Harald H. Quick PhD, Presenter: Nothing to Disclose

Philipp Kahlert MD, Abstract Co-Author: Nothing to Disclose

Holger Eggebrecht MD, PhD, Abstract Co-Author: Nothing to Disclose

Gernot Kaiser MD, Abstract Co-Author: Nothing to Disclose

Nina Parohl DVM, Abstract Co-Author: Nothing to Disclose

Juliane Albert, Abstract Co-Author: Nothing to Disclose

Lena Schäfer, Abstract Co-Author: Nothing to Disclose

Oliver Kraff MSc, Abstract Co-Author: Nothing to Disclose

Raimund Erbel, Abstract Co-Author: Nothing to Disclose

Mark E. Ladd PhD, Abstract Co-Author: Nothing to Disclose

MR-guided transcatheter, transarterial aortic valve implantation (TAVI) has been performed in swine following device modifications towards magnetic resonance (MR) compatibility of the comercially available stent valve delivery device.

The self-expandable Medtronic CoreValve® aortic bioprosthesis (Medtronic, Inc., Minneapolis, MN, USA) is composed of a nitinol stent frame with an integrated trileaflet porcine pericardial tissue valve and is either implanted via the femoral or subclavian artery. Its over-the-wire delivery catheter has a 12 Fr shaft with 18 Fr distal end comprising the crimped prosthesis which can be released stepwise with continuous transaortic blood flow. The original catheter shaft revealed ferromagnetic braiding, considerably compromizing MR imaging and MR safety. Device modifications obviating any metal braiding resulted in full MR compatibility of the delivery device. MR-guided TAVI was performed on 8 farm pigs (75-85 kg) via subclavian access on a 1.5 T MRI system (Avanto, Siemens Healthcare, Germany) equipped with an interventional in-room monitor. Catheter placement and stent release was performed under real-time MR guidance with a rt-TrueFISP sequence providing 5 images/s.

Device modifications resulted in artifact elimination and excellent real-time visualization of catheter movement and valve deployment using rt-TrueFISP imaging. MR-guided TAVI was successful in 6/8 swine. Post-interventional therapeutic success could be confirmed using ECG-triggered cine-TrueFISP sequences and flow-sensitive phase contrast sequences revealing or excluding regurgitation, respectively. Final stent valve position was confirmed by ex vivo histology.

The self-expandable CoreValve aortic stent-valve is potentially suited for real-time MRI-guided placement after suggested design modifications of the delivery-system. MR imaging in this interventional setup provided excellent pre-interventional anatomic and functional evaluation of the native aortic valve, precise real-time instrument guidance allowing accurate placement of the stent-valve within the native aortic annulus, and finally detailed post-interventional evaluation of therapeutic success.  

Catheter design modifications of the commercially available CoreValve aortic stent valve have laid the groundwork for real-time MR-guided transarterial aortic valve implantation (TAVI) in swine.

Quick, H, Kahlert, P, Eggebrecht, H, Kaiser, G, Parohl, N, Albert, J, Schäfer, L, Kraff, O, Erbel, R, Ladd, M, Towards Real-Time MR-guided Transarterial Aortic Valve Implantation (TAVI): In Vivo Evaluation in Swine.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014207.html