Imaging of the Mitral Valve

Echocardiographic imaging is the foundation for the evaluation of mitral valve dysfunction. Both transthoracic and transesophageal echocardiography provide insight into the anatomy, pathology, and classification mitral valve dysfunction. Echocardiography also provides a multi-parametric approach with semi-quantitative and quantitative parameters to assess the severity of mitral regurgitation and mitral stenosis. Transesophageal imaging is essential in the assessment of patients considered for surgical or transcatheter interventional strategies to treat mitral valve dysfunction. Cardiac computed tomography (CT) and cardiac MRI are useful adjunctive imaging techniques in mitral valve disease with CT providing detailed procedural specificity and MRI providing detailed ventricular and regurgitant flow analysis.

Prognostic Value of Tricuspid Valve Gradient After Transcatheter Edge-to-Edge Repair: Insights From the TriValve Registry

BACKGROUND

Data regarding the impact of the tricuspid valve gradient (TVG) after tricuspid transcatheter edge-to-edge repair (TEER) are scarce.

OBJECTIVES

This study sought to evaluate the association between the mean TVG and clinical outcomes among patients who underwent tricuspid TEER for significant tricuspid regurgitation.

METHODS

Patients with significant tricuspid regurgitation who underwent tricuspid TEER within the TriValve (International Multisite Transcatheter Tricuspid Valve Therapies) registry were divided into quartiles based on the mean TVG at discharge. The primary endpoint was the composite of all-cause mortality and heart failure hospitalization. Outcomes were assessed up to the 1-year follow-up.

RESULTS

A total of 308 patients were included from 24 centers. Patients were divided into quartiles of the mean TVG as follows: quartile 1 (n = 77), 0.9 ± 0.3 mm Hg; quartile 2 (n = 115), 1.8 ± 0.3 mm Hg; quartile 3 (n = 65), 2.8 ± 0.3 mm Hg; and quartile 4 (n = 51), 4.7 ± 2.0 mm Hg. The baseline TVG and the number of implanted clips were associated with a higher post-TEER TVG. There was no significant difference across TVG quartiles in the 1-year composite endpoint (quartiles 1-4: 35%, 30%, 40%, and 34%, respectively; P = 0.60) or the proportion of patients in New York Heart Association class III to IV at the last follow-up (P = 0.63). The results were similar after adjustment for clinical and echocardiographic characteristics (composite endpoint quartile 4 vs quartile 1-quartile 3 adjusted HR: 1.05; 95% CI: 0.52-2.12; P = 0.88) or exploring post-TEER TVG as a continuous variable.

CONCLUSIONS

In this retrospective analysis of the TriValve registry, an increased discharge TVG was not significantly associated with adverse outcomes after tricuspid TEER. These findings apply for the explored TVG range and up to the 1-year follow-up. Further investigations on higher gradients and longer follow-up are needed to better guide the intraprocedural decision-making process.

Atrial secondary mitral regurgitation: prevalence, characteristics, management, and long-term outcomes

BACKGROUND

The prevalence, clinical characteristics, management and long-term outcomes of patients with atrial secondary mitral regurgitation (ASMR) are not well described.

METHODS

We performed a retrospective, observational study of consecutive patients with grade III/IV MR determined by transthoracic echocardiography. The aetiology of MR was grouped as being either primary (due to degenerative mitral valve disease), ventricular SMR (VSMR: due to left ventricular dilatation/dysfunction), ASMR (due to LA dilatation), or other.

RESULTS

A total of 388 individuals were identified who had grade III/IV MR; of whom 37 (9.5%) had ASMR, 113 (29.1%) had VSMR, 193 had primary MR (49.7%), and 45 (11.6%) were classified as having other causes. Compared to MR of other subtypes, patients with ASMR were on average older (median age 82 [74-87] years, p < 0.001), were more likely to be female (67.6%, p = 0.004) and usually had atrial fibrillation (83.8%, p = 0.001). All-cause mortality was highest in patients with ASMR (p < 0.001), but similar to that in patients with VSMR once adjusted for age and sex (hazard ratio [HR] 0.81, 95% confidence interval [CI] 0.52-1.25). Hospitalisation for worsening heart failure was more commonly observed in those with ASMR or VSMR (p < 0.001) although was similar between these groups when age and sex were accounted for (HR 0.74, 95% CI 0.34-1.58). For patients with ASMR, the only variables associated with outcomes were age and co-morbidities.

CONCLUSIONS

ASMR is a prevalent and distinct disease process associated with a poor prognosis, with much of this related to older age and co-morbidities.

Comparative quantification of primary mitral regurgitation by computer modeling and simulated echocardiography

Clinical investigations have demonstrated that mitral regurgitation (MR) quantification using echocardiography (echo) may significantly underestimate or overestimate the regurgitant volume, especially for two-dimensional (2D) echo. Computer modeling and simulated echo were conducted to evaluate the fundamental assumptions in the echo quantification of primary MR that is due to posterior mitral leaflet prolapse. The theoretical flaw of the proximal isovelocity surface area (PISA) method originates from the assumption that the MR flow rate is the product of the isovelocity surface area and aliasing velocity, which is only valid when the velocity vectors are perpendicular to the isovelocity surface. Other factors such as the Doppler angle effect, the view planes of 2D echo, and the single time instant of PISA were also analyzed. We find that the hemielliptic PISA method gives the smallest error for moderate and severe MR cases compared with other PISA methods. Compared with the PISA method, the volumetric technique (VT) is theoretically more robust. By considering correction factors that are caused by nonflat velocity profiles and the closing volume of the aortic valve, the accuracy of the VT method can be significantly improved. The corrected volumetric technique provides more accurate results compared with the PISA methods, especially for mild MR.NEW & NOTEWORTHY We evaluate the accuracy of common echocardiography techniques for the quantification of primary mitral regurgitations using computer modeling. The hemielliptic proximal isovelocity surface area (PISA) method gives the smallest error (within 15%) for moderate and severe mitral regurgitation cases compared with other PISA methods. The volumetric method is theoretically more robust than the PISA method. The accuracy of the volumetric method can be improved by a correction factor around 0.7 because of the nonflat velocity profiles and the closing volume of the aortic valve.

Added Value of Interactive 3-D Stereo Vision Echocardiography in the Heart Valve Team: A Post Hoc Analysis for Optimal Decision Making in Patients With Mitral Valve Regurgitation

OBJECTIVE

We assessed the added value of advanced echocardiography post hoc analysis for optimal decision-making in the Heart Valve Team (HVT) using an interactive, dynamic, live visualization system with true three-dimensional (3-D) stereo vision.

METHODS

HVT scrutinized the incremental value of 3 consecutive methods of presentation of full-volume echocardiographic data sets in terms of diagnosis and possibility of repair in 11 selected patients having mitral regurgitation (MR)(Table 1). The questionnaire investigated consecutively (a) standard two-dimensional (2-D) transesophageal echocardiography, (b) single-beat 3-D zoom of the surgical view of the mitral valve, and (c) advanced 3-D volumetric rendering technology (Personal Space Station, Vesalius 3D software, PS-Medtech, Netherlands).

RESULTS

In 4 of 11 reviews (36%), single-beat 3-D zoom had additional value over 2-D echocardiography in terms of mechanism/adjustments or adjustment of confirmation of diagnosis. Single-beat 3-D zoom had no additional value over 2-D echocardiography in terms of proposal/probability of repair. In 7 out of 11 (64%) reviews, true stereo 3-D visualization had additional value in terms of mechanism of pathology compared to 2-D and 3-D zoom and in 5 out of 11 (45%) reviews in confirmation of diagnosis. In 3 out of 11 (27%) reviews, true stereo 3-D visualization had additional value in terms of proposal of repair and in 4 of 11 (36%) in probability of repair over 2-D and 3-D zoom.

CONCLUSIONS

Advanced easy-to-use true 3-D echocardiography limited differences in interpretation and strengthened the confidence in understanding the mechanisms and suitability for repair of mitral valve regurgitation, typically in more complex valve pathology.

Clinical impact of elevated tricuspid valve inflow gradients after transcatheter edge-to-edge tricuspid valve repair

AIMS

The aim of this study was to compare the outcome of patients with a post-procedural tricuspid valve gradient (TVG) of >3 mmHg vs ≤3 mmHg after transcatheter edge-to-edge tricuspid valve repair (TTVR).

METHODS AND RESULTS

Between March 2016 and October 2018 we treated 145 patients with severe tricuspid regurgitation (TR) with TTVR by placing 2.2±0.7 clips per patient. Device success (TR reduction ≥1° to at least moderate) was achieved in 125 patients (86.2%). TTVR resulted in an elevated TVG >3 mmHg in 25 (17.2%) patients. Device success (84% vs 86.7%, p=0.9), number of clips implanted (2.3±0.7 vs 2.2±0.7, p=0.33), clinical improvement including NYHA class (III/IV 24% vs 28%, p=0.92) and increase in six-minute walking test at one month (67 m [IQR 5-103 m] vs 56 m [IQR 8-97 m], p=0.93), mortality (HR 1.07, 95% CI: 0.43-2.65, plogrank=0.88) and the combined endpoint mortality and hospitalisation for heart failure at one year (HR 1.07, 95% CI: 0.46-2.48, plogrank=0.88) were similar between patients with a TVG >3 mmHg versus patients with a TVG ≤3 mmHg.

CONCLUSIONS

A small cohort of patients demonstrated an elevated TVG higher than 3 mmHg at discharge. This elevation had no impact on clinical improvement, mortality or hospitalisation for heart failure.

[Clinical Course and Predictors of Ischemic Mitral Regurgitation in Patients with Myocardial Infarctions of Different Localizations]

PURPOSE

to assess the clinical course of ischemic mitral regurgitation (IMR) in patients with myocardial infarction of different localizations and reveal its mechanisms and predictors.

MATERIALS AND METHODS

We enrolled in this study patients with first inferoposterior myocardial infarction (IPMI) (n=77), and anteroseptal MI (ASMI) (n=79) revascularized within 12 hours after symptoms onset, as well as age, sex and weight matched healthy control subjects (n=50). Parameters of mitral structures and mitral annulus areas (MAA), left ventricular (LV) volumes (LVV) and sphericity index (SI), global (G) and segmental (S) longitudinal LV strain (GLS, SLS), papillary muscles (PM) LS (PMLS) and PM systolic dyssynchrony (PMSD) were measured by echocardiography on the 7th and 180th days of follow up.

RESULTS

On the 7th day of follow up IMR was diagnosed more frequently in IPMI vs. ASMI (42 vs. 28%, р&lt;0.001). In both groups patients with TIMI 0 flow before angioplasty had highest, while those with TIMI 3 flow - lowest incidence of IMR. Presence of IMR depended on collateral flow availability in vascular bed of infarct related artery. Wall motion abnormalities (WMA) of infarcted segments, MAA, posteromedial PM posterior displacement (PPMPD), SLS, PMLS, PMSD correlated with IMR in patients with IPMI on the 7th day of follow up. VLV, GLS and MAA correlated with IMR in patients with ASMI on the 7th day follow up. Patients with IPMI without IMR in 7th day did not develop IMR for 180 days of follow up while IMR developed in 19.3% of patients with ASMI without IMR at initial examination. Among patients with IPMI and ASMI 37.5% and 45.5%, respectively, of those with IMR at initial examination had no IMR after 180 days of follow up. Patients with IPMI more frequently had eccentric IMR than patients with ASMI (78 and 24%, respectively, p&lt;0.002). At examination after 6 months WMA, MAA, PMSD, PPMPD, SLS, PMLS, PMSD correlated with IMR in patients with IPMI, while VLV, AMA, PM apical displacement (PMAD), GLS and PMSD correlated with IMR in patients with ASMI. AMA, PMAD and PMSD were predictors of IMR in patients with MI of both localizations. In addition, in patients with ASMI VLV and SI were also predictors of IMR.

Imaging 4D morphology and dynamics of mitral annulus in humans using cardiac cine MR feature tracking

Feature tracking in cine cardiac magnetic resonance (CMR) is a quantitative technique to assess heart structure and function. We investigated 4-dimensional (4D) dynamics and morphology of the mitral annulus (MA) using a novel tracking system based on radially rotational long-axis cine CMR series. A total of 30 normal controls and patients with mitral regurgitation were enrolled. The spatiotemporal changes of the MA were characterized by an in-house developed program. Dynamic and morphological parameters extracted from all 18 radial slices were used as references and were compared with those from subsequently generated sub-datasets with different degrees of sparsity. An excellent agreement was found among all datasets including routine 2-, 3- and 4-chamber views for MA dynamics such as peak systolic velocity (Sm) and mitral annular plane systolic excursion (MAPSE). MA morphology for size and shape was addressed adequately by as few as 6 radial slices, but poorly by only three routine views. Patients with regurgitation showed significantly reduced mitral dynamics and mild annular deformation, which was consistent between three routine views and 18 reference slices. In conclusion, feature tracking cine CMR provided a comprehensive and distinctive profile for 4D MA dynamics and morphology, which may help in studying different cardiac diseases.

Multi-Modality Imaging in the Evaluation and Treatment of Mitral Regurgitation

OPINION STATEMENT

Mitral regurgitation (MR) is frequent and associated with increased mortality and morbidity when severe. It may be caused by intrinsic valvular disease (primary MR) or ventricular deformation (secondary MR). Imaging has a critical role to document the severity, mechanism, and impact of MR on heart function as selected patients with MR may benefit from surgery whereas other will not. In patients planned for a surgical intervention, imaging is also important to select candidates for mitral valve (MV) repair over replacement and to predict surgical success. Although standard transthoracic echocardiography is the first-line modality to evaluate MR, newer imaging modalities like three-dimensional (3D) transesophageal echocardiography, stress echocardiography, cardiac magnetic resonance (CMR), and computed tomography (CT) are emerging and complementary tools for MR assessment. While some of these modalities can provide insight into MR severity, others will help to determine its mechanism. Understanding the advantages and limitations of each imaging modality is important to appreciate their respective role for MR assessment and help to resolve eventual discrepancies between different diagnostic methods. With the increasing use of transcatheter mitral procedures (repair or replacement) for high-surgical-risk patients, multimodality imaging has now become even more important to determine eligibility, preinterventional planning, and periprocedural guidance.

Left Ventricular Mechanics in Functional Ischemic Mitral Regurgitation in Acute Inferoposterior Myocardial Infarction

Ischemic mitral regurgitation (MR) is an established adverse prognostic factor after myocardial infarction (MI). Functional ischemic mitral regurgitation in acute phase of MI remains under‐investigated due to its often transient and dynamic nature. We aimed to assess left ventricular (LV) mechanics by speckle‐tracking echocardiography in acute inferoposterior MI and ischemic mitral regurgitation (MR).

Methods

Sixty‐nine patients with no structural cardiac valve abnormalities and first acute inferoposterior MI were prospectively enrolled into the study. Two‐dimensional transthoracic echocardiography for regional myocardial function and valve assessment was performed within 48 hours of presentation after reperfusion therapy (percutaneous coronary intervention). Based on degree of MR, patients were divided into no significant MR (NMR) group (N = 34, with no or mild (grade 0–I) MR) and ischemic MR (IMR) group (N = 35, with grade ≥2 MR). Thirty‐five age‐ and gender‐matched healthy individuals served as a normal reference group. Offline 2D speckle tracking analysis was performed with GE EchoPAC software.

Results

LV ejection fraction and longitudinal myocardial deformation parameters were significantly better in healthy subjects, but did not differ between both study groups. All circumferential myocardial deformation parameters were significantly worse in IMR group compared to healthy subjects and NMR group. Global, basal, and mid‐ventricular radial strain was significantly lower in IMR group compared to both—healthy subjects and NMR group.

Conclusion

Ischemic mitral regurgitation in acute inferoposterior MI is associated with worse radial and circumferential LV deformation parameters assessed by 2D speckle tracking echocardiography.

Preoperative evaluation before MitraClip®: present and future perspective

Mitral regurgitation (MR) is the second most common heart valve disease worldwide. Currently, the management of MR is based on medical therapy (including biventricular pacing), surgery (mitral valve replacement or repair) and percutaneous therapy. However, in spite of guideline recommendations, 50% of individuals assessed in the Euro Heart Survey were not referred to surgical intervention due to comorbidities or real or perceived high risks for cardiac surgery; thus, in recent years, the focus of research has shifted to the development of percutaneous approaches to treat severe MR in order to restore valve function in a minimally invasive fashion. Among these techniques, the percutaneous mitral valve repair procedure using the MitraClip(®) system (Abbott Vascular, IL, USA) is one of the most promising. Usually, patient selection for MitraClip implantation is based on careful echocardiographic assessment of valve disease; however, although definitive data are lacking, evidence is mounting for a multiparametric approach including the evaluation of the functional status of patients.

The year 2012 in the European Heart Journal-Cardiovascular Imaging: Part I

The new multi-modality cardiovascular imaging journal, European Heart Journal - Cardiovascular Imaging, was started in 2012. During its first year, the new Journal has published an impressive collection of cardiovascular studies utilizing all cardiovascular imaging modalities. We will summarize the most important studies from its first year in two articles. The present 'Part I' of the review will focus on studies in myocardial function, myocardial ischaemia, and emerging techniques in cardiovascular imaging.