Fluoroscopic Anatomy of Right-Sided Heart Structures for Transcatheter Interventions

Holographic mixed reality for planning transcatheter aortic valve replacement

BACKGROUND

Using three-dimensional (3D) modalities for optimal pre-procedure planning in transcatheter aortic valve replacement (TAVR) is critical for procedural success. However, current methods rely on visualizing images on a two-dimensional screen, using shading and colors to create the illusion of 3D, potentially impeding the accurate comprehension of the actual anatomy structures. In contrast, a new Mixed Reality (MxR) based software enables accurate 3D visualization, imaging manipulation, and quantification of measurements.

AIMS

The study aims to evaluate the feasibility, reproducibility, and accuracy of dimensions of the aortic valve complex as measured with a new holographic MxR software (ARTICOR®, Artiness srl, Milano, Italy) compared to a widely used software for pre-operative sizing and planning (3mensio Medical Imaging BV, Bilthoven, The Netherlands).

METHODS

This retrospective, observational, double-center study enrolled 100 patients with severe aortic stenosis who underwent cardiac computed tomography (CCT) before TAVR. The CCT datasets of volumetric aortic valve images were analyzed using 3Mensio and newly introduced MxR-based software.

RESULTS

Ninety-eight percent of the CCT datasets were successfully converted into holographic models. A higher level of agreement between the two software systems was observed for linear metrics (short, long, and average diameter). In comparison, agreement was lower for area, perimeter, and annulus-to-coronary ostia distance measurements. Notably, the annulus area, annular perimeter, left ventricular outflow tract (LVOT) area, and LVOT perimeter were significantly and consistently smaller with the MxR-based software compared to the 3Mensio. Excellent interobserver reliability was demonstrated for most measurements, especially for direct linear measurements.

CONCLUSIONS

Linear measurements of the aortic valve complex using MxR-based software are reproducible compared to the standard CCT dataset analyzed with 3Mensio. MxR-based software could represent an accurate tool for the pre-procedural planning of TAVR.

Personalized Guidance of Edge-to-Edge Transcatheter Tricuspid Valve Repair by Multimodality Imaging

Background: Transcatheter edge-to-edge tricuspid valve repair (T-TEER) for tricuspid regurgitation (TR) is always guided by transesophageal echocardiography (TEE). As each patient has unique anatomy and acoustic window, adding transthoracic echocardiography (TTE) and cardiac CT could improve procedural planning and guidance. Objectives: We aimed to assess T-TEER success and outcomes of a personalized guidance approach, based on multimodality imaging (MMI) of patient-tailored four right-sided chamber views (four-right-ch), as depicted by CT, TTE, TEE and fluoroscopy. Methods: Patients were assigned to MMI or classical TEE guidance, depending on TTE acoustic window. In MMI patients, planning included cardiac CT, which determined the fluoroscopic angulations of the specific four-right-ch, while guidance relied heavily on TTE, with minimal intermittent TEE for leaflet grasping and result confirmation. Both TTE and TEE were matched to respective CT and fluoroscopy four-right-ch. TR severity and quality of life (QoL) parameters were assessed from baseline to 12 months. Results: A total of 40 T-TEER patients were included, with 17 procedures guided by MMI and 23 solely by TEE. Baseline characteristics were similar between groups, e.g., age (83.1 ± 4.1 vs. 81 ± 5.3, p = 0.182) or STS-Score (11.1 ± 7.4% vs. 10.6 ± 5.9%, p = 0.813). The primary efficacy endpoint of ≥one-grade TR reduction at 30 days was 94% (16/17) in MMI vs. 91% (21/23) in TEE patients, with two or more TR grade reduction in 65% vs. 52% (p = 0.793). Device success was overall 100%, with no device-related complications, but three TEE-associated cases of gastrointestinal bleeding in the TEE-only group. By 12 months, all 15 MMI and 19 TEE survivors improved NYHA functional class and QoL, e.g., Kansas City Cardiomyopathy Questionnaire Score Δ29.6 ± 6.7 vs. 21.9 ± 5.8 (p = 0.441) pts., 6-min walk distance Δ101.5 ± 36.4 vs. 85.7 ± 32.1 (p = 0.541) meters. Conclusions: In a subset of patients with good TTE acoustic window, MMI guidance of T-TEER is effective and seems to avoid gastroesophageal injuries caused by TEE probe manipulation. TR reduction, irrespective of guidance method, impacts long-term QoL.

Multimodality Imaging Approach for Planning and Guiding Direct Transcatheter Tricuspid Valve Annuloplasty

Interest in transcatheter treatment of tricuspid regurgitation (TR) has grown significantly in recent years due to increasing evidence correlating TR severity with mortality and to limited availability of surgical options often considered high-risk in these patients. Although edge-to-edge repair is currently the main transcatheter therapeutic strategy, tricuspid valve direct annuloplasty can also be performed safely and effectively to reduce TR and improve heart failure symptoms and quality of life. In the annuloplasty procedure, an adjustable band is implanted around the tricuspid annulus to reduce valvular size and improve TR. Patient selection and careful preoperative imaging, including transthoracic echocardiography, transesophageal echocardiography, and computed tomography, are critical for procedural success and proper device implantation. Compared to edge-to-edge repair, perioperative imaging with transesophageal echocardiography and fluoroscopy is particularly challenging. Alignment and insertion of the anchors are demanding but essential to achieve good results and avoid damaging the surrounding structures. The presence of shadowing artifacts due to cardiac devices makes the acquisition of good-quality images even more challenging. In this review, we discuss the current role of multimodality imaging in planning direct transcatheter tricuspid valve annuloplasty and describe all procedural steps focusing on echocardiographic monitoring.

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.

Utility of CT and MRI in Tricuspid Valve Interventions

Transcatheter tricuspid valve interventions (TTVIs) comprise a variety of catheter-based interventional techniques for treatment of tricuspid regurgitation (TR) in patients at high surgical risk and those with failed previous surgeries. Several TTVI devices with different mechanisms of action are either currently used or in preclinical evaluation. Echocardiography is the first-line modality for evaluation of tricuspid valve disease that provides information on tricuspid valve morphology, mechanism of TR, and hemodynamics. Cardiac CT and MRI have several advantages for a comprehensive preprocedure evaluation. CT and MRI provide complementary information to that of echocardiography on the mechanism and cause of TR. MRI can quantify the severity of TR using indirect or direct techniques that involve two-dimensional or four-dimensional flow sequences. MRI and CT can also accurately quantify right ventricular volumes and function, which is crucial for timing of intervention. CT provides comprehensive three-dimensional information on the morphology of the valve, annulus, subvalvular apparatus, and adjacent structures. CT is the procedure of choice for evaluation of several device-specific measurements, including tricuspid annulus dimensions, annulus-to-right coronary artery distance, leaflet morphology, coaptation gaps, caval dimensions, and cavoatrial-to-hepatic vein distance. CT allows evaluation of the vascular access as well as optimal procedure fluoroscopic angles and catheter trajectory. Postprocedure CT and MRI are useful in detection of complications such as paravalvular leak, pseudoaneurysm, thrombus, pannus, infective endocarditis, and device migration. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Advances in Imaging for Tricuspid Transcatheter Edge-to-Edge Repair: Lessons Learned and Future Perspectives

Severe tricuspid valve (TV) regurgitation (TR) has been associated with adverse long-term outcomes in several natural history studies, but isolated TV surgery presents high mortality and morbidity rates. Transcatheter tricuspid valve interventions (TTVI) therefore represent a promising field and may currently be considered in patients with severe secondary TR that have a prohibitive surgical risk. Tricuspid transcatheter edge-to-edge repair (T-TEER) represents one of the most frequently used TTVI options. Accurate imaging of the tricuspid valve (TV) apparatus is crucial for T-TEER preprocedural planning, in order to select the right candidates, and is also fundamental for intraprocedural guidance and post-procedural follow-up. Although transesophageal echocardiography represents the main imaging modality, we describe the utility and additional value of other imaging modalities such as cardiac CT and MRI, intracardiac echocardiography, fluoroscopy, and fusion imaging to assist T-TEER. Developments in the field of 3D printing, computational models, and artificial intelligence hold great promise in improving the assessment and management of patients with valvular heart disease.

Overview of the Interatrial Septum: Review of Cardiac Nomenclature for Transseptal Puncture

Transseptal puncture is an increasingly common procedure undertaken to gain access to the left side of the heart during structural heart disease interventions. Precision guidance during this procedure is paramount to ensure success and patient safety. As such, multimodality imaging, such as echocardiography, fluoroscopy, and fusion imaging, is routinely used to guide safe transseptal puncture. Despite the use of multimodal imaging, there is currently no uniform nomenclature of cardiac anatomy between the various imaging modes and proceduralists, and echocardiographers tend to use imaging modality-specific terminology when communicating among the various imaging modes. This variability in nomenclature among imaging modes stems from differing anatomic descriptions of cardiac anatomy. Given the required level of precision in performing transseptal puncture, a clearer understanding of the basis of cardiac anatomic nomenclature is required by both echocardiographers as well as proceduralists; enhanced understanding can help facilitate communication across specialties and possibly improve communication and safety. In this review, the authors highlight the variation in cardiac anatomy nomenclature among various imaging modes.

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.

Impact of inferior vena cava entry characteristics on tricuspid annular access during transcatheter interventions

OBJECTIVES

The purpose of this study was to characterize the anatomic relationship between the inferior vena cava (IVC) and tricuspid annulus (TA) and its potential impact on the performance of transcatheter TV interventions.

BACKGROUND

Transcatheter tricuspid valve (TV) interventions are emerging as a therapeutic alternative for the treatment of severe, symptomatic tricuspid regurgitation (TR). Progression of TR is associated with right heart dilatation. These anatomic changes may distort the IVC-TA relationship and impact successful implantation of transcatheter devices.

METHODS

Fifty patients who presented with symptomatic TR for consideration of transcatheter TV therapy with an available CT were included in the study. Comprehensive transesophageal echocardiogram and CT analyses were performed to assess the right-sided cardiac chambers, TA and IVC-TA relationship.

RESULTS

The mean age of the study cohort was 78.4 ± 8.9 years. Torrential TR was present in 54% (n = 27). There was considerable variation in the short axis mid-IVC to mid-TA offset (SAX_MID 18.2 ± 7.9 mm, range 4.7-42.1 mm).

CONCLUSIONS

The IVC-to-TA relationship exhibits significant variability in patients with symptomatic TR. CT analysis of the tricuspid anatomy, including the relationship to the surrounding structures and the IVC, is essential for planning transcatheter TV interventions. Further studies are needed to define whether the IVC-to-TA relationship is a predictor of technical success in the context of specific transcatheter delivery systems.

Cardiac Computed Tomography and Magnetic Resonance Imaging of the Tricuspid Valve: Preprocedural Planning and Postprocedural Follow-up

Transcatheter tricuspid valve interventions (TTVIs) are rapidly growing as a less invasive treatment of high surgical risk patients with advanced TR. A comprehensive anatomic and functional assessment of the tricuspid valve and right-sided chambers is essential for candidate selection and procedural planning. Advanced imaging with cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) can provide accurate anatomic and functional assessment of the tricuspid valve, its apparatus, and the right-sided chambers. In this review, we provide an updated overview of the emerging role of CCT and CMR for TR patient evaluation, TTVI planning, and follow-up.

Transcatheter treatment for tricuspid valve disease

Approximately 4% of subjects aged 75 years or more have clinically relevant tricuspid regurgitation (TR). Primary TR results from anatomical abnormality of the tricuspid valve apparatus and is observed in only 8-10% of the patients with tricuspid valve disease. Secondary TR is more common and arises as a result of annular dilation caused by right ventricular enlargement and dysfunction as a consequence of pulmonary hypertension, often caused by left-sided heart disease or atrial fibrillation. Irrespective of its aetiology, TR leads to volume overload and increased wall stress, both of which negatively contribute to detrimental remodelling and worsening TR. This vicious circle translates into impaired survival and increased heart failure symptoms in patients with and without reduced left ventricular ejection fraction. Interventions to correct TR are underutilised in daily clinical practice owing to increased surgical risk and late patient presentation. The recently introduced transcatheter tricuspid valve interventions aim to address this unmet need. Dedicated expertise and an interdisciplinary Heart Team evaluation are essential to integrate these new techniques successfully and select patients. The present article proposes a standardised approach to evaluate patients with TR who may be candidates for transcatheter interventions. In addition, a state-of-the-art review of the available transcatheter therapies, the main criteria for patient and device selection, and information concerning the remaining uncertainties are provided.

Imaging for transcatheter native tricuspid valve intervention: patient selection, procedural planning and interventional guidance

There are an increasing number of transcatheter tricuspid valve interventions being performed worldwide using commercially available and investigational devices. Imaging in the pre-procedural and periprocedural period is essential for procedural and clinical success. Echocardiographic-based techniques are particularly important in these procedures, especially for interventional guidance. This review summarizes the current devices in use and how imaging is used for patient selection, procedural planning, and interventional guidance. The most commonly used method of transcatheter tricuspid intervention is edge-to-edge repair using the MitraClip or TriClip devices (Abbott, Santa Clara, CA, USA). Randomized controlled data is pending but observational studies have demonstrated success, especially in the setting of smaller coaptation gaps and adequate transesophageal imaging windows. Direct annuloplasty with the Cardioband (Edwards Lifesciences, Irvine, CA, USA) has also been used in many centers and has demonstrated success when the anatomy and mechanism of tricuspid regurgitation are appropriate for annuloplasty based on imaging evaluation. Lastly, transcatheter valve replacement is becoming more common using several investigational devices and relies heavily on imaging methods to achieve procedural success.

Contemporary review in the multi-modality imaging evaluation and management of tricuspid regurgitation

The tricuspid valve has gained interest recently because of the poor outcomes with current treatments and advances in percutaneous valve interventions. A sound understanding of the anatomy and pathologies of the tricuspid valve is critical in its evaluation and management of tricuspid regurgitation (TR). A multi-modality imaging approach with transthoracic echocardiography, transesophageal echocardiography, computed tomography, magnetic resonance imaging all have their individual and collective roles in the evaluation of TR and guidance of surgical and percutaneous procedures. This combined with clinical factors will contribute to defining timing, indications, modality selection and risk stratification for tricuspid valve interventions, which currently remains controversial.

Future Perspectives in Percutaneous Treatment of Tricuspid Regurgitation

Tricuspid regurgitation (TR) has a not negligible prevalence and its severity is correlated with poorer outcomes. However, surgical options are rarely offered to these patients because of their high surgical risk. Given that medical therapy plays a limited role in the management of these patients, there is an increasing clinical need for transcatheter treatment options. Although, transcatheter tricuspid valve interventions (TTVIs) are still at an early stage, emerging data suggests their clinical effectiveness and safety, with preliminary results highlighting the potential benefits of transcatheter treatments over medical therapy. In this review, we highlight the challenges and future directions of current and emerging technologies dedicated to the treatment of TR along with an analysis of the next steps required in future clinical trials and studies dedicated to the treatment of the forgotten valve.

Imaging for Tricuspid Valve Repair and Replacement

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

Stepwise manipulation of cardiac computed tomography multi-planar reconstruction to mimic transesophageal echocardiography

Cardiac computed tomography (CT) is increasingly used to plan transcatheter structural heart interventions. However, intraoperative guidance relies on transesophageal echocardiography (TEE) and fluoroscopy. This study sought to develop a stepwise CT multi-planar reconstruction manipulation method to mimic TEE, bridging the gap between preoperative planning and intraoperative guidance tools. This CT manipulation reproduced similar configurations as TEE views in the mid-esophageal left ventricle (LV) views, transgastric LV 2-chamber views for mitral apparatus, and other miscellaneous views. Stepwise cardiac CT manipulation to mimic TEE is the final piece of the puzzle in the mental co-registration of these three crucial imaging modalities. Now, we can predict the TEE images and fluoroscopy projections in a preoperative rehearsal, thus improving the intraoperative accuracy of interventions.

Imaging and Patient Selection for Transcatheter Tricuspid Valve Interventions

With the emergence of transcatheter solutions for the treatment of tricuspid regurgitation (TR) increased attention has been directed to the once neglected tricuspid valve (TV) complex. Recent studies have highlighted new aspects of valve anatomy and TR etiology. The assessment of valve morphology along with quantification of regurgitation severity and RV function pose several challenges to cardiac imagers guiding transcatheter valve procedures. This review article aims to give an overview over the role of modern imaging modalities during assessment and treatment of the TV.

Multimodality Imaging of the Tricuspid Valve and Right Heart Anatomy

The characterization of tricuspid valve and right-heart anatomy has been gaining significant interest in the setting of new percutaneous transcatheter interventions for tricuspid regurgitation. Multimodality cardiac imaging provides a wealth of information about the anatomy and function of the tricuspid valve apparatus, right ventricle, and right atrium, which is pivotal for diagnosis and prognosis and for planning of percutaneous interventions. The present review describes the role of echocardiography, cardiac magnetic resonance, and multidetector row cardiac computed tomography for right heart and tricuspid valve assessment.

Optimal fluoroscopic viewing angles of right-sided heart structures in patients with tricuspid regurgitation based on multislice computed tomography

AIMS

This study sought to analyse multislice computed tomography (MSCT) data of patients with tricuspid regurgitation and to report the variability of fluoroscopic viewing angles for several right-sided heart structures, as well as chamber views of the right heart in order to determine the optimal fluoroscopic viewing angles of six right-sided heart structures and right-heart chamber views.

METHODS AND RESULTS

The MSCT data of 44 patients with mild to severe tricuspid regurgitation (TR) were retrospectively analysed. For each patient, we determined the optimal fluoroscopic viewing angles of the annulus/orifice en face view of the tricuspid valve, atrial septum, superior vena cava (SVC), inferior vena cava (IVC), coronary sinus (CS) and pulmonary valve. In this TR patient cohort, the average fluoroscopic viewing angle for the en face view of the tricuspid valve annulus was LAO 54-CAUD 15; RAO 10-CAUD 66 for the SVC orifice; LAO 27-CRA 59 for the IVC orifice; RAO 28-CRA 19 for the CS orifice; RAO 33-CAUD 33 for the atrial septum and LAO 13-CAUD 52 for the pulmonary valve annulus. The average viewing angle for right-heart chamber views was LAO 55-CAUD 15 for the one-chamber view; RAO 59-CAUD 54 for the two-chamber view; RAO 27-CRA 19 for the three-chamber view and LAO 5-CRA 60 for the four-chamber view.

CONCLUSIONS

MSCT can provide patient-specific fluoroscopic viewing angles of right-sided heart structures. This information may facilitate transcatheter right-heart interventions.

Transcatheter Tricuspid Valve Interventions: An Emerging Field

PURPOSE OF REVIEW

This review aims to provide an updated overview and a clinical perspective on novel transcatheter tricuspid valve interventions (TTVI), highlighting potential challenges and future directions.

RECENT FINDINGS

Severe tricuspid regurgitation (TR) is a predictor of mortality. However, a sizeable number of patients remain untreated until the end-stage when cardiac surgery presents a prohibitive risk. The emergent need in finding a treatment for patients with TR, deemed for surgery options, has encouraged the development of TTVI. These procedures mimic classical surgery techniques and are mainly divided in four categories: annuloplasty and coaptation devices, edge-to-edge techniques and transcatheter tricuspid valve replacement. Early studies showed promising results, but long-term follow-up data are not available. For patients with severe TR and high surgical risk, several percutaneous options are available. However, these therapies are in a growing phase and bigger studies and long term follow-up are needed to prove their efficacy.