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An innovative design of transcatheter implantable mitral valve prosthesis. Anatomy of the mitral valve in patients with functional mitral regurgitation and preliminary results of the implant in the animal model using quantitative 3D echocardiography and particle imaging velocimetry
Full text linkBackground: Transcatheter mitral valve replacement (TMVR) is a new therapeutic option for high surgical risk patients with mitral regurgitation (MR) and several prostheses are currently at different stages of development. Indeed, once prototypes of these prosthesis are designed, they need to undergo both bench testing and preclinical evaluation to test the performance and safety of the device and acquire useful information for guiding the secondary improvements. After this stage, if the prosthesis shows favourable results in terms of performance and safety, the manufacturer can apply for CE marking. In case of achievement of the CE mark, the clinical use can start in the European countries. The application of advanced echocardiography is useful not only in a preclinical experimental stage but results to be an irreplaceable tool in the proper selection of the treatment strategy with respect to the case-specific anatomic and functional mitral valve (MV) disease pattern and in the guidance of the correct bioprosthesis positioning and implantation during the procedure.
Aims: To describe the feasibility and advantage of 3D and contrast echocardiography in a preclinical study and report the acute hemodynamic results after implantation of a novel transcatheter self- expandable D-shape mitral bioprosthesis characterized by asymmetric stent and advanced mono- leaflet structure. In addition, we aimed to assess the MV geometry in patients with functional MR (FMR) that would potentially benefit from TMVR, focusing on the comparison between mitral annulus (MA) geometry of patients with ischemic (IMR) and non-ischemic mitral regurgitation (nIMR).
Methods: From May 2015 to August 2018, prosthesis prototypes were implanted under echocardiography guidance in 112 small-size healthy sheep using both trans-atrial (Ta) and trans- apical (TA) access. Multimodality imaging was used for animal selection and trans-pericardial echocardiography (TPE) was applied to obtain humanized image during intervention. Particle imaging velocimetry was used to assess intraventricular flow dynamics. We retrospectively selected 94 patients with severe FMR, both IMR and nIMR. 3D MA analysis was performed in early-diastole
and mid-systoleby using a recent, commercially-available software package. Measure of interest were MA dimensions and geometry parameters, left atrial and left ventricular volumes.
Results: 2D and 3D TPE was performed before and after implantation to measure MA dimensions (area: 6.4±0.8 cm2, perimeter: 9.4±0.8 cm) and assess prosthesis alignment and function. The vast majority of implantations showed none or just trivial intra- (n=104, 93%) and peri-prosthesis leak (n=86, 77%) with good valve function (mean gradient 4 ± 3 mmHg). At particle imaging velocimetry, left ventricular vortex properties did not change after implantation.
In patients with severe FMR, 41 (43,6%) with IMR and 53 (56,4%) with nIMR, maximum MA 3D area (10.7±2.5 cm2 vs 11.6±2.7 cm2, p=0.124) and the best fit plane MA area (9.9±2.3 cm2 vs 10.7±2.5 cm2, p=0.135, respectively) were similar between IMR and nIMR. nIMR patients showed larger mid- systolic 3D area (9.8±2.3 cm2 vs 10.8±2.7 cm2, p=0.046) and perimeter (11.2±1.3 cm vs 11.8±1.5 cm, p=0.048), longer and larger leaflets, and wider aorto-mitral angle (135±10° vs 141±11°, p=0.011). Conversely, the area of MA at the best fit plane did not differ between IMR and nIMR patients (9±1.1 cm2 vs 9.9±1.5 cm2, p=0.063).
Conclusions: In the healthy sheep model, initial preclinical experience with a novel mono-leaflet transcatheter self-expandable mitral prosthesis showed that the TA implantation of the valve was feasible, safe, and supported by good hemodynamic results. The application of advanced echocardiography on an animal model was feasible and helpful in guiding the continuous refinements needed to enhance the development of this new concept of bioprosthesis.
Patients with ischemic and non-ischemic etiology of FMR have similar maximum dimension, yet systolic differences between the two groups should be considered to tailor prosthesis’s selection
Use of fully automated software to quantify left ventricular ejection fraction and left ventricular global longitudinal strain
No full textSabre dance pattern in mid-ventricular-apical hypertrophic cardiomyopathy: an unusual finding
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New cutoffs are needed for the assessment of functional mitral regurgitation severity using three-dimensional echocardiography
No full textFEASIBILITY AND RELATIVE ACCURACY OF THREE-DIMENSIONAL PRINTING OF NORMAL AND PATHOLOGIC TRICUSPID VALVES FROM TRANSTHORACIC THREE-DIMENSIONAL ECHOCARDIOGRAPHIC DATA SETS
No full textEarly systolic anterior motion of interventricular septum due to increased right ventricular dyssynchrony predicts accurately impaired right ventricular ejection fraction
No full textCurrent Clinical Applications of Three-Dimensional Echocardiography: When the Technique Makes the Difference
Full text linkAdvances in ultrasound, computer, and electronics technology have permitted three-dimensional echocardiography (3DE) to become a clinically viable imaging modality, with significant impact on patient diagnosis, management, and outcome. Thanks to the inception of a fully sampled matrix transducer for transthoracic and transesophageal probes, 3DE now offers much faster and easier data acquisition, immediate display of anatomy, and the possibility of online quantitative analysis of cardiac chambers and heart valves. The clinical use of transthoracic 3DE has been primarily focused, albeit not exclusively, on the assessment of cardiac chamber volumes and function. Transesophageal 3DE has been applied mostly for assessing heart valve anatomy and function. The advantages of using 3DE to measure cardiac chamber volumes derive from the lack of geometric assumptions about their shape and the avoidance of the apical view foreshortening, which are the main shortcomings of volume calculations from two-dimensional echocardiographic views. Moreover, 3DE offers a unique realistic en face display of heart valves, congenital defects, and surrounding structures allowing a better appreciation of the dynamic functional anatomy of cardiac abnormalities in vivo. Offline quantitation of 3DE data sets has made significant contributions to our mechanistic understanding of normal and diseased heart valves, as well as of their alterations induced by surgical or interventional procedures. As reparative cardiac surgery and transcatheter procedures become more and more popular for treating structural heart disease, transesophageal 3DE has expanded its role as the premier technique for procedure planning, intra-procedural guidance, as well as for checking device function and potential complications after the procedure
Implementation of proprietary plugins in the DICOM-based computerized echo reporting system fuels the use of 3D echo and deformation imaging in the clinical routine of a multivendor laboratory
No full textThe Severity of Functional Mitral Regurgitation Assessed by Three-Dimensional Echocardiography: New Cut-Offs Are Needed
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