Transapical mitral valved stent implantation: a survival series in swine.
OBJECTIVE
To assess short-term survival after transcatheter mitral valve replacement using a unique mitral valved stent design and anchoring system.


METHODS
The new nitinol self-expandable valved stent houses a trileaflet glutaraldehyde-preserved bioprosthesis and contains atrial and ventricular fixation systems. Eight pigs underwent transesophageal echocardiogram-guided transapical mitral valved stent implantation through a lower mini-sternotomy. Intracardiac pressure gradients were estimated by transesophageal echocardiogram.


RESULTS
The mean mitral annulus size was 24.6 +/- 1.4 mm, and the valved stent size was 26.0 +/- 2.6 mm. The average mean transvalvular gradient across the valved stent immediately after deployment, at 6 hours, and after 1 week remained low. The gradient across the neighboring left ventricular outflow tract was not affected. Average animal survival was 7.3 days (8 hours to 29 days). Animals that died before 1 week (n = 4) were found at necropsy to have valved stent malpositioning. Animals that survived 1 week or more had accurate deployment and only trace post-deployment paravalvular leak. The causes of death in this latter group were endocarditis (n = 1), failure of atrial fixation (n = 2), and failure of ventricular fixation (n = 1). There was no valved stent embolization in any of the animals.


CONCLUSIONS
Adequate function and effective anchoring of the new mitral valved stent allowed for short-term animal survival after transapical mitral valved stent implantation.
Department of Cardiothoracic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wis, USA.
Lucian
L
Lozonschi
Rene
R
Bombien
Satoru
S
Osaki
Jian
J
Hu
Dolores
D
Snell
Niloo M
NM
Edwards
Jochen
J
Cremer
Georg
G
Lutter
D000497:Alloys; D000818:Animals; D001705:Bioprosthesis; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D017548:Echocardiography, Transesophageal; D005404:Fixatives / Q000737:chemistry; D005548:Foreign-Body Migration / Q000209:etiology; D005976:Glutaral / Q000737:chemistry; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D056346:Sternotomy; D013552:Swine; D013997:Time Factors; D018084:Ultrasonography, Interventional
D000497:Alloys; D005404:Fixatives; C013616:nitinol; D005976:Glutaral