1. Heart Center, Turku University Hospital and University of Turku, Turku, Finland
2. Department of Surgery, Oulu University Hospital, Oulu, Finland
3. Heart Center, Kuopio University Hospital, Kuopio, Finland
4. Department of Cardiothoracic Surgery, Helsinki University Hospital, Helsinki, Finland
5. Department of Internal Medicine, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
6. Department of Internal Medicine, South Karelia Central Hospital, Lappeenranta, Finland