Comprehensive Assessment of Mitral Valve Geometry and Cardiac Remodeling With 3-Dimensional Echocardiography After Percutaneous Mitral Valve Repair

Three-Dimensional Multi-Modality Registration for Orthopaedics and Cardiovascular Settings: State-of-the-Art and Clinical Applications

The multimodal and multidomain registration of medical images have gained increasing recognition in clinical practice as a powerful tool for fusing and leveraging useful information from different imaging techniques and in different medical fields such as cardiology and orthopedics. Image registration could be a challenging process, and it strongly depends on the correct tuning of registration parameters. In this paper, the robustness and accuracy of a landmarks-based approach have been presented for five cardiac multimodal image datasets. The study is based on 3D Slicer software and it is focused on the registration of a computed tomography (CT) and 3D ultrasound time-series of post-operative mitral valve repair. The accuracy of the method, as a function of the number of landmarks used, was performed by analysing root mean square error (RMSE) and fiducial registration error (FRE) metrics. The validation of the number of landmarks resulted in an optimal number of 10 landmarks. The mean RMSE and FRE values were 5.26 ± 3.17 and 2.98 ± 1.68 mm, respectively, showing comparable performances with respect to the literature. The developed registration process was also tested on a CT orthopaedic dataset to assess the possibility of reconstructing the damaged jaw portion for a pre-operative planning setting. Overall, the proposed work shows how 3D Slicer and registration by landmarks can provide a useful environment for multimodal/unimodal registration.

Transcatheter edge-to-edge-repair of functional mitral regurgitation induces significant remodeling of mitral annular geometry

Background

Mitral annular alterations in the context of heart failure often lead to severe functional mitral regurgitation (FMR), which should be treated with transcatheter edge-to-edge repair (M-TEER) according to current guidelines. M-TEER's effects on mitral valve (MV) annular remodeling have not been well elucidated.

Methods

141 consecutive patients undergoing M-TEER for treatment of FMR were included in this investigation. Comprehensive intraprocedural transesophageal echocardiography was used to assess the acute effects of M-TEER on annular geometry.

Results

Average patient age was 76.2 ± 9.6 years and 46.1% were female patients. LV ejection fraction was reduced (37.0% ± 13.7%) and all patients had mitral regurgitation (MR) grade ≥III. M-TEER achieved optimal MR reduction (MR ≤ I) in 78.6% of patients. Mitral annular anterior-posterior diameters (A-Pd) were reduced by -6.2% ± 9.5% on average, whereas anterolateral-posteromedial diameters increased (3.7% ± 8.9%). Overall, a reduction in MV annular areas was observed (2D: -1.8% ± 13.1%; 3D: -2.7% ± 13.7%), which strongly correlated with A-Pd reduction (2D: r = 0.6, p < 0.01; 3D: r = 0.65, p < 0.01). Patients that achieved A-Pd reduction above the median (≥6.3%) showed significantly lower rates of the composite endpoint rehospitalization for heart failure or all-cause mortality than those with less A-Pd reduction (9.9% vs. 28.6%, p = 0.037, log-rank p = 0.039). Furthermore, patients reaching the composite endpoint had an increase in annular area (2D: 3.0% ± 15.4%; 3D: 1.9% ± 15.3%), whereas those not reaching the endpoint showed a decrease (2D: -2.7% ± 12.4%; 3D: -3.6% ± 13.3%), although residual MR after M-TEER was similar between these groups (p = 0.57). In multivariate Cox regression adjusted for baseline MR, A-Pd reduction ≥6.3% remained a significant predictor of the combined endpoint (OR: 0.35, 95% CI: 0.14-0.85, p = 0.02).

Conclusion

Our findings indicate that effects of M-TEER in FMR are not limited to MR reduction, but also have significant impact on annular geometry. Moreover, A-Pd reduction, which mediates annular remodeling, has a significant impact on clinical outcome independent of residual MR.

3D echocardiography in mitral valve prolapse

Mitral valve prolapse (MVP) is the leading cause of mitral valve surgery. Echocardiography is the principal imaging modality used to diagnose MVP, assess the mitral valve morphology and mitral annulus dynamics, and quantify mitral regurgitation. Three-dimensional (3D) echocardiographic (3DE) imaging represents a consistent innovation in cardiovascular ultrasound in the last decades, and it has been implemented in routine clinical practice for the evaluation of mitral valve diseases. The focus of this review is the role and the advantages of 3DE in the comprehensive evaluation of MVP, intraoperative and intraprocedural monitoring.

Left atrial strain and clinical outcome in patients with significant mitral regurgitation after surgical mitral valve repair

Background

This study aimed to investigate the prognostic value of left atrial (LA) strain in patients with significant mitral regurgitation (MR) after surgical mitral valve (MV) repair.

Methods

A total of 169 patients (age 55 ± 15 years, 88 men) with moderate or severe MR on echocardiogram at least 6 months after surgical MV repair for primary MR were studied. Two-dimensional, Doppler, and speckle tracking echocardiography including MR quantitative measures, chamber size, and LA strain were comprehensively analyzed. The primary outcome was a composite of cardiovascular death, heart failure hospitalization, and MV reoperation.

Results

During a median of 44.4 months [interquartile range (IQR): 18.7-70.3 months] of follow-up, 44 patients (26%) experienced clinical events; these patients had greater MR volume, elevated mean diastolic pressure gradient and pulmonary artery systolic pressure, and enlarged chamber size compared with patients who did not experience events. Patients with events showed significantly lower LA strain [13.3% (IQR: 9.3-23.8%) vs. 24.0% (IQR: 13.1-31.4%), p = 0.003] and higher MR volume/LA strain [3.09 ml/% (IQR: 2.06-5.80 ml/%) vs. 1.57 ml/% (IQR: 1.04-2.72 ml/%), p < 0.001] than those without events. MR volume/LA strain was a good predictor of clinical outcomes (cut-off 1.57 ml/%, area under the curve 0.754, p < 0.001). On multivariable Cox proportional analysis, MR volume/LA strain was independently associated with clinical outcomes (hazard ratio: 1.269, 95% confidence interval: 1.109-1.452, p < 0.001) along with pulmonary artery systolic pressure.

Conclusion

A measure of LA mechanical function relative to MR volume is associated with clinical outcomes in patients with significant MR after surgical MV repair.

Acute changes in mitral valve geometry after percutaneous valve repair with MitraClip XTR by three-dimensional echocardiography

BACKGROUND

Mitral valve (MV) repair with MitraClip system is a safe treatment option for high-risk patients with significant mitral regurgitation (MR). We aimed to characterize, by three-dimensional echocardiography (3D-E), changes occurring in MV after implantation of third generation MitraClip XT_R device, with specific reference to the underlying MR mechanism (functional vs degenerative, FMR vs DMR).

METHODS

We prospectively enrolled 59 patients, who underwent intra-procedural 3D-E before and after device deployment. Three-D datasets were analyzed off-line, using a dedicated semiautomatic software, to obtain parametric quantification of mitral anatomy.

RESULTS

Post-procedural MR of mild or lesser degree was achieved in 40 patients (68%), with no differences between FMR and DMR (p 0.9). After MitraClip XT_R implantation, the FMR group experienced an immediate annular resizing, with reduction of antero-posterior diameter (p 0.024) and sphericity index (p 0.017), next to a recovery of physiological saddle-shape, defined by lower non-planar angle (p ≤0.001) and higher annulus height to commissural width ratio (p ≤0.001). On the opposite, the DMR group revealed a significant decrease of maximum annular velocity (p 0.027), addressing a mechanic effect of the device deployment. Finally, baseline anterior mitral leaflet angle was found as an independent predictor of acute procedural result (OR 6.7, [CI 1.01-44.33], p 0.049).

CONCLUSIONS

MitraClip XT_R implantation acts in restoring the original mitral geometry, with distinctive effects according to MR mechanism. Three-D parametric quantification of MV sheds new light on changes occurring in the valvular apparatus, and helps identifying possible new predictors of acute procedural success.

Anatomical and Technical Predictors of Three-Dimensional Mitral Valve Area Reduction After Transcatheter Edge-To-Edge Repair

BACKGROUND

Among current transcatheter therapies for the treatment of mitral regurgitation, the MitraClip (MC; Abbott Vascular, Abbott Park, IL) system is the most commonly used. MitraClip implantation is usually contraindicated in patients with a mitral valve area (MVA) < 4.0 cm². However, little is known about the real impact of MC implantation on MVA. Our goal was to investigate the factors influencing MVA reduction and derive the minimal MVA required to prevent the development of a clinically significant mitral stenosis (MVA < 1.5 cm²) in different clinical scenarios.

METHODS

Using three-dimensional data sets, the annulus and leaflet anatomy and MVA before clip implantation (MVA_BC) were assessed. After each MC implant (NTR or XTR), the relative MVA reduction and the absolute residual MVA were measured and their predictors evaluated.

RESULTS

The present analysis included 116 patients. An MC XTR was the first device implanted in 50% of the subjects, and 53% were treated with a single implant. The MVA reduction following one XTR was 57% ± 7% versus 52% ± 8% after one NTR (P = .001). A lower MVA reduction was observed when the MC was placed commissural/central versus paracentral (50% ± 8% vs 57% ± 7%, P < .0001). After a second device, the additional MVA reduction was higher when creating a triple-compared with a double-orifice morphology (34% ± 11% vs 25% ± 9%, P = .001). The MVA after one MC correlated with MVA_BC as well as with the clip type and position (r = 0.91, P < .0001). The MVA_BC, orifice morphology, and first device position predicted MVA after two implants (r = 0.82, P < .0001). Based on the mathematical relationship between these parameters, the minimal MVA_BC needed in eight different clinical scenarios was summarized in a decision algorithm: the values ranged from 3.5 to 4.7 cm² for one and 4.5 to 6.3 cm² for two MC strategies.

CONCLUSIONS

The minimal native MVA preventing clinically relevant MS after transcatheter edge-to-edge repair is predicted by the number and location of clip(s), orifice morphology, and device type. Based on these parameters, an algorithm has been derived to optimize patient selection and preprocedural planning.

Impact of Mitral Annular Dilation on Edge-to-Edge Therapy With MitraClip-XTR

[Figure: see text].

Head to Head Comparison between Different 3-Dimensional Echocardiographic Rendering Tools in the Imaging of Percutaneous Edge-to-Edge Mitral Valve Repair

MitraClip (MC) is the most common percutaneous treatment for severe mitral regurgitation (MR). An accurate two-dimensional and three-dimensional echocardiographic (3DTEE) imaging is mandatory for the optimal procedural result. Recently transillumination 3DTEE rendering (3DTr) has been introduced integrating a virtual light source into the dataset and with the addition of glass effect (3DGl) allows to adjust tissue transparency improving depth perception and anatomical structure delineation in comparison with the standard 3DTEE (3DSt). The aim of this retrospective study in 30 patients undergoing MC, was to compare 3DSt, 3DTr, and 3DGl in mitral valve (MV) evaluation and procedural result assessment. 3DTEE acquisitions obtained before and after MC were processed with 3DSt, 3DTr, and 3DGl rendering. Each reconstruction was scored for quality and for ability to recognize MV anatomy, MR origin, clip position, dimension and grasping. Imaging quality was judged good or optimal in 52%, 76%, and 96% in 3DSt, 3DTr, and 3DGl reconstructions respectively. In 26/30 patients a diagnostic incremental value was found with 3DTr vs. 3DSt and in 15/26 with 3DGl vs. 3DTr and 3DSt. Only 3DGl with perpendicular cropping of the clip allowed to visualize and measure the grasped portion of each mitral leaflets. 3DTEE imaging during MC may be improved by 3DTr and 3DGl providing a better evaluation of MV, of leaflet grasping and of residual MR jets after MC.

Impact of Leaflet Tethering on Residual Regurgitation in Patients With Degenerative Mitral Disease After Interventional Edge-to-Edge Repair

Background: Grade 2+ residual mitral regurgitation (MR 2+) is associated with the recurrence of MR and a lower survival rate in interventional mitral valve (MV) edge-to-edge (EE) repair. We sought to determine the MV anatomic factors affecting residual MR 2+ during interventional EE repair with the ValveClamp system in patients with degenerative MR (DMR).

Methods: In this multicenter study, 62 patients with significant (grade 3+ to 4+) DMR underwent ValveClamp implantation across eight centers from July 2018 to December 2019. Patient clinical, anatomical, and procedural characteristics were prospectively collected and retrospectively analyzed.

Results: A single clamp was implanted in 59 patients, and two clamps were implanted in three patients. Residual MR 2+ was found in 14 patients (22.6%) immediately after the ValveClamp procedure. Patients with residual MR 2+ showed significantly larger preoperative tenting sizes and annular dimensions than the residual MR ≤1+ group. Multivariate analysis identified tenting volume as the major determinant of residual MR 2+ after ValveClamp procedures (odds ratio, 1.410 per 0.1-mL/m² increase; 95% confidence interval, 1.167–1.705; P < 0.001). Receiver operating characteristic curves identified a tenting volume index ≥0.82 mL/m² as the optimal cutoff point to predict residual MR 2+ (area under curve, 0.84). Patients with a tenting volume index ≥0.82 mL/m² were more likely to develop recurrent 3+ MR or undergo MV surgery during short-term follow-up (P < 0.001).

Conclusions: Preoperative assessment of the tenting volume index will help to predict intraoperative residual MR 2+ in patients with DMR receiving EE-based interventional repair. Improvements in the interventional strategy are warranted for sustained MR reduction in patients with DMR with unfavorable anatomy.

Utility of Three-Dimensional Transesophageal Echocardiography for Mitral Annular Sizing in Transcatheter Mitral Valve Replacement Procedures: A Cardiac Computed Tomographic Comparative Study

BACKGROUND

Three-dimensional (3D) transesophageal echocardiographic (TEE) imaging is frequently used as an initial screening tool in the evaluation of patients who are candidates for transcatheter mitral valve replacement (TMVR). However, little is known about the imaging correlation with the gold standard, computed tomographic (CT) imaging. The aims of this study were to test the quantitative differences between these two modalities and to determine the best 3D TEE parameters for TMVR screening.

METHODS

Fifty-seven patients referred to the heart valve clinic for TMVR with prostheses specifically designed for the mitral valve were included. Mitral annular (MA) analyses were performed using commercially available software on 3D TEE and CT imaging.

RESULTS

Three-dimensional TEE imaging was feasible in 52 patients (91%). Although 3D TEE measurements were slightly lower than those obtained on CT imaging, measurements of both projected MA area and perimeter showed excellent correlations, with small differences between the two modalities (r = 0.88 and r = 0.92, respectively, P < .0001). Correlations were significant but lower for MA diameters (r = 0.68-0.72, P < .0001) and mitroaortic angle (r = 0.53, P = .0001). Receiver operating characteristic curve analyses showed that 3D TEE imaging had a good ability to predict TMVR screening success, defined by constructors on the basis of CT measurements, with ranges of 12.9 to 15 cm² for MA area (area under the curve [AUC] = 0.88-0.91, P < .0001), 128 to 139 mm for MA perimeter (AUC = 0.85-0.91, P < .0001), 35 to 39 mm for anteroposterior diameter (AUC = 0.79-0.84, P < .0001), and 37 to 42 mm for posteromedial-anterolateral diameter (AUC = 0.81-0.89, P < .0001).

CONCLUSIONS

Three-dimensional TEE measurements of MA dimensions display strong correlations with CT measurements in patients undergoing TMVR screening. Three-dimensional TEE imaging should be proposed as a reasonable alternative to CT imaging in this vulnerable population.

Effect of a novel transcatheter edge-to-edge repair device on the three-dimensional geometry of mitral valve in degenerative mitral regurgitation

OBJECTIVES

We sought to assess the acute intraprocedural effects of the ValveClamp system in DMR patients on the mitral valve (MV) three-dimensional (3D) geometry and the association of these effects with mitral regurgitation (MR) reduction.

BACKGROUND

Few data are available about the specific impact of transcatheter edge-to-edge repair in patients with degenerative mitral regurgitation (DMR).

METHODS

Thirty-five symptomatic patients (age 74.26 ± 6.61 years) with Grade 3 to 4+ degenerative MR underwent 3D transoesophageal echocardiography (TEE) during ValveClamp implantation. Volumetric data sets were retrospectively analyzed using mitral valve quantitative 3D modeling software.

RESULTS

Mitral valve annular anterior-posterior (AP) diameter decreased from 33.24 ± 4.03 to 31.12 ± 3.66 mm (p < .001), and prolapse height from 4.78 ± 2.19 to 2.32 ± 1.92 mm (p < .001), and total exposed leaflet area from 1,110.29 ± 224.21 mm² to 1,013.44 ± 228.71 mm (p = .004). Accordingly, we observed a significant reduction of MR severity after ValveClamp implantation. Multivariable analysis revealed postprocedural MR reduction was associated with shortening in anterior-posterior diameter (coefficient 0.427, p = .008) and reduction in prolapse height (coefficient 0.369, p = .021).

CONCLUSIONS

ValveClamp implantation exerts an acute effect on the 3D MV geometry. Postprocedural reduction in AP diameter and reduction in prolapse height correlates with MR downgrading in patients with degenerative MR.

A Comprehensive Engineering Analysis of Left Heart Dynamics After MitraClip in a Functional Mitral Regurgitation Patient

Percutaneous edge-to-edge mitral valve (MV) repair using MitraClip has been recently established as a treatment option for patients with heart failure and functional mitral regurgitation (MR), which significantly expands the number of patients that can be treated with this device. This study aimed to quantify the morphologic, hemodynamic and structural changes, and evaluate the biomechanical interaction between the MitraClip and the left heart (LH) complex of a heart failure patient with functional MR using a fluid-structure interaction (FSI) modeling framework. MitraClip implantation using lateral, central and double clip positions, as well as combined annuloplasty procedures were simulated in a patient-specific LH model that integrates detailed anatomic structures, incorporates age- and gender-matched non-linear elastic material properties, and accounts for mitral chordae tethering. Our results showed that antero-posterior distance, mitral annulus spherecity index, anatomic regurgitant orifice area, and anatomic opening orifice area decreased by up to 28, 39, 52, and 71%, respectively, when compared to the pre-clip model. MitraClip implantation immediately decreased the MR severity and improved the hemodynamic profile, but imposed a non-physiologic configuration and loading on the mitral apparatus, with anterior and posterior leaflet stress significantly increasing up to 210 and 145% during diastole, respectively. For this patient case, while implanting a combined central clip and ring resulted in the highest reduction in the regurgitant volume (46%), this configuration also led to mitral stenosis. Patient-specific computer simulations as used here can be a powerful tool to examine the complex device-host biomechanical interaction, and may be useful to guide device positioning for potential favorable clinical outcomes.

Mid-term repair durability after MitraClip implantation in patients with functional mitral regurgitation

BACKGROUND

The aim of this study was to identify variables that are associated with the durability of percutaneous repair of secondary mitral regurgitation at 6-month follow-up.

METHODS AND RESULTS

Thirty-five consecutive patients with functional mitral regurgitation scheduled for MitraClip implant were enrolled. Left ventricular (LV) volumes and function and mitral valve characteristics were assessed before and immediately after MitraClip implantation using three-dimensional transesophageal echocardiography. Five patients with an unsuccessful procedure were excluded. The other patients were subdivided according to repair durability: group 1 with a durable repair (19 patients, 65%) and group 2 with significant mitral regurgitation recurrence (11 patients, 35%). At baseline, group 1 patients had smaller and more elliptical mitral valve annulus (1055 ± 241 vs. 1273 ± 359 mm, P = 0.02 and 125 ± 11 vs. 117 ± 16%, P = 0.02), a smaller left atrial volume (54.1 ± 26 vs. 71.5 ± 20 ml, P = 0.005) and lower systolic pulmonary artery pressure (38 ± 11 vs. 49 ± 12 mmHg, P = 0.03). Baseline LV end systolic volume had a linear correlation with the 3D annulus area (P = 0.048) and an inverse correlation with annulus ellipticity (P = 0.021). Group 1 patients showed an increase in annulus ellipticity after MitraClip (125 ± 17 vs. 141 ± 23%, P = 0.014).

CONCLUSION

Percutaneous mitral valve repair leads to a significant and stable mitral regurgitation reduction in a large number of patients. Annulus dimensions and remodeling as well as left atrial area and pulmonary hypertension seem to be associated with durability of the procedure.