[1] Univ Zurich, Univ Hosp Zurich, Heart Valve Clin, Zurich, Switzerland
[2] Univ Padua, Dept Cardiac Thorac & Vasc Sci, Cardiovasc Pathol Unit, Padua, Italy
[3] San Raffaele Univ Hosp, Cardiac Surg Dept, Milan, Italy
[4] New York Presbyterian Columbia Univ Med Ctr, New York, NY USA
[5] Univ Klinikum Bonn, Bonn, Germany
[6] Albertinen Heart Ctr, Hamburg, Germany
[7] Univ Washington, Dept Med, Div Cardiol, Seattle, WA USA