Objective: Transcatheter techniques of aortic valve replacement are a treatment option for valvular heart disease in high-risk surgical candidates. We evaluated a self-expanding valve system with a novel mechanism of fixation in an experimental setting in an acute animal model and ex vivo in aortic root specimens.
Method: A self-expanding nitinol stent containing a pericardial tissue valve was implanted in a transapical approach in 15 sheeps. The valve was introduced under fluoroscopic guidance through a 22F sheath by means of a specially designed delivery catheter. Deployment was performed on the beating heart without cardiopulmonary bypass or rapid ventricular pacing and facilitated by positioning feelers anchoring the device to the native aortic cusps. To investigate release and anchoring of the device during retrograde implantation, the stent was also implanted in aortic root specimens obtained from an autopsy series.
Results: In animal experiments, stent deployment was primarily successful in 12 (80%) animals. Positioning feelers facilitated implantation by confirming the correct implantation plane of the stent and anchoring to the native aortic cusps. If primary location was not satisfactory the stent was retracted into the catheter and repositioned. After successful implantation no significant changes of hemodynamics were observed. Two animals (13%) developed ventricular fibrillation early in this experimental series due to displacement of one positioning element into a coronary ostium, major regurgitation was observed in two animals. Ex vivo evaluation of the device in aortic root specimens proved feasibility of stent release and leaflet fixation; ex vivo implantation was successful in all cases.
Conclusion: In this study, we demonstrate feasibility of a leaflet-fixation device in nondiseased aortic valves. The JenaClip provides an effective concept of fixation with positioning feelers that allows exact positioning without outflow obstruction and anchoring the valve to the native leaflets. Further studies are necessary to investigate this concept in diseased aortic valves.
2009 Wiley-Liss, Inc.