Steps Toward Percutaneous Aortic Valve Replacement

Background — To date, the surgical approach is the only option to replace the aortic valve. Percutaneous pulmonary valve replacement has recently opened new perspectives on transcatheter replacement of cardiac valves. We report our experience of aortic valve replacement through a percutaneous technique in lambs. Methods and Results — A bovine jugular vein containing a valve was dissected and sutured into a stent. Twelve lambs were divided into 3 groups. In the first, a valved stent was implanted in the descending aorta after creation of an aortic insufficiency. In the second, the valve was implanted in the native position. In the third, we inserted a valved stent in the native position using an orientation mechanism. All valves were successfully delivered and functioned perfectly in short-term evaluation. All experiments in group 2 failed: 1 valve obstructed the coronary artery orifices, 1 stent was responsible for a major mitral valve insufficiency, and the third implant migrated prematurely. A paraprosthetic leak occurred in the last animal in this group. Animals in group 3 had successful implantation of the valved stent. The orientation mechanism allowed perfect alignment of the device without any damage to the coronary circulation or to mitral valve function. Conclusions — Nonsurgical implantation of an aortic valve is possible in lambs in the descending aorta and in the native position. An orientation mechanism is obviously needed to avoid obstruction of the coronary orifices. With further improvements, this technique should be feasible in humans.