1. Department of Cardiothoracic Surgery, Leiden University Medical Center, Leiden, The Netherlands
2. Department of Cardiothoracic Surgery, Houston Methodist DeBakey Heart and Vascular Center, Houston, Texas, United States
3. Department of Cardiovascular Surgery, Toronto General Hospital, Toronto, Canada
4. Department of Cardiovascular Surgery, German Heart Center Munich, Munich, Germany
5. Department of Cardiac Surgery, University of Michigan, Ann Arbor, Michigan, United States
6. Department of Biostatistics, Medtronic, Mounds View, Minnesota, United States
7. Department of Surgery, University Hospitals, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States