Echocardiographic-Fluoroscopic Fusion Imaging in Transseptal Puncture: A New Technology for an Old Procedure

Tricuspid Regurgitation: From Imaging to Clinical Trials to Resolving the Unmet Need for Treatment

Tricuspid regurgitation (TR) is a highly prevalent and heterogeneous valvular disease, independently associated with excess mortality and high morbidity in all clinical contexts. TR is profoundly undertreated by surgery and is often discovered late in patients presenting with right-sided heart failure. To address the issue of undertreatment and poor clinical outcomes without intervention, numerous structural tricuspid interventional devices have been and are in development, a challenging process due to the unique anatomic and physiological characteristics of the tricuspid valve, and warranting well-designed clinical trials. The path from routine practice TR detection to appropriate TR evaluation, to conduction of clinical trials, to enriched therapeutic possibilities for improving TR access to treatment and outcomes in routine practice is complex. Therefore, this paper summarizes the key points and methods crucial to TR detection, quantitation, categorization, risk-scoring, intervention-monitoring, and outcomes evaluation, particularly of right-sided function, and to clinical trial development and conduct, for both interventional and surgical groups.

Advances in TEE-Centric Intraprocedural Multimodal Image Guidance for Congenital and Structural Heart Disease

Percutaneous interventions are gaining rapid acceptance in cardiology and revolutionizing the treatment of structural heart disease (SHD). As new percutaneous procedures of SHD are being developed, their associated complexity and anatomical variability demand a high-resolution special understanding for intraprocedural image guidance. During the last decade, three-dimensional (3D) transesophageal echocardiography (TEE) has become one of the most accessed imaging methods for structural interventions. Although 3D-TEE can assess cardiac structures and functions in real-time, its limitations (e.g., limited field of view, image quality at a large depth, etc.) must be addressed for its universal adaptation, as well as to improve the quality of its imaging and interventions. This review aims to present the role of TEE in the intraprocedural guidance of percutaneous structural interventions. We also focus on the current and future developments required in a multimodal image integration process when using TEE to enhance the management of congenital and SHD treatments.

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.

Transseptal puncture: procedural guidance, challenging situations and management of complications

A number of interventional procedures based on the transseptal puncture (TSP) have been developed in recent years. The increasing number of interventional procedures, as well as the use of large-bore sheaths and complex devices, has led to improvements in technique and equipment. The combined use of fluoro-scopy and of transoesophageal echocardiography (TEE) has increased safety and precision. However, TSP still represents a tricky procedure, which may become even more difficult in cases of challenging interatrial septa, and life-threatening complications may occur. Consequently, an in-depth knowledge of procedural steps, equipment, echocardiographic views, fossa ovalis anatomy and how to manage the most frequent complications is critical to performing a successful TSP.

Systematic Fluoroscopic-Echocardiographic Fusion Imaging Protocol for Transcatheter Edge-to-Edge Mitral Valve Repair Intraprocedural Monitoring

BACKGROUND

Whether fluoroscopic-echocardiographic fusion imaging (FI) might offer added value for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair is yet unknown, and few data exist regarding the safety and feasibility of this novel technology.

METHODS

The aim of this single-center study was to test and validate a FI protocol for intraprocedural monitoring of transcatheter edge-to-edge mitral valve repair and assess its clinical usefulness. Eighty patients underwent MitraClip implantation using FI guidance (FI+) for either degenerative (35%) or functional (65%) mitral regurgitation and were compared with the last 80 patients before FI introduction, treated using conventional echocardiography and fluoroscopic monitoring (FI-).

RESULTS

The number of patients treated for functional and degenerative mitral regurgitation was similar between the FI+ and FI- groups, as well as the number of devices implanted (1.51 ± 0.5 vs 1.58 ± 0.6, P = .46). The prevalence of complex mitral anatomy for percutaneous repair was high (32.5%, up to 39.2% in the hybrid arm). Fluoroscopy time was significantly lower in FI+ patients (37.3 ± 14.6 vs 48.3 ± 28.3 min, P = .003), but not kerma area product (91.5 ± 74.1 vs 108.8 ± 105.0 Gy · cm², P = .23) or procedural time (92.2 ± 36.1 vs 103.1 ± 42.7 min, P = .086). After adjusting for confounding factors (MitraClip XT device and complex anatomy), FI reduced fluoroscopy time (coefficient = -10.4 min; 95% CI, -18.03 to -2.82; P = .007) and improved procedural success at the end of the procedure (odds ratio, 2.87; 95% CI, 1.00 to 8.24; P = .049) and discharge (odds ratio, 2.24; 95% CI, 1.04 to 4.80; P = .039). Rates of periprocedural complications were similar in both groups (8.9% vs 13.0%, P = .40).

CONCLUSIONS

The authors describe the systematic use of an FI protocol for intraprocedural guidance during transcatheter edge-to-edge mitral valve repair, demonstrating a reduction in fluoroscopy time and an improvement in procedural success in a population with a high prevalence of challenging mitral anatomy for percutaneous repair.

Imaging the mitral valve: a primer for the interventional surgeon

Transcatheter mitral valve interventions (TMVI) have evolved over the past decade as alternatives to open surgical repair for the therapeutic management of patients with severe mitral regurgitation (MR). Concurrent with the development of these technologies, quality multi-modality cardiac imaging has become essential in patient selection and procedural guidance. The former involves assessments of the pathophysiologic mechanisms of regurgitation, valvular anatomy and morphology, as well as objective quantification of the severity of MR. Both transthoracic and transesophageal echocardiography (TEE) are crucial and serve as the gateway to diagnosis and management of mitral valvular disease. Along with multi-detector computed tomography (CT) and cardiac magnetic resonance imaging (CMR), echocardiography plays an important role for preprocedural planning and evaluation of the spatial relationships of the mitral valvular complex with the coronary sinus, circumflex coronary artery and left ventricular (LV) outflow tract. Procedures that target mitral leaflets (e.g., MitraClip, PASCAL) or annulus (e.g., Cardioband, Carillon), or provide chordal (e.g., NeoChord, Harpoon) or valvular replacement, tend to be guided by TEE and assisted by fluoroscopy. As newer devices become available and outcomes of TMVI improve, cardiac imaging will undoubtedly continue to play an essential role in the success of percutaneous mitral valve repair (MVr) and replacement. The interventional surgeon of the future must therefore have a thorough understanding of the various imaging modalities while synthesizing and integrating novel concepts (e.g., neo-LV outflow tract) as applicable to assessing valvular function and pathology.

Fusion Imaging of X-ray and Transesophageal Echocardiography Improves the Procedure of Left Atrial Appendage Closure

BACKGROUND

Left atrial appendage closure (LAAC) is an alternative treatment strategy for patients with atrial fibrillation who are at risk for thromboembolic events and considered not suitable for oral anticoagulation (OAC). LAAC is mainly performed under the guidance of transesophageal echocardiography (TEE) and fluoroscopy. The study presented here should analyze whether fusion imaging (FI) of transesophageal echocardiography and X-ray performed during LAAC is feasible and can improve the results of the procedure.

METHODS

The data presented here are from a retrospective single center study. Sample size was defined as 50 patients in which LAAC was performed without fusion imaging (control group) and 25 patients were the LAAC procedure was guided by fusion imaging (treatment group). Inclusion criteria were defined as age > 18 years and completion of an LAAC procedure defined as deployment of a WATCHMAN 2.5 LAA occluder. Study endpoints were procedure time, amount of used contrast medium, radiation dose, final position of the WATCHMAN in TEE (deviation from ideal positioning), and clinical endpoints, respectively.

RESULTS

LAA closure was successfully performed in all patients. No case of device embolism was occurring, and none of the patients experienced a periprocedural stroke/TIA nor a systemic embolism, respectively. Mean procedure time was 15 min shorter in the group of patients where fusion imaging was applied (p < 0.001). Additionally, the use of fusion imaging was associated with a significant reduction of contrast medium (20.6 ml less than in control; p < 0.045). Regarding the final position of the WATCHMAN, no relevant differences were found between the groups. The use of fusion imaging significantly reduced procedure time and the amount of contrast medium in patients undergoing LAAC.

Multimodality cardiac imaging in the 21st century: evolution, advances and future opportunities for innovation

Cardiovascular imaging has significantly evolved since the turn of the century. Progress in the last two decades has been marked by advances in every modality used to image the heart, including echocardiography, cardiac magnetic resonance, cardiac CT and nuclear cardiology. There has also been a dramatic increase in hybrid and fusion modalities that leverage the unique capabilities of two imaging techniques simultaneously, as well as the incorporation of artificial intelligence and machine learning into the clinical workflow. These advances in non-invasive cardiac imaging have guided patient management and improved clinical outcomes. The technological developments of the past 20 years have also given rise to new imaging subspecialities and increased the demand for dedicated cardiac imagers who are cross-trained in multiple modalities. This state-of-the-art review summarizes the evolution of multimodality cardiac imaging in the 21st century and highlights opportunities for future innovation.

Fusion imaging in interventional cardiology

The number and complexity of percutaneous interventions for the treatment of structural heart disease has increased in clinical practice in parallel with the development of new imaging technologies, in order to render these interventions safer and more accurate. Complementary imaging modalities are commonly used, but they require additional mental reconstruction and effort by the interventional team. The concept of fusion imaging, where two different modalities are fused in real time and on a single monitor, aims to solve these limitations. This is an important tool to guide percutaneous interventions, enabling a good visualization of catheters, guidewires and devices employed, with enhanced spatial resolution and anatomical definition. It also allows the marking of anatomical reference points of interest for the procedure. Some studies show decreased procedural time and total radiation dose with fusion imaging; however, there is a need to obtain data with more robust scientific methodology to assess the impact of this technology in clinical practice. The aim of this review is to describe the concept and basic principles of fusion imaging, its main clinical applications and some considerations about the promising future of this imaging technology.

Electroanatomic guidance versus conventional fluoroscopy during transseptal puncture for atrial fibrillation ablation

INTRODUCTION

Technological advancement in the setting of atrial fibrillation (AF) ablation has decreased radiation exposure and complications associated with the procedure. Yet, transseptal puncture (TSP) remains a challenging step that necessitates accurate guidance. We describe our experience performing TSP under electroanatomic (EA) guidance.

METHODS AND RESULTS

The analysis included 145 consecutive EA-guided ablation procedures performed between June 2018 and April 2019 and 145 consecutive standard ablations performed before June 2018. EA guidance utilized the CARTO 3 three-dimensional mapping system to reconstruct anatomic and electrical characteristics of the right atrium and fossa ovalis. Patients with a history of previous cardiac surgery were excluded. For EA-guided procedures, the mean patient age was 60 ± 10 years, 75.2% were male, and 69.0% had paroxysmal AF. Similarly, the mean age for conventional procedures was 60 ± 11 years, 71.0% were male, and 71.7% had paroxysmal AF. The fossa ovalis was detected as a region of low voltage, <0.75 mV. EA guidance yielded shorter fluoroscopy times (EA vs. conventional, 3.6 ± 2.5 vs. 13.5 ± 10.5 min; p < .001) and a lower dose area product than conventional guidance (13 ± 11 Gy* cm² vs. 28 ± 27  Gy* cm² ; p < .001). The total procedure duration was similar between groups (146 ± 48 vs. 148 ± 54 min). There were no significant complications related to TSP.

CONCLUSION

During AF ablation, TSP with EA guidance facilitated safe access to the left atrium while reducing radiation risk to both patients and operators.

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.

Percutaneous Techniques, Limitations and Challenges for the Failed Surgical Mitral Intervention

The advent of percutaneous therapies has significantly altered therapeutic options for patients with valvular heart disease. Building on the success of transcatheter aortic valve replacement, both expanded indications and purpose-built devices are now being used to address percutaneous approaches for mitral valve pathology. While surgical mitral valve repair remains the gold standard for addressing significant mitral valve pathology, there has been a progressive increase in the utilization of bioprosthetic valves despite their limited lifespan. The risks of reoperation to address mitral valve repair failure or bioprosthetic valve dysfunction is not insignificant. In light of the aging population and the potential for significant associated comorbidities, less invasive alternative techniques hold particular appeal. Utilization of commercially available transcatheter aortic valve replacement valves for failed surgical valves has been shown to have better short-term mortality than would be predicted for open reoperation. As a result, the US Food and Drug Administration approved the utilization of transcatheter mitral valve-in-valve replacement for the failed bioprosthetic valve in high surgical risk patients. Despite the favorable outcomes, transcatheter mitral valve-in-valve is not without procedural challenges and potential complications including malpositioning, embolization, paravalvular leak, and outflow tract obstruction. Awareness of these challenges, mitigation strategies, and therapeutic options is imperative to optimizing outcomes in this high-risk patient population.

Automated segmentation of the atrial region and fossa ovalis towards computer-aided planning of inter-atrial wall interventions

BACKGROUND AND OBJECTIVE

Image-fusion strategies have been applied to improve inter-atrial septal (IAS) wall minimally-invasive interventions. Hereto, several landmarks are initially identified on richly-detailed datasets throughout the planning stage and then combined with intra-operative images, enhancing the relevant structures and easing the procedure. Nevertheless, such planning is still performed manually, which is time-consuming and not necessarily reproducible, hampering its regular application. In this article, we present a novel automatic strategy to segment the atrial region (left/right atrium and aortic tract) and the fossa ovalis (FO).

METHODS

The method starts by initializing multiple 3D contours based on an atlas-based approach with global transforms only and refining them to the desired anatomy using a competitive segmentation strategy. The obtained contours are then applied to estimate the FO by evaluating both IAS wall thickness and the expected FO spatial location.

RESULTS

The proposed method was evaluated in 41 computed tomography datasets, by comparing the atrial region segmentation and FO estimation results against manually delineated contours. The automatic segmentation method presented a performance similar to the state-of-the-art techniques and a high feasibility, failing only in the segmentation of one aortic tract and of one right atrium. The FO estimation method presented an acceptable result in all the patients with a performance comparable to the inter-observer variability. Moreover, it was faster and fully user-interaction free.

CONCLUSIONS

Hence, the proposed method proved to be feasible to automatically segment the anatomical models for the planning of IAS wall interventions, making it exceptionally attractive for use in the clinical practice.

Innovation in 3D Echocardiographic Imaging

PURPOSE OF REVIEW

The purpose of this review is to detail three-dimensional echocardiographic (3DE) innovations in pre-surgical planning of congenital heart disease, guidance of catheter interventions such as fusion imaging, and functional assessment of patients with congenital heart disease.

RECENT FINDINGS

Innovations in 3DE have helped us delineate the details of atrioventricular valve function and understand the mechanism of atrioventricular valve failure in patients with atrioventricular septal defect and single ventricle post repair. Advancement in holographic display of 3D datasets allows for better manipulation of 3D images in three dimensions and better understanding of anatomic relationships. 3DE with fusion imaging reduces radiation in catheter interventions and provides presentations of 3DE images in the similar fashion as the fluoroscopic images to improve communication between cardiologists. Lastly, 3DE allows for quantitative ventricular volumetric and functional assessment. Recent innovations in 3DE allow for pre-surgical planning for congenital heart disease, reduce radiation using fusion imaging in catheter interventions, and enable accurate assessment of ventricular volume and function without geometric assumptions.

Fusion Imaging for Procedural Guidance

The field of percutaneous structural heart interventions has grown tremendously in recent years. This growth has fueled the development of new imaging protocols and technologies in parallel to help facilitate these minimally-invasive procedures. Fusion imaging is an exciting new technology that combines the strength of 2 imaging modalities and has the potential to improve procedural planning and the safety of many commonly performed transcatheter procedures. In this review we discuss the basic concepts of fusion imaging along with the relative strengths and weaknesses of static vs dynamic fusion imaging modalities. This review will focus primarily on echocardiographic-fluoroscopic fusion imaging and its application in commonly performed transcatheter structural heart procedures.