Computed tomography imaging in preprocedural planning of transcatheter valvular heart interventions

Cardiac Computed Tomography (CCT) has become a reliable imaging modality in cardiology providing robust information on the morphology and structure of the heart with high temporal and isotropic spatial resolution. For the past decade, there has been a paradigm shift in the management of valvular heart disease since previously unfavorable candidates for surgery are now provided with less-invasive interventions. Transcatheter heart valve interventions provide a real alternative to medical and surgical management and are often the only treatment option for valvular heart disease patients. Successful transcatheter valve interventions rely on comprehensive multimodality imaging assessment. CCT is the mainstay imaging technique for preprocedural planning of these interventions. CCT is critical in guiding patient selection, choice of procedural access, device selection, procedural guidance, as well as allowing postprocedural follow-up of complications. This article aims to review the current evidence of the role of CCT in the preprocedural planning of patients undergoing transcatheter valvular interventions.

Cardiac Computed Tomography of Native Cardiac Valves

Valvular heart disease (VHD) is a significant clinical problem associated with high morbidity and mortality. Although not being the primary imaging modality in VHD, cardiac computed tomography (CCT) provides relevant information about its morphology, function, severity grading, and adverse cardiac remodeling assessment. Aortic valve calcification quantification is necessary for grading severity in cases of low-flow/low-gradient aortic stenosis. Moreover, CCT details significant information necessary for adequate percutaneous treatment planning. CCT may help to detail the etiology of VHD as well as to depict other less frequent causes of valvular disease, such as infective endocarditis, valvular neoplasms, or other cardiac pseudomasses.

Comparison between multimodality imaging approaches for measurement of the tricuspid annulus in severe tricuspid regurgitation

BACKGROUND

Tricuspid valve (TV) sizing is crucial for surgical or interventional procedures planning. Imaging TV is frequently challenging and often requires multimodal imaging techniques. Computed tomography (CT) is the gold standard for sizing. The authors compared measurements of the tricuspid annulus (TA) acquired using echocardiography and CT.

METHODS

Thirty-six patients with severe symptomatic tricuspid regurgitation were included in this retrospective analysis. During mid-diastole, the maximal two-dimensional (2D) TA diameter was directly measured in multiple views using transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). Three-dimensional (3D) TA size was assessed using cross-sectional long-axis and short-axis diameters, areas, and perimeters measured in the projected plane. The TA diameter was quantified by the perimeter measured on the CT images (CT imaging_indirect) and compared with echocardiography measurements. Tenting height and tenting area were also measured using TTE at mid systole.

RESULTS

The long-axis dimensions measured using 3DTEE (3DTEE_direct) best correlated with the TA diameter (CT imaging_indirect) (R = 0.851, P = 0.0001) and the least discrepancies (difference 1.2 ± 2.4 mm, P = 0.012). The TA diameters quantified by the perimeters measured using 3DTEE (3DTEE_indirect) were smaller than the CT values (difference 2.5 ± 2.5 mm, P = 0.0001). The maximal dimensions directly measured by 2DTEE (2DTEE_direct) were modestly correlated with the CT values. Overall, the maximal dimensions by TTE_direct were less reliable than those by CT. TA eccentricity index correlated with the maximal tenting height and area.

CONCLUSION

The patients with severe tricuspid regurgitation had a dilated and circular annulus. The long-axis TA dimensions (3DTEE_direct) were similar to the diameters (CT imaging_indirect).

Congenital agenesis of anterior leaflet of tricuspid valve

Complete absence of anterior tricuspid valve leaflet is a rare anomaly. We report the case of a 10-year-old girl who presented with severe tricuspid regurgitation with annular dilatation and non-coapting leaflets. Intra-operatively, an incidental finding of complete agenesis of the anterior leaflet was observed. A tricuspid valve replacement was carried out; the patient made an uneventful recovery and remains well at follow-up.

Assessment of Right Ventricle Function and Tricuspid Regurgitation in Heart Failure: Current Advances in Diagnosis and Imaging

Right ventricular (RV) systolic dysfunction increases mortality among heart failure patients, and therefore, accurate diagnosis and monitoring is paramount. RV anatomy and function are complex, usually requiring a combination of imaging modalities to completely quantitate volumes and function. Tricuspid regurgitation usually occurs with RV dysfunction, and quantifying this valvular lesion also may require multiple imaging modalities. Echocardiography is the first-line imaging tool for identifying RV dysfunction, with cardiac MRI and cardiac computed tomography adding valuable additional information.

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.

Tricuspid Valve Imaging and Right Ventricular Function Analysis Using Cardiac CT and MRI

Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (CMR) can reveal the detailed anatomy and function of the tricuspid valve and right ventricle (RV). Quantification of tricuspid regurgitation (TR) and analysis of RV function have prognostic implications. With the recently available transcatheter treatment options for diseases of the tricuspid valve, evaluation of the tricuspid valve using CT and CMR has become important in terms of patient selection and procedural guidance. Moreover, CT enables post-procedural investigation of the causes of valve dysfunction, such as pannus or thrombus. This review describes the anatomy of the tricuspid valve and CT and CMR imaging protocols for right heart evaluation, including RV function and TR analyses. We also demonstrate the pre-procedural planning for transcatheter treatment of TR and imaging of postoperative complications using CT.

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.

Isolated Tricuspid Valve Surgery: the Auckland Experience 2011-2019

INTRODUCTION

Isolated tricuspid valve surgery is an uncommon operation. Historical reports, including a previous review from our unit, demonstrated high morbidity and mortality associated with this operation. Many of these patients had severely impaired right ventricular function at the time of the surgery. Since our previous review, we have actively encouraged our local cardiologists to refer patients with severe isolated tricuspid disease for surgery before right ventricular remodelling occurs. This present study was performed to assess our current results.

MATERIAL AND METHODS

A prospectively-maintained hospital database was used to identify all adult non-congenital patients receiving standalone tricuspid valve repair or replacement at New Zealand's largest cardiothoracic surgical unit from July 2011 to July 2019. Additional demographic and clinical data were collected by review of patient electronic records.

RESULTS

During the 8-year study period, a total of 50 patients underwent isolated tricuspid valve surgery. Most patients were operated on for functional (40%) or rheumatic (30%) tricuspid disease. The majority of patients underwent surgery when the right ventricular function preoperatively was normal (30%) or mildly/moderately impaired (60%). Over half the patient sample (56%) underwent valve replacement. The 30-day mortality rate and stroke rate were 6% and 2% respectively. The medium-term survival was 80% at 4 years mean follow-up.

CONCLUSION

Isolated tricuspid surgery is no longer a high mortality operation when it is performed on patients who have preserved right ventricular function.

Computed tomography imaging needs for novel transcatheter tricuspid valve repair and replacement therapies

Transcatheter tricuspid valve therapies are an emerging field in structural heart interventions due to the rising number of patients with severe tricuspid regurgitation and the high risk for surgical treatment. Computed tomography (CT) allows exact measurements of the annular plane, evaluation of adjacent structures, assessment of the access route, and can also be used to identify optimal fluoroscopic projection planes to enhance periprocedural imaging. This review provides an overview of current transcatheter tricuspid valve repair and replacement therapies and to what extent CT can support these interventions.

Appropriate use criteria for cardiovascular MRI: SIC - SIRM position paper Part 2 (myocarditis, pericardial disease, cardiomyopathies and valvular heart disease)

Cardiovascular magnetic resonance (CMR) has emerged as an accurate diagnostic technique for the evaluation of patients with cardiac disease in the majority of clinical settings, thanks to an established additional diagnostic and prognostic value. This document has been developed by a joined group of experts of the Italian Society of Cardiology (SIC) and Italian Society of Radiology (SIRM) to provide a summary about the current state of technology and clinical applications of CMR, to improve the clinical diagnostic pathways and to promote its inclusion in clinical practice. The writing committee consisted of members and experts of both societies in order to develop a more integrated approach in the field of cardiac imaging. This section 2 will cover myocarditis, pericardial disease, cardiomyopathies and valvular heart disease.

Morphology and Position of the Right Atrioventricular Valve in Relation to Right Atrial Structures

The right atrioventricular valve (RAV) is an important anatomical structure that prevents blood backflow from the right ventricle to the right atrium. The complex anatomy of the RAV has lowered the success rate of surgical and transcatheter procedures performed within the area. The aim of this study was to describe the morphology of the RAV and determine its spatial position in relation to selected structures of the right atrium. We examined 200 randomly selected human adult hearts. All leaflets and commissures were identified and measured. The position of the RAV was defined. Notably, 3-leaflet configurations were present in 67.0% of cases, whereas 4-leaflet configurations were present in 33.0%. Septal and mural leaflets were both significantly shorter and higher in 4-leaflet than in 3-leaflet RAVs. Significant domination of the muro-septal commissure in 3-leflet valves was noted. The supero-septal commissure was the most stable point within RAV circumference. In 3-leaflet valves, the muro-septal commissure was placed within the cavo-tricuspid isthmus area in 52.2% of cases, followed by the right atrial appendage vestibule region (20.9%). In 4-leaflet RAVs, the infero-septal commissure was located predominantly in the cavo-tricuspid isthmus area and infero-mural commissure was always located within the right atrial appendage vestibule region. The RAV is a highly variable structure. The supero-septal part of the RAV is the least variable component, whereas the infero-mural is the most variable. The number of detected RAV leaflets significantly influences the relative position of individual valve components in relation to right atrial structures.

Tricuspid valve in congenital heart disease: multimodality imaging and electrophysiological considerations

The tricuspid valve (TV) has been neglected for many years. Only recently, new studies demonstrated the prognostic role of the tricuspid valve lesions. In addition to that, new interventional approaches offer the possibility to non-invasively treat tricuspid valve disease. In this review, our aim is to summarize the role of different imaging techniques in the assessment of tricuspid valve with particular regards to congenital heart diseases. Finally, we analyze the importance of the TV and its adjacent regions from an electrophysiological point of view, both in structurally normal hearts and in congenital heart diseases. The most relevant transthoracic echocardiography (TTE) views to visualize the TV are the "modified" parasternal long axis, the apical views and subcostal projections, such as right oblique or left oblique views. However, simultaneous visualization of the three leaflets is possible only with three-dimensional TTE, or, sometimes, in parasternal short axis and subcostal short axis views in children. 3D echocardiography (3DE) is promising in this field. Indeed, its unique projections, such as en face views from the right ventricular and atrial perspectives, are able to define the spatial relationship of the tricuspid leaflets with the surrounding structures. Moreover, multimodality imaging assessment has been recently proposed for the diagnostic assessment of the TV, especially before percutaneous intervention. Cardiac Computed Tomography (CCT) provides valuable anatomic spatial information of the TV apparatus. Cardiac Magnetic Resonance (CMR) is able to provide, non-invasively, detailed morphological and functional information of the valve.

Multi-Modality Imaging for Interventions in Tricuspid Valve Disease

Several studies have demonstrated that severe tricuspid regurgitation (TR) has a significant negative impact on morbidity and mortality. Nowadays, several therapeutic options to treat TR are available and patients at high surgical risk can also be treated with transcatheter procedures. For the management of patients with TR, an accurate assessment of the tricuspid valve and its surrounding structures is therefore of crucial importance and has gained significant interest in the medical community. Different imaging modalities can provide detailed information on the tricuspid valve apparatus, right ventricle, right atrium, and coronary circulation which are fundamental to define the timing and anatomic suitability of surgical and percutaneous procedures. The present review illustrates the role of 2D and 3D echocardiography, cardiac magnetic resonance, and multidetector row computed tomography for the assessment of the tricuspid valve and right heart with a particular focus on the data needed for planning and guiding interventional procedures.

State-of-the-Art Review: Anatomical and Imaging Considerations During Transcatheter Tricuspid Valve Repair Using an Annuloplasty Approach

Transcatheter techniques for the treatment of tricuspid regurgitation (TR) are being more frequently used and several new devices are in development. Since 90% of patients with TR have secondary TR, catheter based systems which reduce the dilated tricuspid annulus area are of particular interest. In order to perform an annuloplasty procedure effectively and safely, knowledge about the anatomy of the tricuspid valve apparatus and especially of the annulus in relation to the important neighboring structures such as the aortic root, the RCA, the electrical pathways and the CS is fundamental. In addition, comprehensive understanding of the device itself, the delivery system, its maneuverability and the individual procedural steps is required. Furthermore, the use of multi-modality imaging is important. For each step of the procedure the appropriate imaging modality as well as the optimal; imaging planes are crucial to provide the necessary information to best guide the individual procedural step.

Cardiovascular imaging modalities in the diagnosis and management of rheumatic heart disease

Rheumatic heart disease (RHD) is prevalent in sub-Saharan Africa, where the capacity for diagnosis and evaluation of disease severity and complications is not always optimal. While the medical history and physical examination are important in the assessment of patients suspected to have RHD, cardiovascular imaging techniques are useful for confirmation of the diagnosis. Echocardiography is the workhorse modality for initial evaluation and diagnosis of RHD. Cardiovascular magnetic resonance is complementary and may provide additive information, including tissue characteristics, where echocardiography is inadequate or non-diagnostic. There is emerging evidence on the role of computed tomography, particularly following valve replacement surgery, in the monitoring and management of RHD. This article summarises the techniques used in imaging RHD patients, considers the evidence base for their utility, discusses their limitations and recognises the clinical contexts in which indications and imaging with various modalities are expanding.

Calcification of tricuspid valve chordae tendineae on echocardiography and computed tomography

We present the appearance of chordae tendineae calcification on transthoracic echocardiography and ECG-gated cardiac computed tomography in a 75 year-old woman. While the etiology is unclear, the abnormality can be clearly delineated on a properly performed CT study. We also discuss modification of the cardiac CT protocol to optimize visualization of the tricuspid valve apparatus.

Right Atrioventricular Valve Leaflet Morphology Redefined: Implications for Transcatheter Repair Procedures

OBJECTIVES

The authors aimed to comprehensively detail the right atrioventricular valve functional leaflet anatomies.

BACKGROUND

The rapid development of both surgical and percutaneous repair techniques for tricuspid regurgitation has renewed interest in variations in the morphology of the right atrioventricular valve.

METHODS

The functioning right atrioventricular valves of 40 reanimated human hearts were imaged using Visible Heart methodologies. Hearts were then perfusion-fixed and dissected, uniquely allowing for the comparative assessments of functional versus fixed valve anatomies from the same set of donor hearts.

RESULTS

The right atrioventricular valves have "3-leaflet" configurations in 57.5% and "4-leaflet" configurations in the remaining hearts. For 4-leaflet valves, extra leaflets were commonly observed in the most inferior regions of the annuli. No difference in valve perimeters between 2 valve types were observed (112.2 vs. 117.1 mm; p = 0.14). In 3-leaflet valves, septal, mural, and superior leaflets occupied 32.2 ± 6.5%, 15.9 ± 5.5%, and 25.5 ± 6.2% of the annulus, respectively, whereas in the 4-leaflet arrangements, these values were 27.0 ± 5.8% (septal), 12.0 ± 4.5% (inferior), 13.7 ± 9.4% (mural), and 19.8 ± 6.1% (superior). The muroseptal/inferoseptal commissures were usually located in the cavotricuspid regions, whereas the inferomural and superomural commissures were in the right atrial appendage vestibule area.

CONCLUSIONS

The right atrioventricular valve has 4 functional leaflets in more than 40% of cases. The authors found that the inferomural region is the most variable area of the valve and believe that anatomic variation is an important consideration for planned 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.

Computed Tomography of Cardiac Valves: Review

Valvular heart disease is a common clinical problem. Although echocardiography is the standard technique for the noninvasive evaluation of the valves, cardiac CT has evolved to become a useful tool in the evaluation of the cardiac structures as well. Importantly, CT allows for improved quantification of valvular calcification due to its superior spatial resolution. It may improve the detection of small valvular or perivalvular pathology or the characterization of valvular masses and vegetations. This review describes the assessment of normal and diseased heart valves by cardiac CT and discusses its strengths and weaknesses.

Diagnostic value of Omniview technique on the agenesis of corpus callosum

Objective: This study aimed to discuss the diagnostic value of Omniview technique on the agenesis of corpus callosum. Methods: A total of 43 pregnant women with no obvious structural abnormality and eight pregnant women who diagnosed with agenesis of corpus callosum (ACC) were included in this study. The 2D ultrasonography and the 3D ultrasonography Omniview technique were used to carry out ultrasonic examination on 43 normal fetuses and eight fetuses with agenesis of corpus callosum (as verified through magnetic resonance), respectively. Results: The Omniview technique visually displayed the median sagittal plane of the fetus. The ROC curve of Omniview (0.999) was much higher than that of 2D ultrasonography (0.817). Rating of ACC and normal fetuses showed that the diagnostic efficiency of 3D ultrasonography Omniview technique was much higher than 2D ultrasonography. Conclusion: 3D ultrasonography Omniview technique has certain advantage in the diagnosis of agenesis of corpus callosum, and is of great significance in the prenatal screening of callosum.

Clinical aspects of myocardial fibrosis in adults with Ebstein's anomaly

Heart failure and arrhythmia are common complications in adults with Ebstein's anomaly. They may result not only from hemodynamic alterations, but also from myocardial fibrosis. Late gadolinium enhancement (LGE) by CMR enables the evaluation of myocardial fibrosis. The aim of the study was to asses the presence of LGE and its relation to clinical outcome. We studied a group of 37 unoperated adults aged 43.0 ± 14.4 years with Ebstein's anomaly from the congenital heart disease outpatient clinic. Study protocol included: cardiopulmonary test, assessment of supraventricular arrhythmia (SVA), and CMR with evaluation of cardiac chambers' morphology and function, and presence of LGE. Variables following normal distribution were shown as mean ± SD if otherwise median (range) was applied. Fibrosis was found in 18 patients (48.6%) and was distributed as follows: 12 patients (32.4%) in the right atrium, 12 (32.4%) in the atrialized right ventricle, and 2 (5.4%) in the functional right ventricle. In patients with fibrosis, the tricuspid regurgitation fraction was bigger (48.3 ± 19.7 vs. 36.1 ± 22.6%, p = 0.048) and SVA was more frequent [12 (66.7%) vs. 6 (31.6%), p = 0.046] when compared to patients without fibrosis. However, exercise capacity did not differ between patients with and without LGE (peak VO2 24.0 ± 4.7 vs. 23.7 ± 4.4, p = 0.87). In adults with Ebstein's anomaly fibrosis estimated by LGE-CMR was localized in the right atrium and the right ventricle only. Volume overload resulting from tricuspid regurgitation might be a factor conducive to fibrosis. Myocardial fibrosis did not influence exercise capacity. Association between myocardial fibrosis and supraventricular arrhythmia was confirmed.

Evaluation of right ventricular function by coronary computed tomography angiography using a novel automated 3D right ventricle volume segmentation approach: a validation study

OBJECTIVES

To evaluate right ventricle (RV) function by coronary computed tomography angiography (CTA) using a novel automated three-dimensional (3D) RV volume segmentation tool in comparison with clinical reference modalities.

METHODS

Twenty-six patients with severe end-stage heart failure [left ventricle (LV) ejection fraction (EF) <35%] referred to CTA were enrolled. A specific individually tailored biphasic contrast agent injection protocol was designed (80%/20% high/low flow) was designed. Measurement of RV function [EF, end-diastolic volume (EDV), end-systolic volume (ESV)] by CTA was compared with tricuspid annular plane systolic excursion (TAPSE) by transthoracic echocardiography (TTE) and right heart invasive catheterisation (IC).

RESULTS

Automated 3D RV volume segmentation was successful in 26 (100%) patients. Read-out time was 3 min 33 s (range, 1 min 50s-4 min 33s). RV EF by CTA was stronger correlated with right atrial pressure (RAP) by IC (r = -0.595; p = 0.006) but weaker with TAPSE (r = 0.366, p = 0.94). When comparing TAPSE with RAP by IC (r = -0.317, p = 0.231), a weak-to-moderate non-significant inverse correlation was found. Interobserver correlation was high with r = 0.96 (p < 0.001), r = 0.86 (p < 0.001) and r = 0.72 (p = 0.001) for RV EDV, ESV and EF, respectively. CT attenuation of the right atrium (RA) and right ventricle (RV) was 196.9 ± 75.3 and 217.5 ± 76.1 HU, respectively.

CONCLUSIONS

Measurement of RV function by CTA using a novel 3D volumetric segmentation tool is fast and reliable by applying a dedicated biphasic injection protocol. The RV EF from CTA is a closer surrogate of RAP than TAPSE by TTE.

KEY POINTS

• Evaluation of RV function by cardiac CTA by using a novel 3D volume segmentation tool is fast and reliable. • A biphasic contrast agent injection protocol ensures homogenous RV contrast attenuation. • Cardiac CT is a valuable alternative modality to CMR for the evaluation of RV function.

"Guidelines Recommendations on the Treatment of Tricuspid Regurgitation. Where Are We and Where Do We Go With Transcatheter Valve Intervention"

Tricuspid regurgitation (TR) is an important clinical problem because it is frequent and carries a poor prognosis when it is left uncorrected. However, there is still a lack of awareness of tricuspid disease in the medical community. The indications for evaluation and surgical interventions in patients with TR were recently updated in the ESC/EACTS guidelines. Transcatheter tricuspid valve intervention (TTVI), almost exclusively valve repair, is at an early stage of development as only a few hundreds of patients have been treated. The first-in-man valve implantation was very recently performed. The recent ESC/EACTS Guidelines state that “The potential role of transcatheter tricuspid valve treatment in high-risk patients needs to be determined”. We shall review here which lessons of interest for TTVI can be learned from the Guidelines as regards evaluation and indications for surgery and try to imagine what could be the place of TTVI in the Guidelines in the future.

Recent advances in managing tricuspid regurgitation

Isolated tricuspid valve surgery is usually carried out with very high morbidity and mortality given the complexity of the affected patients. In light of this, trans-catheter tricuspid valve interventions have been emerging as an attractive alternative to surgery over the last few years. Although feasibility has been shown with a number of devices, clinical experience remains preliminary and associated with significant clinical and technical challenges. Here we describe currently available trans-catheter treatment options for severe tricuspid regurgitation implanted in different locations.

Anatomy of the Tricuspid Valve, Pathophysiology of Functional Tricuspid Regurgitation, and Implications for Percutaneous Therapies

The tricuspid valve is a complex dynamic apparatus made up of many different closely linked structures: the annulus, the three leaflets, the chordae, the papillary muscles and the right ventricle. Other nearby structures, such as the coronary sinus ostium, the conduction system, the membranous septum, and the right coronary artery must be taken into account when dealing with the tricuspid. Annulus dilation and leaflet tethering due to right ventricular remodeling are the 2 major mechanisms responsible for most tricuspid regurgitation cases. Precise knowledge of tricuspid anatomy and function, as well as careful preoperative planning, is fundamental for successful transcatheter tricuspid procedures.

Diagnosis and treatment of tricuspid valve disease: current and future perspectives

The assessment and management of tricuspid valve disease have evolved substantially during the past several years. Whereas tricuspid stenosis is uncommon, tricuspid regurgitation is frequently encountered and is most often secondary in nature and caused by annular dilatation and leaflet tethering from adverse right ventricular remodelling in response to any of several disease processes. Non-invasive assessment of tricuspid regurgitation must define its cause and severity; advanced three-dimensional echocardiography, MRI, and CT are gaining in clinical application. The indications for tricuspid valve surgery to treat tricuspid regurgitation are related to the cause of the disorder, the context in which it is encountered, its severity, and its effects on right ventricular function. Most operations for tricuspid regurgitation are done at the time of left-sided heart valve surgery. The threshold for restrictive ring annuloplasty repair of secondary tricuspid regurgitation at the time of left-sided valve surgery has decreased over time with recognition of the risk of progressive tricuspid regurgitation and right heart failure in patients with moderate or lesser degrees of tricuspid regurgitation and tricuspid annular dilatation, as well as with appreciation of the high risks of reoperative surgery for severe tricuspid regurgitation late after left-sided valve surgery. However, many patients with unoperated severe tricuspid regurgitation are also deemed at very high or prohibitive surgical risk. Novel transcatheter therapies have begun to emerge for the treatment of tricuspid regurgitation in such patients. Experience with such therapies is preliminary and further studies are needed to determine their role in the management of this disorder.

Multimodal imaging of the tricuspid valve: normal appearance and pathological entities

The tricuspid valve, which is the atrioventricular valve attached to the morphological right ventricle, is affected by a wide range of pathological processes. Tricuspid valve diseases are now increasingly recognized as a significant cause of morbidity and mortality. Echocardiography is the most widely available and, hence, the first-line imaging modality used in the evaluation of tricuspid valve disorders; however, CT and MRI are also increasingly used for further evaluation and characterization of these entities. In this article, we first review the normal anatomy and embryology of the tricuspid valve, followed by a discussion of the role of multiple imaging modalities in the evaluation of tricuspid valve abnormalities. We then review and illustrate the imaging appearance of several congenital and acquired tricuspid valve abnormalities.

Main Messages

• Tricuspid valve diseases have a significant impact on morbidity and mortality.

• CT and MRI are increasingly used in the evaluation of tricuspid disorders.

• CT and MRI help in diagnosis, functional evaluation, pre-surgical planning and post-surgical follow-up.

• The most common cause of tricuspid regurgitation is functional.