Guidance within the heart: Can we rely on ultrasound for direct access trans-apical valved stent implantation?

Objective: Assess outcome of transapical Valved Stent implantation (TAP) for off-pump aortic valve replacement using simultaneous intravascular and intracardiac ultrasound guidance for target-site-identification, per-procedural dimension assessment and deployment monitoring.

Methods: Valved Stent implantation in 18 pigs (71.4±10.5Kg) via trans-apical approach. Simultaneous intracardiac (ICUS) and intravascular ultrasound (IVUS) were inserted via femoral vein and ventricular apex respectively for dimension assessment of the aortic root, valve and identification of target-site for Valved Stent deployment. The IVUS catheter transducer was tracked in parallel with ICUS and fluoroscopy in order to mark the target site. Next, the Valved Stent delivery-system was introduced under fluoroscopy and ICUS monitoring and the Valved Stent deployed over the native valve. In-vivo assessment included: leaflet motion, planimetric valve orifice, transvalvular gradient, regurgitation and paravalvular leaking.

Results: The target location was correctly identified by IVUS and ICUS. No difference between the aortic root and valve dimensions were found between the IVUS and ICUS measures. As correctly identified by ICUS and IVUS, of 18 Valved Stents, 12 were accurately delivered at target site. All of the 12 valves showed good valvular function, 3 valves had minor paravalvular leak. Three and 3 Valved Stent seated or too or dislodged back into the left ventricle

Conclusions: IVUS and ICUS precisely identify aortic landing-zone for Valved Stent implantation and accurately guides delivery and deployment within the left ventricle and the native valve without the use of angiography. Furthermore ICUS and IVUS independently can assess postimplantation valve function and allow for post-implantation coronary flow analysis.