Imaging in Transcatheter Mitral Valve Replacement: State-of-Art Review

Abstract

Mitral regurgitation is the second-most frequent valvular heart disease in Europe and it is associated with high morbidity and mortality. Recognition of MR should encourage the assessment of its etiology, severity, and mechanism in order to determine the best therapeutic approach. Mitral valve surgery constitutes the first-line therapy; however, transcatheter procedures have emerged as an alternative option to treat inoperable and high-risk surgical patients. In patients with suitable anatomy, the transcatheter edge-to-edge mitral leaflet repair is the most frequently applied procedure. In non-reparable patients, transcatheter mitral valve replacement (TMVR) has appeared as a promising intervention. Thus, currently TMVR represents a new treatment option for inoperable or high-risk patients with degenerated or failed bioprosthetic valves (valve-in-valve); failed repairs, (valve-in-ring); inoperable or high-risk patients with native mitral valve anatomy, or those with severe annular calcifications, or valve-in-mitral annular calcification. The patient selection requires multimodality imaging pre-procedural planning to select the best approach and device, study the anatomical landing zone and assess the risk of left ventricular outflow tract obstruction. In the present review, we aimed to highlight the main considerations for TMVR planning from an imaging perspective; before, during, and after TMVR.

Keywords: cardiac computed tomography; mitral regurgitation; structural heart intervention; transcatheter mitral valve replacement; transoesophageal echocardiography.

Figure 1

TMVR valve-in-MAC pre-procedural planning. (A) Mitral annular calcification with a 180° extension in the posterior and lateral aspect of mitral annulus. Internal dimensions can be noted on the image (TT: inter-trigone diameter; AP: anterior-posterior diameter; area and perimeter). (B) Three-dimensional virtual valve implantation (SAPIEN 3 23 mm) with a distance neo-valve to interventricular septum of 8 mm. (C) Neo-LVOT area according to the virtual valve implantation (Area 193 mm²).

Figure 2

CT-fluoroscopy fusion imaging. The superior row shows a TMVR valve-in-valve procedure in a patient with extreme left atrium enlargement and modified projection required for transeptal puncture (A). Markers (red lines) may be over-imposed to fluoroscopy imaging to guide depth deployment (B,C). Inferior row, TMVR valve-in-MAC CT preprocedural planning (D), interatrial septal balloon dilatation (E) and initial phase of THV deployment with coaxial projection to mitral annulus (F).

Figure 3

Three-dimensional transoesophageal echocardiography with photo-realistic rendering during TMVR valve-in-valve procedure. (A) En-face view of a degenerated mitral surgical prosthetic valve, with severe prosthetic stenosis. (B) Same image with light source place behind mitral prosthetic valve during diastole. Prosthetic leaflets thickening and mobility reduction can be easily noted. (C) THV positioning inside SHV. (D) Balloon-expandable THV deployment. (E) Immediate result after deployment. Same image configuration than (B), significant improvement in diastolic opening can be noted. (F) TMVR ViV final result en-face view.

Figure 4

TMVR in native mitral anatomy with Tendyne (Abbott Medical) system. (A) Mitral annular dimension assessed with cardiac CT. (B,C) Neo-LVOT area after virtual valve implantation with specific Tendyne system design. (D) Three-dimensional TEE en-face view of initial THV device deployment and orientation. (E) Final result after complete deployment on 3D-TEE and in 2D-TEE color doppler on simultaneous bicommissural and LVOT views (F).