The effect of surgical and transcatheter aortic valve replacement on mitral annular anatomy

Transcatheter aortic valve implantation and its impact on mitral valve geometry and function

BACKGROUND

The aim of this study was to evaluate the impact of transcatheter aortic valve implantation (TAVI) on mitral valve geometry and function.

METHODS

Eighty-four patients underwent TAVI. Forty-four (52%) patients received a balloon-expandable valve and 40 (48%) were implanted with a self-expandable valve. All patients underwent three-dimensional-volumetric transesophageal echocardiography of the mitral valve before and immediately after TAVI. A dedicated software was used for assisted semiautomatic measurement of mitral annular geometry.

RESULTS

During systole, the anterior to posterior (AP) diameter was significantly reduced after the procedure (3.4 ± 0.5 cm vs 3.2 ± 0.5 cm; P < .05). The mitral annular area (10.8 ± 2.8cm² vs 9.9 ± 2.6cm² ; P < .05) as well as the tenting area (1.6 ± 0.7 cm² vs 1.2 ± 0.6 cm² ; P < .001) measured at mid-systole were reduced after TAVI. Diastolic measures were similar. Patients treated with balloon-expandable valves showed a significantly larger reduction in the AP diameter compared to self-expandable valves (-0.25 cm vs -0.11 cm; P < .05). The reduction of the annular area was higher in the balloon-expandable group (-1.2 ± 1.59 vs -0.22 ± 1.41; P < .05). Grade of mitral regurgitation did improve or remained stable after TAVI.

CONCLUSION

TAVI significantly impacts the mitral valve and mitral annular geometry and morphology. The choice of the prosthesis (balloon- vs self-expandable) may be relevant for those changes.

The Effects of Transcatheter Aortic Valve Replacement on Mitral Valve Function

The transcatheter aortic valve replacement (TAVR) procedure provides a way to treat severe aortic stenosis in the large population of patients who are not candidates for surgical aortic valve replacement. Mitral regurgitation is often concomitant to aortic stenosis in these patients due to the high pressure of the left ventricle and long-term damage to the mitral valve. Due to the proximity of the aortic valve to the mitral valve, TAVR can impact the functional status of the mitral valve by affecting left ventricular outlet obstruction and the mitral valve annular shape. As TAVR becomes increasingly prevalent to treat aortic stenosis, consideration into the impact of TAVR on mitral valve function is important in order determine whether patients will be able to undergo mitral valve repair or replacement, whether surgically or percutaneously. In this review, we seek to explore the effect of TAVR on the mitral annular geometry, mitral valve flow, and the impact of TAVR on the mitral valve in the presence of mitral annular calcification.

The Impact of Self-Expandable Transcatheter Aortic Valve Replacement on Concomitant Functional Mitral Regurgitation: A Comprehensive Engineering Analysis

Background

Mitral regurgitation (MR) is present in a large proportion of patients who undergo transcatheter aortic valve replacement (TAVR). However, existing clinical data on the impact of TAVR on early post-procedural MR severity are contradictory. Using a comprehensive computational engineering methodology, this study aimed to evaluate quantitatively the structural and hemodynamic impact of TAVR on aortic-mitral continuity and MR severity in a rigorously developed and validated patient-specific left heart (LH) computer model with aortic stenosis and concomitant functional MR.

Methods

TAVR procedure was virtually simulated using a self-expandable valve (SEV) at three implantation heights. Pre- and post-TAVR LH dynamics as well as intra-operative biomechanics were analyzed.

Results

No significant differences in early MR improvement (<10%) were noted at the three implantation depths when compared to the pre-TAVR state. The high deployment model resulted in the highest stress in the native aortic leaflets, lowest stent-tissue contact force, highest aortic-mitral angle, and highest MR reduction for this patient case. When comparing SEV vs. balloon-expandable valve (BEV) performance at an optimal implantation height, the SEV gave a higher regurgitant volume ⋅ than the pre-TAVR model (40.49 vs 37.59 ml), while the BEV model gave the lowest regurgitant volume (33.84 vs 37.59 ml).

Conclusions

Contact force, aortic-mitral angle, and valve annuli compression were identified as possible mechanistic parameters that may suggest avenues for acute MR improvement. Albeit a single patient parametric study, it is our hope that such detailed engineering analysis could shed some light into the underlying biomechanical mechanisms of TAVR impact on MR.

Severe mitral regurgitation due to geometric changes in the mitral valve after surgical aortic valve replacement

BACKGROUND

Severe mitral regurgitation (MR) after aortic valve replacement (AVR) is a serious complication. Although several causes of MR after AVR have been reported, severe MR due to geometric changes in the mitral valve imposed by an aortic valve prosthesis has not been reported. We here report a case of severe MR after AVR that was improved after re-AVR.

CASE PRESENTATION

A 77-year-old male underwent elective total aortic arch replacement and AVR. Mild MR was preoperatively identified. After surgery and separation from cardiopulmonary bypass, transesophageal echocardiography (TEE) demonstrated restriction and distortion of the anterior mitral leaflet and severe MR. Displacement of the anterior mitral annulus by the prosthetic aortic valve was strongly suspected to be the cause of MR, which should be surgically restored. Re-AVR using a small-sized valve was then performed. Consequently, the structural changes in the mitral valve were reverted and the MR was reduced.

CONCLUSIONS

Geometric changes in the mitral valve induced by an aortic valve prosthesis can cause massive increment of MR. Intraoperative TEE examination of the mitral apparatus is important when severe MR occurs after AVR.

The impact of balloon-expandable transcatheter aortic valve replacement on concomitant mitral regurgitation: a comprehensive computational analysis

The aortic and mitral valves function in a reciprocal interdependent fashion. However, the impact of transcatheter aortic valve replacement (TAVR) on the aortic-mitral continuity and severity of mitral regurgitation (MR) are poorly understood. In this study, a comprehensive engineering analysis was performed to investigate the impact of TAVR on MR severity and left heart dynamics in a retrospective patient case who harbours bicuspid aortic valve stenosis and concomitant functional MR. The TAVR procedure was computer simulated using a balloon-expandable valve, and the impact of three implantation heights on aortic-mitral coupling, MR severity and device performance were analysed. The accuracy and predictability of the computer modelling framework were validated with pre- and post-operative echo data. The highest deployment model resulted in higher stresses in the native leaflets, contact radial force and stent recoil, while the midway implantation model gave better haemodynamic performance and MR reduction in this patient case. Although the regurgitant volume decreased (less than 10%) for the three deployment configurations, no significant differences in MR severity improvement and mitral leaflet tethering were found. Acute improvement in MR was (i) due to the mechanical compression of the stent against the aortic-mitral curtain, (ii) due to an immediate drop in the ventricular pressure and transmitral pressure gradient. Albeit a single real clinical case, it is our hope that such detailed engineering computational analysis could shed light on the underlying biomechanical mechanisms of TAVR impact on MR.

Mitral Valve Stenosis after Transcatheter Aortic Valve Replacement: Case Report and Review of the Literature

Mitral stenosis is a rare and potentially severe complication of transcatheter aortic valve replacement (TAVR). Given the anatomic coupling and interdependence of the aortic and mitral valves, it comes by itself that procedures (either surgical or percutaneous) involving the aortic valve imply the risk of altering mitral valve function. Indeed, transcatheter aortic prostheses may impair adequate anterior mitral leaflet (AML) opening, especially when implanted in a "low" position, thus resulting in high transvalvular gradients. Hereby, we report the case of a 71-year-old male with symptomatic severe aortic stenosis and a history of previous surgical mitral valve repair who underwent TAVR with a self-expandable prosthesis. Notwithstanding an acceptable angiographic position, the prosthetic frame was shown to interfere with the AML, as evidenced by augmented transmitral gradients; nonetheless, pulmonary artery pressures remained unchanged, and the patient experienced symptomatic improvement. Therefore, a conservative approach was chosen and the patient was discharged home after medical therapy optimization. Moreover, we provide a review of the available literature regarding the incidence, predictors and possible management of this infrequent complication.

Association of postprocedural aortic regurgitation with mitral regurgitation worsened after transcatheter aortic valve replacement

BACKGROUND

There is a paucity of investigation which demonstrates a predictor of mitral regurgitation (MR) worsened after aortic valve replacement (TAVR).

AIM

The aim of this study was to identify the predictor of worsened MR after transcatheter TAVR.

METHODS

We retrospectively studied a total of 209 patients with mild or less MR at baseline who underwent TAVR for the treatment of severe aortic stenosis with the balloon-expandable device. We found the presence of MR worsened after TAVR in 6% (12 patients) of all patients. Moderate or more postprocedural aortic regurgitation (AR) (odds ratio, 8.104; 95% confidence interval, 1.78-36.87; P = .007) was identified as a predictor of MR worsening after TAVR. In-hospital outcomes indicated that patients within whom MR worsened suffered congestive heart failure more than those with unchanged or improved MR after TAVR (P < .05).

CONCLUSION

Significant postprocedural AR was associated with MR worsened from mild or less to moderate or more after TAVR. Worsened MR might affect in-hospital congestive heart failure.

A novel passive left heart platform for device testing and research

Integration of biological samples into in vitro mock loops is fundamental to simulate real device's operating conditions. We developed an in vitro platform capable of simulating the pumping function of the heart through the external pressurization of the ventricle. The system consists of a fluid-filled chamber, in which the ventricles are housed and sealed to exclude the atria from external loads. The chamber is connected to a pump that drives the motion of the ventricular walls. The aorta is connected to a systemic impedance simulator, and the left atrium to an adjustable preload. The platform reproduced physiologic hemodynamics, i.e. aortic pressures of 120/80 mmHg with 5 L/min of cardiac output, and allowed for intracardiac endoscopy. A pilot study with a left ventricular assist device (LVAD) was also performed. The LVAD was connected to the heart to investigate aortic valve functioning at different levels of support. Results were consistent with the literature, and high speed video recordings of the aortic valve allowed for the visualization of the transition between a fully opening valve and a permanently closed configuration. In conclusion, the system showed to be an effective tool for the hemodynamic assessment of devices, the simulation of surgical or transcatheter procedures and for visualization studies.

Four-dimensional modelling of the mitral valve by real-time 3D transoesophageal echocardiography: proof of concept

OBJECTIVES

The complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Assessing the dynamic movement and interaction of MV components to define MV physiology during the complete cardiac cycle remains a challenge. We herein describe a novel semi-automated 4D MV model.

METHODS

The model applies quantitative analysis of the MV over a complete cardiac cycle based on real-time 3D transoesophageal echocardiography (RT3DE) data. RT3DE data of MVs were acquired for 18 patients. The MV annulus and leaflets were semi-automatically reconstructed. Dimensions of the mitral annulus (anteroposterior and anterolateral-posteromedial diameter, annular circumference, annular area) and leaflets (MV orifice area, intercommissural distance) were acquired. Variability and reproducibility (intraclass correlation coefficient, ICC) for interobserver and intraobserver comparison were quantified at 4 time points during the cardiac cycle (mid-systole, end-systole, mid-diastole and end-diastole).

RESULTS

Mitral annular dimensions provided highly reliable and reproducible measurements throughout the cardiac cycle for interobserver (variability range, 0.5-1.5%; ICC range, 0.895-0.987) and intraobserver (variability range, 0.5-1.6%; ICC range, 0.827-0.980) comparison, respectively. MV leaflet parameters showed a high reliability in the diastolic phase (variability range, 0.6-9.1%; ICC range, 0.750-0.986), whereas MV leaflet dimensions showed a high variability and lower correlation in the systolic phase (variability range, 0.6-22.4%; ICC range, 0.446-0.915) compared with the diastolic phase.

CONCLUSIONS

This 4D model provides detailed morphological reconstruction as well as sophisticated quantification of the complex MV structure and dynamics throughout the cardiac cycle with a precision not yet described.

Effect of Transcatheter Aortic Valve Replacement on the Mitral Valve Apparatus and Mitral Regurgitation

Background—

The effect of transcatheter aortic valve replacement (TAVR) on the mitral valve apparatus and factors influencing the reduction of mitral regurgitation with or without mitral leaflet tethering after TAVR are poorly understood. The present 3-dimensional (3D) transesophageal echocardiography study aimed to elucidate early changes further in the structure and function of the mitral valve apparatus after TAVR.

Methods and Results—

We analyzed 90 patients (nontenting group, 56 patients and tenting group, 34 patients) who underwent TAVR using the Edwards SAPIEN and had intraprocedural 3D transesophageal echocardiography evaluation of the mitral valve. Of all patients, mitral regurgitation improved in 54%, remained the same in 38%, and worsened in 8% 1 day after TAVR. There were no statistically significant differences in mitral annular 3D parameters before and after TAVR in both groups. In the tenting group, tenting area ( P <0.01) and tenting height ( P <0.01) were decreased, and coaptation length was increased ( P <0.05) after TAVR. In a multivariable analysis, the predictors of improved mitral regurgitation were the decrease of tenting area (odds ratio, 8.15; 95% confidence interval, 1.31–50.7; P <0.05) and the decrease of valvuloarterial impedance (odds ratio, 7.57; 95% confidence interval, 1.15–49.9; P <0.05) in the tenting group and the decrease of valvuloarterial impedance (odds ratio, 6.96; 95% confidence interval, 1.24–39.2; P <0.05) in the nontenting group.

Conclusions—

Mitral leaflet tethering was improved immediately by TAVR in patients with mitral leaflet tenting regardless of mitral annular geometry. Acute improvement in mitral regurgitation after TAVR is predominantly related to global left ventricular hemodynamics and mitral leaflet tethering change.

Incidental moderate mitral regurgitation in patients undergoing aortic valve replacement for aortic stenosis: review of guidelines and current evidence

Recent evidence has shown that moderate mitral regurgitation is common and clinically relevant in patients presenting for surgical and transcatheter aortic valve replacement for aortic stenosis. Prospective multicenter clinical trials are now indicated to resolve the clinical equipoise about whether or not mitral valve intervention also is indicated at the time of aortic valve intervention. Advances in three-dimensional transesophageal echocardiography, transcatheter mitral interventions, and surgical aortic valve replacement, including the advent of sutureless valves, likely will expand the therapeutic possibilities for moderate mitral regurgitation in the setting of aortic valve interventions for severe aortic stenosis.

New concepts for mitral valve imaging

The high complexity of the mitral valve (MV) anatomy and function is not yet fully understood. Studying especially the dynamic movement and interaction of MV components to describe MV physiology during the cardiac cycle remains a challenge. Imaging is the key to assessing details of MV disease and to studying the lesion and dysfunction of MV according to Carpentier. With the advances of computational geometrical and biomechanical MV models, improved quantification and characterization of the MV has been realized. Geometrical models can be divided into rigid and dynamic models. Both models are based on reconstruction techniques of echocardiographic or computed tomographic data sets. They allow detailed analysis of MV morphology and dynamics throughout the cardiac cycle. Biomechanical models aim to simulate the biomechanics of MV to allow for examination and analysis of the MV structure with blood flow. Two categories of biomechanical MV models can be distinguished: structural models and fluid-structure interaction (FSI) models. The complex structure and dynamics of MV apparatus throughout the cardiac cycle can be analyzed with different types of computational models. These represent substantial progress in the diagnosis of structural heart disease since MV morphology and dynamics can be studied in unprecedented detail. It is conceivable that MV modeling will contribute significantly to the understanding of the MV.

Impact of aortic valve replacement for aortic stenosis on dynamic mitral annular motion and geometry

The impact of aortic valve replacement (AVR) on the dynamic geometry and motion of the mitral annulus remains unknown. We analyzed the effects of AVR on the dynamic geometry and motion of the mitral annulus. We used 3-dimensional transesophageal echocardiography to analyze 39 consecutive patients undergoing elective surgical AVR for aortic stenosis. Intraoperative 3-dimensional transesophageal echocardiography was performed immediately before and after AVR. Volumetric data sets were analyzed using a software package capable of dynamically tracking the mitral annulus and leaflets during the entire systolic ejection phase. After AVR, there were significant decreases (p <0.01) in annular dimensions such as anteroposterior (3.5 ± 0.1 vs 3.2 ± 0.1 cm), anterolateral-posteromedial (3.7 ± 0.1 vs 3.5 ± 0.1 cm), and commissural diameters (3.7 ± 0.1 vs 3.3 ± 0.1 cm), as well as annular circumference (12.0 ± 0.30 vs 11.1 ± 0.2 cm) and 3-dimensional mitral annular area (mean 10.9 ± 0.6 vs 9.3 ± 0.3 cm(3)). Vertical mitral annular displacement was also reduced (6.2 ± 3.1 vs 4.3 ± 2.2 mm). Mitral annular nonplanarity angle (154 ± 1.5° vs 161 ± 1.6°) and aorto-mitral angle (133 ± 3.3° vs 142 ± 2.0°) were both increased after AVR, suggesting reduced nonplanar shape of the mitral annulus and reduced aorto-mitral flexion. In conclusion, these data demonstrate that mitral annular size is reduced immediately after AVR and that the dynamic motion of the mitral annulus is restricted. These findings may have important clinical implications for patients undergoing AVR with concurrent mitral regurgitation.