1. Tampere Heart Hospital, Department of Cardiothoracic Surgery , Tampere, Finland
2. Faculty of Medicine and Health Technologies, Tampere University , Tampere, Finland
3. Surgery Research Unit, Medical Research Center Oulu, Oulu University Hospital and University of Oulu , Oulu, Finland
4. Department of Surgery, Central Finland Hospital Nova , Jyväskylä, Finland
5. Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet and Karolinska University Hospital , Stockholm, Sweden