provide real 3D tactile replicas of cardiac anatomy.

Objective

To make 3D printed heart models in order to provide real 3D tactile replicas of the cardiac anatomy that allow a detailed visualization from all possible perspectives, either of extracardiac or intracardiac structures.

Methods

This information is useful for surgical decision making, especially in patients with complex cardiac defects. DICOM, edited in a software package “3D slicer 4.3” and exported for printing in file format (.stl).

Results and conclusions

With 3D printing, the intracardiac and extracardiac anatomy can be evaluated in detail with real-scale cardiac models of the patient, avoiding unexpected findings. This technique is very useful especially in complex congenital heart defects, since it allows precise planning of the surgical procedure.

Quantitative Assessment of 3D Printed Model Accuracy in Delineating Congenital Heart Disease

Background: Three-dimensional (3D) printing is promising in medical applications, especially presurgical planning and the simulation of congenital heart disease (CHD). Thus, it is clinically important to generate highly accurate 3D-printed models in replicating cardiac anatomy and defects. The present study aimed to investigate the accuracy of the 3D-printed CHD model by comparing them with computed tomography (CT) images and standard tessellation language (STL) files. Methods: Three models were printed, comprising different CHD pathologies, including the tetralogy of Fallot (ToF), ventricular septal defect (VSD) and double-outlet right-ventricle (DORV). The ten anatomical locations were measured in each comparison. Pearson’s correlation coefficient, Bland–Altman analysis and intra-class correlation coefficient (ICC) determined the model accuracy. Results: All measurements with three printed models showed a strong correlation (r = 0.99) and excellent reliability (ICC = 0.97) when compared to original CT images, CT images of the 3D-printed models, STL files and 3D-printed CHD models. Conclusion: This study demonstrated the high accuracy of 3D-printed heart models with excellent correlation and reliability when compared to multiple source data. Further investigation into 3D printing in CHD should focus on the clinical value and the benefits to patients.

Cinematic Rendering in Mixed-Reality Holograms: A New 3D Preoperative Planning Tool in Pediatric Heart Surgery

Cinematic rendering (CR) is based on a new algorithm that creates a photo-realistic three-dimensional (3D) picture from cross-sectional images. Previous studies have shown its positive impact on preoperative planning. To date, CR presentation has only been possible on 2D screens which limited natural 3D perception. To depict CR-hearts spatially, we used mixed-reality technology and mapped corresponding hearts as holograms in 3D space. Our aim was to assess the benefits of CR-holograms in the preoperative planning of cardiac surgery. Including 3D prints allowed a direct comparison of two spatially resolved display methods. Twenty-six patients were recruited between February and September 2019. CT or MRI was used to visualize the patient's heart preoperatively. The surgeon was shown the anatomy in cross-sections on a 2D screen, followed by spatial representations as a 3D print and as a high-resolution hologram. The holographic representation was carried out using mixed-reality glasses (HoloLens®). To create the 3D prints, corresponding structures were segmented to create STL files which were printed out of resin. In 22 questions, divided in 5 categories (3D-imaging effect, representation of pathology, structure resolution, cost/benefit ratio, influence on surgery), the surgeons compared each spatial representation with the 2D method, using a five-level Likert scale. The surgical preparation time was assessed by comparing retrospectively matched patient pairs, using a paired t-test. CR-holograms surpassed 2D-monitor imaging in all categories. CR-holograms were superior to 3D prints in all categories (mean Likert scale 4.4 ± 1.0 vs. 3.7 ± 1.3, P < 0.05). Compared to 3D prints it especially improved the depth perception (4.7 ± 0.7 vs. 3.7 ± 1.2) and the representation of the pathology (4.4 ± 0.9 vs. 3.6 ± 1.2). 3D imaging reduced the intraoperative preparation time (n = 24, 59 ± 23 min vs. 73 ± 43 min, P < 0.05). In conclusion, the combination of an extremely photo-realistic presentation via cinematic rendering and the spatial presentation in 3D space via mixed-reality technology allows a previously unattained level of comprehension of anatomy and pathology in preoperative planning.

3D Modeling and Printing in Congenital Heart Surgery: Entering the Stage of Maturation

3D printing allows the most realistic perception of the surgical anatomy of congenital heart diseases without the requirement of physical devices such as a computer screen or virtual headset. It is useful for surgical decision making and simulation, hands-on surgical training (HOST) and cardiovascular morphology teaching. 3D-printed models allow easy understanding of surgical morphology and preoperative surgical simulation. The most common indications for its clinical use include complex forms of double outlet right ventricle and transposition of the great arteries, anomalous systemic and pulmonary venous connections, and heterotaxy. Its utility in congenital heart surgery is indisputable, although it is hard to "scientifically" prove the impact of its use in surgery because of many confounding factors that contribute to the surgical outcome. 3D-printed models are valuable resources for morphology teaching. Educational models can be produced for almost all different variations of congenital heart diseases, and replicated in any number. HOST using 3D-printed models enables efficient education of surgeons in-training. Implementation of the HOST courses in congenital heart surgical training programs is not an option but an absolute necessity. In conclusion, 3D printing is entering the stage of maturation in its use for congenital heart surgery. It is now time for imagers and surgeons to find how to effectively utilize 3D printing and how to improve the quality of the products for improved patient outcomes and impact of education and training.

Three-Dimensional Printed Model Fabrication and Effectiveness Evaluation in Fetuses With Congenital Heart Disease or With a Normal Heart

OBJECTIVES

The purpose of this study was to investigate the technical feasibility and accuracy of applying 3-dimensional (3D) printing of normal and abnormal fetal hearts based on spatiotemporal image correlation (STIC) volume-rendered data.

METHODS

Spatiotemporal image correlation volume images of 15 healthy fetuses and 15 fetuses with cardiac abnormalities were collected, and Mimics software (Materialise NV, Leuven, Belgium) was used to postprocess the volume data to obtain a 3D digital model of fetal heart and large blood vessel morphologic characteristics and to output the file to a 3D printer for printing the 3D model of the fetal heart and large blood vessels. The effect accuracy of the 3D printed model was qualitatively evaluated by showing the 3D anatomic structure of the model combined with echocardiographic or autopsy results, and the dimensional accuracy of the 3D printed model was quantitatively evaluated by comparing the measured data of the model and echocardiography.

RESULTS

In all 30 fetuses, STIC volume data of the fetal heart were successfully reprocessed and printed out, which could visually display the morphologic characteristics of the fetal heart chamber and passage of the great vessels under normal and abnormal pathologic conditions. No significant differences in all of the heart size parameters were found between the 3D digital model, 3D printed model, and routine echocardiographic images (all P > .05). Moreover, the size parameters were concordant well between the methods, and all of the data points fell within the limits of agreement.

CONCLUSIONS

It is feasible to 3D print the fetal heart using STIC volumetric images as the data source, and the 3D printed model can fully and accurately display abnormal anatomic structures of the heart.

Three-step preoperative sequential planning for pulmonary valve replacement in repaired tetralogy of Fallot using computed tomography

OBJECTIVES

Our goal was to compare results between a standard computed tomography (CT)-based strategy, the 'three-step preoperative sequential planning' (3-step PSP), for pulmonary valve replacement in repaired tetralogy of Fallot versus a conventional planning approach.

METHODS

We carried out a retrospective study with unmatched and matched groups. The 3-step PSP comprised the planning of mediastinal re-entry, cannulation for cardiopulmonary bypass (CPB) and the main procedure, using standard 3-dimensional videos. Operative times (skin incision to CPB, CPB time, end of CPB to skin closure and cross-clamp time) as well as postoperative length of stay and in-hospital mortality were compared.

RESULTS

Eighty-two patients (49% classical tetralogy of Fallot) underwent an operation (85% with pulmonary homograft) with 1.22% in-hospital mortality. The 3-step PSP (n = 14) and the conventional planning (n = 68) groups were compared. There were no statistically significant differences in the preoperative characteristics. Differences were observed in the total operative time (P = 0.009), skin incision to CPB (P = 0.034) and cross-clamp times (74 ± 33 vs 108 ± 47 min; P = 0.006), favouring the 3-step PSP group. Eight matched pairs were compared showing differences in the total operative time (263 ± 44 vs 360 ± 66 min; P = 0.008), CPB time (123 ± 34 vs 190 ± 43 min; P = 0.008) and postoperative length of stay (P = 0.031), favouring the 3-step PSP group.

CONCLUSIONS

In patients with repaired tetralogy of Fallot undergoing pulmonary valve replacement, preoperative planning using a standard CT-based strategy, the 3-step PSP, is associated with shorter operative times and shorter postoperative length of stay.

Quantifying the Brain Metastatic Tumor Micro-Environment using an Organ-On-A Chip 3D Model, Machine Learning, and Confocal Tomography

Brain metastases are the most lethal cancer lesions; 10-30% of all cancers metastasize to the brain, with a median survival of only ~5-20 months, depending on the cancer type. To reduce the brain metastatic tumor burden, gaps in basic and translational knowledge need to be addressed. Major challenges include a paucity of reproducible preclinical models and associated tools. Three-dimensional models of brain metastasis can yield the relevant molecular and phenotypic data used to address these needs when combined with dedicated analysis tools. Moreover, compared to murine models, organ-on-a-chip models of patient tumor cells traversing the blood brain barrier into the brain microenvironment generate results rapidly and are more interpretable with quantitative methods, thus amenable to high throughput testing. Here we describe and demonstrate the use of a novel 3D microfluidic blood brain niche (µmBBN) platform where multiple elements of the niche can be cultured for an extended period (several days), fluorescently imaged by confocal microscopy, and the images reconstructed using an innovative confocal tomography technique; all aimed to understand the development of micro-metastasis and changes to the tumor micro-environment (TME) in a repeatable and quantitative manner. We demonstrate how to fabricate, seed, image, and analyze the cancer cells and TME cellular and humoral components, using this platform. Moreover, we show how artificial intelligence (AI) is used to identify the intrinsic phenotypic differences of cancer cells that are capable of transit through a model µmBBN and to assign them an objective index of brain metastatic potential. The data sets generated by this method can be used to answer basic and translational questions about metastasis, the efficacy of therapeutic strategies, and the role of the TME in both.

Utility of 3D printed cardiac models in congenital heart disease: a scoping review

OBJECTIVE

Three-dimensional printing (3DP) is a novel technology with applications in healthcare, particularly for congenital heart disease (CHD). We sought to explore the spectrum of use of 3D printed CHD models (3D-CM) and identify knowledge gaps within the published body of literature to guide future research.

METHODS

We conducted a scoping review targeting published literature on the use of 3D-CMs. The databases of MEDLINE, EMBASE and Web of Science were searched from their inception until 19 July 2019. Inclusion criteria were primary research; studies reporting use of 3D-CMs; and human subjects. Exclusion criteria were studies where 3D-CMs were generated for proof of concept but not used; and studies focused on bioprinting or computational 3D-CMs. Studies were assessed for inclusion and data were extracted from eligible articles in duplicate.

RESULTS

The search returned 648 results. Following assessment, 79 articles were included in the final qualitative synthesis. The majority (66%) of studies are case reports or series. 15% reported use of a control group. Three main areas of utilisation are for (1) surgical and interventional cardiology procedural planning (n=62), (2) simulation (n=25), and (3) education for medical personnel or patients and their families (n=17). Multiple studies used 3D-CMs for more than one of these areas.

CONCLUSIONS

3DP for CHD is a new technology with an evolving literature base. Most of the published literature are experiential reports as opposed to manuscripts on scientifically robust studies. Our study has identified gaps in the literature and addressed priority areas for future research.

Three-dimensional printing facilitates surgical planning for resection of an atypical cardiac myxoma

BACKGROUND

Cardiac myxomas are common and account for 50% of primary intracardiac tumors. Atypical locations of cardiac myxoma increase the risk of intraoperative iatrogenic injuries. Herein, we report a case of using three-dimensional printing (3D) to facilitate the removal of an atypical cardiac myxoma in a 63-year-old woman.

METHODS AND RESULTS

Mass in the high posterior atrial septum was confirmed through imaging. Due to the potential involvement of the mass to surrounding vital structures, 3D printing of the cardiac mass was performed. The tumor was completely resected via median sternotomy and the resulting defect was repaired with the bovine pericardium. The patient had an uncomplicated postoperative course except for the development of sick sinus syndrome. One-year follow-up showed no tumor recurrent.

CONCLUSION

3D printing technology in patients with atypical cardiac tumors enhances our understanding of the extent of the tumor invasion and facilitates planning the operation to avoid intraoperative complications.

Application of Three-Dimensional Printed Models in Congenital Heart Surgery: Surgeon's Perspective

선천성 심장질환의 치료에 있어서 그 해부학적인 구조를 올바르게 이해하는 것은 아주 중요하다. 이러한 선천성 심장질환의 구조적인 특징을 이해하는데 있어서 삼차원 프린팅 모델을 이용하는 것은 아주 효과적이다. 기존에 얻어진 전산화단층촬영이나 자기공명영상 혹은 심장 초음파 검사의 자료만으로는 정확한 복잡심장기형의 특징을 이해하는 것이 어려운 경우가 있으며, 삼차원 프린팅 모델의 사용이 이러한 제한점 들을 극복하는데 도움을 줄 수 있다. 최근 들어서는 삼차원 프린팅 모델을 이용해 선천성 심장질환의 교육과 수술 전 시뮬레이션 그리고 치료의 방침을 결정하는데 많은 도움을 받고 있으며, 실제 구체적인 환아들의 예를 통해서 이를 살펴보고자 한다. 또한 향후 그 기술의 발전 방향에 대해 알아보고, 심장외과 의사의 관점에서 수술 수기의 발전이나 훈련 등 여러 방면의 이용에 대해서도 살펴보고자 한다.

Tetralogy of Fallot Will be Treated Interventionally Within Two Decades

Tetralogy of Fallot is considered a prototype congenital heart disease because of its embryological, anatomical, pathophysiological, and management aspects. Current management usually relies on a complete surgical repair that is electively performed between 3 and 6 months of age. With the advances of interventional cardiology especially in the fields of ventricular septal defect closure, stent, and pulmonary valve replacement, the question of complete repair of tetralogy of Fallot by interventional means can be discussed. Tetralogy of Fallot is a complex disease with multiple lesions, all individually amenable to transcatheter treatment. In this article, we will review current status of various aspects of tetralogy of Fallot focusing on interventional aspects, giving insights of what would be the ideal platform of a fully interventional repair.

Dimensional Accuracy and Clinical Value of 3D Printed Models in Congenital Heart Disease: A Systematic Review and Meta-Analysis

The aim of this paper is to summarize and evaluate results from existing studies on accuracy and clinical value of three-dimensional printed heart models (3DPHM) for determining whether 3D printing can significantly improve on how the congenital heart disease (CHD) is managed in current clinical practice. Proquest, Google Scholar, Scopus, PubMed, and Medline were searched for relevant studies until April 2019. Two independent reviewers performed manual data extraction and assessed the risk of bias of the studies using the tools published on National Institutes of Health (NIH) website. The following data were extracted from the studies: author, year of publication, study design, imaging modality, segmentation software, utility of 3DPHM, CHD types, and dimensional accuracy. R software was used for the meta-analysis. Twenty-four articles met the inclusion criteria and were included in the systematic review. However, only 7 studies met the statistical requirements and were eligible for meta-analysis. Cochran's Q test demonstrated significant variation among the studies for both of the meta-analyses of accuracy of 3DPHM and the utility of 3DPHM in medical education. Analysis of all included studies reported the mean deviation between the 3DPHM and the medical images is not significant, implying that 3DPHM are highly accurate. As for the utility of the 3DPHM, it is reported in all relevant studies that the 3DPHM improve the learning experience and satisfaction among the users, and play a critical role in facilitating surgical planning of complex CHD cases. 3DPHM have the potential to enhance communication in medical practice, however their clinical value remains debatable. More studies are required to yield a more meaningful meta-analysis.

Personalized Three-Dimensional Printed Models in Congenital Heart Disease

Patient-specific three-dimensional (3D) printed models have been increasingly used in cardiology and cardiac surgery, in particular, showing great value in the domain of congenital heart disease (CHD). CHD is characterized by complex cardiac anomalies with disease variations between individuals; thus, it is difficult to obtain comprehensive spatial conceptualization of the cardiac structures based on the current imaging visualizations. 3D printed models derived from patient's cardiac imaging data overcome this limitation by creating personalized 3D heart models, which not only improve spatial visualization, but also assist preoperative planning and simulation of cardiac procedures, serve as a useful tool in medical education and training, and improve doctor-patient communication. This review article provides an overall view of the clinical applications and usefulness of 3D printed models in CHD. Current limitations and future research directions of 3D printed heart models are highlighted.

Three-Dimensional Printing of Fetal Models of Congenital Heart Disease Derived From Microfocus Computed Tomography: A Case Series

This article presents a case series of n = 21 models of fetal cardiovascular anatomies obtained from post mortem microfocus computed tomography (micro-CT) data. The case series includes a broad range of diagnoses (e.g., tetralogy of Fallot, hypoplastic left heart syndrome, dextrocardia, double outlet right ventricle, atrio-ventricular septal defect) and cases also had a range of associated extra-cardiac malformations (e.g., VACTERL syndrome, central nervous system anomalies, renal anomalies). All cases were successfully reconstructed from the microfocus computed tomography data, demonstrating the feasibility of the technique and of the protocols, including in-house printing with a desktop 3D printer (Form2, Formlabs). All models were printed in 1:1 scale as well as with the 5-fold magnification, to provide insight into the intra-cardiac structures. Possible uses of the models include education and training.