"Gazing Into the Abyss": Transcatheter Mitral Valve-in-Valve Implantation Through a Cavernous Left Atrium.

We describe the case of a 73-year-old woman presenting with heart failure, a degenerating bioprosthetic mitral valve, and severely dilated left atrium, and highlight the role of multimodality imaging in planning transseptal transcatheter mitral valve-in-valve implantation. (Level of Difficulty: Advanced.). Crown

History of Presentation

A 73-year-old woman presented with New York Heart Association functional class III dyspnea. On examination, oxygen saturations were 94%, blood pressure was 110/65 mm Hg, heart rate was 65 beats/min, and peripheral edema to the knees, and on auscultation there were bibasilar crackles and a predominant systolic murmur at the apex.

Learning Objectives

To identify the key steps of complex transcatheter MViV intervention.

To understand the importance of multimodality imaging in planning patient-specific mitral valve therapies.

Past Medical History

Her history included a surgical mitral valve repair followed by surgical bioprosthetic mitral valve replacement 9 years ago, atrial fibrillation (AF), and obstructive pulmonary disease.

Differential Diagnosis

Symptoms could have been caused by impaired left ventricular function, exacerbation of AF, or degeneration of the mitral valve replacement.

Investigations

Blood results were unremarkable other than an elevated N-terminal pro–B-type natriuretic peptide of 4,900. Her electrocardiogram demonstrated rate-controlled AF. Transthoracic echocardiography showed severe bioprosthetic mitral valve degeneration (Figure 1A) with a mean diastolic transvalvular pressure gradient of 12 mm Hg and severe regurgitation. The left atrium was grossly dilated (volume 712 ml) and biventricular function was preserved (Figure 1B). Surgical risk was amplified by her multiple previous surgical interventions and comorbidities (Society of Thoracic Surgeons score 3.8%, EuroSCORE II 8.1%). Mitral valve-in-valve (MViV) intervention was recommended following heart team discussion.

Figure 1

Multimodality Imaging Planning

(A) Transthoracic echocardiogram (TTE) in parasternal long-axis view showing abnormal angulation of the prosthetic mitral valve toward the interventricular septum and turbulent color Doppler flow through the prosthesis. (B) TTE in apical 4-chamber view showing a severely dilated left atrium (LA) (volume 712 mL). (C) Cardiac computed tomography (CT) cinematic 3-dimensional volume rendering showing the severely dilated LA and distorted orientation to the left ventricle (LV). (D to F) Cardiac CT postprocessing for transcatheter mitral valve planning. (D) Automated segmentation of the severely dilated left atrium; (E) simulated implantation of a 26-mm transcatheter heart valve and the resultant neo- left ventricular outflow tract (LVOT) area; and (F) the derived optimal fluoroscopic projection for mitral valve-in-valve implantation. Ao = aorta; RA = right atrium; RV = right ventricle.

Multiphase retrospective electrocardiogram-gated cardiac computed tomography (CT) was performed for preprocedural planning. Cinematic volume rendering (Siemens Healthineers) was used to provide enhanced visualization of the distorted cardiac geometry and severely dilated left atrium (Figure 1C). The CT dataset were segmented (Figure 1D) and postprocessed (Materialise Mimics Enlight) to determine optimal transcatheter heart valve deployment height, projected neo-left ventricular outflow tract (LVOT) area (Figure 1E), and optimal fluoroscopic projection angles (Figure 1F). The projected neo-LVOT area of 290 ml2 determined risk of neo-LVOT obstruction was low, despite the concerning features of a perpendicular aortomitral angle and small left ventricular cavity (1). Finite element modelling predicted favorable behavioral properties of the bioprosthetic valve (Figure 2A, Video 1) (FeOPS) (2). Cardiac CT endoscopy (Figure 2B) and 3-dimensional (3D) printing (Figure 2C) (Materialise) allowed for pre-procedural visualization to better plan device manipulation. On the day of the procedure, CT simulations were made available to the interventional cardiologists through an interactive virtual reality headset (GE Healthcare) to assimilate all of the preprocedural planning data onto 1 platform (Figure 2D, Video 2).

Figure 2

Preprocedural and Procedural Imaging

(A) Finite element analysis simulation showing the expected deformation of the existing tissue heart valve, appearance of the tissue heart valve following deployment, and impact upon the neo-LVOT. (B) Cardiac CT “endoscopy” to visualize the location of the tissue heart valve from the roof of the left atrium. (C) 3-dimensional print of the STL file obtained from the cardiac CT with different materials used for the cardiac skeleton and existing tissue heart valve. (D) Virtual reality projection of the cardiac CT finite element analysis simulation data set to enable anatomical manipulation of the imaging data prior to implantation by the interventional cardiologist. (E and F) Fluoroscopic procedural images: (E) the guidewire with a secondary curve; and (F) the final result of the THV deployment with a conical shape as predicted by preprocedural simulations. Abbreviations as in Figure 1.

Management

The procedure was performed under general anesthesia in a hybrid operating theatre, with transesophageal echocardiography (TEE) and fluoroscopic guidance. The femoral vein was accessed with an 8-F sheath using ultrasound guidance and was preclosed with a Perclose ProGlide device (Abbott). Under TEE guidance, the interatrial septum was crossed with a Brockenbrough needle (Abbott) in an inferoposterior position as planned on 3D analysis. A large-curl Agilis steerable catheter (Abbott) directed an Amplatz left 0.75 (AL0.75) and 0.035-inch J-wire across the bioprosthetic mitral valve to the left ventricular apex. A pigtail catheter and a Safari guidewire (Boston Scientific) (with a large secondary curve approximately 20 cm from the distal tip [Figure 2E] to improve stability in the left ventricle and facilitate device delivery) were used to exchange to a 14-F delivery sheath. The interatrial septum was dilated with a 14-mm VACS II balloon (Osypka) before delivery of an antegradely aligned (skirt-to-atrium) 26-mm Sapien 3 Ultra valve (Edwards Lifesciences) over the guidewire and positioning within the bioprosthetic valve, 10% above the fluoroscopic sewing ring marker. The valve was inflated under rapid pacing via the guidewire to achieve conical deployment (Figure 2F, Video 3). TEE confirmed a fall in the transmitral gradient to 6 mm Hg, no valvular or paravalvular leak, no significant neo-LVOT obstruction, and a small left-to-right interatrial shunt. Femoral venous hemostasis was achieved with an 8-F Angio-Seal (Terumo) deployed within the ProGlide.

Discussion

Recent international guidelines provide a Class IIa recommendation for aortic and mitral valve-in-valve intervention for severely symptomatic patients who have high or prohibitive surgical risk (3). Although experience with MViV is more limited, registry data suggest high rates of procedural success (94.4%) and low rates of neo-LVOT obstruction (2.2%) and postprocedural regurgitation (5.6% ≥ moderate), with a 30-day and 1-year mortality of 6.2% and 14.0%, respectively (4,5). Although outcomes of transcatheter mitral interventions in patients with a valve ring or extensive mitral annular calcification require further refinement (5,6), the data suggest that MViV intervention can be safe and effective with high-quality planning (5).

Follow-Up

The patient’s symptoms improved to New York Heart Association functional class II with transthoracic echocardiography demonstrating a mean transmitral gradient of 6 mm Hg and no regurgitation.

Conclusions

This case highlights the role of multimodality imaging in planning complex MViV procedures. Imaging modalities included geometric analysis of CT data sets using semiautomated platforms, finite element analysis simulation, 3D printing, and virtual reality solutions. These tools are likely to serve a greater role in improving patient outcomes by enabling better anticipation of procedural technique and patient outcomes and enhanced communication of key imaging findings among heart team members (1,7,8).

Funding Support and Author Disclosures

Dr. Redwood has received speaker fees from Edwards Lifesciences; and has served as an international advisory board member for Medtronic. Dr. Prendergast has received speaker fees from Edwards Lifesciences. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.