1. Department of Cardiothoracic Surgery, University of Groningen, University Medical Center Groningen , Groningen, Netherlands
2. Department of Cardiology, Reinier de Graaf Hospital , Delft, Netherlands
3. Department of Cardiac Surgery, University Hospital Brussels , Brussels, Belgium
4. Thorax Centrum Twente, Medisch Spectrum Twente , Enschede, Netherlands
5. Department of Cardiothoracic Surgery, University Medical Center Utrecht , Utrecht, Netherlands
6. Department of Cardiology, University of Groningen, University Medical Center Groningen , Groningen, Netherlands