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Double Outlet Right Ventricle: Introductory Concepts and Applications
Abstract
There is marked anatomical variability present in those with double outlet right ventricle, often posing a challenge to the interpretation of the 3D anatomy from 2D imaging. Rapid prototyping has certainly found a niche in presurgical planning for double outlet right ventricle, specifically aiding in better understanding of the best potential pathways to performing biventricular repair. In this chapter, we review the common variants of double outlet right ventricle, and the applications of rapid prototyping, giving specific examples to highlight the growing potential for not only presurgical planning, but surgical simulation to improving the surgical management and outcomes in these patients.
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Double outlet right ventricle (DORV) is a heterogeneous group of congenital heart diseases that require individualized surgical approach based on precise understanding of the complex cardiovascular anatomy. Physical 3-dimensional (3D) print models not only allow fast and unequivocal perception of the complex anatomy but also eliminate misunderstanding or miscommunication among imagers and surgeons. Except for those cases showing well-recognized classic surgical anatomy of DORV such as in cases with a typical subaortic or subpulmonary ventricular septal defect, 3D print models are of enormous value in surgical decision and planning. Furthermore, 3D print models can also be used for rehearsal of the intended procedure before the actual surgery on the patient so that the outcome of the procedure is precisely predicted and the procedure can be optimally tailored for the patient’s specific anatomy. 3D print models are invaluable resource for hands-on surgical training of congenital heart surgeons.
Patient-specific computational models have been extensively developed over the last decades and applied to investigate a wide range of cardiovascular problems. However, translation of these technologies into clinical applications, such as planning of medical procedures, has been limited to a few single case reports. Hence, the use of patient-specific models is still far from becoming a standard of care in clinical practice. The aim of this study is to describe our experience with a modelling framework that allows patient-specific simulations to be used for prediction of clinical outcomes. A cohort of 12 patients with congenital heart disease who were referred for percutaneous pulmonary valve implantation, stenting of aortic coarctation and surgical repair of double-outlet right ventricle was included in this study. Image data routinely acquired for clinical assessment were post-processed to set up patient-specific models and test device implantation and surgery. Finite-element and computational fluid dynamics analyses were run to assess feasibility of each intervention and provide some guidance. Results showed good agreement between simulations and clinical decision including feasibility, device choice and fluid-dynamic parameters. The promising results of this pilot study support translation of computer simulations as tools for personalization of cardiovascular treatments.
Three-dimensional (3D) whole heart techniques form a cornerstone in cardiovascular magnetic resonance imaging of congenital heart disease (CHD). It offers significant advantages over other CHD imaging modalities and techniques: no ionizing radiation; ability to be run free-breathing; ECG-gated dual-phase imaging for accurate measurements and tissue properties estimation; and higher signal-to-noise ratio and isotropic voxel resolution for multiplanar reformatting assessment. However, there are limitations, such as potentially long acquisition times with image quality degradation. Recent advances in and current applications of 3D whole heart imaging in CHD are detailed, as well as future directions.
We present an interactive algorithm to segment the heart chambers and epicardial surfaces, including the great vessel walls, in pediatric cardiac MRI of congenital heart disease. Accurate whole-heart segmentation is necessary to create patient-specific 3D heart models for surgical planning in the presence of complex heart defects. Anatomical variability due to congenital defects precludes fully automatic atlas-based segmentation. Our interactive segmentation method exploits expert segmentations of a small set of short-axis slice regions to automatically delineate the remaining volume using patch-based segmentation. We also investigate the potential of active learning to automatically solicit user input in areas where segmentation error is likely to be high. Validation is performed on four subjects with double outlet right ventricle, a severe congenital heart defect. We show that strategies asking the user to manually segment regions of interest within short-axis slices yield higher accuracy with less user input than those querying entire short-axis slices.
Rapid prototyping facilitates comprehension of complex cardiac anatomy. However, determining when this additional information proves instrumental in patient management remains a challenge. We describe our experience with patient-specific anatomic models created using rapid prototyping from various imaging modalities, suggesting their utility in surgical and interventional planning in congenital heart disease (CHD). Virtual and physical 3-dimensional (3D) models were generated from CT or MRI data, using commercially available software for patients with complex muscular ventricular septal defects (CMVSD) and double-outlet right ventricle (DORV). Six patients with complex anatomy and uncertainty of the optimal management strategy were included in this study. The models were subsequently used to guide management decisions, and the outcomes reviewed. 3D models clearly demonstrated the complex intra-cardiac anatomy in all six patients and were utilized to guide management decisions. In the three patients with CMVSD, one underwent successful endovascular device closure following a prior failed attempt at transcatheter closure, and the other two underwent successful primary surgical closure with the aid of 3D models. In all three cases of DORV, the models provided better anatomic delineation and additional information that altered or confirmed the surgical plan. Patient-specific 3D heart models show promise in accurately defining intra-cardiac anatomy in CHD, specifically CMVSD and DORV. We believe these models improve understanding of the complex anatomical spatial relationships in these defects and provide additional insight for pre/intra-interventional management and surgical planning.
Congenital heart diseases causing significant hemodynamic and functional consequences require surgical repair. Understanding of the precise surgical anatomy is often challenging and can be inadequate or wrong. Modern high resolution imaging techniques and 3D printing technology allow 3D printing of the replicas of the patient’s heart for precise understanding of the complex anatomy, hands-on simulation of surgical and interventional procedures, and morphology teaching of the medical professionals and patients. CT or MR images obtained with ECG-gating and breath-holding or respiration navigation are best suited for 3D printing. 3D echocardiograms are not ideal but can be used for printing limited areas of interest such as cardiac valves and ventricular septum. Although the print materials still require optimization for representation of cardiovascular tissues and valves, the surgeons find the models suitable for practicing closure of the septal defects, application of the baffles within the ventricles, reconstructing the aortic arch, and arterial switch procedure. Hands-on surgical training (HOST) on models may soon become a mandatory component of congenital heart disease surgery program. 3D printing will expand its utilization with further improvement of the use of echocardiographic data and image fusion algorithm across multiple imaging modalities and development of new printing materials. Bioprinting of implants such as stents, patches and artificial valves and tissue engineering of a part of or whole heart using the patient’s own cells will open the door to a new era of personalized medicine.
Background:
Double outlet right ventricle (DORV) with two well-developed ventricles and with a remote ventricular septal defect (VSD) may present a therapeutic challenge. Echocardiographic imaging of such complex cases does not always provide all of the information required to decide on an operative approach (biventricular or univentricular) and to design an intracardiac baffle to direct left ventricular outflow through the VSD and to the aorta for biventricular repair. A three dimensional (3D) printed model of the heart based upon data derived from computed tomography (CT) or magnetic resonance imaging (MRI) may contribute to a more complete appreciation of the intracardiac anatomy.
Methods:
From April to September 2015, six consecutive patients with DORV and remote VSD underwent CT/MRI scans. Data sets from these studies were used to generate life-size 3D models using a 3D printer. We compared the assessment of 3D printed heart model findings with information obtained from echocardiography, CT, or cardiac MRI and with details of the surgeon's intraoperative direct observations when available. Quantification of the information provided by the 3D model was achieved using a unique scale that was created for the purpose of this study. The accuracy and utility of information derived preoperatively from the models were assessed.
Results:
Six data sets from six patients were analyzed. Five data sets could be successfully used to create sandstone models using 3D printing. The five patients ranged from 7 months to 11 years of age and weighed 6.7 to 26 kg. The spatial orientation of the heart in the thorax, the relationships of the great arteries and the semilunar valves, the size and location of the VSD were well appreciated in all models, as were the anticipated dimensions and orientation of a surgically planned interventricular baffle. Three of the five patients underwent successful biventricular repair.
Conclusion:
The 3D printed models scored higher than conventional imaging, with respect to most aspects of the surface spatial orientation and intracardiac anatomy. The models are a useful adjunct in preoperative assessment of complex DORV. The unique scale helps quantify the advantages and limitations of the 3D heart models.
Hand-held three dimensional models of the human anatomy and pathology, tailored-made protheses, and custom-designed implants can be derived from imaging modalities, most commonly Computed Tomography (CT). However, standard DICOM format images cannot be 3D printed; instead, additional image post-processing is required to transform the anatomy of interest into Standard Tessellation Language (STL) format is needed. This conversion, and the subsequent 3D printing of the STL file, requires a series of steps. Initial post-processing involves the segmentation-demarcation of the desired for 3D printing parts and creating of an initial STL file. Then, Computer Aided Design (CAD) software is used, particularly for wrapping, smoothing and trimming. Devices and implants that can also be 3D printed, can be designed using this software environment. The purpose of this article is to provide a tutorial on 3D Printing with the test case of complex congenital heart disease (CHD). While the infant was born with double outlet right ventricle (DORV), this hands-on guide to be featured at the 2015 annual meeting of the Radiological Society of North America Hands-on Course in 3D Printing focused on the additional finding of a ventricular septal defect (VSD). The process of segmenting the heart chambers and the great vessels will be followed by optimization of the model using CAD software. A virtual patch that accurately matches the patient’s VSD will be designed and both models will be prepared for 3D printing.
Objectives To assess the communication potential of three-dimensional (3D) patient-specific models of congenital heart defects and their acceptability in clinical practice for cardiology consultations.
Design This was a questionnaire-based study in which participants were randomised into two groups: the ‘model group’ received a 3D model of the cardiac lesion(s) being discussed during their appointment, while the ‘control group’ had a routine visit.
Setting Outpatient clinic, cardiology follow-up visits.
Participants 103 parents of children with congenital heart disease were recruited (parental age: 43±8 years; patient age: 12±6 years). In order to have a 3D model made, patients needed to have a recent cardiac MRI examination; this was the crucial inclusion criterion.
Interventions Questionnaires were administered to the participants before and after the visits and an additional questionnaire was administered to the attending cardiologist.
Main outcome measures Rating (1–10) for the liking of the 3D model, its usefulness and the clarity of the explanation received were recorded, as well as rating (1–10) of the parental understanding and their engagement according to the cardiologist. Furthermore, parental knowledge was assessed by asking them to mark diagrams, tick keywords and provide free text answers. The duration of consultations was recorded and parent feedback collected.
Results Parents and cardiologists both found the models to be very useful and helpful in engaging the parents in discussing congenital heart defects. Parental knowledge was not associated with their level of education (p=0.2) and did not improve following their visit. Consultations involving 3D models lasted on average 5 min longer (p=0.02).
Conclusions Patient-specific models can enhance engagement with parents and improve communication between cardiologists and parents, potentially impacting on parent and patient psychological adjustment following treatment. However, in the short-term, parental understanding of their child's condition did not improve.
Ventricular volumes and ejection fraction are often used in clinical decision making in patients with congenital heart disease (CHD). The referral diagnosis, radiation exposure and image quality of functional cardiac computed tomography (CT) in a relatively large cohort of patients of CHD has not been reported. This is a retrospective evaluation of functional CT studies performed in CHD patients from three institutions (1/2007-3/2013). Patient and scanner characteristics, radiation dose estimates and image quality were compared. Two hundred ninety-eight functional CT studies were evaluated. The most common referral diagnosis were tetralogy of Fallot (33 %), transposition complexes (24 %) single ventricle heart disease (15 %), and left sided obstruction (15 %). The reason for cardiac CT was presence of pacemaker (60 %), need for detailed coronary artery imaging (18 %), metallic artifact in CMR (12 %), evaluation of prosthetic valve function (4 %), and claustrophobia or BMI too large for the available MR scanner (6 %). 266 (89.3 %) scans allowed quantification of ventricular function, 25 (8.4 %) scans allowed qualitative assessment of function, and 7 (2.3 %) of the scans were non-diagnostic for functional analysis. Median DLP was 399 mGy cm (186, 614), and median effective dose was 5.5 mSv (2.6, 8.5). Radiation dose and image quality varied across institutions. Cardiac CT function imaging can be performed in patients with congenital heart disease when CMR is contraindicated or has poor image quality. Radiation dose and image quality varies across institutions.
Our purpose was to describe the outcome of the Rastelli repair in D -transposition of the great arteries and to determine the risk factors associated with unfavorable events.
From March 1973 to April 1998, 101 patients with D -transposition of the great arteries and ventricular septal defect underwent a Rastelli type of repair. Median age and weight were 3.1 years (10th to 90th percentiles 0.3-9.9 years) and 12.8 kg (5.9-28.2). Pulmonary stenosis was present in 73 patients and pulmonary atresia in 18; 10 patients had no left ventricular outflow tract obstruction.
There were 7 early deaths (7%) and no operative deaths in the last 7 years of the study. Risk factors for early death, by univariable analysis, included straddling tricuspid valve (P =.04) and longer aortic crossclamping times (P =.04). At a median follow-up of 8.5 years, there were 17 late deaths and 1 patient had undergone heart transplantation. Forty-four patients had reoperations for conduit stenosis, 11 for left ventricular outflow tract obstruction, and 28 had interventional catheterization to relieve conduit stenosis. Nine patients had late arrhythmias, and there were 5 sudden deaths. Overall freedom from death or transplantation (Kaplan-Meier) was 82%, 80%, 68%, and 52% at 5, 10, 15, and 20 years, respectively. Freedom from death or reintervention (catheterization or surgical treatment) was 53%, 24%, and 21% at 5, 10, and 15 years of follow-up, respectively.
The Rastelli repair can be performed with low early mortality. However, substantial late morbidity and mortality are associated with conduit obstruction, left ventricular outflow tract obstruction, and arrhythmia.
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.
Aims
Proof of concept and feasibility study for preoperative diagnostic use of mixed reality (MR) holograms of individual 3D heart models from standard cardiac computed tomography angiograms (CTA) images. Optimal repair for complex congenital heart disease poses high demands on 3D anatomical imagination. Three-dimensional printed heart models are increasingly used for improved morphological understanding during surgical and interventional planning. Holograms are a dynamic and interactive alternative, probably with wider applications.
Methods and results
A 3D heart model was segmented from CTA images in a patient with double outlet right ventricle and transposition of the great arteries (DORV-TGA). The hologram was visualized in the wearable MR platform HoloLens® for 36 paediatric heart team members who filled out a diagnostic and quality rating questionnaire. Morphological and diagnostic output from the hologram was assessed and the 3D experience was evaluated. Locally developed app tools such as hologram rotation, scaling, and cutting were rated. Anatomy identification and diagnostic output was high as well as rating of 3D experience. Younger and female users rated the app tools higher.
Conclusion
This preliminary study demonstrates that MR holograms as surgical planning tool for congenital heart disease may have a high diagnostic value and contribute to understanding complex morphology. The first users experience of the hologram presentation was found to be very positive, with a preference among the female and the younger users. There is potential for improvement of the hologram manipulation tools.
Objectives:
Double-outlet right ventricle is a form of ventriculoarterial connection. The definition formulated by the International Society for Nomenclature of Paediatric and Congenital Heart Disease is based on hearts with both arterial trunks supported in their greater part by a morphologically right ventricle. Bilateral infundibula and ventricular septal defects are highly debated criteria. This study examines the anatomic controversies surrounding double-outlet right ventricle. We show that hearts with double-outlet right ventricle can have atrioventricular-to-arterial valvular continuity. We emphasize the difference between the interventricular communication and the zone of deficient ventricular septation.
Methods:
The hearts examined were from the University of Florida in Gainesville; Johns Hopkins All Children's Hospital, St Petersburg, Fla; and Lurie Children's Hospital, Chicago, Ill. Each specimen had at least 75% of both arterial roots supported by the morphologically right ventricle, with a total of 100 hearts examined. The morphologic method was used to assess anatomic features, including arterial-atrioventricular valvular continuity, subarterial infundibular musculature, and the location of the hole between the ventricles.
Results:
Most hearts had fibrous continuity between one of the arterial valves and an atrioventricular valve, with bilateral infundibula in 23%, and intact ventricular septum in 5%.
Conclusions:
Bilateral infundibula are not a defining feature of double-outlet right ventricle, representing only 23% of the specimens in our sample. The interventricular communication can have a posteroinferior muscular rim or extend to become perimembranous (58%). Double-outlet right ventricle can exist with an intact ventricular septum.
Rapid prototyping may be beneficial in properly selected cases of complex congenital heart disease, providing detailed anatomical understanding that helps to guide potential surgical and cardiac catheterization interventions. We present a case of double-outlet right ventricle, where the decision to obtain a three-dimensional printed model helped for better understanding of the anatomy, with the additional advantage of surgical simulation in planning the surgical approach and type of surgical repair.
Many, if not most, of the controversies regarding the description of the congenitally malformed heart have been resolved over the turn of the 20th century. A group of lesions that remains contentious is the situation in which both arterial trunks, in their greater part, are supported by the morphologically right ventricle. It was considered, for many years, that presence of bilateral infundibulums, or conuses, was a necessity for such a diagnosis. It has now been appreciated that this suggestion founders on many counts. In the first instance, such bilateral infundibulums are to be found in patients with other ventriculo-arterial connections, including the otherwise normal heart. In the second instance, it is clear that such an approach abrogates the important principle now known as the morphological method. This states that entities should be defined in terms of their intrinsic morphology and not on the basis of other variable features. It is now also clear that, when assessed simply on the basis of the ventricular origin of the arterial trunks, a significant number of patients fulfil the criteria for so-called “200%” origin of the trunks from the right ventricle when there is fibrous continuity between the leaflets of the atrioventricular and arterial valves. In this review, we show how attention to the morphology of the channel between the ventricles now provides the key to accurately diagnose the ventriculo-arterial connection in patients with suspected double-outlet right ventricle.
This is because, when both arterial trunks arise exclusively or predominantly from the morphologically right ventricle, the outlet septum, of necessity, is itself a right ventricular structure. The channel between the ventricles, therefore, is roofed by the inner heart curvature, whether that structure is fibrous or muscular. Our observations then confirm that it is the attachment of the outlet septum, which itself can be muscular or fibrous, which determines the commitment of the interventricular communication to the subarterial outlets. The interventricular communication itself, when directly committed to the ventricular outlets, opens between the limbs of the septomarginal trabeculation or septal band. The defect is subaortic when the outlet septum is attached to the cranial limb of the trabeculation, subpulmonary when attached to the caudal limb, and doubly committed when attached to the inner heart curvature in the roof of the defect. Non-committed defects are no longer positioned within the limbs of the septomarginal trabeculation. Although readily demonstrable by a skilled echocardiographer, we show how these anatomical features are more easily demonstrated with added accuracy when using CT data sets.
Preamble This is the second of two complementary documents commissioned by the SCCT to provide recommendations on the use and optimal performance of cardiac computed tomography (CT) in patients of all ages with congenital heart disease (CHD). The aim of the first document was to describe the current uses of cardiac CT in CHD, review the risks and limitations of current CT technology, provide lesion specific indications for appropriately selected patients , and outline a consensus opinion on the essential skills and knowledge needed to perform cardiac CT in patients with CHD. 1 An extensive literature review is included in the part 1 document. The aim of this second document is to provide recommendations on patient preparation and technical scan acquisition for the most commonly referred CHD lesions, and to provide a brief description of radiation dose reduction techniques specific to CT in CHD. The clinical use of cardiac CT in CHD is evolving rapidly and this document is based on the authors' experience, supported by literature when available. The population of adults with congenital heart disease is rapidly increasing as a result of improved outcomes of medical, surgical and catheter-based treatment strategies. 2e4 As patients live longer, there is a greater need for coronary imaging in addition to anatomic imaging, increased use of electrophysiology devices that are MRI unsafe, and higher prevalence of metallic implants that adversely affect MRI image quality. For these patients, CT is increasingly the preferred imaging modality when echocar-diography is insufficient to answer the clinical question. This consensus document assumes competence in cardiac CT imaging, and will focus on tailoring the exam for the most commonly referred CHD lesions. The goal of this document is to provide guidance regarding: Individualized patient preparation. Acquisition protocols for the most commonly referred CHD lesions. Brief overview of radiation dose reduction techniques.
Approximately 1% of children are born with a moderate to severe congenital heart defect, and half of them undergo one or more surgeries to fix it. SURGEM, a solid modeling environment, is used to improve surgical outcome by allowing the surgeon to design the geometry for several possible surgical options before the operation and to evaluate their relative merits using computational fluid simulation. We describe here the solid modeling and graphical user interface challenges that we have encountered while developing support for three surgeries: (1) repair of double-outlet right ventricle, which adds a graft wall within the cardiac chambers to split the solid model of the unique ventricle, (2) the Fontan procedure, which routes a graft tube to connect the inferior vena cava to the pulmonary arteries, and (3) stenosis repair, which adds a stent to expand a constricted artery. We describe several solutions that we have developed to address these challenges and to improve the performance, reliability, and usability of SURGEM for these tasks.
Our goal was to construct three-dimensional (3D) virtual models to allow simultaneous visualization of the ventricles, ventricular septal defect (VSD) and great arteries in patients with complex intracardiac anatomy to aid in surgical planning. We also sought to correlate measurements from the source cardiac magnetic resonance (CMR) image dataset and the 3D model. Complicated ventriculo-arterial relationships in patients with complex conotruncal malformations make preoperative assessment of possible repair pathways difficult. Patients were chosen with double outlet right ventricle for the complexity of intracardiac anatomy and potential for better delineation of anatomic spatial relationships. Virtual 3D models were generated from CMR 3D datasets. Measurements were made on the source CMR as well as the 3D model for the following structures: aortic diameter in orthogonal planes, VSD diameter in orthogonal planes and long axis of right ventricle. A total of six patients were identified for inclusion. The path from the ventricles to each respective outflow tract and the location of the VSD with respect to each great vessel was visualized clearly in all patients. Measurements on the virtual model showed excellent correlation with the source CMR when all measurements were included by Pearson coefficient, r = 0.99 as well as for each individual structure. Construction of virtual 3D models in patients with complex conotruncal defects from 3D CMR datasets allows for simultaneous visualization of anatomic relationships relevant for surgical repair. The availability of these models may allow for a more informed preoperative evaluation in these patients.
D ouble-outlet right ventricle falls under the category of congenital heart disease known as conotruncal defects, which possess abnormal ventriculoarterial relationships. 1 For complex cases, the surgeon must determine whether the left ventricle and one of the great arteries can be aligned using the ventricular septal defect to construct an unobstructed pathway or baffle, resulting in a 2-ventricle repair. 2 Creation of the baffle can be complicated by anatomic obstructions because of prominent conal septum, straddling atrioventricular valve attachments, or location of the ventricular septal defect in the inlet septum, remote from any great artery. Three-dimensional (3D) printing has been applied in the management of many different congenital heart diseases. 3 In this specific patient population, in whom communicating the complex intracardiac anatomy to the surgeon is so critical, the use of 3D modeling and printing is invaluable. We used this approach in a patient with dextrocardia, complex double-outlet right ventricle (S,L,A) 1 and supratricuspid ring. She underwent pulmonary artery banding in infancy and had been doing relatively well clinically; so that any further surgical intervention was deferred until she was 8 years old. Although she was growing well and required no medication, she had some dyspnea on exertion and had become progressively more desaturated with oxygen saturations in the low 80s. The patient underwent a cardiac MRI to better outline the anatomy (Figure 1). The 3D balanced steady state free pre-cession images were used to create a 3D virtual model that allowed visualization of the intracardiac anatomy (Figure 2, left). The 3D stereolithography file was then printed (Projet 3500 HD Max; 3D systems, Rock Hill, SC) to create a physical model that allowed clear delineation of potential baffle pathways (Figure 2, right). The aorta, which was anterior to the pulmonary artery in this patient, was relatively far removed from the left ventricle, and the ventricular septal defect was subpulmonary. After assessment of the 3D intra-cardiac anatomy, it was decided that the patient would have a double-switch procedure. The right atrium was baffled to the right ventricle (left-sided), and the left ventricle (right-sided) was baffled, via the ventricular septal defect, to the pulmonary artery. An arterial switch was then performed to direct the deoxygenated blood to the pulmonary artery and the oxy-genated blood to the aorta. There was an excellent correlation between the 3D model and the actual anatomy. She is doing well clinically 6 months post procedure. There are a wide range of applications for 3D printing technology in preprocedural planning for patients with cardiac pathology. In addition to simply demonstrating complex intracardiac anatomy, as in our patient, it also allows us the possibility to test an intervention. For example, our interven-tional colleagues can use a 3D printed left ventricular outflow tract for sizing before transcatheter aortic valve implantation or a model of the dilated right ventricular outflow tract to size a valved conduit in a patient with previously repaired tetral-ogy of Fallot. A surgeon may use a whole heart 3D printed in a soft material to cut into and simulate the surgical procedure in a complex patient. Although this technology holds much promise, there are limitations which currently prevent its widespread application. The entire process of image post-processing and printing can take several hours depending on the image quality, the experience of the imaging specialist, and the 3D printer used. Ideally, the image data set has good blood to myocardium contrast allowing easy differentiation of the 2 across all planes. In addition, the cost of both the image processing software and 3D printer can make this technology inaccessible for programs interested in using this imaging technique. It seems most useful to use these models in more complex patients in whom the model would add some 3D spatial information or allow simulation of an intervention. The intricate complexity of these patients' anatomy demonstrates the optimal setting in which 3D intracardiac modeling and printing can offer a transition from virtual to real spatial modeling. The use of these models bridges this gap and humbly acknowledges that in these patients, in whom clear delineation
Background:
With the advent of three-dimensional (3D) printers and high-resolution cardiac imaging, rapid prototype constructions of congenital cardiac defects are now possible. Typically, source images for these models derive from higher resolution, cross-sectional cardiac imaging, such as cardiac magnetic resonance imaging or computed tomography. These imaging methods may involve intravenous contrast, sedation, and ionizing radiation. New echocardiographic transducers and advanced software and hardware have optimized 3D echocardiographic images for this purpose. Thus, the objectives of this study were to confirm the feasibility of creating cardiac models from 3D echocardiographic data and to assess accuracy by comparing 3D model measurements with conventional two-dimensional (2D) echocardiographic measurements of cardiac defects.
Methods:
Nine patients undergoing 3D echocardiography were identified (eight with ventricular septal defects, one with three periprosthetic aortic valve leaks). Raw echocardiographic image data were exported anonymously and converted to Digital Imaging and Communications in Medicine format. The image data were filtered for noise reduction, imported into segmentation software to create a 3D digital model, and printed. Measurements of the defects from the 3D model were compared with defect measurements from conventional 2D echocardiographic data. Meticulous care was taken to ensure identical measurement planes.
Results:
Long- and short-axis measurements of eight ventricular septal defects and three perivalvar leaks were obtained. Mean ± SD values for the 3D model measurements and conventional 2D echocardiographic measurements were 7.5 ± 6.3 and 7.1 ± 6.2 mm respectively (P = .20), indicating no significant differences between the standard 2D and 3D model measurements. The two groups were highly correlated, with a Pearson correlation coefficient of 0.988. The mean absolute error (2D - 3D) for each measurement was 0.4 ± 0.9 mm, indicating accuracy of the 3D model of <1 mm.
Conclusions:
Three-dimensional printed models of echocardiographic data are technically feasible and may accurately reflect ventricular septal defect anatomy. Three-dimensional models derived from 3D echocardiographic data sets represent a new tool in procedural planning for children with congenital heart disease.
Congenital heart defects (CHD) are the most common single organ malformations in humans. A comprehensive study was initiated within the Competence Network for Congenital Heart Defects to assess population-based nationwide prevalence data for Germany.
Study register of demographic and medical data of live births with CHD born between July 2006 and June 2007.
Seven thousand two hundred forty-five live births and infants with CHD were registered in Germany by 260 participating institutions (prevalence 107.6 per 10,000 live births). The most common lesions were ventricular septal defect, atrial septal defect and valvular pulmonary stenosis with 52.7, 18.3 and 6.6 per 10,000 live births, respectively. A single ventricle, tetralogy of Fallot and the complete transposition of the great arteries were the most common severe cardiac lesions (3.0, 2.7 and 2.3 per 10,000 live births). Parents reported that prenatal echocardiography had been performed in 53.8% of severe CHD cases with a cardiac defect detected in 77.5% of them.
The reported prevalences of severe CHD are within the range of regional and European comparative data. The prenatal detection rate of severe cardiovascular malformations is comparable to contemporary European registries. Postnatal diagnosis of the CHD has been made early in life.
From November 1982 to July 1989, fifty patients were treated by the REV procedure for complete transposition associated with ventricular septal defect and obstruction of the pulmonary outflow tract. The age at operation ranged from 4 months to 15 years (mean 3.8 years). The technique, based on the resection of the outlet (infundibular) septum, is described in detail. Operative mortality was 18%, essentially related to technical errors or faulty indications at the beginning of our experience. There was no late death. Six patients needed reoperation for pulmonary stenosis (2 cases) or a residual defect, in some cases associated with tricuspid regurgitation. All survivors were in excellent clinical condition. The REV procedure has fewer limitations and better results than the classical approach using Rastelli's procedure.
We sought to investigate the influence of prenatal diagnosis and risk factors for adverse outcomes in double outlet right ventricle (DORV) not associated with heterotaxy.
Patients with a pre or postnatal diagnosis of DORV from 2000 to 2007 were identified and classified into 3 subgroups: subaortic ventricular septal defect (VSD) and normal great artery (GA) arrangement (=VSD type), tetralogy of Fallot type, and transposition of the GA type (=TGA type). Patients with heterotaxy, atrioventricular septal defect, valve atresia, and ventricular hypoplasia were excluded. Complex postnatal care was defined as prematurity, need for prostaglandins, surgical repair <2 months, or univentricular palliation. Risk factors for complex postnatal care and demise were sought in multivariable logistic regression models. One hundred fort-five patients were included (93 prenatal, 52 postnatal).
There were 24 pregnancy terminations and 7 in utero deaths. Fetal demise was associated with abnormal karyotype (odds ratio [OR] 1.9, P = .01), any tricuspid valve regurgitation (OR 10.6, P = .01), and hydrops (OR 23.8, P = .02). Of 114 liveborn patients, 23 were tetralogy-type, 67 VSD-type, and 24 TGA-type patients. Postnatal survival of liveborn patients at 1 year was similar in pre- versus postnatally diagnosed patients (84% vs 85%). Abnormal GA relationship (OR 2.9, P = .02), subpulmonary VSD (OR 6.0, P = .001), unobstructed pulmonary blood flow at birth (OR 2.8, P = .05), and aortic coarctation (OR 9.0, P = .007) were associated with suboptimal postsurgical outcomes.
Double outlet right ventricle, even without heterotaxy, is associated with complex postnatal care and high risk of early demise. Morphologic subtype, irrespective of pre- or postnatal diagnosis, is a major determinant of outcome.
Biventricular repair of double-outlet right ventricle (DORV) with noncommitted ventricular septal defect (VSD) or subpulmonary VSD, associated with pulmonary stenosis, remains controversial. The usual technique, Rastelli or réparation à l'étage ventriculaire (REV) procedure, may not meet a perfect biventricular outflow tract reconstruction in terms of hemodynamic performance and long-term outcome. Here we present an early result of an alternative solution for these anomalies by double-root translocation technique.
Between August 2006 and August 2009, a total of 10 consecutive patients underwent a double-root translocation procedure, at a median age of 48 +/- 55 months (range, 1 to 16 years). The VSD was repaired with a Dacron patch, and VSD enlargement was done in 3 patients. The aortic translocation was done with (n = 4) or without (n = 6) coronary reimplantation. The neopulmonary artery was reconstructed with a monocusp bovine jugular vein patch (n = 8) or a homograft patch (n = 2). The mean follow-up interval was 21.9 +/- 11 months (range, 2 to 36). Biventricular outflow tract function was assessed by echocardiography.
There were no early or late deaths, and no required reoperations. Two patients required early support by extracorporeal membrane oxygenation. Postoperative echocardiography showed satisfactory hemodynamic effect of the reconstructed biventricular outflow tract and ventricular function. One patient had trivial aortic regurgitation and 4 patients had trivial or mild pulmonary insufficiency in follow-up.
The early results showed an optimized solution for DORV with noncommitted VSD or DORV with subpulmonary VSD, associated with pulmonary stenosis. Long-term benefits need to be evaluated with a larger number of patients and longer follow-up.
Two infants, aged 36 days old (Case 1) and 18 days old (Case 2) with interrupted aortic arch types B and A, respectively, and with severe aortic stenosis, were successfully operated on by use of pulsatile cardiopulmonary bypass. The great arteries were normally related in Case 1 and were transposed in Case 2. Repair involved the following procedure: ligation of the patent ductus arteriosus, restoration of aortic continuity with an 8 mm polytetrafluoroethylene graft, placement of an internal patch to tunnel all left ventricular blood from the left ventricle through the ventricular septal defect into the pulmonary artery in Case 1 and patch closure of the ventricular septal defect in Case 2, transection of the main pulmonary artery, anastomosis between the proximal pulmonary artery and the ascending aorta, and interposition of a valved conduit between the right ventricle and the distal pulmonary artery. The operative field could be approached easily through a median sternotomy. Postoperative cardiac catheterization revealed satisfactory anatomical and hemodynamic results in both cases.
Double outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great vessels arise entirely or predominantly from the right ventricle. Although the presence of aortic-mitral discontinuity and bilateral coni are important descriptors, they should not serve as absolute prerequisites for the diagnosis of DORV. The morphology of DORV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the great artery relationships to each other, the coronary artery anatomy, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), the tricuspid-pulmonary annular distance, and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the left ventricle to the systemic circulation by an intraventricular tunnel repair connecting the VSD to the systemic semilunar valve. This ideal surgical therapy is not always possible due to the presence of confounding anatomical barriers. A multitude of alternative surgical procedures has been devised to accommodate these more complex situations. A framework for the development of the DORV module for a pediatric cardiac surgical database is proposed.
Midterm follow-up is analyzed after the aortic translocation (Nikaidoh) procedure, an alternative to the Rastelli procedure for ventriculoarterial discordance, ventricular septal defect, and pulmonary stenosis.
Nineteen patients underwent a Nikaidoh procedure at a median age of 3.3 years (0.9-9.3 years). The native aortic valve was translocated from the right to the left ventricular outflow tract by full (n = 6) or partial (n = 13) mobilization of the aortic root. Seven patients with partial mobilization had the right coronary artery reimplanted as a button. The conal septum was divided in 13 patients. The right ventricular outflow tract was reconstructed with either a homograft (n = 4) or a right ventricular outflow tract patch (n = 15). The median follow-up was 11.4 years (0.1-23 years), and the median age at follow-up was 17.4 years (1-30 years). Left ventricular outflow tract obstruction and aortic insufficiency were assessed by echocardiography.
One patient died of right coronary arterial ischemia. All remaining patients (95%) survived. The median survival was 13.6 years (longest, 23.0 years). Seven right ventricular outflow tract reoperations were required in 5 patients (6 with obstruction and 1 with pulmonary insufficiency). No reoperations have been performed on the left ventricular outflow tract or aortic valve. No patient had any left ventricular outflow tract obstruction or aortic insufficiency more than mild (mild in 9 patients, trivial in 3 patients, and absent in 6 patients).
Midterm actuarial survival was 95% after the Nikaidoh procedure. Reintervention for the right ventricular outflow tract is more common when valved conduits are used versus valveless reconstruction; however, the Nikaidoh procedure provides complete freedom from important aortic insufficiency and left ventricular outflow tract obstruction.
We sought to define the prevalence of definitive end-states and their determinants in children with double-outlet right ventricle.
We performed a clinical record review of 393 children with double-outlet right ventricle presenting to our institution from 1980 to 2000.
Double-outlet right ventricle classification was as follows: subaortic ventricular septal defect with or without pulmonary stenosis in 47%, subpulmonic ventricular septal defect in 23%, noncommitted ventricular septal defect in 26%, and doubly committed ventricular septal defect in 4%. Hypoplastic ventricles were present in 39%, pulmonary stenosis was present in 65%, and aortic arch obstruction was present in 24%. Biventricular repair was performed in 194 patients (55%) at a median age of 10 months (range: birth to 14.0 years), and the Fontan operation (n = 182; 23%) was performed at a median age of 3.7 years (range: 6 months to 14.9 years). Results improved over time (P < .001). Factors discriminating among end-states included younger patient age at presentation (P < .001), lower weight (P < .001), and adequacy of left-sided heart structures, especially the size of the left ventricle (P < .001), aortic arch (P < .001), and mitral valve (P = .004). For complex double-outlet right ventricle, Rastelli-type repair increased early reintervention risk (P = .04) and late post-repair mortality (P = .02), whereas the arterial switch operation increased early post-repair mortality (P = .02) with a benefit of improved late post-repair survival.
Biventricular repair, especially Rastelli-type reconstruction, is associated with higher late mortality and reintervention than is Fontan repair. The wisdom of extending biventricular repair to borderline anatomic candidates with hypoplastic left-sided structures or a nonsubaortic ventricular septal defect is questionable.
3D-printed ventricular septal defect patch: a primer for the
- A A Giannopoulos
- L Chepelev
- A Sheikh
- AA Giannopoulos
3D printing in medicine of congenital heart diseases
- S J Yoo
- O Thabit
- E K Kim
- SJ Yoo
Application of virtual three-dimensional models for simultaneous visualization of intracardiac anatomic relationships in double outlet right ventricle
- K M Farooqi
- S C Uppu
- K Nguyen
- KM Farooqi