3D printing of normal and pathologic tricuspid valves from transthoracic 3D echocardiography data sets

A Systematic Analysis of Additive Manufacturing Techniques in the Bioengineering of In Vitro Cardiovascular Models

Additive Manufacturing is noted for ease of product customization and short production run cost-effectiveness. As our global population approaches 8 billion, additive manufacturing has a future in maintaining and improving average human life expectancy for the same reasons that it has advantaged general manufacturing. In recent years, additive manufacturing has been applied to tissue engineering, regenerative medicine, and drug delivery. Additive Manufacturing combined with tissue engineering and biocompatibility studies offers future opportunities for various complex cardiovascular implants and surgeries. This paper is a comprehensive overview of current technological advancements in additive manufacturing with potential for cardiovascular application. The current limitations and prospects of the technology for cardiovascular applications are explored and evaluated.

Semi-automated quantification of tricuspid valve dynamics and structure in tetralogy of Fallot and hypoplastic left heart syndrome using three-dimensional echocardiography

Anomalies of the tricuspid valve (TV) are associated with worsened prognosis in congenital heart disease (CHD). Here, we present a descriptive study examining changes in TV morphology in two CHD conditions-repaired tetralogy of Fallot (rTOF) and hypoplastic left heart syndrome (HLSH), using three-dimensional echocardiography. Full volume acquisitions of the TV and right ventricle (RV) were performed from an RV-focused apical view using ECG gating over 2-5 consecutive cardiac cycles using 3D echocardiography, from which TV annulus and leaflet parameters were quantified. A total of 40 rTOF patients (age 14 ± 9.8 years), 40 HLHS patients (age1.0 ± 1.5 years) and 80 age and gender matched controls were included. Among leaflet parameters, antero-posterior and posterior-septal TV coaptation heights were smaller in rTOF (p < 0.001) vs. control. Conversely, only the short-axis TV height was different in HLHS vs. controls (HLHS 1.6 ± 0.4 cm vs. control 1.4 ± 0.3 cm). TV leaflet parameters tended to be larger in HLHS, while leaflet coaptation distances were similar between groups. We demonstrate that 3D echocardiography for assessment of the TV is feasible in rTOF and HLHS patients and identifies unique differences in TV morphology. Future studies should clarify the clinical significance of TV morphology in these patient populations.

Three-dimensional echocardiography of the tricuspid valve

Due to the proportionally high mortality rates associated with isolated tricuspid valve surgery, the invasive treatment of such pathology, historically, has been left largely unaddressed. Recently, there has been an appreciation for the mortality and morbidity of tricuspid valve disease, giving rise to the movement towards identifying less invasive, transcatheter approaches for treatment. Due to the technical complexity of these procedures along with the uniqueness and variability of tricuspid valve anatomy, a better appreciation of the tricuspid valve anatomy and pathology is required for pre-procedural planning. While two-dimensional echocardiography serves as the initial non-invasive modality for tricuspid valve evaluation, three-dimensional echocardiography provides a complete en face view of the tricuspid valve and surrounding structures, as well contributes further information regarding disease etiology and severity. In this review, we discuss the utility of three-dimensional echocardiography as a supplement to two-dimensional imaging to better assess tricuspid valve disease and anatomy to aide in future innovative therapies.

Three-Dimensional Echocardiography for Tricuspid Valve Assessment

PURPOSE OF REVIEW

This review article provides an overview of the various roles of 3-dimensional (3D) echocardiography in the evaluation of the tricuspid valve (TV) with specific focus on tricuspid regurgitation (TR) and its treatment.

RECENT FINDINGS

The prognostic implications of TR and the advent of new transcatheter therapies have underscored the need of accurate assessment of the TV. 3D echocardiography is key to assess the anatomy and function of TV and has provided new insights that have led to new classifications of the type of TR. Furthermore, 3D echocardiography is superior to 2-dimensional echocardiography to assess the right ventricle, an important parameter to select the patients with severe TR who may benefit from intervention. Finally, the use of 3D echocardiography during the guidance of transcatheter interventions is pivotal to ensure procedural success and minimize the complications. Three-dimensional echocardiography provides the soft tissue resolution that fluoroscopy does not provide.

Reference ranges of tricuspid annulus geometry in healthy adults using a dedicated three-dimensional echocardiography software package

Background

Tricuspid annulus (TA) sizing is essential for planning percutaneous or surgical tricuspid procedures. According to current guidelines, TA linear dimension should be assessed using two-dimensional echocardiography (2DE). However, TA is a complex three-dimensional (3D) structure.

Aim

Identify the reference values for TA geometry and dynamics and its physiological determinants using a commercially available three-dimensional echocardiography (3DE) software package dedicated to the tricuspid valve (4D AutoTVQ, GE).

Methods

A total of 254 healthy volunteers (113 men, 47 ± 11 years) were evaluated using 2DE and 3DE. TA 3D area, perimeter, diameters, and sphericity index were assessed at mid-systole, early- and end-diastole. Right atrial (RA) and ventricular (RV) end-diastolic and end-systolic volumes were also measured by 3DE.

Results

The feasibility of the 3DE analysis of TA was 90%. TA 3D area, perimeter, and diameters were largest at end-diastole and smallest at mid-systole. Reference values of TA at end-diastole were 9.6 ± 2.1 cm2 for the area, 11.2 ± 1.2 cm for perimeter, and 38 ± 4 mm, 31 ± 4 mm, 33 ± 4 mm, and 34 ± 5 mm for major, minor, 4-chamber and 2-chamber diameters, respectively. TA end-diastolic sphericity index was 81 ± 11%. All TA parameters were correlated with body surface area (BSA) (r from 0.42 to 0.58, p &lt; 0.001). TA 3D area and 4-chamber diameter were significantly larger in men than in women, independent of BSA (p &lt; 0.0001). There was no significant relationship between TA metrics with age, except for the TA minor diameter (r = −0.17, p &lt; 0.05). When measured by 2DE in 4-chamber (29 ± 5 mm) and RV-focused (30 ± 5 mm) views, both TA diameters resulted significantly smaller than the 4-chamber (33 ± 4 mm; p &lt; 0.0001), and the major TA diameters (38 ± 4 mm; p &lt; 0.0001) measured by 3DE. At multivariable linear regression analysis, RA maximal volume was independently associated with both TA 3D area at mid-systole (R2 = 0.511, p &lt; 0.0001) and end-diastole (R2 = 0.506, p &lt; 0.0001), whereas BSA (R2 = 0.526, p &lt; 0.0001) was associated only to mid-systolic TA 3D area.

Conclusions

Reference values for TA metrics should be sex-specific and indexed to BSA. 2DE underestimates actual 3DE TA dimensions. RA maximum volume was the only independent echocardiographic parameter associated with TA 3D area in healthy subjects.

Transcatheter Double Valve Replacement to Treat Aortic Stenosis and Severe Tricuspid Regurgitation with 3D Printing Guidance after Mechanical Mitral Valve Replacement

Background: Transcatheter treatments of tricuspid regurgitation (TR) have been emerging as alternatives for high-risk patients. In contrast to the immobilization of the common transcatheter tricuspid device, using a radial force-independent stent valve device at the native tricuspid annular site has several distinct advantages. Case summary: A 76-year-old patient with renal insufficiency who underwent mechanical mitral valve replacement in 2001 and transcatheter aortic valve replacement in 2021 due to severe aortic stenosis presented with chest pain and shortness of breath. Echocardiography suggested that the flow velocities of the mitral mechanical valve and aortic prosthetic valve were both within the normal range, with no significant paravalvular regurgitation; the tricuspid valve exhibited massive regurgitation (VMAX 258 cm/s, PGMAX 27 mmHg). Due to the high surgical risk, we simulated the procedure with a three-dimensional (3D)-printed model and performed transcatheter tricuspid valve replacement using a LuX-Valve (Ningbo Jenscare Biotechnology Co., Ningbo, China). Discussion: We describe transcatheter tricuspid valve replacement using the LuX-Valve and preprocedural guidance with 3D printing. Postprocedural TR was significantly reduced, indicating that 3D printing plays an important role in preprocedural guidance and that the LuX-Valve was safe and practicable for tricuspid valve replacement.

3D Approaches in Complex CHD: Where Are We? Funny Printing and Beautiful Images, or a Useful Tool?

Echocardiography, CT and MRI have a crucial role in the management of congenital heart disease (CHD) patients. All of these modalities can be presented in a 2D or a 3D rendered format. The aim of this paper is to review the key advantages and potential limitations, as well as the future challenges of a 3D approach in each imaging modality. The focus of this review is on anatomic rather than functional assessment. Conventional 2D echocardiography presents limitations when imaging complex lesions, whereas 3D imaging depicts the anatomy in all dimensions. CT and MRI can visualise extracardiac vasculature and guide complex biventricular repair. Three-dimensional printed models can be used in depicting complex intracardiac relationships and defining the surgical strategy in specific lesions. Extended reality imaging retained dynamic cardiac motion holds great potential for planning surgical and catheter procedures. Overall, the use of 3D imaging has resulted in a better understanding of anatomy, with a direct impact on the surgical and catheter approach, particularly in more complex cases.

Three-dimensional modeling of the mitral valve for surgical planning in a pediatric patient: A case-based discussion of the technical challenges of segmentation and printing from 3D transthoracic echocardiographic datasets

Abnormal atrioventricular valve present great challenges to the surgeon in achieving a successful repair, and thus present a great opportunity for enhanced 3D imaging to guide pre- and intra-operative management. Spatial and temporal resolution of 3D echocardiography enables 3D printing of valve morphology. However, non-linearity, angle dependence, speckle, blur, and resampling complicate segmentation compared to computed tomography (CT) and magnetic resonance imaging (MRI). A case of complex mitral valve disease in a pediatric patient is therefore presented to illustrate the technical challenges of segmentation and 3D printing from echocardiographic data.

Recent advances in multimodality imaging of the tricuspid valve

INTRODUCTION

The tricuspid valve (TV) and the right heart chambers are complex three-dimensional structures that are difficult to assess using tomographic imaging techniques. The progressive aging of the general population and the advancements in treating left-sided heart diseases by transcatheter procedures have contributed to the tricuspid regurgitation (TR) becoming a major public health problem associated with progression to refractory heart failure and poor outcome. Recent advances in multimodality cardiac imaging allow a better understanding of the pathophysiology of TR that may translate in better management of patients.

AREAS COVERED

Three-dimensional echocardiography, cardiac magnetic resonance, and computed tomography provide complementary information to i. assess the TV complex; ii. identify the etiology and the mechanisms of TR; iii. evaluate its severity and hemodynamic consequences; iv. explore the remodeling of the right heart chambers; and v. properly plan, guide, and monitor the transcatheter interventions aimed to reduce the severity of TR.

EXPERT OPINION

We need thorough understanding of both the TV and the right heart chamber geometry and function to understand the pathophysiology of TR. The integrated use of multimodality cardiac imaging is pivotal to assess patients with TR and to identify tailored and timely treatment of TR in properly selected patients.

Parameterization, geometric modeling, and isogeometric analysis of tricuspid valves

Approximately 1.6 million patients in the United States are affected by tricuspid valve regurgitation, which occurs when the tricuspid valve does not close properly to prevent backward blood flow into the right atrium. Despite its critical role in proper cardiac function, the tricuspid valve has received limited research attention compared to the mitral and aortic valves on the left side of the heart. As a result, proper valvular function and the pathologies that may cause dysfunction remain poorly understood. To promote further investigations of the biomechanical behavior and response of the tricuspid valve, this work establishes a parameter-based approach that provides a template for tricuspid valve modeling and simulation. The proposed tricuspid valve parameterization presents a comprehensive description of the leaflets and the complex chordae tendineae for capturing the typical three-cusp structural deformation observed from medical data. This simulation framework develops a practical procedure for modeling tricuspid valves and offers a robust, flexible approach to analyze the performance and effectiveness of various valve configurations using isogeometric analysis. The proposed methods also establish a baseline to examine the tricuspid valve's structural deformation, perform future investigations of native valve configurations under healthy and disease conditions, and optimize prosthetic valve designs.

Patient-specific preprocedural planning for tricuspid valve repair and replacement procedures

PURPOSE OF REVIEW

Despite the prevalence of tricuspid valve regurgitation disorders, isolated interventions on tricuspid valves were previously infrequent due to high mortality rates and lack of advanced clinical imaging technology. Due to advancements in cardiovascular imaging and interventional technologies tricuspid valve repairs and replacement interventions became increasingly more attainable.

RECENT FINDINGS

Noninvasive clinical imaging of the tricuspid valve can be challenging, providing anincomplete assessment of unique tricuspid anatomy. 3D printing technology represents an additional tool for more comprehensive preprocedural planning of tricuspid interventions and observation of tricuspid valve geometry. Patient-specific 3D printed replicas of tricuspid valve apparatus are especially useful in highly complicated cases, where physiological tricuspid replicas allow benchtop observation of individual patient's anatomy, device implantation in physiological tricuspid valves and interactions of devices with native tricuspid tissue, frequently leading to optimization or change in operational strategy.

SUMMARY

Comprehensive use of clinical imaging including echocardiography, computed tomography, and cardiac magnetic resonance along with 3D printed modeling is key to successful tricuspid repair and replacements. Patient-specific 3D printed models of tricuspid anatomy can facilitate preprocedural planning, educate patients and clinicians, and improve device design, leading to the overall improvement of patients' outcomes and care.

Multimodality cardiac imaging and new display options to broaden our understanding of the tricuspid valve

PURPOSE OF REVIEW

The prognostic impact of tricuspid regurgitation (TR) and the subsequent development of percutaneous procedures targeting the tricuspid valve (TV), has brought to the forefront the role of imaging for the assessment of the forgotten valve. As illustrated in several studies and summarized in this review, currently a multimodality imaging approach is required to understand the pathophysiology of TR, due to the complex TV anatomy and the close relationship between the severity of TR and the extent of the remodeling of the right heart chambers.

RECENT FINDINGS

Recently, the advance in the tranhscatheter treatment of the TV has led to a growing interest in the development of dedicated software packages and new display modalities to increase our understanding of the TV. As a consequence, a transversal knowledge of the different imaging modalities is required for contemporary cardiac-imaging physicians.

SUMMARY

This review highlights the main features, and the pros and cons of echocardiography, cardiac computed tomography, cardiac magnetic resonance and emerging technologies, as 3D printing and virtual reality, in the assessment of patients with TR.

3D Echocardiography for Rheumatic Heart Disease Analysis: Ready for Prime Time

Rheumatic heart disease (RHD) remains to be a very important health issue worldwide, mainly in underdeveloped countries. It continues to be a leading cause of morbidity and mortality throughout developing countries. RHD is a delayed non-suppurative immunologically mediated inflammatory response to the throat infection caused by a hemolytic streptococcus from the A group (Streptococcus pyogenes). RHD keeps position 1 as the most common cardiovascular disease in young people aged <25 years considering all the continents. The disease can lead to valvular cardiac lesions as well as to carditis. Rheumatic fever valvular injuries lead most commonly to the fusion and thickening of the edges of the cusps and to the fusion, thickening, and shortening of the chordae and ultimately to calcification of the valves. Valvular commissures can also be deeply compromised, leading to severe stenosis. Atrial and ventricular remodeling is also common following rheumatic infection. Mixed valvular lesions are more common than isolated valvular disorders. Echocardiography is the most relevant imaging technique not only to provide diagnostic information but also to enable prognostic data. Further, it presents a very important role for the correction of complications after surgical repair of rheumatic heart valvulopathies. Three-dimensional (3D) echocardiography provides additional anatomical and morphofunctional information of utmost importance for patients presenting rheumatic valvopathies. Accordingly, three-dimensional echocardiography is ready for routine use in patients with RHD presenting with valvular abnormalities.

[Comprehensive review of 3D printing use in medicine: Comparison with practical applications in urology]

INTRODUCTION

Over the past few years, 3D printing has evolved rapidly. This has resulted in an increasing number of scientific publications reporting on the medical use of 3D printing. These applications can range from patient information, preoperative planning, education, or 3D printing of patient-specific surgical implants. The objective of this review was to give an overview of the different applications in urology and other disciplines based on a selection of publications.

METHODS

In the current narrative review the Medline database was searched to identify all the related reports discussing the use of 3D printing in the medical field and more specifically in Urology. 3D printing applications were categorized so they could be searched more thoroughly within the Medline database.

RESULTS

Three-dimensional printing can help improve pre-operative patient information, anatomy and medical trainee education. The 3D printed models may assist the surgeon in preoperative planning or become patient-specific surgical simulation models. In urology, kidney cancer surgery is the most concerned by 3D printing-related publications, for preoperative planning, but also for surgical simulation and surgical training.

CONCLUSION

3D printing has already proven useful in many medical applications, including urology, for patient information, education, pre-operative planning and surgical simulation. All areas of urology are involved and represented in the literature. Larger randomized controlled studies will certainly allow 3D printing to benefit patients in routine clinical practice.

3D Echocardiography Provides Highly Accurate 3D Printed Models in Congenital Heart Disease

Cardiac 3D printing is mainly performed from magnetic resonance imaging (MRI) and computed tomography (CT) 3D datasets, though anatomic detail of atrioventricular (AV) valves may be limited. 3D echo provides excellent visualization of AV valves. Thus, we tested the feasibility and accuracy of 3D printing from 3D echo in this pilot series of subjects with congenital heart disease (CHD), with a focus on valve anatomy. Five subjects with CHD were identified. 3D echo data were converted to 3D printable files and printed in collaboration with 3D Systems Healthcare (Golden, Colorado). A novel technique for valve modeling was utilized using commercially available software. Two readers (KM, SA) independently measured valve structures from 3D models and compared to source echo images. 3D printing was feasible for all cases. Table 1 shows measurements comparing 2D echo to 3D models. Bland Altman analysis showed close agreement and no significant bias between 2D and digital 3D models (mean difference 0.0, 95% CI 1.1 to - 1.1) or 2D vs printed 3D models, though with wider limits of agreement (mean difference - 0.3, 95% CI 1.9 to - 2.6). Accuracy of 3D models compared to 2D was within < 0.5 mm. This pilot study shows 3D echo datasets can be used to reliably print AV and semilunar valve structures in CHD. The 3D models are highly accurate compared to the source echo images. This is a novel and value-added technique that adds incremental information on cardiac anatomy over current methods.

Three-dimensional printing for cardiovascular diseases: from anatomical modeling to dynamic functionality

Three-dimensional (3D) printing is widely used in medicine. Most research remains focused on forming rigid anatomical models, but moving from static models to dynamic functionality could greatly aid preoperative surgical planning. This work reviews literature on dynamic 3D heart models made of flexible materials for use with a mock circulatory system. Such models allow simulation of surgical procedures under mock physiological conditions, and are; therefore, potentially very useful to clinical practice. For example, anatomical models of mitral regurgitation could provide a better display of lesion area, while dynamic 3D models could further simulate in vitro hemodynamics. Dynamic 3D models could also be used in setting standards for certain parameters for function evaluation, such as flow reserve fraction in coronary heart disease. As a bridge between medical image and clinical aid, 3D printing is now gradually changing the traditional pattern of diagnosis and treatment.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: adult cardiac conditions

BACKGROUND

Medical 3D printing as a component of care for adults with cardiovascular diseases has expanded dramatically. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness criteria for adult cardiac 3D printing indications.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with a number of adult cardiac indications, physiologic, and pathologic processes. Each study was vetted by the authors and graded according to published guidelines.

RESULTS

Evidence-based appropriateness guidelines are provided for the following areas in adult cardiac care; cardiac fundamentals, perioperative and intraoperative care, coronary disease and ischemic heart disease, complications of myocardial infarction, valve disease, cardiac arrhythmias, cardiac neoplasm, cardiac transplant and mechanical circulatory support, heart failure, preventative cardiology, cardiac and pericardial disease and cardiac trauma.

CONCLUSIONS

Adoption of common clinical standards regarding appropriate use, information and material management, and quality control are needed to ensure the greatest possible clinical benefit from 3D printing. This consensus guideline document, created by the members of the RSNA 3D printing Special Interest Group, will provide a reference for clinical standards of 3D printing for adult cardiac indications.

3D Printing, Computational Modeling, and Artificial Intelligence for Structural Heart Disease

Structural heart disease (SHD) is a new field within cardiovascular medicine. Traditional imaging modalities fall short in supporting the needs of SHD interventions, as they have been constructed around the concept of disease diagnosis. SHD interventions disrupt traditional concepts of imaging in requiring imaging to plan, simulate, and predict intraprocedural outcomes. In transcatheter SHD interventions, the absence of a gold-standard open cavity surgical field deprives physicians of the opportunity for tactile feedback and visual confirmation of cardiac anatomy. Hence, dependency on imaging in periprocedural guidance has led to evolution of a new generation of procedural skillsets, concept of a visual field, and technologies in the periprocedural planning period to accelerate preclinical device development, physician, and patient education. Adaptation of 3-dimensional (3D) printing in clinical care and procedural planning has demonstrated a reduction in early-operator learning curve for transcatheter interventions. Integration of computation modeling to 3D printing has accelerated research and development understanding of fluid mechanics within device testing. Application of 3D printing, computational modeling, and ultimately incorporation of artificial intelligence is changing the landscape of physician training and delivery of patient-centric care. Transcatheter structural heart interventions are requiring in-depth periprocedural understanding of cardiac pathophysiology and device interactions not afforded by traditional imaging metrics.

Imaging for Tricuspid Valve Repair and Replacement

Primary or secondary tricuspid regurgitation (TR) represents an important health care burden and challenge which has often been neglected or undertreated in the past. The expansion and reinforcement of the indications for tricuspid valve (TV) intervention in the 2017 editions of the guidelines as well as the introduction of transcatheter tricuspid valve intervention (TTVI) has considerably increased the attention of the community on the TV and the volume of TV interventions in the past years. Depending on the anatomic target, TTVI can be categorized as the following: 1) direct or indirect tricuspid restrictive annuloplasty; 2) direct (edge-to-edge repair) or indirect (coaptation device) restoration of leaflet coaptation; 3) heterotopic tricuspid valve implantation; and 4) transcatheter tricuspid valve replacement. Multimodality imaging has crucial role for the following: 1) patient selection for TTVI and procedure planning; 2) guiding and monitoring the procedure; and 3) assessing and following over time the results of the procedure. The key points for pre-procedural imaging are: 1) accurate quantitation of TR severity; 2) proper identification of the mechanism(s) responsible for the TR; and 3) quantitation of RV dysfunction and pulmonary arterial hypertension. This imaging work-up is essential to select the right type of intervention for the right patient and TV. Transesophageal echocardiography and fluoroscopy imaging is also key for guiding the TTVI procedures and fusion between these 2 modalities may further enhance the quality of procedure guiding.

Utility of Three-Dimensional (3D) Modeling for Planning Structural Heart Interventions (with an Emphasis on Valvular Heart Disease)

PURPOSE OF REVIEW

Advanced imaging has played a vital role in the contemporary, rapid rise of structural heart interventions. 3D modeling and printing has emerged as one of the most recent imaging tools and the implementation of 3D modeling is expected to increase with further advances in imaging, print hardware, and materials.

RECENT FINDINGS

3D modeling can be used to educate patients and clinical teams, provide ex vivo procedural simulation, and improve outcomes. Intra-procedural success rates may be improved, and post-procedural complications can be predicted more robustly with appropriate application of 3D modeling. Recent advances in technology have increased the availability of this tool, such that there can be more ready adoption into a routine clinical workflow. Familiarity with 3D modeling and its current utilization and role in structural interventions will help inform how to approach and adapt this exciting new technology.

What would you like to print? Students' opinions on the use of 3D printing technology in medicine

Background

Recent advances in 3D printing technology, and biomaterials are revolutionizing medicine. The beneficiaries of this technology are primarily patients, but also students of medical faculties. Taking into account that not all students have full, direct access to the latest advances in additive technologies, we surveyed their opinion on 3D printing and education in this area. The research aimed to determine what knowledge about the use of 3D printing technology in medicine, do students of medical faculties have.

Methods

The research was carried out in the form of a questionnaire among 430 students of the Medical University of Silesia in Katowice (Poland) representing various fields of medicine and health sciences. The questions included in the survey analyzed the knowledge of the respondents for 3D printing technology and the opportunities it creates in medicine.

Results

The results indicate that students do have knowledge about 3D printing obtained mainly from the internet. They would be happy to deepen their knowledge at specialized courses in this field. Students appreciated the value of 3D printing in order to obtain accurate anatomical models, helpful in learning. However, they do not consider the possibility of complete abandonment of human cadavers in the anatomy classes. Their knowledge includes basic information about current applications of 3D printing in medicine, but not in all areas. However, they have no ethical doubts regarding the use of 3D printing in any form. The vast majority of students deemed it necessary to incorporate information regarding 3D printing technology into the curriculum of different medical majors.

Conclusion

This research is the first of its kind, which allows for probing students' knowledge about the additive technologies in medicine. Medical education should be extended to include issues related to the use of 3D printing for medical applications.

3-Dimensional Echocardiography in Imaging the Tricuspid Valve

Tricuspid regurgitation (TR) is an independent predictor of death. Lately, emerging technologies for the treatment of TR have increased the interest of physicians. Due to the complex 3-dimensional (3D) geometry of the tricuspid valve (TV) and its anterior position in the mediastinum, conventional 2D echocardiography is unsuitable to study the anatomy and pathophysiologic mechanisms of the regurgitant TV. 3D echocardiography has emerged as a very cost-effective imaging modality with which to: 1) visualize the TV anatomy; 2) define the mechanism of TR; 3) measure the size and geometry of the tricuspid annulus; 4) analyze the anatomic relationships between TV apparatus and surrounding cardiac structures; 5) assess volumes and function of the right atrium and ventricle; and 6) plan surgical repair or guide and monitor transcatheter interventional procedures.

Imaging Needs in Novel Transcatheter Tricuspid Valve Interventions

The advent of novel transcatheter therapies for severe tricuspid regurgitation (TR) has attracted much attention. Novel 3-dimensional imaging techniques have permitted analysis of the tricuspid valve (TV) anatomy from unparalleled views and better understanding of the underlying pathophysiology of TR. Grading TR and assessment of right ventricular function remain challenging, and although 2-dimensional echocardiography is the mainstay imaging technique to evaluate patients with severe TR the use of 3-dimensional echocardiography and cardiovascular magnetic resonance is increasing. The number of transcatheter interventions for TR is growing, and procedural success relies significantly on the pre-procedural evaluation of the anatomy of the TV, etiology and severity of TR, right ventricular size and function, and importantly, the anatomic relationships of the TV. The role of multimodality imaging in patient selection and procedural planning for transcatheter TV repair is reviewed.

Three-dimensional printing in congenital heart disease: Considerations on training and clinical implementation from a teaching session

In light of growing interest for three-dimensional printing technology in the cardiovascular community, this study focused on exploring the possibilities of providing training for cardiovascular three-dimensional printing in the context of a relevant international congress and providing considerations on the delivery of such courses. As a second objective, the study sought to capture preferences in relation to three-dimensional printing uses and set-ups from those attending the training session. A survey was administered to n = 30 professionals involved or interested in three-dimensional printing cardiovascular models following a specialised teaching session. Survey results suggest the potential for split training sessions, with a broader introduction for those with no prior experience in three-dimensional printing followed by a more in-depth and hands-on session. All participants agreed on the potential of the technology in all its applications, particularly for aiding decision-making around complex surgical or interventional cases. When exploring setting up an in-house three-dimensional printing service, the majority of participants reported that their centre was already equipped with an in-house facility or expressed a desire that such a facility should be available, with a minority preferring consigning models to an external third party for printing.

3D printing for heart valve disease: a systematic review

BACKGROUND

Current developments showed a fast-increasing implementation and use of three-dimensional (3D) printing in medical applications. Our aim was to review the literature regarding the application of 3D printing to cardiac valve disease.

METHODS

A PubMed search for publications in English with the terms "3D printing" AND "cardiac valve", performed in January 2018, resulted in 64 items. After the analysis of the abstract and text, 27 remained related to the topic. From the references of these 27 papers, 7 papers were added resulting in a total of 34 papers. Of these, 5 were review papers, thus reducing the papers taken into consideration to 29.

RESULTS

The 29 papers showed that about a decade ago, the interest in 3D printing for this application area was emerging, but only in the past 2 to 3 years it really gained interest. Computed tomography is the most common imaging modality taken into consideration (62%), followed by ultrasound (28%), computer-generated models (computer-aided design) (7%), and magnetic resonance imaging (3%). Acrylonitrile butadiene styrene (4/14, 29%) and TangoPlus FullCure 930 (5/14, 36%) are the most used printing materials. Stereolithography (40%) and fused deposition modeling (30%) are the preferred printing techniques, while PolyJet (25%) and laser sintering (4%) are used in a minority of cases. The reported time ranges from 30 min to 3 days. The most reported application area is preoperative planning (63%), followed by training (19%), device testing (11%), and retrospective procedure evaluation (7%).

CONCLUSIONS

In most cases, CT datasets are used and models are printed for preoperative planning.

3D Printing and Heart Failure: The Present and the Future

Advanced imaging modalities provide essential anatomic and spatial information in patients with complex heart disease. Two-dimensional imaging can be limited in the extent to which true 3-dimensional (3D) relationships are represented. The application of 3D printing technology has increased the creation of physical models that overcomes the limitations of a 2D screen. Many groups have reported the use of 3D printing for preprocedural planning in patients with different causes of heart failure. This paper reviews the innovative applications of this technique to provide patient-specific models to improve patient care.

The Various Applications of 3D Printing in Cardiovascular Diseases

PURPOSE OF REVIEW

To highlight the various applications of 3D printing in cardiovascular disease and discuss its limitations and future direction.

RECENT FINDINGS

Use of handheld 3D printed models of cardiovascular structures has emerged as a facile modality in procedural and surgical planning as well as education and communication. Three-dimensional (3D) printing is a novel imaging modality which involves creating patient-specific models of cardiovascular structures. As percutaneous and surgical therapies evolve, spatial recognition of complex cardiovascular anatomic relationships by cardiologists and cardiovascular surgeons is imperative. Handheld 3D printed models of cardiovascular structures provide a facile and intuitive road map for procedural and surgical planning, complementing conventional imaging modalities. Moreover, 3D printed models are efficacious educational and communication tools. This review highlights the various applications of 3D printing in cardiovascular diseases and discusses its limitations and future directions.

3D Printing is a Transformative Technology in Congenital Heart Disease

Survival in congenital heart disease has steadily improved since 1938, when Dr. Robert Gross successfully ligated for the first time a patent ductus arteriosus in a 7-year-old child. To continue the gains made over the past 80 years, transformative changes with broad impact are needed in management of congenital heart disease. Three-dimensional printing is an emerging technology that is fundamentally affecting patient care, research, trainee education, and interactions among medical teams, patients, and caregivers. This paper first reviews key clinical cases where the technology has affected patient care. It then discusses 3-dimensional printing in trainee education. Thereafter, the role of this technology in communication with multidisciplinary teams, patients, and caregivers is described. Finally, the paper reviews translational technologies on the horizon that promise to take this nascent field even further.

Comparison of 3D Echocardiogram-Derived 3D Printed Valve Models to Molded Models for Simulated Repair of Pediatric Atrioventricular Valves

Mastering the technical skills required to perform pediatric cardiac valve surgery is challenging in part due to limited opportunity for practice. Transformation of 3D echocardiographic (echo) images of congenitally abnormal heart valves to realistic physical models could allow patient-specific simulation of surgical valve repair. We compared materials, processes, and costs for 3D printing and molding of patient-specific models for visualization and surgical simulation of congenitally abnormal heart valves. Pediatric atrioventricular valves (mitral, tricuspid, and common atrioventricular valve) were modeled from transthoracic 3D echo images using semi-automated methods implemented as custom modules in 3D Slicer. Valve models were then both 3D printed in soft materials and molded in silicone using 3D printed "negative" molds. Using pre-defined assessment criteria, valve models were evaluated by congenital cardiac surgeons to determine suitability for simulation. Surgeon assessment indicated that the molded valves had superior material properties for the purposes of simulation compared to directly printed valves (p < 0.01). Patient-specific, 3D echo-derived molded valves are a step toward realistic simulation of complex valve repairs but require more time and labor to create than directly printed models. Patient-specific simulation of valve repair in children using such models may be useful for surgical training and simulation of complex congenital cases.

Preliminary study of the application of transthoracic echocardiography-guided three-dimensional printing for the assessment of structural heart disease

OBJECTIVE

To investigate the feasibility and diagnostic value of a preoperative transthoracic echocardiography-guided three-dimensional printed model (TTE-guided 3DPM) for the assessment of structural heart disease (SHD).

METHODS

Fourty-four patients underwent cardiac surgery at Tianjin Chest Hospital. The patients were preoperatively assessed using TTE-guided 3DPM, which was compared to conventional three-dimensional transthoracic echocardiography (3DTTE) along with direct intraoperative findings, which were considered the "gold standard." Twelve patients had SHD, including four with mitral prolapse, two with partial endocardial cushion defects, two with secondary atrial septal defects, two with rheumatic mitral stenosis, one with tetralogy of Fallot, and one with a ventricular septal defect (VSD). Thirty-two patients who did not have SHDs were designated as the negative control group.

RESULTS

The sensitivity and specificity of the TTE-guided 3DPM were greater than or equal to those of the 3DTTE. The P-value of the McNemar test of 3DTTE was >.05, which indicates that the difference was not statistically significant (Kappa = 0.745, P < .001). The P-value of the McNemar test of TTE-guided 3DPM was >.05, which indicates that the difference was not statistically significant (Kappa = 0.955, P < .001). A comparison of 3DTTE and TTE-guided 3DPM resulted in a P-value >.05, which indicates that the difference was not statistically significant (Kappa = 0.879, P < .001). TTE-guided 3DPM displayed the 3D structure of SHDs and cardiac lesions clearly and was consistent with the intra-operative findings.

CONCLUSION

Transthoracic echocardiography-guided three-dimensional printed model (TTE-guided 3DPM) provides essential information for preoperative evaluation and decision making for patients with SHDs.