Case Presentation
The child’s weight was 38 kg, her
height was 1.48 m, 32th percentile
according to the Centers for Disease Control and Prevention (CDC) growth
charts.. An examination revealed a diastolic rumbling murmur (grade
IV/VI) with maximum intensity at the apex and propagation to the axilla.
Transthoracic echocardiography showed a degenerated bioprosthetic MV
with thickened, calcific, and restricted leaflets. The right ventricle
(RV) was severely dilated with significantly depressed function, and the
interventricular septum shifted substantially towards the left side
(Videos 1 and 2). The aorta-MV
angle was 63° (Figure 1A), the left ventricular outflow tract (LVOT)
diameter was 19 mm, and the LVOT mean pressure gradient was 5 mm Hg with
no septal bulge. Thus, LVOT obstruction was unlikely. Severe mitral
stenosis was observed, with a mean pressure gradient of 18 mm Hg (Figure
1B). There was mild tricuspid regurgitation, with an estimated systolic
pulmonary artery pressure of 66 mm Hg (Figure 1C). Transoesophageal
echocardiography confirmed these findings (Figure 1D and Video 3), and
3D zoom of the MV from the left atrium and left ventricle showed a
fusion of the three leaflets (Figure 1E and 1F and Video 4). The heart
team deemed her a high risk for surgery due to severe RV dilation, RV
dysfunction, and severe pulmonary hypertension. The team thus
recommended a transcatheter mitral valve replacement (TMVR).
The procedure was conducted in a standard catheterization laboratory
under general anaesthesia and with transoesophageal echocardiography
guidance. Right femoral arterial and venous accesses were established,
and left venous access 6F for the pacemaker lead was established as a
backup. Transseptal access was difficult due to the heavily fibrotic and
thick septum. A diathermy pen in cautery mode was applied to the hub of
a BRK transseptal needle for 2 seconds, which facilitated septum
crossing. A 5-F multipurpose catheter (Cook Medical, Bloomington, IN,
USA) was advanced over a standard 0.035-inch guidewire using an Agilis™
catheter (St. Jude Medical, St. Paul, MN, USA). A Glidewire® (Terumo
Medical Corporation, Somerset, NJ, USA) facilitated crossing of the
mitral valve bioprosthesis (Figure 2A). A stiff, pre-shaped, 0.035-inch
Confida Wire (Medtronic, Minneapolis, MN, USA) was positioned in the
left ventricle apex. An Armada 35 peripheral 14-mm balloon (Abbott,
Santa Clara, CA, USA) was used to dilate the atrial septum (Figure 2B),
followed by dilatation of the stenosed valve using the same balloon
(Figure 2C and 2D).
An Edwards E-sheath 14F was introduced through the right femoral vein to
the level of the hepatic veins. A 23-mm SAPIEN 3 valve was crossed to
the left atrial cavity with the Edwards mark facing upside down to
improve flexion via the macro knob. Unfortunately, the system loop
inside the left atrium failed to cross. We attempted to establish apical
left ventricular access to allow for system stability, unfortunately the
access was established in the right ventricular apex due to the severe
enlargement of the right ventricle. Confida wire was snared through the
aortic valve (Figure 2E) to facilitate crossing the bioprosthesis.
After the valve delivery system crossed the degenerated valve, the
SAPIEN valve balloon was inflated slowly without need for rapid pacing
to enable positioning on 80% of the ventricular and 20% of the atrial
valve stent (Figure 2F, Figure 3A, and Video 5). The balloon was
inflated an additional 2 ml for ventricular flaring of the SAPIEN valve.
A multipurpose catheter facilitated removal of the Confida wire (Figure
3B). Transoesophageal echocardiography evaluation revealed a mean
gradient of 5 mm Hg with no valvular or paravalvular incompetence
(Figure 3C). 3D imaging showed a well-opened valve (Figures 3D and 3E
and Video6). The unintentional RV apical access was closed using an 8-mm
Amplatzer Vascular Plug II (St. Jude Medical, St. Paul, MN, USA), as
shown in Figure 3F and Video 7. The patient was discharged after 2 days.
At the patient’s 30-month
follow-up, her weight was 50 kg, height was 1.5 m, 70th percentile
according to the CDC growth charts . She had regular daily activity with
no shortness of breath. Transthoracic echocardiography revealed that the
RV reduced in size and demonstrated normal functioning in comparison to
preoperative images (Figure 4A and 4B and Video 8). Systolic pulmonary
artery pressure reduced to 33 mm Hg (Figure 4C), the LVOT mean pressure
gradient at LVOT was 10 mm Hg (Figure 4D), and the MV mean pressure
gradient was 6 mm Hg (Figure 4E).