1. Department of Internal Medicine, Oulu University Hospital, Oulu, Finland;
2. Heart Center, Turku University Hospital and University of Turku, Turku, Finland;
3. Heart Center, Kuopio University Hospital, Kuopio, Finland;
4. Heart Hospital, Tampere University Hospital, Tampere, Finland;
5. Heart Center, Helsinki University Hospital, Helsinki, Finland;
6. Department of Surgery, Oulu University Hospital and University of Oulu, Finland;
7. Department of Surgery, University of Turku, Turku, Finland