TMVI procedure
Experimental
pigs
were anesthetized with 4-10mg
propofol
for induction and maintained with 4-12mg/kg/h propofol. A left
anterolateral thoracotomy was performed minimally in the fifth
intercostal space for access to the left ventricle (LV) apex.
Echocardiography
and fluoroscopy were utilized as intraoperative guidance. Heparin (200
IU/kg) was administered intravenously before apical catheterization. An
LV apex incision was performed following the echocardiographic
measurement and sutured with two box stitches (Polyprolene2-0). A
0.035-inch J-shaped guidewire was inserted into the LV and retrograded
across the mitral
valve
into the left atrium under the guidance of epicardial echocardiography
and fluoroscopy. Then it was manipulated into the left inferior
pulmonary vein and exchanged with a super-stiff guidewire. After the LV
apex incision was dilated, a delivery system with a crimped valve
prosthesis and two recurrent strings was introduced into the LV. The
prosthesis was rotated to fit the anatomical position (one anchor
matched anterior leaflet and another matched and posterior leaflet) and
deployed following the tri-step implantation process.
If
the stent deployment is found to be inappropriate, the mitral stent was
retrieved and redeployed. After valve implantation,
intraoperative
echocardiography was performed to confirm and evaluate the position and
function of the implanted valve. (Figure 4) The delivery system was
subsequently removed and replaced with a pigtail catheter for
fluoroscopy to identify valvular insufficiency, paravalvular leakage
(PVL), and left ventricular outflow tract (LVOT) obstruction, and
coronary artery obstruction. (Figure 3) Finally, the chest incision was
processed routinely. After implantation, all experiment animals received
standardized care. All surviving pigs were monitored clinically and then
sacrificed for four weeks. All the hearts were explanted for macroscopic
evaluation. (Figure 5)