Three-dimensional transesophageal echocardiography: Principles and clinical applications

Impact of left atrial appendage thrombus location on diagnostic accuracy of cardiac CT: a single-centre case-control study

OBJECTIVE

Cardiac CT (CCT) is an emerging non-invasive modality for assessing left atrial appendage (LAA) thrombus, but the results were conflicting. Our study aims to evaluate the accuracy of CCT for detecting LAA thrombus in patients undergoing catheter ablation of atrial fibrillation, using trans-oesophageal echocardiography (TEE) as the reference standard.

DESIGN

Case-control study.

SETTING

Patient data were collected from a tertiary hospital in China between 2017 and 2022.

PARTICIPANTS

The study enrolled 726 patients (male: 60.2%, age: 61±11 years) who had both TEE and CCT before catheter ablation of atrial fibrillation.

MEASURES

The CCT protocol consisted of one angiographic phase and one delayed scan 30 s later. LAA thrombi were defined as solid masses on TEE or persistent defects on CCT. The thrombus dimension and location, the LAA filling and emptying flow velocity were assessed by TEE.

RESULTS

Of the 57 (7.9%) patients with LAA thrombi identified by TEE, 29 (50.9%) were located at the LAA ostium, and 28 (49.1%) were in the LAA. The former showed higher motility following blood flow and heartbeats than the latter. The CCT detected 14 (48.3%) of the LAA-ostium thrombi but 25 (89.3%) of those in the LAA (p=0.001). The LAA-ostium thrombi with the LAA mean flow velocity >0.35 m/s and maximum diameters <10 mm were more prone to have CCT false-negative results.

CONCLUSION

For patients undergoing catheter ablation for atrial fibrillation, CCT with a 30 s delay scan is less sensitive to LAA thrombi than TEE, especially for LAA-ostium thrombi with smaller sizes and higher LAA flow velocity.

Reproducibility of transthoracic 3D echocardiography in the assessment of mitral valve area in patients with rheumatic mitral stenosis: real time versus ECG-gated 3D echocardiography

PURPOSE

To assess reproducibility of Real time 3D echocardiography (RT3D) and ECG-gated 3D echocardiography (EG3D) when measuring the mitral valve area (MVA) in rheumatic mitral stenosis (MS).

METHODS

MVA was assessed by three operators in 68 MS patients using RT3D and EG3D. Reproducibility of each technique was determined by calculating the standard error of measurements (SEM).

RESULTS

SEM was similar between RT3D and EG3D. MVA variability was of 0.4 cm² or 30% of any RT3D or EG3D measured MVA. The minimal change in MVA above which two measurements should be considered to differ significantly for the same operator was of 0.4 cm² for RT3D and 0.5 cm² for EG3D. For two different operators making successive measurements, the minimum significant change was of 0.5 cm² for RT3D and 0.6 cm² for EG3D. The minimum significant difference when switching from RT3D to EG3D or vice versa is of 0.6 cm². Low temporal resolution of 6 Hz has the least variability when using RT3D (0.19 cm² vs. 0.26 cm², p = 0.009) but significantly underestimated MVA (1.3 ± 0.4 cm² vs. 1.4 ± 0.4 cm², p < 10- 3) when compared to EG3D. MVA variability was significantly higher in mild MS when compared to severe MS whether it is RT3D (0.23 cm² vs. 0.18 cm², p = 0.02) or EG3D (0.27 cm² vs. 0.16 cm², p < 0.001).

CONCLUSION

RT3D and EG3D are equally reproducible in the assessment of MVA in patients with MS. Further measurements standardization is required to have a clinically acceptable estimations of the true 3D MVA and minimal detectable differences.

Imaging and guiding intervention for tricuspid valve disorders using 3-dimensional transesophageal echocardiography in pediatric and congenital heart disease

In the pediatric and congenital heart disease (CHD) population, tricuspid valve (TV) disorders are complex due to the variable TV morphology, its sophisticated interaction with the right ventricle as well as associated congenital and acquired lesions. While surgery is the standard of care for TV dysfunction in this patient population, transcatheter treatment for bioprosthetic TV dysfunction has been performed successfully. Detailed and accurate anatomic assessment of the abnormal TV is essential in the preoperative/preprocedural planning. Three-dimensional transthoracic and 3D transesophageal echocardiography (3DTEE) provides added value to 2-dimensional imaging in the characterization of the TV to guide therapy and 3DTEE serves as an excellent tool for intraoperative assessment and procedural guidance of transcatheter treatment. Notwithstanding advances in imaging and therapy, the timing and indication for intervention for TV disorders in this population are not well defined. In this manuscript, we aim to review the available literature, provide our institutional experience with 3DTEE, and briefly discuss the perceived challenges and future directions in the assessment, surgical planning, and procedural guidance of (1) congenital TV malformations, (2) acquired TV dysfunction from transvenous pacing leads, or following cardiac surgeries, and (3) bioprosthetic TV dysfunction.

Utility of cardiac imaging in patients with ventricular tachycardia

Ventricular tachycardia (VT) is a life-threatening arrhythmia that may be idiopathic or result from structural heart disease. Cardiac imaging is critical in the diagnostic workup and risk stratification of patients with VT. Data gained from cardiac imaging provides information on likely mechanisms and sites of origin, as well as risk of intervention. Pre-procedural imaging can be used to plan access route(s) and identify patients where post-procedural intensive care may be required. Integration of cardiac imaging into electroanatomical mapping systems during catheter ablation procedures can facilitate the optimal approach, reduce radiation dose, and may improve clinical outcomes. Intraprocedural imaging helps guide catheter position, target substrate, and identify complications early. This review summarises the contemporary imaging modalities used in patients with VT, and their uses both pre-procedurally and intra-procedurally.

Clinical Utility of Three-Dimensional Echocardiography in the Evaluation of Mitral Valve Disease: Tips and Tricks

Although real-time 3D echocardiography (RT3DE) has only been introduced in the last decades, its use still needs to be improved since it is a time-consuming and operator-dependent technique and acquiring a good quality data can be difficult. Moreover, the additive value of this important diagnostic tool still needs to be wholly appreciated in clinical practice. This review aims at explaining how, why, and when performing RT3DE is useful in clinical practice.

Renaissance of Cardiac Imaging to Assist Percutaneous Interventions in Congenital Heart Diseases:The Role of Three-Dimensional Echocardiography and Multimodality Imaging

Percutaneous interventions have completely refashioned the management of children with congenital heart diseases (CHD) and the use of non-invasive imaging has become the gold standard to plan and guide these procedures in the modern era. We are now facing a dual challenge to improve the standard of care in low-risk patients, and to shift our strategies from the classic open chest surgery to imaging-guided percutaneous interventions in high-risk patients. Such rapid evolution of ultrasound technologies over the last 20 years have permitted the integration of transthoracic, transesophageal and intracardiac echocardiography into the interventional workflow to improve image guidance and reduce radiation burden from fluoroscopy and angiography. Specifically, miniaturization of transesophageal probe and advances in three-dimensional (3D) imaging techniques have enabled real-time 3D image guidance during complex interventional procedure, In addition, multimodality and fusion imaging techniques harness the strengths of different modalities to enhance understanding of anatomical and spatial relationship between different structures, improving communication and coordination between interventionalists and imaging specialists. In this review, we aim to provide an overview of 3D imaging modalities and multimodal fusion in procedural planning and live guidance of percutaneous interventions. At the present times, 3D imaging can no longer be considered a luxury but a routine clinical tool to improve procedural success and patient outcomes.

Real-Time 3D Intracardiac Echocardiography

With real-time three-dimensional ultrasound, live volumetric images with adequate spatial and temporal resolution are obtained to accurately display structures with complex anatomy and guide interventional procedures. In this review, we will provide an overview of current ultrasound technologies that allow for real-time three-dimensional imaging, with a focus on their application for three-dimensional intracardiac echocardiography.

Applications of three-dimensional transesophageal echocardiography in congenital heart disease

Three-dimensional echocardiography allows for presurgical planning for congenital heart disease, reduces radiation using fusion imaging in catheter interventions, and provides guidance during catheter interventions and lead placements or extractions. The purpose of this review is to detail applications of three-dimensional transesophageal echocardiography in presurgical planning of congenital heart disease, guidance of catheter interventions such as fusion imaging, and guidance in electrophysiology lead extractions or placements.

Comparison Between 3D Echocardiography and Cardiac Magnetic Resonance Imaging (CMRI) in the Measurement of Left Ventricular Volumes and Ejection Fraction

BACKGROUND

Echocardiography and Cardiac Magnetic Resonance Imaging (CMRI) are two noninvasive techniques for the evaluation of cardiac function for patients with coronary artery diseases. Although echocardiography is the commonly used technique in clinical practice for the assessment of cardiac function, the measurement of LV volumes and left ventricular ejection fraction (LVEF) by the use of this technique is still influenced by several factors inherent to the protocol acquisition, which may affect the accuracy of echocardiography in the measurement of global LV parameters.

OBJECTIVE

The aim of this study is to compare the end systolic volume (ESV), the end diastolic volume (EDV), and the LVEF values obtained with three dimensional echocardiography (3D echo) with those obtained by CMRI (3 Tesla) in order to estimate the accuracy of 3D echo in the assessment of cardiac function.

METHODS

20 subjects, (9 controls, 6 with myocardial infarction, and 5 with myocarditis) with age varying from 18 to 58, underwent 3D echo and CMRI. LV volumes and LVEF were computed from CMRI using a stack of cine MRI images in a short axis view. The same parameters were calculated using the 3D echo. A linear regression analysis and Bland Altman diagrams were performed to evaluate the correlation and the degree of agreement between the measurements obtained by the two methods.

RESULTS

The obtained results show a strong correlation between the 3D echo and CMR in the measurement of functional parameters (r = 0.96 for LVEF values, r = 0.99 for ESV and r= 0.98 for EDV, p < 0.01 for all) with a little lower values of LV volumes and higher values of LVEF by 3D echo compared to CMRI. According to statistical analysis, there is a slight discrepancy between the measurements obtained by the two methods.

CONCLUSION

3D echo represents an accurate noninvasive tool for the assessment of cardiac function. However, other studies should be conducted on a larger population including some complicated diagnostic cases.

Mitral Annulus Segmentation Using Deep Learning in 3-D Transesophageal Echocardiography

3D Transesophageal Echocardiography is an excellent tool for evaluating the mitral valve and is also well suited for guiding cardiac interventions. We introduce a fully automatic method for mitral annulus segmentation in 3D Transesophageal Echocardiography, which requires no manual input. One hundred eleven multi-frame 3D transesophageal echocardiography recordings were split into training, validation, and test sets. Each 3D recording was decomposed into a set of 2D planes, exploiting the symmetry around the centerline of the left ventricle. A deep 2D convolutional neural network was trained to predict the mitral annulus coordinates, and the predictions from neighboring planes were regularized by enforcing continuity around the annulus. Applying the final model and post-processing to the test set data gave a mean error of 2.0 mm - with a standard deviation of 1.9 mm. Fully automatic segmentation of the mitral annulus can alleviate the need for manual interaction in the quantification of an array of mitral annular parameters and has the potential to eliminate inter-observer variability.

Three-dimensional printing in structural heart disease and intervention

Three-dimensional (3D) printing refers to the process by which physical objects are built by depositing materials in layers based on a specific digital design. It was initially used in manufacture industry. Inspired by the technology, clinicians have recently attempted to integrate 3D printing into medical applications. One of the medical specialties that has recently made such attempt is cardiology, especially in the field of structural heart disease (SHD). SHD refers to a group of non-coronary cardiovascular disorders and related interventions. Obvious examples are aortic stenosis, mitral regurgitation, atrial septal defect, and known or potential left atrial appendage (LAA) clots. In the last decade, cardiologists have witnessed a dramatic increase in the types and complexity of catheter-based interventions for SHD. Current imaging modalities have important limitations in accurate delineation of cardiac anatomies necessary for SHD interventions. Application of 3D printing in SHD interventional planning enables tangible appreciation of cardiac anatomy and allows in vitro interventional device testing. 3D printing is used in diagnostic workup, guidance of treatment strategies, and procedural simulation, facilitating hemodynamic research, enhancing interventional training, and promoting patient-clinician communication. In this review, we attempt to define the concept, technique, and work flow of 3D printing in SHD and its interventions, highlighting the reported clinical benefits and unsolved issues, as well as exploring future developments in this field.

The Use of Intraoperative Three-Dimensional Echocardiography to Evaluate Origin of Bioprosthetic Aortic Valve Regurgitant Jets

Degradation of bioprosthetic aortic valves can eventually lead to both paravalvular and intravalvular regurgitation. However, differentiating between the two may be difficult in the case of multiple lesions in close proximity or highly eccentric jets. Whereas such exact distinction may be of little procedural significance in open cardiac surgery, it is of crucial importance when approaching such lesions in the catheterization laboratory or hybrid operating room. Interventions on one lesion often have a significant effect on the other. For example, guidewires may damage new bioprosthetic valve leaflets and dislodge vascular plugs. Even more concerning is the possibility of undergoing a lengthy and risky procedure on a lesion that does not truly exist. Fortunately, the use of three-dimensional Doppler echocardiography can expand our vision beyond the single imaging plane of a standard two-dimensional examination, allowing extensive manipulation of cutting planes and a wider field of view. Regurgitant jets can thus be tracked in a way that may be otherwise impossible, better quantifying their true origins. Here the authors present a unique case of misdiagnosis after surgical aortic valve degradation, where the use of intraoperative three-dimensional echocardiography significantly altered the preoperative plan and reduced operative time.

Mechanics of the Tricuspid Valve-From Clinical Diagnosis/Treatment, In-Vivo and In-Vitro Investigations, to Patient-Specific Biomechanical Modeling

Proper tricuspid valve (TV) function is essential to unidirectional blood flow through the right side of the heart. Alterations to the tricuspid valvular components, such as the TV annulus, may lead to functional tricuspid regurgitation (FTR), where the valve is unable to prevent undesired backflow of blood from the right ventricle into the right atrium during systole. Various treatment options are currently available for FTR; however, research for the tricuspid heart valve, functional tricuspid regurgitation, and the relevant treatment methodologies are limited due to the pervasive expectation among cardiac surgeons and cardiologists that FTR will naturally regress after repair of left-sided heart valve lesions. Recent studies have focused on (i) understanding the function of the TV and the initiation or progression of FTR using both in-vivo and in-vitro methods, (ii) quantifying the biomechanical properties of the tricuspid valve apparatus as well as its surrounding heart tissue, and (iii) performing computational modeling of the TV to provide new insight into its biomechanical and physiological function. This review paper focuses on these advances and summarizes recent research relevant to the TV within the scope of FTR. Moreover, this review also provides future perspectives and extensions critical to enhancing the current understanding of the functioning and remodeling tricuspid valve in both the healthy and pathophysiological states.

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.

Surgical Echocardiography of the MV: Focus on 3D

The mitral valve remains a complex structure where multiple forms of pathology can be seen. Mitral regurgitation continues to be one of the most common valvular diseases in the industrialized world. While intraoperative 2-dimensional transesophageal echocardiography has been commonplace for some time, 3-dimensional technology has emerged and has shown great benefit for diagnosis and guidance during mitral valve surgery. In the hands of a trained sonographer, high-quality real-time images can easily be obtained and correlate well with gross anatomical findings. The use of multiple angled views and color Doppler within 3-dimensional transesophageal echocardiography has become a valuable asset in the understanding and interpretation of the mitral valve for surgical interventions.

Three-Dimensional Printing for Planning of Structural Heart Interventions

Three-dimensional (3D) printing is a process leading to the creation of a physical 3D model used for teaching, patient education, device evaluation, and procedural planning. 3D printed models of patient-specific anatomy can be generated from 3D transesophageal, cardiac MRI, or cardiac computed tomographic datasets. This article discusses the potential advantages of 3D printing, reviews the different modalities to acquire a 3D dataset, and highlights the application of 3D printing to enhance patient screening and procedural planning in structural heart intervention.

Three-dimensional Transesophageal Echocardiographic Diagnosis of Catheter Endocarditis Hidden in Intracaval Stent

In recent years, with an increasing number of central venous access procedures and cardiac implantable electronic device implantation, the incidence of infective endocarditis (IE) has become more prevalent. Two-dimensional transthoracic echocardiography (2D-TTE) and transesophageal echocardiography (TEE) are a key part of the evaluation of IE, but advances in three-dimensional echocardiography have enabled a better spatial resolution and visualization of cardiac structures, allowing the identification of any valvular vegetations, abscesses, or nodules. Herein, we report the usefulness of 3D-TEE in a difficult diagnosis of hemodialysis catheter endocarditis hidden in intracaval stent.

Transthoracic 3D Echocardiographic Imaging of Type A Aortic Dissection – Case Presentation

In type A aortic dissection (AoD) an early and accurate diagnosis is essential to improve survival, by applying urgent surgical repair. 3D transthoracic echocardiography (3D-TTE), an advanced noninvasive imaging technique, could offer a comprehensive evaluation of the ascending aorta and aortic arch in this regard. Both modalities of real-time 3D imaging – live 3D and full-volume aquisition – proved to be useful in evaluating the localization and extent of AoD. Our case illustrates the utility of 3D-TTE in the complex assessment AoD. By providing the proper anatomical dataset, 3D-TTE could facilitate considerably the diagnosis of type A AoD.

Role of 3D Echocardiography in Cardiac Surgery: Strengths and Limitations

PURPOSE OF REVIEW

This review aims to highlight the general and specific strengths and limitations of intraoperative 3D echocardiography. This article explains the value of real-time three-dimensional transesophageal echocardiography (RT 3D TEE) during cardiac surgery and cardiac interventions.

RECENT FINDINGS

Recently published recommendations and guidelines include the use of RT 3D TEE. RT 3 D TEE provides additional value particularly for guidance during cardiac interventions (i.e., transcatheter mitral valve repair, left atrial appendix and atrial septal defect closures), assessment of the mitral valve in surgical repair, measurement of left ventricular outflow tract area for transcatheter valvular replacements, and estimating right and left ventricular volumes and function. The exact localization of paravalvular leakage is another strength of RT 3D TEE. The major limitation is the reduced temporal resolution compared to 2D TEE.

SUMMARY

Three-dimensional echocardiography is a powerful tool that improves communication and accurate measurements of cardiac structures.