3D-printed heart model to guide LAA closure: useful in clinical practice?

Preprocedural Planning of Left Atrial Appendage Occlusion: A Review of the Use of Additive Manufacturing

Stroke is a significant public health problem, with non-valvular atrial fibrillation (NVAF) being one of its main causes. This cardiovascular arrhythmia predisposes to the production of intracardiac thrombi, mostly formed in the left atrial appendage (LAA). When there are contraindications to treatment with oral anticoagulants, another therapeutic option to reduce the possibility of thrombus formation in the LAA is the implantation of an occlusion device by cardiac catheterization. The effectiveness of LAA occlusion is dependent on accurate preprocedural device sizing and proper device positioning at the LAA ostium, to ensure sufficient device anchoring and avoid peri-device leaks. Additive manufacturing, commonly known as three-dimensional printing (3DP), of LAA models is beginning to emerge in the scientific literature to address these challenges through procedural simulation. This review aims at clarifying the impact of 3DP on preprocedural planning of LAA occlusion, specifically in the training of cardiac surgeons and in the assessment of the perfect adjustment between the LAA and the biomedical implant.

3D Printing for Cardiovascular Surgery and Intervention: A Review Article

3D printing technology can be applied to practically every aspect of modern life, fulfilling the needs of people from various backgrounds. The utilization of 3D printing in the context of adult heart disease can be succinctly categorized into 3 primary domains: preoperative strategizing or simulation, medical instruction, and clinical consultations. 3D-printed model utilization improves surgical planning and intraoperative decision-making and minimizes surgical risks, and it has demonstrated its efficacy as an innovative educational tool for aspiring surgeons with limited practical exposure. Despite all the applications of 3D printing, it has not yet been shown to improve long-term outcomes, including safety. There are no data on the outcomes of controlled trials available. To appropriately diagnose heart disease, 3D-printed models of the heart can provide a better understanding of the intracardiac anatomy and provide all the information needed for operative planning. Experientially, 3D printing provides a wide range of perceptions for understanding lower extremity arteries' spatial geometry and anatomical features of pathology. Practicing cardiac surgery processes using objects printed using 3D imaging data can become the norm rather than the exception, leading to improved accuracy and quality of treatment. This study aimed to review the various applications of 3D printing technology in cardiac surgery and intervention.

Views on Augmented Reality, Virtual Reality, and 3D Printing in Modern Medicine and Education: A Qualitative Exploration of Expert Opinion

Although an increased usage and development of 3D technologies is observed in healthcare over the last decades, full integration of these technologies remains challenging. The goal of this project is to qualitatively explore challenges, pearls, and pitfalls of AR/VR/3D printing applications usage in the medical field of a university medical center. Two rounds of face-to-face interviews were conducted using a semi-structured protocol. First an explorative round was held, interviewing medical specialists (8), PhD students (7), 3D technology specialists (5), and university teachers (3). In the second round, twenty employees in high executive functions of relevant departments were interviewed on seven statements that resulted from the first interviewing round. Data analysis was performed using direct content analyses. The first interviewing round resulted in challenges and opportunities in 3D technology usage that were grouped in 5 themes: aims of using AR/VR/3D printing (1), data acquisition (2), data management plans (3), software packages and segmentation tools (4), and output data and reaching end-user (5). The second interviewing round resulted in an overview of ideas and insights on centralization of knowledge, improving implementation of 3D technology in daily healthcare, reimbursement of 3D technologies, recommendations for further studies, and requirement of using certified software. An overview of challenges and opportunities of 3D technologies in healthcare was provided. Well-designed studies on clinical effectiveness, implementation and cost-effectiveness are warranted for further implementation into the clinical setting.

Cells-in-Touch: 3D Printing in Reconstruction and Modelling of Microscopic Biological Geometries for Education and Future Research Applications

Additive manufacturing (3D printing) and computer-aided design (CAD) still have limited uptake in biomedical and bioengineering research and education, despite the significant potential of these technologies. The utility of organ-scale 3D-printed models of living structures is widely appreciated, while the workflows for microscopy data translation into tactile accessible replicas are not well developed yet. Here, we demonstrate an accessible and reproducible CAD-based methodology for generating 3D-printed scalable models of human cells cultured in vitro and imaged using conventional scanning confocal microscopy with fused deposition modeling (FDM) 3D printing. We termed this technology CiTo-3DP (Cells-in-Touch for 3D Printing). As a proof-of-concept, we created dismountable CiTo-3DP models of human epithelial, mesenchymal, and neural cells by using selectively stained nuclei and cytoskeletal components. We also provide educational and research context for the presented cellular models. In the future, the CiTo-3DP approach can be adapted to different imaging and 3D printing modalities and comprehensively present various cell types, subcellular structures, and extracellular matrices. The resulting CAD and 3D printed models could be used for a broad spectrum of education and research applications.

Virtual reality utilization for left atrial appendage occluder device size prediction

Aim

To explore the feasibility and accuracy of virtual reality (VR) derived from cardiac computed angiography (CCTA) data to predict left atrial appendage occlusion (LAAO) device size.

Method

Retrospective data of patients who underwent LAAO according to clinical indication were reviewed; all patients underwent a pre-procedural CCTA. Measurements of the left atrial appendage (LAA) orifice diameters by CCTA, VR, and transesophageal echocardiography (TEE) (acquired during the procedure) were compared to the implanted device size. The LAA perimeter was calculated using the Ramanujan approximation. Statistical analyses included Lin's Concordance Correlation Coefficient (ρ _c ), the mean difference, and the mean square error (MSE).

Results

The sample was composed of 20 patients (mean age 75.7 ± 7.5 years, 60% males) who underwent successful LAAO insertion (ACP™ N = 8, Watchman™ N = 12). The CCTA, VR, and TEE maximal diameter ρ _c was 0.52, 0.78 and 0.60, respectively with mean differences of +0.92 ± 4.0 mm, -1.12 ± 2.3 mm, and -3.45 ± 2.69 mm, respectively. The CCTA, VR, and TEE perimeter calculations ρ _c were 0.49, 0.54, and 0.39 respectively with mean differences of +4.69 ± 11.5 mm, -9.88 ± 8.0 mm, and -16.79 ± 7.8 respectively.

Discussion

A VR visualization of the LAA ostium in different perspectives allows for a better understanding of its funnel-shaped structure. VR measurement of the maximal ostium diameter had the strongest correlation with the diameter of the inserted device. VR may thus provide new imaging possibilities for the evaluation of complex pre-procedural structures such as the LAA.

Advanced 3D Visualization and 3D Printing in Radiology

Since the discovery of X-rays in 1895, medical imaging systems have played a crucial role in medicine by permitting the visualization of internal structures and understanding the function of organ systems. Traditional imaging modalities including Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Ultrasound (US) present fixed two-dimensional (2D) images which are difficult to conceptualize complex anatomy. Advanced volumetric medical imaging allows for three-dimensional (3D) image post-processing and image segmentation to be performed, enabling the creation of 3D volume renderings and enhanced visualization of pertinent anatomic structures in 3D. Furthermore, 3D imaging is used to generate 3D printed models and extended reality (augmented reality and virtual reality) models. A 3D image translates medical imaging information into a visual story rendering complex data and abstract ideas into an easily understood and tangible concept. Clinicians use 3D models to comprehend complex anatomical structures and to plan and guide surgical interventions more precisely. This chapter will review the volumetric radiological techniques that are commonly utilized for advanced 3D visualization. It will also provide examples of 3D printing and extended reality technology applications in radiology and describe the positive impact of advanced radiological image visualization on patient care.

Computed tomography angiography/magnetic resonance imaging-based preprocedural planning and guidance in the interventional treatment of structural heart disease

Preprocedural planning and periprocedural guidance based on image fusion are widely established techniques supporting the interventional treatment of structural heart disease. However, these two techniques are typically used independently. Previous works have already demonstrated the benefits of integrating planning details into image fusion but are limited to a few applications and the availability of the proprietary tools used. We propose a vendor-independent approach to integrate planning details into periprocedural image fusion facilitating guidance during interventional treatment. In this work, we demonstrate the feasibility of integrating planning details derived from computer tomography and magnetic resonance imaging into periprocedural image fusion with open-source and commercially established tools. The integration of preprocedural planning details into periprocedural image fusion has the potential to support safe and efficient interventional treatment of structural heart disease.

A systematic review of the use of 3D printing in left atrial appendage occlusion procedures

The placement of a left atrial appendage occlusion (LAAO) device can be a technically challenging transcatheter-based procedure. Key challenges include accurate pre-procedural device sizing and proper device positioning at the LAA ostium to ensure sufficient device anchoring and avoid peri-device leaks. To address these challenges, 3D printing (3DP) of LAA models has recently emerged in the literature, first being described in 2015. We present a review of the benefits and drawbacks of employing this technology for LAAO procedures. Pre-procedurally the use of 3DP can consistently and accurately determine LAAO device size over standard of care approaches. Intra-procedurally 3DP's impact entailed a statistically significant decrease in the number of devices used per procedure, as well as in the fluoroscopic time and dose. Post-procedurally, there is some evidence that 3DP could reduce the rate of peri-device leaks, with limited data on its effect on complication rates. Based on existing evidence, we recommend the focused application of 3DP to cases of complex LAA anatomy and for the training of proceduralists. Lastly, we address the emergence of next generation LAAO devices and AR/VR systems that could limit even this narrow window of clinical benefit afforded by 3DP. This article is protected by copyright. All rights reserved.

Imaging-Based, Patient-Specific Three-Dimensional Printing to Plan, Train, and Guide Cardiovascular Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

To tailor cardiovascular interventions, the use of three-dimensional (3D), patient-specific phantoms (3DPSP) encompasses patient education, training, simulation, procedure planning, and outcome-prediction.

AIM

This systematic review and meta-analysis aims to investigate the current and future perspective of 3D printing for cardiovascular interventions.

METHODS

We systematically screened articles on Medline and EMBASE reporting the prospective use of 3DPSP in cardiovascular interventions by using combined search terms. Studies that compared intervention time depending on 3DPSP utilisation were included into a meta-analysis.

RESULTS

We identified 107 studies that prospectively investigated a total of 814 3DPSP in cardiovascular interventions. Most common settings were congenital heart disease (CHD) (38 articles, 6 comparative studies), left atrial appendage (LAA) occlusion (11 articles, 5 comparative, 1 randomised controlled trial [RCT]), and aortic disease (10 articles). All authors described 3DPSP as helpful in assessing complex anatomic conditions, whereas poor tissue mimicry and the non-consideration of physiological properties were cited as limitations. Compared to controls, meta-analysis of six studies showed a significant reduction of intervention time in LAA occlusion (n=3 studies), and surgery due to CHD (n=3) if 3DPSPs were used (Cohen's d=0.54; 95% confidence interval, 0.13 to 0.95; p=0.001), however heterogeneity across studies should be taken into account.

CONCLUSIONS

3DPSP are helpful to plan, train, and guide interventions in patients with complex cardiovascular anatomy. Benefits for patients include reduced intervention time with the potential for lower radiation exposure and shorter mechanical ventilation times. More evidence and RCTs including clinical endpoints are needed to warrant adoption of 3DPSP into routine clinical practice.

3D printing for left atrial appendage closure: A meta-analysis and systematic review

BACKGROUND

Three-dimensional printing (3D) has emerged as an alternative to imaging to guide left atrial appendage closure (LAAC) device sizing.

AIMS

We assessed the usefulness of 3D printing compared to a standard imaging-only approach for LAAC.

METHODS

We identified studies comparing an imaging-only with a 3D printing approach in LAAC. A fixed-effects meta-analysis was performed targeting a co-primary endpoint of disagreement in device sizing and leaks.

RESULTS

Eight studies that assigned 283 participants to an imaging-only approach and 3D printing approach (145 patients) were included. 3D printing significantly reduced the risk of the co-primary endpoint (risk raio (RR) = 0.19; 95% confidence interval (CI) 0.09-0.37), with consistency across the studies (I2 = 0%). Individually, both device size disagreements [RR 0.13 (95% CI 0.06-0.29), P < 0.001] and leaks [RR 0.24 (95% CI 0.09-0.64) P = 0.004] were reduced under a 3D printing modeling strategy.

CONCLUSION

Compared with an imaging-only strategy, 3D printing is associated with reduction in device size disagreements and leaks.

Effect of 3D-printed hearts used in left ventricular outflow tract obstruction: a multicenter study

Objective

The purpose of this research was to explore the application value of a three-dimensional (3D)-printed heart in surgery for left ventricular outflow tract (LVOT) obstruction.

Methods

From August 2019 to October 2021, 46 patients with LVOT obstruction underwent surgical treatment at our institution. According to the treatment method, 22 and 24 patients were allocated to the experimental and control groups, respectively. In the experimental group, each patient’s 3D-printed heart model was used for simulated preoperative surgery, and then the Morrow operation was performed. In the control group, only the Morrow operation was performed, without simulated preoperative surgery using a 3D-printed heart model. The intraoperative and postoperative data of patients in the two groups were recorded, and the clinical data of patients were compared between the two groups.

Results

The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, LVOT pressure difference (LVP), postoperative interventricular septal thickness (IST), aortic regurgitation (AR), systolic anterior motion (SAM), and postoperative left ventricular flow velocity (LVFV) were significantly lower in the experimental group than in the control group (P < 0.05). The inner diameter of the left ventricular outflow tract (IDLV) was larger in the experimental group than in the control group (P < 0.05). There was no significant difference in the postoperative ejection fraction, atrioventricular block rate or complication rate between the two groups (P > 0.05).

Conclusion

A 3D-printed heart model for simulated surgery in vitro is conducive to formulating a more reasonable surgical plan and reducing the trauma and duration of surgery, thereby promoting the recovery and maintenance of the heart.

An impact of three dimensional techniques in virtual reality

Three dimensional (3D) imaging play a prominent role in the diagnosis, treatment planning, and post-therapeutic monitoring of patients with Rheumatic Heart Disease (RHD) or mitral valve disease. More interactive and realistic medical experiences take an advantage of advanced visualization techniques like augmented, mixed, and virtual reality to analyze the 3D models. Further, 3D printed mitral valve model is being used in medical field. All these technologies improve the understanding of the complex morphologies of mitral valve disease. Real-time 3D Echocardiography has attracted much more attention in medical researches because it provides interactive feedback to acquire high-quality images as well as timely spatial information of the scanned area and hence is necessary for intraoperative ultrasound examinations. In this article, three dimensional techniques and its impacts in mitral valve disease are reviewed. Specifically, the data acquisition techniques, reconstruction algorithms with clinical applications are presented. Moreover, the advantages and disadvantages of state-of-the-art approaches are discussed in detail.

Improving Left Atrial Appendage Occlusion Device Size Determination by Three-Dimensional Printing-Based Preprocedural Simulation

Background

The two-dimensional (2D)-based left atrial appendage (LAA) occluder (LAAO) size determination by using transesophageal echocardiography (TEE) is limited by the structural complexity and wide anatomical variation of the LAA.

Objective

This study aimed to assess the accuracy of the LAAO size determination by implantation simulation by using a three-dimensional (3D)-printed model compared with the conventional method based on TEE.

Methods

We retrospectively reviewed patients with anatomically and physiologically properly implanted the Amplatzer Cardiac Plug and Amulet LAAO devices between January 2014 and December 2018 by using the final size of the implanted devices as a standard for size prediction accuracy. The use of 3D-printed model simulations in device sizing was compared with the conventional TEE-based method.

Results

A total of 28 cases with the percutaneous LAA occlusion were reviewed. There was a minimal difference [−0.11 mm; 95% CI (−0.93, 0.72 mm); P = 0.359] between CT-based reconstructed 3D images and 3D-printed left atrium (LA) models. Device size prediction based on TEE measurements showed poor agreement (32.1%), with a mean difference of 2.3 ± 3.2 mm [95% CI (−4.4, 9.0)]. The LAAO sizing by implantation simulation with 3D-printed models showed excellent correlation with the actually implanted LAAO size (r = 0.927; bias = 0.7 ± 2.5). The agreement between the 3D-printed and the implanted size was 67.9%, with a mean difference of 0.6 mm [95% CI (−1.9, 3.2)].

Conclusion

The use of 3D-printed LA models in the LAAO size determination showed improvement in comparison with conventional 2D TEE method.

The accuracy and reliability of 3D printed aortic templates: a comprehensive three-dimensional analysis

Background

Advances in 3D printing technology allow us to continually find new medical applications. One of them is 3D printing of aortic templates to guide vascular surgeons or interventional radiologists to create fenestrations in the stent-graft surface for the implantation procedure called fenestrated endovascular aortic aneurysm repair. It is believed that the use of 3D printing significantly improves the quality of modified fenestrated stent-grafts. However, the accuracy and reliability of personalized 3D printed models of aortic templates are not well established.

Methods

Thirteen 3D printed templates of the visceral aorta and sixteen of the aortic arch and their corresponding computer tomography of angiography images were included in this accuracy study. The 3D models were scanned in the same conditions on computed tomography (CT) and evaluated by three physicians experienced in vascular CT assessment. Model and patient CT measurements were performed at key landmarks to maintain quality for stent-graft modification, including side branches and aortic diameters. CT-scanned aortic templates were segmented, aligned with sourced patient data, and evaluated for the Hausdorff matrix. Next, Bland-Altman plots determined the degree of agreement.

Results

The Intraclass Correlation Coefficients values were more than 0.9 for all measurements of aortic diameters and aortic branches diameter in all landmark locations. Therefore, the reliability of the aortic templates was considered excellent. The Bland-Altman plots analysis indicated measurement biases of 0.05 to 0.47 for aortic arch templates and 0.06 to 0.38 for reno-visceral aortic templates. The arithmetic mean of Hausdorff's mean distances of the aortic arch templates was 0.47 mm (SD =0.06) and ranged from 0.34 to 0.58. The mean metrics for abdominal models was 0.24 mm (SD =0.03) and ranged from 0.21 to 0.31.

Conclusions

The printed models of 3D aortic templates are accurate and reliable, thus can be widely used in endovascular surgery and interventional radiology departments as aortic templates to guide the physician-modified fenestrated stent-graft fabrication.

Computed Tomography-Derived Three-Dimensional Printed Models versus Two-Dimensional Transesophageal Echocardiography for Left Atrial Appendage Occlusion Device Planning: A Systematic Review and Meta-Analysis

Objective

This systematic review and meta-analysis compared computed tomography (CT)-derived three-dimensional (3D) modeling versus two-dimensional transesophageal echocardiography (TEE) for left atrial appendage occluder (LAAO) device planning.

Background

LAAO device planning is commonly performed with TEE. However, procedures often require multiple devices and deployments due to inaccurate sizing from TEE. The use of CT three-dimensional (3D) models for LAAO device planning may improve accuracy.

Methods

Four clinical studies that reported procedural and clinical outcomes for CT-derived 3D modeling versus TEE for LAAO device planning were identified. End points were accurate device sizing, procedure failure, number of devices used per procedure, fluoroscopy time, and post-procedure leak. Risk ratio (RR) and mean difference (MD) with a 95% confidence interval (CI) were calculated by the Mantel-Haenszel and inverse variance methods.

Results

A total of 166 participants were included. When compared with conventional imaging, the use of 3D printed models was associated with less fluoroscopy time (MD -6.98 minutes, 95% CI -12.68 to -1.28, p=0.02) and lower risk of occluder device peri-prosthetic leak (RR 0.23, 95% CI 0.07-0.73, p=0.01) for LAAO. There were signals towards lower number of devices per procedure (MD -0.56 devices, 95% CI -1.16-0.05, p=0.07) and less total procedure time (MD -13.50 minutes, 95% CI -28.14-1.14, p=0.07) with printed modeling for LAAO. There was no difference between modalities in rates of procedure failure.

Conclusions

CT-derived 3D printed models for LAAO device planning may offer the advantages of lower LAAO device peri-prosthetic leak and less fluoroscopy time when compared with conventional TEE guidance.

Pre- and Postprocedural CT of Transcatheter Left Atrial Appendage Closure Devices

Transcatheter left atrial appendage (LAA) closure is an alternative to long-term anticoagulation therapy in selected patients with nonvalvular atrial fibrillation who have an increased risk for stroke. LAA closure devices can be implanted by means of either an endocardial or a combined endocardial and epicardial approach. Preprocedural imaging is key to identifying contraindications, accurately sizing the device, and minimizing complications. Transesophageal echocardiography (TEE) has been the reference standard imaging modality to assess the anatomy for LAA closure and to provide intraprocedural guidance. However, CT has emerged as a less-invasive alternative to TEE for pre- and postprocedural imaging. CT is comparable to TEE for exclusion of thrombus but is superior to TEE for the delineation of complex LAA anatomy, measurement for device sizing, and evaluation of pulmonary venous and extracardiac structures. CT provides accurate measurements of the LAA ostial diameter, landing zone diameter, and LAA length, which are vital for accurate sizing of the device. CT allows evaluation of the relationship with the pulmonary veins and other adjacent structures that can be injured during the procedure. CT also simulates procedural fluoroscopic angles and provides evaluation of the interatrial septum, which is punctured during LAA closure. CT also provides a more convenient method for the evaluation of postprocedural complications such as incomplete closure, peridevice leaking, device-related thrombus, and device dislodgement. Online supplemental material is available for this article. ^©RSNA, 2021.

Application of 3D Printing in Preoperative Planning

Preoperative planning is critical for success in the surgical suite. Current techniques for surgical planning are limited; clinicians often rely on prior experience and medical imaging to guide the decision-making process. Furthermore, two-dimensional (2D) presentations of anatomical structures may not accurately portray their three-dimensional (3D) complexity, often leaving physicians ill-equipped for the procedure. Although 3D postprocessed images are an improvement on traditional 2D image sets, they are often inadequate for surgical simulation. Medical 3D printing is a rapidly expanding field and could provide an innovative solution to current constraints of preoperative planning. As 3D printing becomes more prevalent in medical settings, it is important that clinicians develop an understanding of the technologies, as well as its uses. Here, we review the fundamentals of 3D printing and key aspects of its workflow. The many applications of 3D printing for preoperative planning are discussed, along with their challenges.

Big data and new information technology: what cardiologists need to know

Technological progress in medicine is constantly garnering pace, requiring that physicians constantly update their knowledge. The new wave of technologies breaking through into clinical practice includes the following: a) mHealth, which allows constant monitoring of biological parameters, anytime, anyplace, of hundreds of patients at the same time; b) artificial intelligence, which, powered by new deep learning techniques, are starting to beat human experts at their own game: diagnosis by imaging or electrocardiography; c) 3-dimensional printing, which may lead to patient-specific prostheses; d) systems medicine, which has arisen from big data, and which will open the way to personalized medicine by bringing together genetic, epigenetic, environmental, clinical and social data into complex integral mathematical models to design highly personalized therapies. This state-of-the-art review aims to summarize in a single document the most recent and most important technological trends that are being applied to cardiology, and to provide an overall view that will allow readers to discern at a glance the direction of cardiology in the next few years.

Clinical Applications of Patient-Specific 3D Printed Models in Cardiovascular Disease: Current Status and Future Directions

Three-dimensional (3D) printing has been increasingly used in medicine with applications in many different fields ranging from orthopaedics and tumours to cardiovascular disease. Realistic 3D models can be printed with different materials to replicate anatomical structures and pathologies with high accuracy. 3D printed models generated from medical imaging data acquired with computed tomography, magnetic resonance imaging or ultrasound augment the understanding of complex anatomy and pathology, assist preoperative planning and simulate surgical or interventional procedures to achieve precision medicine for improvement of treatment outcomes, train young or junior doctors to gain their confidence in patient management and provide medical education to medical students or healthcare professionals as an effective training tool. This article provides an overview of patient-specific 3D printed models with a focus on the applications in cardiovascular disease including: 3D printed models in congenital heart disease, coronary artery disease, pulmonary embolism, aortic aneurysm and aortic dissection, and aortic valvular disease. Clinical value of the patient-specific 3D printed models in these areas is presented based on the current literature, while limitations and future research in 3D printing including bioprinting of cardiovascular disease are highlighted.

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.

Reference value of perimeter-derived diameter assessed by three-dimensional transesophageal echocardiography in left atrial appendage occluder size selection

BACKGROUND

The aim of this study was to investigate the utility of perimeter-derived diameter (PDD) measured by three-dimensional (3D) transesophageal echocardiography (TEE) in predicting the size of left atrial appendage (LAA) occluder.

METHODS AND RESULTS

Left atrial appendage landing zone diameter (LZD) was measured by two-dimensional (2D) TEE, 3DTEE, and digital subtraction angiography (DSA) as LZD-2Dmax, LZD-2Dmean, LZD-3Dmax, LZD-3Dmean, LZD-PDD, LZD-DSAmax, respectively, before and during transcatheter LAA closure with Watchman devices in 100 patients. A difference of one or more device size intervals between the predicted size and the size actually implanted was defined as mismatching. Seventy-eight patients were followed up by TEE to obtain occluder compression ratio. The correlation between LZD and the final implanted occluder size was 0.559, 0.641, 0.754, 0.760, 0.782, and 0.848 for LZD-2Dmax, LZD-2Dmean, LZD-3Dmax, LZD-3Dmean, LZD-PDD and LZD-DSAmax, respectively (P < .001). Matching ratio between the size predicted by retrospective measurements of LZD and the device size actually implanted was 65%, 57%, 66%, 63%, 70%, and 83% for LZD-2Dmax, LZD-2Dmean, LZD-3Dmax, LZD-3Dmean, LZD-PDD and LZD-DSAmax, respectively. There was no significant difference in LZD value, matching ratio, and compression ratio between the patients with eccentric and noneccentric LAA landing zone (P > .05). Compression ratio of the mismatching subjects was higher than that in the matching subjects when evaluated by LZD-2Dmean, LZD-3Dmean, and LZD-PDD (P < .05).

CONCLUSIONS

Landing zone diameter derived from LAA perimeter measured by preprocedure 3DTEE showed reference value for LAA occluder size selection, providing superior correlation and matching ratio with the final implanted size and indicating the adjustment of oversizing.

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.

Patient-Specific Modeling for Structural Heart Intervention: Role of 3D Printing Today and Tomorrow CME

Structural heart interventions (SHIs) are increasingly applicable in a wide range of heart defects, but the intricate and dynamic nature of cardiac structures can make SHIs challenging to perform. Three-dimensional (3D) printed modeling integrates advanced clinical imaging and 3D printing technology to replicate patient-specific anatomy for comprehensive planning and simulation of SHIs. This review discusses the basic principles of patient-specific 3D print model development, print material selection, and model fabrication and highlights how cardiovascular 3D printing can be used in preprocedural planning, device sizing, enhanced communication, and procedure simulation.

Personalized Fluoroscopic Angles in Watchman™ Left Atrial Appendage Closure Landing Zone Assessment: A Three-Dimensional Printed Simulation Study

Background

Atrial fibrillation causes ischemic stroke when thrombi dislodge from a cardiac outpouching, the left atrial appendage (LAA), and embolize to the brain. LAA occlusion with the Watchman™ device (Boston Scientific Corporation, MA, USA), which prevents stroke, requires accurate LAA measurements for device sizing. We explore whether standard fluoroscopic LAA measurements improve when obtained at CT-derived viewing angles personalized to LAA anatomy while concurrently referring to three-dimensional (3D) CT.

Methods

Left atrial 3D reconstructions created from contrast CT (n=28) were analysed to identify personalized viewing angles wherein LAA dimensions (LAA maximum landing zone diameter and LAA length) were best observed. The 3D-CT reconstructions were then 3D printed with stands. Fluoroscopy of anatomically oriented models in the catheter lab simulated LAA angiography. Fluoroscopic images were acquired at standard (caudal 20˚/right anterior oblique 30˚) and personalized viewing angles. Repeated measurements of LAA dimensions were taken from CT (Control), fluoroscopy at standard angles (Standard), personalized angles (Blinded), and personalized angles while concurrently referring to 3D CT (Referred).

Results

Control measurements correlated and agreed better with Referred and Blinded measurements than with Standard measurements (diameter correlation and agreement: Control/Standard r=.554, limits of agreement [LOAs]=6.83/-5.91; Control/Blinded r=.641, LOA =5.67/-5.54; Control/Referred r=.741, LOA=4.69/-4.14; length correlation and agreement: Control/Standard r_s=.829, LOA=9.61/-3.02; Control/Blinded r_s=0.789, LOA=7.13/-4.94; Control/Referred r_s=.907, LOA=4.84/-4.13). Personalized angles resulted in hypothetical device size predictions more consistent with Control (device size correlation: Control/Standard r_s=.698, Control/Blinded r_s=.731, Control/Referred r_s=.893, P<0.001). False ineligibility rates were Standard=6/28, Blinded=6/28, and Referred=2/28.

Conclusion

This simulation suggests that personalized fluoroscopic viewing angles with in-procedural reference to 3D CT may improve the accuracy of LAA maximum landing zone diameter and length measurements at the Watchman landing zone. This improvement may result in more consistent device size selection and procedural eligibility assessment. Further clinical research on these interventions is merited.

3D printing in adult cardiovascular surgery and interventions: a systematic review

3D printing in adult cardiac and vascular surgery has been evaluated over the last 10 years, and all of the available literature reports benefits from the use of 3D models. In the present study, we analyzed the current applications of 3D printing for adult cardiovascular disease treated with surgical or catheter-based interventions, including the clinical medical simulation of physiological or pathology conducted with 3D printing in this field. A search of PubMed and MEDLINE databases were supplemented by searching through bibliographies of key articles. Thereafter, data on demographic, clinical scenarios and application, imaging modality, purposes of using with 3D printing, outcomes and follow-up were extracted. A total of 43 articles were deemed eligible and included. 296 patients (mean age: 65.4±14.2 years; male, 58.2%) received 3D printing for cardiac and vascular surgery or conditions [percutaneous left atrial appendage occlusion (LAAO), TAVR, mitral valve disease, aortic valve replacement, coronary artery abnormality, HOCM, aortic aneurysm and aortic dissection, Kommerell's diverticulum, primary cardiac tumor and ventricular aneurysm]. Eight papers reported the utility of 3D printing in the medical simulator and training fields. Most studies were conducted starting in 2014. Twenty-six was case report. The major scenario used with 3D printing technology was LAAO (50.3%) and followed by TAVR (17.6%). CT and echocardiography were two main imaging techniques that were used to generate 3D-printed heart models. All studies showed that 3D-printed models were helpful for preoperative planning, orientation, and medical teaching. The important finding is that 3D printing provides a unique patient-specific method to assess complex anatomy and is helpful for intraoperative orientation, decision-making, creating functional models, and teaching adult cardiac and vascular surgery, including catheter-based heart surgery.

3D modeling: a future of cardiovascular medicine

Cardiovascular disease resulting from atypical cardiac structures continues to be a leading health concern despite advancements in diagnostic imaging and surgical techniques. However, the ability to visualize spatial relationships using current technologies remains a challenge. Therefore, 3D modeling has gained significant interest to understand complex and atypical cardiovascular disorders. Moreover, 3D modeling can be personalized and patient-specific. 3D models have been demonstrated to aid surgical planning and simulation, enhance communication among surgeons and patients, optimize medical device design, and can be used as a potential teaching tool in medical schools. In this review, we discuss the key components needed to generate cardiac 3D models. We highlight prevalent structural conditions that have utilized 3D modeling in pre-operative planning. Furthermore, we discuss the current limitations of routine use of 3D models in the clinic as well as future directions for utilization of this technology in the cardiovascular field.