Abstract 2537: Transapical Aortic Valve Replacement Using Real-Time Magnetic Resonance Imaging Guidance
Background Percutaneous techniques to replace the aortic valve are limited by suboptimal visualization and untested prostheses. This study investigated the use of real-time magnetic resonance imaging to provide precise anatomic detail and visual feedback to implant a proven bioprosthesis.
Methods Employing a minimally invasive approach using real-time magnetic resonance imaging guidance 14 pigs underwent off-pump aortic valve replacement. Via transapical access a series of bioprosthetic aortic valves (21–25mm) were inserted. Magnetic Resonance imaging was used to precisely identify critical anatomic landmarks. Additional intraoperative perfusion, flow velocity and functional imaging were used to confirm adequacy of placement and function of the valve.
Results Under real-time magnetic resonance imaging, multiple oblique planes were prescribed. Enhanced by the use of an active marker wire, this imaging allowed correct placement and orientation of the prosthetic valve. The time to implantation after the placement of the trocar to deployment of the valve was less than ninety seconds (77 ± 12). In addition to anatomic confirmation of adequate placement of the prosthetic valve in relation to the aortic annulus and the coronary arteries, functional confirmation of the valve and left ventricle was also obtained with magnetic resonance imaging. Intraoperative first pass perfusion scanning documented adequacy of myocardial blood flow after valve placement. Phase velocity confirmed adequate opening of the prosthetic valve leaflets and lack of valvular or paravalvular regurgitation.
Conclusions Real-time magnetic resonance imaging provides excellent anatomic detail and intraoperative assessment that permits placement of durable valve prostheses on the beating heart without the limitations of percutaneous approaches.