1. Department of Cardiac Surgery, University Heart Center, Universitaetsspital Zurich, University of Zurich, Zurich, Switzerland
2. Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria
3. Division of Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland
4. Division of Cardiothoracic Surgery, West Virginia University, Morgantown, WV, USA