Is Ultrasound sufficiently reliable for Transapical Valved Stent Implantation?
Christoph H. Huber, Ludwig K. von Segesser.
University Hospital Lausanne -CHUV, Switzerland, Lausanne, Switzerland.
OBJECTIVE:
Outcome assessment of transapical (TAP) Valved Stent implantation for off-pump aortic and pulmonary valve replacement with simultaneous intravascular (IVUS) and intracardiac echo (ICE) guidance for target site identification, per-procedural dimension assessment and deployment monitoring.
METHODS:
26 Valved Stents were implanted off-pump via TAP. Group A: 18 pigs (71.4±10.5Kg) got aortic valve replacement. Group B: 8 pigs (48.5±6.0Kg) got pulmonary valve replacement. Simultaneous IVUS and ICE were inserted via a femoral vein and the ventricular apex respectively for dimension assessment of the aortic/pulmonary root, aortic/pulmonary valve and identification of the preferred delivery location for device deployment. The IVUS transducer was tracked with ICE and fluoroscopy in order to mark the target site. The delivery system was introduced under fluoroscopy and ICE visualization and the devices deployed over the native valves. In-vivo assessment included: leaflet motion, planimetric valve orifice transvalvular gradient, regurgitation and paravalvular leaking. Macroscopic analysis was performed at necropsy.
RESULTS:
The target locations for device delivery were correctly identified by IVUS as confirmed by the ICE. No significant differences were found between the IVUS and ICE measures. In group A of 18 Valved Stents 14 were accurately delivered and all 14 showed good acute function and low gradients (5.5±3.4mmHg), 3 valves had a minor paravalvular leak. Four Valved Stent seated or too high or dislodged back in the left ventricle. Necropsy confirmed the correct positioning and safe anchoring of 14 Valved Stents without structural device defects. Group B: all 8 Valved Stents were delivered at target site with good acute valve function. No Valved Stents dislodged into the right ventricle or the pulmonary trunk. No animal had significant regurgitation or a paravalvular leak. No damage to the pulmonary artery or structural defects of the Valved Stents was found at necropsy.
CONCLUSIONS:
Simultaneous IVUS and ICE can precisely identify the landing zone and accurately guide Valved Stent delivery and deployment for aortic and pulmonary device implantation via TAP. 
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